Abstract

There is a significant lack of research on how climate change influences long-term temporal trends in the biodiversity of soil organisms. Nematodes may be specifically adequate to test soil biodiversity changes, because they account for similar to 80% of all Metazoans and play key roles in the functioning of terrestrial ecosystems. Here, we report on the first synthesis study focused on temporal trends of nematode fauna over a period of 14 years (1986-1999) across the Carpathian Ecoregion. We provide new evidence that wetter conditions associated to global change contributes to driving nematode diversity at genus/family level. We observed opposite trends in soil nematode alpha diversity (increase) and beta diversity (decrease) consistent across ecosystem types and soil horizons, providing strong evidence for the influence of climate change on soil biodiversity at large spatial scales. An increase in the community functional uniformity along with a decline in beta diversity indicated more homogenous soil conditions over time. The Soil Stability Index (metric devised to assess soil homeostasis based on the functional composition of nematode communities) increased over time, indicating a decline of soil disturbances and more complex soil food webs. Our results highlight the importance of nematodes as powerful indicators of soil biodiversity trends affected by multiple facets of environmental change in long-term soil monitoring.

Abstract

1. The relationship of plant diversity and several ecosystem functions strengthens over time. This suggests that the restructuring of biotic interactions in the process of a community's assembly and the associated changes in function differ between species-rich and species-poor communities. An important component of these changes is the feedback between plant and soil community history.2. In this study, we examined the interactive effects of plant richness and community history on the trophic functions of the soil fauna community. We hypothesized that experimental removal of either soil or plant community history would diminish the positive effects of plant richness on the multitrophic functions of the soil food web, compared to mature communities. We tested this hypothesis in a long-term grassland biodiversity experiment by comparing plots across three treatments (without plant history, without plant and soil history, controls with similar to 20 years of plot-specific community history).3. We found that the relationship between plant richness and below-ground multitrophic functionality is indeed stronger in communities with shared plant and soil community history. Our findings indicate that anthropogenic disturbance can impact the functioning of the soil community through the loss of plant species but also by preventing feedbacks that develop in the process of community assembly.

Abstract

Global warming and ocean acidification are having an unprecedented impact on marine ecosystems, yet we do not yet know how phytoplankton will respond to simultaneous changes in multiple drivers. To better comprehend the combined impact of oceanic warming and acidification, we experimentally estimated how evolution shifted the temperature-CO2 growth response surfaces of two strains of Skeletonema marinoi that were each previously adapted to four different temperature x CO2 combinations. These adapted strains were then grown under a factorial combination of five temperatures and five CO2 concentrations to capture the temperature-CO2 response surfaces for their unacclimated growth rates. The development of the first complete temperature-CO2 response surfaces showed the optimal CO2 concentration for growth to be substantially higher than expected future CO2 levels (similar to 6000 ppm). There was minimal variation in the optimal CO2 concentration across the tested temperatures, suggesting that temperature will have a greater influence on growth rates compared to enhanced CO2. Optimal temperature did not show a unimodal response to CO2, either due to the lack of acclimation or the highly efficient CO2 concentrating mechanisms, which diatoms (e.g. Skeletonema) can up-/downregulate depending on the CO2 conditions. We also found that both strains showed evidence of evolutionary shifts as a result of adaptation to temperature and CO2. The evolutionary response differed between strains, underscoring how genetic differences (perhaps related to historical regimes) can impact phytoplankton performance. Understanding how a dominant algal species responds to multiple drivers provides insight into real-world scenarios and helps construct theoretical predictions of environmental change.

Abstract

Worldwide tree diversity loss raises concerns about functional and energetic declines across trophic levels. In this study, we coupled 160 above-and belowground food webs, quantifying energy fluxes to microorganisms and invertebrates in a tree-mycorrhiza diversity experiment, to test how tree diversity affects fluxes of energy above and below the ground. The experiment differentiates three mycorrhizal type treatments: only AM tree species (with arbuscular mycorrhizae), only EcM tree species (with ectomycorrhizae; one, two, and four tree species), or mixtures of both AM and EcM tree species (AM+EcM; two and four tree species). Our results indicate that most energy initially flowed through belowground communities, with soil microorganisms contributing 97.7% of total energy and belowground fauna accounting for 60.9% of energy to animals. Consequently, belowground fauna fueled surface (62.3% of predation) and aboveground (30.5% of predation) predators. Tree diversity increased ecosystem multifunctionality (indicated by total and averaged energy fluxes) by '30% and energy across most trophic levels in EcM tree communities, while it shifted food webs from fast (such as bacterial-dominated) to slow (such as fungal-dominated) channels in AM tree communities. Tree diversity primarily impacted energy fluxes through belowground communities and strengthened the coupling of above-and belowground food webs, with increasing importance of below-ground prey for predators at the soil surface and above the ground. These findings highlight that tree diversity and mycorrhizal types drive above-and belowground ecosystem functioning via belowground energy fluxes.

Abstract

Aims: We introduce ReSurveyEurope - a new data source of resurveyed vegetation plots in Europe, compiled by a collaborative network of vegetation scientists. We describe the scope of this initiative, provide an overview of currently available data, governance, data contribution rules, and accessibility. In addition, we outline further steps, including potential research questions. Results: ReSurveyEurope includes resurveyed vegetation plots from all habitats. Version 1.0 of ReSurveyEurope contains 283,135 observations (i.e., individual surveys of each plot) from 79,190 plots sampled in 449 independent resurvey projects. Of these, 62,139 (78%) are permanent plots, that is, marked in situ, or located with GPS, which allow for high spatial accuracy in resurvey. The remaining 17,051 (22%) plots are from studies in which plots from the initial survey could not be exactly relocated. Four data sets, which together account for 28,470 (36%) plots, provide only presence/absence information on plant species, while the remaining 50,720 (64%) plots contain abundance information (e.g., percentage cover or cover-abundance classes such as variants of the Braun-Blanquet scale). The oldest plots were sampled in 1911 in the Swiss Alps, while most plots were sampled between 1950 and 2020. Conclusions: ReSurveyEurope is a new resource to address a wide range of research questions on fine-scale changes in European vegetation. The initiative is devoted to an inclusive and transparent governance and data usage approach, based on slightly adapted rules of the well-established European Vegetation Archive (EVA). ReSurvey:Europe data are ready for use, and proposals for analyses of the data set can be submitted at any time to the coordinators. Still, further data contributions are highly welcome.

Abstract

We searched for patterns supporting the hypothesis of compositional and functional linkage between forest floor nematode communities and dominant tree canopies, while controlling for some relevant soil and climate variables. Twenty-one forest sampling sites scattered throughout the South-Eastern Carpathian basin were selected under spruce, beech, and hornbeam-oak canopies. The relative contribution of forest canopy type to nematode assemblage differentiation was estimated through nematode taxonomic composition and feeding guild structure. The forest canopy type had a significant effect on nematode taxon/feeding guild composition and diversity at stand level. Several (diagnostic) nematode taxa and feeding guilds were positively associated with and accurately predicted the forest canopy types considered. Apart from the herbivorous nematodes, all the other trophic guilds were significantly related, in terms of their relative abundance, to the forest canopy type. Both nematode taxonomic and trophic diversity were significantly higher under beech canopy compared with its two counterparts. The highest total nematode beta diversity, either taxonomic or trophic, was attained between hornbeam- oak and spruce canopies. Nematode taxonomic and trophic beta diversity between forest canopy types were largely determined by taxon replacement and respectively, by a nested trophic structure. Overall, four concordant and two discordant patterns were revealed between nematode taxon and feeding guild composition with respect to overlying forest canopy, all underpinning the addressed ecological linkage. The present results bring evidence regarding the important contribution of the forest canopy, along with climatic variables, in driving the taxonomic and functional composition/diversity of nematode communities from the soil organic horizon.

Abstract

Series Maximi is a group within Desmodesmus (Chlorophyta) which contains the three species D. maximus, D. perforatus and D. tropicus. Besides their large cell sizes, the most striking morphological trait unique to the members of this genus is the presence of large perforations between the coenobial cells. The perforations are either present (D. perforatus and D. tropicus) or the space between the cells is completely sealed (D. maximus). We report here a fourth species of the series based on two strains (AICB 1155 and AICB 1572) from freshwater environments of the Danube Delta, Romania. The ultrastructure of the cell walls revealed a partial closure of the space between the cells which creates slightly visible perforations in light microscopy. Analyses of DNA sequences and secondary structure of the ITS2 fragment by coalescent (PTP, GMYC), distance (ASAP), and evolutionary modelbased methods (ML, BI) indicated a fourth candidate species which included both the AICB strains investigated and other strains with similar morphological traits from reference literature. Despite its poor representation in public databases, analysis of the SSU rDNA gene for the series Maximi strengthened the ITS2 results. Therefore, based on its larger cell sizes relative to the other members of the series, cell morphology, the presence of partial perforations and other peculiarities of the cell wall ultrastructure, the independent phylogenetic position, CBCs analysis, and a different 'DNA signature' within the ITS2 fragment we suggest that this clade should be described as a new taxon of the series Maximi, Desmodesmus pseudoperforatus sp. nov. HIGHLIGHTS center dot Morphological differences and DNA-based lines of evidence indicate new species. center dot Microperforations of the space between the coenobial cells. center dot Strains have the largest cell sizes in the series Maximi.

Abstract

River microbial communities regularly act as the first barrier of defense against the spread of antimicrobial resistance genes (ARGs) that enter environmental microbiomes through wastewater. However, how the invasion dynamics of wastewater-borne ARGs into river biofilm communities will shift due to climate change with increasing average and peak temperatures remains unknown. Here, we aimed to elucidate the effects of increasing temperatures on the naturally occurring river biofilm resistome, as well as the invasion success of foreign ARGs entering through wastewater. Natural biofilms were grown in a low-anthropogenic impact river and transferred to artificial laboratory recirculation flume systems operated at three different temperatures (20 degrees C, 25 degrees C, and 30 degrees C). After 1 week of temperature acclimatization, significant increases in the abundance of the naturally occurring ARGs in biofilms were detected at higher temperatures. After this acclimatization period, biofilms were exposed to a single pulse of wastewater, and the invasion dynamics of wastewater-borne ARGs were analyzed over 2 weeks. After 1 day, wastewater-borne ARGs were able to invade the biofilms successfully with no observable effect of temperature on their relative abundance. However, thereafter, ARGs were lost at a far increased rate at 30 degrees C, with ARG levels dropping to the initial natural levels after 14 days. Contrary to the lower temperatures, ARGs were either lost at slower rates or even able to establish themselves in biofilms with stable relative abundances above natural levels. Hence, higher temperatures come with contrary effects on river biofilm resistomes: naturally occurring ARGs increase in abundance, while foreign, invading ARGs are lost at elevated speeds.IMPORTANCEInfections with bacteria that gained resistance to antibiotics are taking millions of lives annually, with the death toll predicted to increase. River microbial communities act as a first defense barrier against the spread of antimicrobial resistance genes (ARGs) that enter the environment through wastewater after enrichment in human and animal microbiomes. The global increase in temperature due to climate change might disrupt this barrier effect by altering microbial community structure and functions. We consequently explored how increasing temperatures alter ARG spread in river microbial communities. At higher temperatures, naturally occurring ARGs increased in relative abundance. However, this coincided with a decreased success rate of invading foreign ARGs from wastewater to establish themselves in the communities. Therefore, to predict the effects of climate change on ARG spread in river microbiomes, it is imperative to consider if the river ecosystem and its resistome are dominated by naturally occurring or invading foreign ARGs. Infections with bacteria that gained resistance to antibiotics are taking millions of lives annually, with the death toll predicted to increase. River microbial communities act as a first defense barrier against the spread of antimicrobial resistance genes (ARGs) that enter the environment through wastewater after enrichment in human and animal microbiomes. The global increase in temperature due to climate change might disrupt this barrier effect by altering microbial community structure and functions. We consequently explored how increasing temperatures alter ARG spread in river microbial communities. At higher temperatures, naturally occurring ARGs increased in relative abundance. However, this coincided with a decreased success rate of invading foreign ARGs from wastewater to establish themselves in the communities. Therefore, to predict the effects of climate change on ARG spread in river microbiomes, it is imperative to consider if the river ecosystem and its resistome are dominated by naturally occurring or invading foreign ARGs.

Abstract

When antimicrobial resistant bacteria (ARB) and genes (ARGs) reach novel habitats, they can become part of the habitat's microbiome in the long term if they are able to overcome the habitat's biotic resilience towards immigration. This process should become more difficult with increasing biodiversity, as exploitable niches in a given habitat are reduced for immigrants when more diverse competitors are present. Consequently, microbial diversity could provide a natural barrier towards antimicrobial resistance by reducing the persistence time of immigrating ARB and ARG. To test this hypothesis, a pan-European sampling campaign was performed for structured forest soil and dynamic riverbed environments of low anthropogenic impact. In soils, higher diversity, evenness and richness were significantly negatively correlated with relative abundance of >85% of ARGs. Furthermore, the number of detected ARGs per sample were inversely correlated with diversity. However, no such effects were present in the more dynamic riverbeds. Hence, microbiome diversity can serve as a barrier towards antimicrobial resistance dissemination in stationary, structured environments, where long-term, diversity-based resilience against immigration can evolve.

Abstract

The currently dominant types of land management are threatening the multifunctionality of ecosystems, which is vital for human well-being. Here, we present a novel ecological-economic assessment of how multifunctionality of agroecosystems in Central Germany depends on land-use type and climate. Our analysis includes 14 ecosystem variables in a large-scale field experiment with five different land-use types under two different climate scenarios (ambient and future climate). We consider ecological multifunctionality measures using averaging approaches with different weights, reflecting preferences of four relevant stakeholders based on adapted survey data. Additionally, we propose an economic multifunctionality measure based on the aggregate economic value of ecosystem services. Results show that intensive management and future climate decrease ecological multifunctionality for most scenarios in both grassland and cropland. Only under a weighting based on farmers' preferences, intensively-managed grassland shows higher multifunctionality than sustainably-managed grassland. The economic multifunctionality measure is about similar to 1.7 to 1.9 times higher for sustainable, compared to intensive, management for both grassland and cropland. Soil biodiversity correlates positively with ecological multifunctionality and is expected to be one of its drivers. As the currently prevailing land management provides high multifunctionality for farmers, but not for society at large, we suggest to promote and economically incentivise sustainable land management that enhances both ecological and economic multifunctionality, also under future climatic conditions.

Abstract

Ecosystem functioning depends on biodiversity at multiple trophic levels, yet relationships between multitrophic diversity and ecosystem multifunctionality have been poorly explored, with studies often focusing on individual trophic levels and functions and on specific ecosystem types. Here, we show that plant diversity can affect ecosystem functioning both directly and by affecting other trophic levels. Using data on 13 trophic groups and 13 ecosystem functions from two large biodiversity experiments-one representing temperate grasslands and the other subtropical forests-we found that plant diversity increases multifunctionality through elevated multitrophic diversity. Across both experiments, the association between multitrophic diversity and multifunctionality was stronger than the relationship between the diversity of individual trophic groups and multifunctionality. Our results also suggest that the role of multitrophic diversity is greater in forests than in grasslands. These findings imply that, to promote sustained ecosystem multifunctionality, conservation planning must consider the diversity of both plants and higher trophic levels. Research on biodiversity-ecosystem functioning relationships tends to focus on single trophic groups. This analysis of two biodiversity experiments, representing forests and grasslands, shows that plant diversity promotes ecosystem multifunctionality not only directly, but also by enhancing the diversity of other trophic levels.

Abstract

Climate change and land-use intensification are threatening soil communities and ecosystem functions. Understanding the combined effects of climate change and land use is crucial for predicting future impacts on soil biodiversity and ecosystem functioning in agroecosystems. Here, we used a field experiment to quantify the combined effects of climate change (warming and altered precipitation patterns) and land use (agricultural type and management intensity) on soil food webs across nematodes, micro-, and macroarthropods. Specifically, we investigated two types of agricultural systems-croplands and grasslands-under both high- and low-intensity management. We focused on assessing the functioning of soil food webs by investigating changes in energy flux to consumers in the main trophic groups: decomposers, microbivores, herbivores, and predators. While the total energy flux and detritivory, herbivory and predation in the soil food web remained unchanged across treatments, low-intensity land use-compared to high intensity-led to higher microbivory and microbial control under future climate conditions (i.e., warming and summer drought) in croplands and grasslands. At the same time, microbial and herbivore control were higher under low-intensity land use in croplands and grasslands. Overall, our results underscore the potential benefits of less intensive, more sustainable management practices for soil food-web functioning under current and future climate scenarios.

Abstract

Improving the predictive power of food web analysis is a major challenge. Identifying the relationships that link topological and dynamical features may help. We used the predictions of loop analysis about the effect of perturbations targeted to the components of Barents sea food web to quantify their sensitivity and community impact, that we summarized in two new indices, NI and NS. Using a multivariate analysis we interpreted the meaning of these indices in a benchmarking exercise using several well recognized indices of species topological (positional) importance. Our findings suggest that the information the two indices proposed here provides does not overlap with that of more diffused topological indices of positional importance (i.e. centrality indices). The former are express the dynamic consequences of the topology in which species are embedded, whereas for the latter such dynamical consequences are mostly hypothesized on a topological base. The indices of loop analysis are based on the effective role a species plays in passing the impacts to other species (NI) and their role as sinks of the perturbations entering anywhere in the system (NS). These two indices, in the end, reveal how the topology of the network affects the response of the species to perturbations and thus emphasize the interaction between topology and dynamics. Based on our results, the question related to conservation is whether to prioritize sensitive species, that can be more strongly influenced when others are perturbed, or species of high impact, that can more strongly influence the rest of the community if perturbed.

Abstract

Telekia speciosa (Schreb.) Baumg. was selected to investigate the phylogeography of tall-herb species, an ecological group in which the Quaternary history has been rarely studied. This species is a characteristic component of mountain forest communities in the Romanian Carpathian Mountains. The analysis employing Amplified Fragment Length Polymorphism (AFLP) fingerprinting has revealed a notable absence of a well-defined phylogeographical structure among the populations assessed. This finding implies that the various regions of the current distribution range of Telekia speciosa in the SE Carpathians have not undergone extended periods of isolation. Such a pattern suggests that this mountain tall-herb species might have experienced the possibility of long-term persistence along a wide altitudinal gradient in isolated mountain ranges, also encompassing the lowlands between them in glacial periods. Beside the unique vegetation history experienced during the most recent glaciation in the SE Carpathians, the observed weak phylogeographical structure of Telekia speciosa can be reasonably attributed to its inherent biological traits, particularly its proficiency in long-distance dispersal. Additionally, the species' ecological adaptations, which facilitated its survival in riparian zones of relatively low, forested mountain ranges, might contributed further to maintaining genetic connectivity among populations, thereby mitigating substantial genetic differentiation across its distribution. The study concludes that the genetic variation observed in T. speciosa is relatively evenly distributed across the species' distribution area. © 2024, Babes-Bolyai University, "Alexandru Borza" Botanic Garden. All rights reserved.

Abstract

Human activities cause substantial changes in biodiversity.1,2 Despite ongoing concern about the implications of invertebrate decline,3-7 few empirical studies have examined the ecosystem consequences of invertebrate biomass loss. Here, we test the responses of six ecosystem services informed by 30 above-and belowground ecosystem variables to three levels of aboveground (i.e., vegetation associated) invertebrate community biomass (100%, 36%, and 0% of ambient biomass) in experimental grassland mesocosms in a controlled Ecotron facility. In line with recent reports on invertebrate biomass loss over the last decade, our 36% biomass treatment also represented a decrease in invertebrate abundance (-70%) and richness (-44%). Moreover, we simulated the pronounced change in invertebrate biomass and turnover in community composition across the season. We found that the loss of invertebrate biomass decreases ecosystem multi -functionality, including two critical ecosystem services, aboveground pest control and belowground decomposition, while harvested plant biomass increases, likely because less energy was channeled up the food chain. Moreover, communities and ecosystem functions become decoupled with a lower biomass of invertebrates. Our study shows that invertebrate loss threatens the integrity of grasslands by decoupling ecosystem processes and decreasing ecosystem-service supply.

Abstract

Background The extremely halophilic archaeon Haloferax (Hfx.) alexandrinus DSM 27206 T was previously documented for the ability to biosynthesize silver nanoparticles while mechanisms underlying its silver tolerance were overlooked. In the current study, we aimed to assess the transcriptional response of this haloarchaeon to varying concentrations of silver, seeking a comprehensive understanding of the molecular determinants underpinning its heavy metal tolerance.Results The growth curves confirmed the capacity of Hfx. alexandrinus to surmount silver stress, while the SEM-EDS analysis illustrated the presence of silver nanoparticles in cultures exposed to 0.5 mM silver nitrate. The RNA-Seq based transcriptomic analysis of Hfx. alexandrinus cells exposed to 0.1, 0.25, and 0.5 mM silver nitrate revealed the differential expression of multiple sets of genes potentially employed in heavy-metal stress response, genes mostly related to metal transporters, basic metabolism, oxidative stress response and cellular motility. The RT-qPCR analysis of selected transcripts was conducted to verify and validate the generated RNA-Seq data.Conclusions Our results indicated that copA, encoding the copper ATPase, is essential for the survival of Hfx. alexandrinus cells in silver-containing saline media. The silver-exposed cultures underwent several metabolic adjustments that enabled the activation of enzymes involved in the oxidative stress response and impairment of the cellular movement capacity. To our knowledge, this study represents the first comprehensive analysis of gene expression in halophillic archaea facing increased levels of heavy metals.

Abstract

Artificial light at night (ALAN) is increasing worldwide, but its effects on the soil system have not yet been investigated. We tested the influence of experimental manipulation of ALAN on two taxa of soil communities (microorganisms and soil nematodes) and three aspects of soil functioning (soil basal respiration, soil microbial biomass and carbon use efficiency) over four and a half months in a highly controlled Ecotron facility. We show that during peak plant biomass, increasing ALAN reduced plant biomass and was also associated with decreased soil water content. This further reduced soil respiration under high ALAN at peak plant biomass, but microbial communities maintained stable biomass across different levels of ALAN and times, demonstrating higher microbial carbon use efficiency under high ALAN. While ALAN did not affect microbial community structure, the abundance of plant-feeding nematodes increased and there was homogenization of nematode communities under higher levels of ALAN, indicating that soil communities may be more vulnerable to additional disturbances at high ALAN. In summary, the effects of ALAN reach into the soil system by altering soil communities and ecosystem functions, and these effects are mediated by changes in plant productivity and soil water content at peak plant biomass.This article is part of the theme issue 'Light pollution in complex ecological systems'.

Abstract

Background and Aims Studying the relationship between phenotypic and genetic variation in populations distributed across environmental gradients can help us to understand the ecological and evolutionary processes involved in population divergence. We investigated the patterns of genetic and phenotypic diversity in the European crabapple, Malus sylvestris, a wild relative of the cultivated apple (Malus domestica) that occurs naturally across Europe in areas subjected to different climatic conditions, to test for divergence among populations. Methods Growth rates and traits related to carbon uptake in seedlings collected across Europe were measured in controlled conditions and associated with the genetic status of the seedlings, which was assessed using 13 microsatellite loci and the Bayesian clustering method. Isolation-by-distance, isolation-by-climate and isolation-by-adaptation patterns, which can explain genetic and phenotypic differentiation among M. sylvestris populations, were also tested. Key Results A total of 11.6 % of seedlings were introgressed by M. domestica, indicating that crop-wild gene flow is ongoing in Europe. The remaining seedlings (88.4 %) belonged to seven M. sylvestris populations. Significant phenotypic trait variation among M. sylvestris populations was observed. We did not observe significant isolation by adaptation; however, the significant association between genetic variation and the climate during the Last Glacial Maximum suggests that there has been local adaptation of M. sylvestris to past climates. Conclusions This study provides insight into the phenotypic and genetic differentiation among populations of a wild relative of the cultivated apple. This might help us to make better use of its diversity and provide options for mitigating the impact of climate change on the cultivated apple through breeding.

Abstract

1. Insect herbivory is a key process in ecosystem functioning. While theory predicts that plant diversity modulates herbivory, the mechanistic links remain unclear. We postulated that the plant metabolome mechanistically links plant diversity and herbivory. 2. In late summer and in spring, we assessed individual plant above-ground herbivory rates and metabolomes of seven plant species in experimental plant communities varying in plant species diversity and resource acquisition strategies. In the same communities, we also measured plant individual biomass as well as soil microbial and nematode community composition. 3. Herbivory rates decreased with increasing plant species richness. Path modelling revealed that plant species richness and community resource acquisition strategy correlated with soil community composition. In particular, changes in nematode community composition were related to plant metabolome composition and thereby herbivory rates. 4. Synthesis. These results suggest that soil community composition plays an important role in reducing herbivory rates with increasing plant diversity by changing plant metabolomes.

Abstract

Karst aquifers are important water resources for drinking water supplies worldwide. Although they are susceptible to anthropogenic contamination due to their high permeability, there is a lack of detailed knowledge on the stable core microbiome and how contamination may affect these communities. In this study, eight karst springs (distributed across three different regions in Romania) were sampled seasonally for one year. The core microbiota was analysed by 16S rRNA gene amplicon sequencing. To identify bacteria carrying antibiotic resistance genes and mobile genetic ele-ments, an innovative method was applied, consisting of high-throughput antibiotic resistance gene quantification per-formed on potential pathogen colonies cultivated on Compact DryTM plates. A taxonomically stable bacterial community consisting of Pseudomonadota, Bacteroidota, and Actinomycetota was revealed. Core analysis reaffirmed these results and revealed primarily freshwater-dwelling, psychrophilic/psychrotolerant species affiliated to Rhodoferax, Flavobacterium, and Pseudomonas genera. Both sequencing and cultivation methods indicated that more than half of the springs were contaminated with faecal bacteria and pathogens. These samples contained high levels of sulfonamide, macrolide, lincosamide and streptogramins B, and trimethoprim resistance genes spread primarily by transposase and insertion sequences. Differential abundance analysis found Synergistota, Mycoplasmatota, and Chlamydiota as suitable candidates for pollution monitoring in karst springs. This is the first study highlighting the ap-plicability of a combined approach based on high-throughput SmartChipTM antibiotic resistance gene quantification and Compact Dry-pathogen cultivation for estimating microbial contaminants in karst springs and other challenging low biomass environments.

Abstract

No information currently exists on the floristic structure and richness of the Artemisia alba scrubs in Romania and their regional/local environmental drivers. We aimed to fill these knowledge gaps by also considering physiognomically similar communities from Hungary, Serbia and Bulgaria. A total of 89 phytosociological releves, including 43 performed in Romania, were analysed through clustering, constrained ordination and generalised linear mixed models. The Carpathian and Pontic scrubs were clustered into three distinct groups, which were assigned to as many new syntaxa. Differences in the regional species pool and elevation have the strongest effects on floristic dissimilarities between all studied communities. As opposed to the bare soil fraction, the elevation and slope have positive but no singular effects on species richness in the Pontic-Carpathian coenoses. Species diversity declines steadily with increasing shrub cover in all these communities. The relative cover of annuals has contrasting effects on species richness, positive in the most xerophilous communities and negative in their most mesophilous counterparts. The relative number of annuals is only (negatively) related to overall species richness in the coenoses least affected by moisture deficit. Overall, species diversity is driven mainly by soil water availability and, to a lesser extent, by the relative abundance of shrubs and annuals.

Abstract

The Carpathians represent not only a European hotspot of plant diversity for both species richness and endemism, but also an important stepping-stone area in historical migrations between the flora of the Asian and European mountain systems and a starting point of postglacial recolonizations for many species. Yet, until recent years, phylogeographical studies for alpine or arctic-alpine plants were focused on the Alps, whereas peripheral mountain ranges, including the Carpathians, were either neglected or insufficiently sampled. In this study, we aimed to complement the Alpine phylogeographic structure of an emblematic high-alpine European endemic taxon, Eritrichium nanum, by focusing on the Carpathian range of the species. We sampled nine populations from the South-Eastern Carpathians and performed ITS1 sequencing and AFLP fingerprinting. In case of ITS1 region, all the populations, no matter of their geographic origin, presented the same ribotype. The AFLP analysis indicated that, within the Carpathians, the extant populations of E. nanum comprised two major allopatric lineages. One important result of the research was the discovery that the species' sole important genetic break was located in the Southern Carpathians, separating populations of the Retezat Mountains from all the others in the Carpathians.

Abstract

Microsatellite markers previously developed for other leguminous species were tested for cross-genus transferability and evaluated for their potential usefulness in providing an improved assessment of the genetic relationships between two closely related taxa belonging to Onobrychis genus (Fabaceae). Candidate microsatellite markers were tested for polymorphism and replicability in sixteen populations of O. montana DC. subsp. transsilvanica (Simonk.) Jáv. and O. montana. Out of the 23 SSRs, there were identified seven polymorphic loci. In total 32 alleles were detected and the number of alleles per locus varied from two to six. PIC values ranged from 0.375 to 0.6454, and four SSRs displayed a PIC > 0.5. Relative uniform rates of genetic diversity were obtained. In case of O. montana DC. subsp. transsilvanica (Simonk.) Jáv. the observed and expected heterozygosity ranged from 0.100 to 0.952 and from 0.219 to 0.525, respectively, while for O. montana ranged from 0.166 to 0.750 and from 0.083 to 0.375, respectively. Seven polymorphic SSRs with clear and reproducible amplification were identified. These markers proved to be very efficient for unambiguous population discrimination based on both geographic and taxonomic criteria. Hereafter, these SSR markers can be used as tools for evolutionary studies in Onobrychis genus, as well in providing knowledge on patterns of the species phylogeography. © Articles by the authors.

Abstract

Onobrychis montana DC. Subsp. transsilvanica (Simonk.) Jáv. (Fabaceae) is a plant taxon, endemic to the South-Eastern Carpathians, whose taxonomic status is treated inconsistently by the classic taxonomy based on morphological traits. In a previous study, by sequencing several chloroplast DNA regions and AFLP genotyping, we tried to elucidate the controversy concerning its taxonomic status in relation to the more widespread O. montana DC., and determined its phylogeographic structure within the Carpathians. The present study, based on DNA fingerprinting by seven SSR markers, brings more insights on this problematic taxon by conferring higher resolution and sub-clustering previously identified phylogeographic groups. However, the newly SSR genetic data are in agreement with molecular evidence revealed by AFLP and chloroplastic SNPs and do not support O. montana DC. Subsp. transsilvanica (Simonk.) Jáv. As a distinct species from O. montana DC. © 2023, Horticulture and Forestry Society from Transylvania. All rights reserved.

Abstract

Fritillaria orientalis Adams is an endangered central Balkan and Illyrian species with a sporadic presence in Romania, that has been declared a "Natural Monument". A new protected area of 22.18 ha located southwards to the village Berchieșu (Frata commune) is proposed for conserving the most important and abundant population of F. orientalis in Cluj county, the assessment based on available literature and personal observations in the field. For this reason, the area has special botanical value and needs to be legally protected in order to preserve this isolated population. This paper presents floristic data and vegetation characteristics along with relevant illustration of the proposed protected area. In order to easily distinguish F. orientalis from F. meleagris L., reported as well in the Cluj county, morphological, biometric and ecological differentiation characters are presented. Individual plants of F. orientalis from Berchieșu are characterized by a pronounced diversity regarding the height of flower stems and colour of perianth. Collection of flowers or whole plants, extension of cultivated land, improvised fireplaces near the forest edge, logging, fertilization of agricultural fields and motorized access threatens this population. Therefore, we propose a set of measures to assure its sustainable conservation and monitoring of the phytocoenoses to assess the effectiveness of protective actions. © 2023, Babes-Bolyai University, "Alexandru Borza" Botanic Garden. All rights reserved.

Abstract

Two new Juniperus communis subsp. communis syntaxa from Romania are presented from floristic, ecological and syntaxonomic points of view, completing the picture of the European distribution area of these shrubby communities. The phytocoenoses of Thymio odoratissimi-Juniperetum communis ass. nova are present on calcareous substrates and are rich in continental Eurasian, meso-xerophilous species, for which reason we assigned it to alliance Brachypodio pinnati-Juniperion communis Mucina et al. 2016, and class Crataego-Prunetea Tx. 1962. The communities belonging to Vaccinio myrtilli-Juniperetum communis Kovács ex Filipaș et al. campanuletosum abietinae subass. nova occur on acidic substrates, crystalline schists and gresous formations, and are rich in acidophilous species, characteristic for the class Calluno-Ulicetea Br.-Bl. et Tx. ex Klika et Hadač 1944. We assigned this new syntaxon to alliance Vaccinio-Juniperion communis Passage in Passage et G. Hoffman 1968 because of the high presence of Vaccinium species (V. myrtillus, V. vitis-idaea) in the sub-shrub layer of these phytocoenoses. © 2023, Babes-Bolyai University, "Alexandru Borza" Botanic Garden. All rights reserved.

Abstract

Abstract

Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km(2) resolution for 0-5 and 5-15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km(2) pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10 degrees C (mean = 3.0 +/- 2.1 degrees C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 +/- 2.3 degrees C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 +/- 2.3 degrees C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications.

Abstract

Species turnover is ubiquitous. However, it remains unknown whether certain types of species are consistently gained or lost across different habitats. Here, we analysed the trajectories of 1827 plant species over time intervals of up to 78 years at 141 sites across mountain summits, forests, and lowland grasslands in Europe. We found, albeit with relatively small effect sizes, displacements of smaller- by larger-ranged species across habitats. Communities shifted in parallel towards more nutrient-demanding species, with species from nutrient-rich habitats having larger ranges. Because these species are typically strong competitors, declines of smaller-ranged species could reflect not only abiotic drivers of global change, but also biotic pressure from increased competition. The ubiquitous component of turnover based on species range size we found here may partially reconcile findings of no net loss in local diversity with global species loss, and link community-scale turnover to macroecological processes such as biotic homogenisation.

Abstract

In Apuseni Mountains (North-Western Romania), many of the inhabitants live in rural communities with limited or no access to the centralized and controlled water supply. This study assesses the microbiological quality of six karst spring waters from Bihor County used by rural communities as drinking water sources. Twenty-four water samples collected in January, April, June, and November 2021 were analyzed for E. coli, total coliforms, intestinal enterococci, Pseudomonas aeruginosa, and heterotrophic plate count at 37 and 22?. Standard microbiological methods based on the membrane filter technique or pour plate method were used for the microbiological characterization of the spring waters. The study revealed that the karst springs from the studied area present microbiological contamination. The microbiological parameters for five out of the six studied spring waters exceeded the maximum limits allowed by the 98/83/EC Directive. Quantitative Microbial Risk Assessment estimated the risk of gastrointestinal illness for both adults and children due to the enteropathogenic E. coli contamination. According to the health risk evaluation model, the risk of infection/day and the risk of infection/year were high, with the maximum values of 0.24 and 1.00, respectively. The probability of illness caused by E. coli contamination of water ranged between 0.09 and 0.35 for five out of six groundwater sources. The local communities using the contaminated springs are exposed to daily and accumulated health threats. Therefore, preventive measures accompanied by continuous monitoring are necessary mainly for those water sources that are critical drinking water sources for the rural communities.

Abstract

The spatiotemporal variation of several carbapenemase-encoding genes (CRGs) was investigated in the influent and effluent of municipal WWTPs, with or without hospital sewage input. Correlations among gene abundances, bacterial community composition, and wastewater quality parameters were tested to identify possible predictors of CRGs presence. Also, the possible role of wastewaters in mirroring clinical resistance is discussed. The taxonomic groups and gene abundances showed an even distribution among wastewater types, meaning that hospital sewage does not influence the microbial diversity and the CRG pool. The bacterial community was composed mainly of Proteobacteria, Firmicutes, Actinobacteria, Patescibacteria, and Bacteroidetes. Acinetobacter spp. was the most abundant group and had the majority of operational taxonomic units (OTUs) positively correlated with CRGs. This agrees with recent reports on clinical data. The influent samples were dominated by bla(KPC), as opposed to effluent, where bla(IMP) was dominant. Also, bla(IMP) was the most frequent CRG family observed to correlate with bacterial taxa, especially with the Mycobacterium genus in effluent samples. Bacterial load, bla(NDM), bla(KPC), and bla(OXA-48) abundances were positively correlated with BOD5, TSS, HEM, Cr, Cu, and Fe concentrations in wastewaters. When influent gene abundance values were converted into population equivalent (PE) data, the highest copies/1 PE were identified for bla(KPC) and bla(OXA-48), agreeing with previous studies regarding clinical isolates. Both hospital and non-hospital-type samples followed a similar temporal trend of CRG incidence, but with differences among gene groups. Colder seasons favored the presence of bla(NDM), bla(KPC), and bla(OXA-48), whereas warmer temperatures show increased PE values for bla(VIM) and bla(IMP). IMPORTANCE Wastewater-based epidemiology has recently been recognized as a valuable, cost-effective tool for antimicrobial resistance surveillance. It can help gain insights into the characteristics and distribution of antibiotic resistance elements at a local, national, and even global scale. In this study, we investigated the possible use of municipal wastewaters in the surveillance of clinically relevant carbapenemase-encoding genes (CRGs), seen as critical antibiotic resistance determinants. In this matter, our results highlight positive correlations among CRGs, microbial diversity, and wastewater physical and chemical parameters. Identified predictors can provide valuable data regarding the level of raw and treated wastewater contamination with these important antibiotic resistance genes. Also, wastewater-based gene abundances were used for the first time to observe possible spatiotemporal trends of CRGs incidence in the general population. Therefore, possible hot spots of carbapenem resistance could be easily identified at the community level, surpassing the limitations of health care-associated settings.

Abstract

Background Previous investigations carried out in ultramafic habitats emphasized the greater importance of site conditions over soil toxic metal content for vegetation composition. Very little is known about the floristic structure of the Southern Carpathian ultramafic grasslands and there is no information on the local environmental drivers of their composition and coenotic features. Here, we aim to fill these knowledge gaps by referring to similar phytocoenoses described in the Balkan Peninsula and central Europe. In particular, we searched for: (i) floristic and ecological patterns supporting the classification and taxonomic assignment of these grasslands, and (ii) simple relationships between serpentine vegetation characteristics and its physiographic environment. A total of 120 phytosociological releves, of which 52 performed in the Southern Carpathians, were analysed through cluster, ordination and regression procedures. Results Despite some floristic similarities with their Balkan counterparts, the Southern Carpathian ultramafic grasslands were clustered into four distinct groups, which were assigned to as many new syntaxa: Plantago serpentinae-Armerietum halleri, Asplenio serpentini-Achnatheretum calamagrostis, Minuartio frutescentis-Plantaginetum holostei and Sileno saxifragae-Plantaginetum holostei. The latter was best individualised through the occurrence of several Carpathian endemic taxa. The first two ordination axes were significantly related with the terrain slope/presence of xerophilous species and respectively, with site elevation/presence of calcifugous species. The total plant cover showed a unimodal relationship with respect to site elevation. While controlling for the effect of the sampled area, species richness showed a unimodal response to both elevation and slope of the terrain, although their effects were not singular. Conclusions The syntaxonomic distinctiveness of the Southern Carpathian ultramafic grasslands is mainly supported by their overall species composition rather than regional differential species. The main limiting factors driving the composition, cover and species richness of all studied ultramafic grasslands are the water deficit at low elevation and on steep slopes, and the low soil fertility at higher elevations. Our results confirm the previous findings according to which physiographic conditions and, to a lesser extent, soil base nutrients are more important than heavy metal concentrations in structuring the ultramafic vegetation.

Abstract

As a consequence of global demographic challenges, both the artificial and the natural environment are increasingly impacted by contaminants of emerging concern, such as bacterial pathogens and their antibiotic resistance genes (ARGs). The aim of this study was to determine the extent to which anthropogenic contamination contributes to the spread of antibiotic resistant enterococci in aquatic compartments and to explore genetic relationships among Enterococcus strains. Antimicrobial susceptibility testing (ampicillin, imipenem, norfloxacin, gentamycin, vancomycin, erythromycin, tetracycline, trimethoprim-sulfamethoxazole) of 574 isolates showed different rates of phenotypic resistance in bacteria from wastewaters (91.9-94.4%), hospital effluents (73.9%), surface waters (8.2-55.3%) and groundwater (35.1-59.1%). The level of multidrug resistance reached 44.6% in enterococci from hospital effluents. In all samples, except for hospital sewage, the predominant species were E. faecium and E. faecalis. In addition, E. avium, E. durans, E. gallinarum, E. aquimarinus and E. casseliflavus were identified. Enterococcus faecium strains carried the greatest variety of ARGs (bla(TEM-1), aac(6 ')-Ie-aph(2 ''), aac(6 ')-Im, vanA, vanB, ermB, mefA, tetB, tetC, tetL, tetM, sul1), while E. avium displayed the highest ARG frequency. Molecular typing using the ERIC2 primer revealed substantial genetic heterogeneity, but also clusters of enterococci from different aquatic compartments. Enterococcal migration under anthropogenic pressure leads to the dispersion of clinically relevant strains into the natural environment and water resources. In conclusion, ERIC-PCR fingerprinting in conjunction with ARG profiling is a useful tool for the molecular typing of clinical and environmental Enterococcus species. These results underline the need of safeguarding water quality as a strategy to limit the expansion and progression of the impending antibiotic-resistance crisis.

Abstract

We investigated the floristic dissimilarities and their ecological drivers between three regional groups of Scots pine woodlands from mires dispersed along a latitudinal gradient in Eastern Europe. Phytosociological data regarding such woodland communities from the Eastern Carpathians (Romania) and lowlands of Poland and Latvia were collected from 47 published releves. In spite of the small number of good discriminant species, the relative positions of the three regional groups of communities in the bi-dimensional ordination space roughly matched their geographical separation along latitude and longitude. When the spatial autocorrelation was filtered out, the three regional groups of communities appeared partly overlapping in the two-dimensional ordination space, whose axes correlated with the occurrences of some species that are typical of either open or wooded bogs and, respectively, either hummocks or hollows. The total herb cover was negatively and significantly correlated with both the first partial ordination axis and total shrub cover. We concluded that the observed, small floristic dissimilarities were mainly induced by weak, small-scale gradients of autogenic successional development and groundwater level/microtopography. Our results do not support the distinction of a montane, Eastern Carpathian vicariant of the syntaxon Vaccinio uliginosi-Pinetum sylvestris from the lowlands of Central and Baltic Europe.

Abstract

Here we report a new population of Capnodis cariosa from the South-Western Romania, at the border with the Republic of Serbia (Danube's Defile). The presence of this species was reported in the past from Southern Dobroudja (South-Eastern Romania, near the Bulgarian bonier), this being its only, yet nowadays probably extinct, local Romanian population. In our citizen science-based investigations, which started in the spring of 2020, we found 16 specimens in the area of the Iron Gates Natural Park, between Dubova and Svinita (Danube's Defile, Mehedinti County). This location represents the northernmost one for this species in Europe and the only verified present-day location for this species in Romania. Some considerations about biology, ecology and distribution of Capnodis cariosa are also provided. Two updated distribution maps of this species in Romania, in the Danube's Defile and in the whole Mediterranean areas, are also presented.

Abstract

Oligotrophic peat bogs reach the southern boundary of their European distribution area in the Romanian Carpathians. They shelter boreal species considered glacial relicts, surviving from the Würmian III period. Such areas (habitats) conserving relict species have major phytohistorical importance. They provide insights into the history of forest vegetation in the region and past climatic conditions. Based on floristic, phytocoenological and phytogeographical data, we propose to include two active raised bogs, namely “Calul de Piatră” and “Izvorul văii Șoimului” in the ROSCI0116 Molhașurile Căpățânei site of community interest. The inclusion of the two bogs in the ROSCI0116 Molhașurile Căpățânei protected area will increase the peat bog surface in the Apuseni Mountains and will be beneficial for the conservation of the wetland habitats and their typical flora, both very vulnerable to natural and anthropogenic disturbances. © 2022, Babes-Bolyai University, "Alexandru Borza" Botanic Garden. All rights reserved.

Abstract

The present vegetation study was elaborated on the basis of geo-referenced phytocoenological relevés carried out in 2007–2010 on the northern slope of the Vlădeasa Mountain. 150 representative relevés for the woody and herbaceous vegetation were selected from a total of 387. These were grouped in 16 plant associations, based on their coenotic affinity and ecological requirements, and represented in a large-scale vegetation map. Of these, six scrub and forest associations were grouped in the class Vaccinio-Picetea and four forest associations in the class Carpino-Fagetea. Among the six herbaceous associations included in the classes Nardetea strictae and Molinio-Arrhenatheretea, only the association Potentillo aureae-Festucetum supinae has a primary character. © 2022, Babes-Bolyai University, "Alexandru Borza" Botanic Garden. All rights reserved.

Abstract

While climatic research about treeline has a long history, the climatic conditions corresponding to the upper limit of closed alpine grasslands remain poorly understood. Here, we propose a climatic definition for this limit, the 'grassline', in analogy to the treeline, which is based on the growing season length and the soil temperature. Eighty-seven mountain summits across ten European mountain ranges, covering three biomes (boreal, temperate, Mediterranean), were inventoried as part of the GLORIA project. Vascular plant cover was estimated visually in 326 plots of 1 x 1 m. Soil temperatures were measured in situ for 2-7 years, from which the length of the growing season and mean temperature were derived. The climatic conditions corresponding to 40% plant cover were defined as the thresholds for alpine grassland. Closed vegetation was present in locations with a mean growing season soil temperature warmer than 4.9 degrees C, or a minimal growing season length of 85 days, with the growing season defined as encompassing days with daily mean >= 1 degrees C. Hence, the upper limit of closed grasslands was associated with a mean soil temperature close to that previously observed at the treeline, and in accordance with physiological thresholds to growth in vascular plants. In contrast to trees, whose canopy temperature is coupled with air temperature, small-stature alpine plants benefit from the soil warmed by solar radiation and consequently, they can grow at higher elevations. Since substrate stability is necessary for grasslands to occur at their climatic limit, the grassline rarely appears as a distinct linear feature.

Abstract

Anthropogenic pressures alter the biodiversity, structure and organization of biological communities with severe consequences for ecosystem processes. Species invasion is such a human-induced ecosystem change with pronounced impacts on recipient ecosystems. Around the globe, earthworms invade habitats and impact abiotic soil conditions and a wide range of above- and belowground organisms. In northern North America, where earthworms have been largely absent since the last glaciation period and most earthworm species present today have only been (re-)introduced a few hundred years ago, invasion impacts have been intensively studied. However, despite several studies assessing impacts of invasive earthworms on soil fauna, studies have rarely investigated the simultaneous responses of different soil-fauna size groups and biodiversity facets which might respond differently to earthworm invasion and independently affect ecosystem processes. Our study goes beyond previously-established knowledge on earthworm-invasion effects by simultaneously assessing differences in four biodiversity facets, namely the abundance, biomass, richness and Shannon index of soil invertebrate macro-, meso- and microfauna communities between high- and low-invasion status plots (n = 80) and in relation to invasion intensity measured as earthworm biomass across four northern North American forests sampled between 2016 and 2017. Across forests and soil-fauna groups, we found reduced abundance (-33 to -45%) and richness (-18 to -25%) in high compared to low-invasion status areas. Additionally, meso- (-14%) and microfauna biomass (-38%) and macro- (-7%) and microfauna Shannon index (-8%) were reduced. Higher invasion intensity (earthworm biomass) was additionally related to reduced soil-fauna biodiversity. While the studied biodiversity facet was important for the soil fauna response, soil-fauna size group was comparably unimportant. Given the global ubiquity of earthworm invasion and the importance of soil fauna for key ecosystem processes, our observational results help to assess future impacts of this invasion and the consequences for anthropogenically-altered ecosystem functioning.

Abstract

Ursu Lake is located in the Middle Miocene salt deposit of Central Romania. It is stratified, and the water column has three distinct water masses: an upper freshwater-to-moderately saline stratum (0-3 m), an intermediate stratum exhibiting a steep halocline (3-3.5 m), and a lower hypersaline stratum (4 m and below) that is euxinic (i.e. anoxic and sulphidic). Recent studies have characterized the lake's microbial taxonomy and given rise to intriguing ecological questions. Here, we explore whether the communities are dynamic or stable in relation to taxonomic composition, geochemistry, biophysics, and ecophysiological functions during the annual cycle. We found: (i) seasonally fluctuating, light-dependent communities in the upper layer (>= 0.987-0.990 water-activity), a stable but phylogenetically diverse population of heterotrophs in the hypersaline stratum (water activities down to 0.762) and a persistent plate of green sulphur bacteria that connects these two (0.958-0.956 water activity) at 3-3.5 to 4 m; (ii) communities that might be involved in carbon- and sulphur-cycling between and within the lake's three main water masses; (iii) uncultured lineages including Acetothermia (OP1), Cloacimonetes (WWE1), Marinimicrobia (SAR406), Omnitrophicaeota (OP3), Parcubacteria (OD1) and other Candidate Phyla Radiation bacteria, and SR1 in the hypersaline stratum (likely involved in the anaerobic steps of carbon- and sulphur-cycling); and (iv) that species richness and habitat stability are associated with high redox-potentials. Ursu Lake has a unique and complex ecology, at the same time exhibiting dynamic fluctuations and stability, and can be used as a modern analogue for ancient euxinic water bodies and comparator system for other stratified hypersaline systems.

Abstract

Forest soil food webs have been assumed to be fueled substantially by root-derived resources. However, until today the flux of root-derived resources into soil animals has been investigated virtually exclusively using isotope labeling experiments, whereas studies on the consequences of disrupting the flux of root-derived resources into the soil animal food web are scarce. We here investigated the importance of rootderived resources for a wide range of soil animals by interrupting the resource flux into the soil of different forest types in Central Europe using a trenching experiment. We recorded the abundance of soil animal taxa varying in body size (micro-, meso-, and macrofauna) 1 and 3 years after root trenching, and quantified changes in biomass, species composition, and trophic shift using stable isotopes and NLFA analysis. Among the microfauna groups studied (trophic groups of Nematode) only the abundance of plant feeding nematodes showed a trend in being decreased by -58% due to root trenching. Major soil mesofauna groups, including Collembola and Oribatida, suffered to a similar extent from root trenching with their abundance and biomass being reduced by about 30-40%. The soil macrofauna groups studied (Diplopoda, Isopoda, Chilopoda, Araneae, Coleoptera) generally were only little affected by root trenching suggesting that they rely less on root-derived resources than micro- and in particular mesofauna. Notably, the community structure of micro-, meso-, and macrofauna was not affected by root trenching. Further, we observed trophic shifts only in 2 out of 10 investigated species with the shifts generally being only minor. The results indicate that soil animal communities are markedly resilient to deprivation of root-derived resources suggesting that links to root-derived resources are non-specific. However, this resilience appears to vary with body size, with mesofauna including both decomposers as well as predators being more sensitive to the deprivation of root-derived resources than microfauna (except for root feeders) and macrofauna. Overall, this suggests that body size constrains the channeling of energy through soil food webs, with rootderived resources in temperate forests being channeled predominantly via soil taxa of intermediate size, i.e., mesofauna.

Abstract

Carbapenemase-producing Klebsiella pneumoniae (CPKP) isolated from influent (I) and effluent (E) of two wastewater treatment plants, with (S1) or without (S2) hospital contribution, were investigated. The strains belonged to the Kp1 phylogroup, their highest frequency being observed in S1, followed by S2. The phenotypic and genotypic hypervirulence tests were negative for all the strains tested. At least one carbapenemase gene (CRG), belonging to the blaKPC, blaOXA-48, blaNDM and blaVIM families, was observed in 63% of CPKP, and more than half co-harboured two to four CRGs, in different combinations. Only five CRG variants were observed, regardless of wastewater type: blaKPC-2, blaNDM-1, blaNDM-6, blaVIM-2, and blaOXA-48. Sequence types ST258, ST101 and ST744 were common for both S1 and S2, while ST147, ST525 and ST2502 were found only in S1 and ST418 only in S2. The strains tested were multi-drug resistant (MDR), all being resistant to beta-lactams, cephalosporins, carbapenems, monobactams and fluoroquinolones, followed by various resistance profiles to aminoglycosides, trimethoprim-sulphamethoxazole, tigecycline, chloramphenicol and tetracycline. After principal component analysis, the isolates in S1 and S2 groups did not cluster independently, confirming that the antibiotic susceptibility patterns and gene-type profiles were both similar in the K. pneumoniae investigated, regardless of hospital contribution to the wastewater type.

Abstract

Questions Abiotic filtering, competitive interactions and niche pre-emption effects, as important drivers of the species sorting in plant communities, were hypothesised to be responsible for the amount of concavity and shoulder distinction in ranked species occupancy curves (RSOCs). In connection with the intermediate productivity hypothesis, we proposed an adjustment and extension of the RSOC models concerning the ecological mechanisms underlying their shaping. We aimed at estimating the effects of the variation in resource availability and functional species composition on the RSOCs of 30 woody vegetation syntaxa. Location Low plains to the subalpine belt (southeastern Carpathians) throughout Romania. Methods The fraction of vascular plant species with either low (< 3) or large (>7) Ellenberg ecological indicator values were used as proxies for abiotic variables. Both the standardised effect size of homotoneity (SES-h, estimated by contrasting empirical vs null RSOCs) and the regression parameters of the fitted RSOCs were used, after adjusting them for differences in sampling scale, as shape descriptors. Results The empirical RSOCs were all fitted best by the power exponential function. With increasing fraction of ruderal species and canopy openness, the slopes of RSOC's heads became gentler (larger power parameter). Higher levels of soil fertility towards lower elevations translated in reduced concavity of the RSOCs (larger exponential parameter). Larger/smaller SES-h were associated with richer/poorer habitat-specific species pools that were ascribed to low-elevation, open-canopy vegetation (oak-dominated forests, shiblyak woodlands, secondary scrubs) and, respectively, (sub)montane, closed-canopy, mixed beech or spruce forests and sub-alpine scrubs. Conclusions Dense species packing and even niche partitioning in communities developed in moderately productive sites are associated with shoulder-free, long-tailed, slightly concave RSOCs. Conversely, strong filtering in stressful environments and/or low light availability under closed, woody canopies are related to steep, short-tailed, exponential-like RSOCs. The availability of resources and the equitability of niche partitioning, underlying the process of species sorting during plant community assembly, play a major role in shaping the RSOCs.

Abstract

Selection and dissemination of resistant bacteria and antibiotic resistance genes (ARGs) require a deeper understanding since antibiotics are permanently released to the environment. The objective of this paper was to evaluate the phenotypic resistance of 499 isolates of Pseudomonas spp. from urban water sources, and the prevalence of 20 ARGs within those isolates. Resistance to penicillins, cephalosporins, carbapenems, quinolones, macrolides, and tetracyclines was mainly observed in the hospital effluent, municipal wastewater and river water downstream the city. Resistant strains were frequently identified as P. aeruginosa and P. putida. P. aeruginosa isolates were mostly resistant to cefepime, ceftazidime, imipenem, and gentamycin, while P. putida strains were especially resistant to piperacillin-tazobactam. ARGs such as bla(TEM-1), bla(SHV-1), bla(PER-1), bla(AmpC), bla(VIM-1), PstS, qnrA, qnrB, ermB, tetA, tetB and tetC have been detected. The bla(AmpC) gene was found in P. aeruginosa, while bla(TEM-1) and bla(PER-1) genes were found in P. putida. Class 1 integron integrase gene was found in 6.81% of the Pseudomonas isolates.

Abstract

Grassland ecosystems are essential for biomass production but are prone to degradation if management practices are inappropriate. Thus, it is necessary to optimize grazing management since the grazing practices and grassland status are interconnected. Herbage mass production and forage quality of the plant species are among the most important factors for grazing livestock performance, grassland carrying capacity, and their sustainable management. We employed optimized methods for the analysis of two historical vegetation datasets (from 1970 and 2008), along with the statistical data on livestock numbers and types from three administrative units within the Vladeasa Mountains area, in the Romanian Carpathians. We looked for trends in grassland quality and productivity and explored their connections to grazing management descriptors and practices. We identified a small but statistically significant decreasing trend between the two periods in both pastoral value (from 63.80 to 61.43) and productivity (from 10.80 t ha(-1) to 9.18 t ha(-1)). The decline in grassland quality and productivity may be associated with the sharp decrease in livestock numbers (from 9,688 LU to 5,085 LU) and the replacement of cattle by sheep as the dominant livestock type. The abandonment of grasslands and traditional practices also increased the deviation from the optimum of the actual stocking rate. This approach can be used as a model for other areas where time-series vegetation data are available from phytosociological literature and/or databases. These insights can be used to design adaptive grazing management plans to optimize grazing management according to the carrying capacity of the grassland ecosystems.

Abstract

Litter decomposition is a key process for carbon and nutrient cycling in terrestrial ecosystems and is mainly controlled by environmental conditions, substrate quantity and quality as well as microbial community abundance and composition. In particular, the effects of climate and atmospheric nitrogen (N) deposition on litter decomposition and its temporal dynamics are of significant importance, since their effects might change over the course of the decomposition process. Within the TeaComposition initiative, we incubated Green and Rooibos teas at 524 sites across nine biomes. We assessed how macroclimate and atmospheric inorganic N deposition under current and predicted scenarios (RCP 2.6, RCP 8.5) might affect litter mass loss measured after 3 and 12 months. Our study shows that the early to mid-term mass loss at the global scale was affected predominantly by litter quality (explaining 73% and 62% of the total variance after 3 and 12 months, respectively) followed by climate and N deposition. The effects of climate were not litter-specific and became increasingly significant as decomposition progressed, with MAP explaining 2% and MAT 4% of the variation after 12 months of incubation. The effect of N deposition was litter-specific, and significant only for 12-month decomposition of Rooibos tea at the global scale. However, in the temperate biome where atmospheric N deposition rates are relatively high, the 12-month mass loss of Green and Rooibos teas decreased significantly with increasing N deposition, explaining 9.5% and 1.1% of the variance, respectively. The expected changes in macroclimate and N deposition at the global scale by the end of this century are estimated to increase the 12-month mass loss of easily decomposable litter by 1.1-3.5% and of the more stable substrates by 3.8-10.6%, relative to current mass loss. In contrast, expected changes in atmospheric N deposition will decrease the mid-term mass loss of high-quality litter by 1.4-2.2% and that of low-quality litter by 0.9-1.5% in the temperate biome. Our results suggest that projected increases in N deposition may have the capacity to dampen the climate-driven increases in litter decomposition depending on the biome and decomposition stage of substrate. © Copyright © 2021 Kwon, Shibata, Kepfer-Rojas, Schmidt, Larsen, Beier, Berg, Verheyen, Lamarque, Hagedorn, Eisenhauer, Djukic and TeaComposition Network.

Abstract

Grassland ecosystems are essential for biomass production but are prone to degradation if management practices are inappropriate. Thus, it is necessary to optimize grazing management since the grazing practices and grassland status are interconnected. Herbage mass production and forage quality of the plant species are among the most important factors for grazing livestock performance, grassland carrying capacity, and their sustainable management. We employed optimized methods for the analysis of two historical vegetation datasets (from 1970 and 2008), along with the statistical data on livestock numbers and types from three administrative units within the Vlădeasa Mountains area, in the Romanian Carpathians. We looked for trends in grassland quality and productivity and explored their connections to grazing management descriptors and practices. We identified a small but statistically significant decreasing trend between the two periods in both pastoral value (from 63.80 to 61.43) and productivity (from 10.80 t ha-1 to 9.18 t ha-1). The decline in grassland quality and productivity may be associated with the sharp decrease in livestock numbers (from 9,688 LU to 5,085 LU) and the replacement of cattle by sheep as the dominant livestock type. The abandonment of grasslands and traditional practices also increased the deviation from the optimum of the actual stocking rate. This approach can be used as a model for other areas where time-series vegetation data are available from phytosociological literature and/or databases. These insights can be used to design adaptive grazing management plans to optimize grazing management according to the carrying capacity of the grassland © **. Articles by the authors; UASVM, Cluj-Napoca, Romania. The journal allows the author(s) to hold the copyright/to retain publishing rights without restriction

Abstract

The article reviews the results obtained through the palynological study of sequences obtained from the Sibiu region and adjacent areas. The oldest Upper Pleistocene sequences we refer to seem to reflect snapshots from the Last Glacial Maximum. The history of the Late Glacial and Holocene vegetation here is broadly part of the succession known for the territory of Romania, in the Carpathians and the surrounding areas of medium and low altitudes. The dynamics of the main forest and grasses taxa were highlighted, influenced both by natural factors and, more recently, by human activity. The reference area is characterized by the domination of the forests during the interstadials and by open landscape of forested steppe during the cold, stadial periods. ©2021 Studia UBB Biologia.

Abstract

Abstract

Introduction: Karstic springs are used worldwide by rural communities as sources of fresh water for humans and livestock. In Romania, one-third of the population has no direct access to a public water supply. The present study is part of a country-wide project to develop simple, quick and cheap methods for seasonal environmental and microbiological monitoring of karstic springs used as drinking water by rural populations. Critical steps for monitoring workflow consist of evaluating water quality and selecting suitable membrane filters to efficiently capture environmental DNA for further microbial diversity estimation using 16S rRNA gene-based metabarcoding. Methods: Several commercial membrane filters of different compositions and pore sizes were tested on the water sampled from three karstic springs in Romania, followed by water chemistry and whole community 16S rRNA gene-based metabarcoding analysis. Results: We found that different types of applied membrane filters provide varying recovery in diversity and abundance of both overall and pathogenic bacteria. Conclusions: The result of the experiment with different filters shows that mixed cellulose ester, cellulose acetate, and nitrate membranes of 0.20 and 0.22 mu m are the best for amplicon-based metabarcoding monitoring of karst springs.

Abstract

Current analyses and predictions of spatially explicit patterns and processes in ecology most often rely on climate data interpolated from standardized weather stations. This interpolated climate data represents long-term average thermal conditions at coarse spatial resolutions only. Hence, many climate-forcing factors that operate at fine spatiotemporal resolutions are overlooked. This is particularly important in relation to effects of observation height (e.g. vegetation, snow and soil characteristics) and in habitats varying in their exposure to radiation, moisture and wind (e.g. topography, radiative forcing or cold-air pooling). Since organisms living close to the ground relate more strongly to these microclimatic conditions than to free-air temperatures, microclimatic ground and near-surface data are needed to provide realistic forecasts of the fate of such organisms under anthropogenic climate change, as well as of the functioning of the ecosystems they live in. To fill this critical gap, we highlight a call for temperature time series submissions to SoilTemp, a geospatial database initiative compiling soil and near-surface temperature data from all over the world. Currently, this database contains time series from 7,538 temperature sensors from 51 countries across all key biomes. The database will pave the way toward an improved global understanding of microclimate and bridge the gap between the available climate data and the climate at fine spatiotemporal resolutions relevant to most organisms and ecosystem processes.

Abstract

This phytosociological study of the Carpathian species-rich mesophilous mountain hay meadows (Triseto flavescentis-Polygonion bistortaealliance,Molinio-Arrhenathereteaclass) presents the first unified large-scale classification system in four countries: Slovakia, Poland, Romania and Ukraine. The starting dataset contained releves of theMolinio-Arrhenatheretea,Mulgedio-AconiteteaandNardetea strictaeclasses. Numerical classification and semi-supervised classification by K-means method were used for the analyses. An electronic expert system and diagnostic species for grassland vegetation served for identification ofa priorigroups in K-means method. The final dataset contained 612 releves. Altitude, climatic data and Ellenberg indicator values were used for ecological differentiation of syntaxa. The main gradients in floristic composition were analysed by Detrended Correspondence Analysis. Finally, the eight well-differentiated associations and one newly described association were determined:Campanulo glomeratae-Geranietum sylvatici,Geranio sylvatici-Trisetetum flavescentis,Crepido mollis-Agrostietum capillaris,Geranio-Alchemilletum crinitae,Alchemillo-Deschampsietum caespitosae,Phyteumo (orbicularis)-Trifolietum pratensis,Astrantio-Trisetetum flavescentis,Trollio altissimi-Knautietum dipsacifoliaeandViolo declinatae-Agrostietum capillarisass. nova. The differences in vegetation diversity of mountain hay meadows between particular countries were confirmed:Alchemillo-Deschampsietum caespitosaeoccurs in all studied territories,Campanulo glomeratae-Geranietum sylvaticioccurs predominantly in Slovakia and the newly described associationViolo declinatae-Agrostietum capillarisass. nova could be found only in Ukraine.

Abstract

A mud volcano (MV) is a naturally hydrocarbon-spiked environment, as indicated by the presence of various quantities of PAHs and aromatic isotopic shifts in its sediments. Recurrent expulsion of various hydrocarbons consolidates the growth of hydrocarbonoclastic bacterial communities in the areas around MVs. In addition to the widely-known availability of biologically malleable alkanes, MVs can represent hotbeds of polyaromatic hydrocarbons (PAHs), as well - an aspect that has not been previously explored. This study measured the availability of highly recalcitrant PAHs and the isotopic signature of MV sediments both by GC-MS and delta C-13 analyses. Subsequently, this study highlighted both the occurrence and distribution of putative PAH-degrading bacterial OTUs using a metabarcoding technique. The putative hydrocarbonoclastic taxa incidence are the following: Enterobacteriaceae (31.5%), Methylobacteriaceae (19.9%), Bradyrhizobiaceae (16.9%), Oxalobacteraceae (10.2%), Comamonadaceae (7.6%) and Sphingomonadaceae (5.5%). Cumulatively, the results of this study indicate that MVs represent polyaromatic hydrocarbonoclastic hotbeds, as defined by both natural PAH input and high incidence of putative PAH-degrading bacterial OTUs.

Abstract

Land-use intensification represents one major threat to the diversity and functioning of terrestrial ecosystems. In the face of concurrent climate change, concerns are growing about the ability of intensively managed agroecosystems to ensure stable food provisioning, as they may be particularly vulnerable to climate extreme-induced harvest losses and pest outbreaks. Extensively managed systems, in contrast, were shown to mitigate climate change based on plant diversity-mediated effects, such as higher functional redundancy or asynchrony of species. In this context, the maintenance of soils is essential to sustain key ecosystem functions such as nutrient cycling, pest control, and crop yield. Within the highly diverse soil fauna, nematodes represent an important group as their trophic spectrum ranges from detritivores to predators and they allow inferences to the overall state of the ecosystem (bioindicators). Here, we investigated the effects of simulated climate change and land-use intensity on the diversity and abundance of soil nematode functional groups and functional indices in two consecutive years. We revealed that especially land use induced complex shifts in the nematode community with strong seasonal dynamics, while future climate led to weaker effects. Strikingly, the high nematode densities associated with altered climatic conditions and intensive land use were a consequence of increased densities of opportunists and potential pest species (i.e., plant feeders). This coincided with a less diverse and less structured community with presumably reduced capabilities to withstand environmental stress. These degraded soil food web conditions represent a potential threat to ecosystem functioning and underline the importance of management practices that preserve belowground organisms.

Abstract

The paper is a synthesis of the palynological studies that have addressed the age of landslides in Transylvania. We discuss the configuration of the paleo-vegetation in the respective areas, but also the probable factors, abiotic or biotic, which promoted the landslides and the relative period when they occurred in Transylvania. The analysis indicates two major periods of onset for landslides, the Pleistocene and Holocene. © 2020, Babes-Bolyai University, "Alexandru Borza" Botanic Garden. All rights reserved.

Abstract

Previous experimental studies found strengthening relationships between biodiversity and ecosystem functioning (BEF) over time. Simultaneous temporal changes of abiotic and biotic conditions, such as in the composition of soil communities, soil carbon and nutrient concentrations, plant community assembly or selection processes, are currently discussed as potential drivers for strengthening BEF relationships. Despite the popularity of these explanations, experimental tests of underlying mechanisms of strengthening BEF relationships over time are scarce, and confounding influences of calendar year cannot be ruled out unless ecosystems of different age are compared in the same calendar years. To address this critical gap of knowledge, we reestablished the plant communities of a long-term biodiversity experiment that had started in 2002 (the Jena Experiment) with new seeds and old or new soil again in 2016. Comparing these treatments with the original communities set up in 2002, we tested whether old communities had stronger plant diversity effects on plant productivity than young ones and if this depended on soil- or plant-related processes. Our first results show that in old communities, the effect of plant diversity on productivity was indeed stronger than in young communities and that this could not be explained by the age of the soil only. However, we found significant effects of soil on the composition of soil organisms, which might be relevant for other ecosystem functions and may have stronger effects over time. Our new experimental approach enables us to test which mechanisms cause strengthening BEF relationships for many different ecosystem functions independent of the study year.

Abstract

Ecological communities are increasingly confronted with multiple global change factors, which can have wide-ranging consequences for ecosystem structure and functions. Yet, we lack studies on the interacting effects of multiple global change factors on ecological communities - particularly long-term studies in field settings. Here, using a grassland field experiment in temperate North America, we report the interactive effects of four of the most common and pressing global change factors of the Anthropocene (elevated CO2, elevated nitrogen, warming, and summer drought) on soil microbial and free-living soil nematode communities, which together form an extensive share of terrestrial biodiversity. In addition, we measured microbial mass-specific soil enzyme activities related to carbon, nitrogen, and phosphorus cycles. Our results showed that mass-specific soil enzyme activities and their stoichiometry were strongly affected by higher-order interactions among the global change factors. In particular, the three-way interaction among elevated CO2, reduced precipitation, and warming decreased the ratio of carbon-to phosphorus-acquiring enzymes as well as nitrogen-to phosphorus-acquiring enzymes in the soil, indicating a relative increase in the breakdown of organic phosphorus in the soil. We also found that the three-way interaction among elevated CO2, reduced precipitation, and warming altered the predominant decomposition pathway in the soil (towards a bacterial-dominated energy channel in future environments), indicated by the Channel Index of nematode communities. Further, the three-way interaction among nitrogen fertilization, reduced precipitation, and warming enhanced acid phosphatase (related to the P cycle). Nematode density increased at elevated nitrogen and ambient CO2 as well as at ambient nitrogen and elevated CO2, whereas it did not differ from controls at elevated nitrogen and elevated CO2. Changes in microbial biomass were mainly driven by the additive effects of elevated CO2 and temperature. Our results reveal various ways in which global change factors affect (both additively and interactively) soil biotic responses mainly via altering nutrient demands of soil microorganisms and changing soil community structure and energy channels.

Abstract

Loss of plant diversity has an impact on ecosystems worldwide, but we lack a mechanistic understanding of how this loss may influence below-ground biota and ecosystem functions across contrasting ecosystems in the long term. We used the longest running biodiversity manipulation experiment across contrasting ecosystems in existence to explore the below-ground consequences of 19 years of plant functional group removals for each of 30 contrasting forested lake islands in northern Sweden. We found that, against expectations, the effects of plant removals on the communities of key groups of soil organisms (bacteria, fungi and nematodes), and organic matter quality and soil ecosystem functioning (decomposition and microbial activity) were relatively similar among islands that varied greatly in productivity and soil fertility. This highlights that, in contrast to what has been shown for plant productivity, plant biodiversity loss effects on below-ground functions can be relatively insensitive to environmental context or variation among widely contrasting ecosystems.

Abstract

Although diversity-dependent plant-soil feedbacks (PSFs) may contribute significantly to plant diversity effects on ecosystem functioning, the influences of underlying abiotic and biotic mechanistic pathways have been little explored to date. Here, we assessed such pathways with a PSF experiment using soil conditioned for >= 12 yr from two grassland biodiversity experiments. Model plant communities differing in plant species and functional group richness (current plant diversity treatment) were grown in soils conditioned by plant communities with either low- or high-diversity (soil history treatment). Our results indicate that plant diversity can modify plant productivity through both diversity-mediated plant-plant and plant-soil interactions, with the main driver (current plant diversity or soil history) differing with experimental context. Structural equation modeling suggests that the underlying mechanisms of PSFs were explained to a significant extent by both abiotic and biotic pathways (specifically, soil nitrogen availability and soil nematode richness). Thus, effects of plant diversity loss on plant productivity may persist or even increase over time because of biotic and abiotic soil legacy effects.

Abstract

Anthropogenic global change alters the activity and functional composition of soil communities that are responsible for crucial ecosystem functions and services. Two of the most pervasive global change drivers are drought and nutrient enrichment. However, the responses of soil organisms to interacting global change drivers remain widely unknown. We tested the interactive effects of extreme drought and fertilization on soil biota ranging from microbes to invertebrates across seasons. We expected drought to reduce the activity of soil organisms and fertilization to induce positive bottom-up effects via increased plant productivity. Furthermore, we hypothesized fertilization to reinforce drought effects through enhanced plant growth, resulting in even drier soil conditions. Our results revealed that drought had detrimental effects on soil invertebrate feeding activity and simplified nematode community structure, whereas soil microbial activity and biomass were unaffected. Microbial biomass increased in response to fertilization, whereas invertebrate feeding activity substantially declined. Notably, these effects were consistent across seasons. The dissimilar responses suggest that soil biota differ vastly in their vulnerability to global change drivers. Thus, important ecosystem processes like decomposition and nutrient cycling, which are driven by the interdependent activity of soil microorganisms and invertebrates, may be disrupted under future conditions.

Abstract

Cyanobacterial scums at the surface of the lakes are potentially harmful phenomena with increasing occurrence in the last decades, and the causes that lead to their formation are still an unresolved issue. In order to better understand what triggers the scums, we investigated the effect of several Mg2+ and Ca2+ ion concentrations in promoting them in eight Microcystis aeruginosa strains. The possibility to prevent scum formation by using the ion chelator EDTA was also explored. We found that in some strains the cell aggregation takes place under lower ion source concentrations (20 mM MgSO4 or CaCl2), while in others this phenomenon does not occur even at 60 mM concentration. The scum formation correlated to the amount of extracellular polymeric substances (between 234 and 351 mu g/cell). EDTA failed to prevent the scum formation in most strains, and in turn it caused cell lysis followed by the release of cellular content into the culture medium. We emphasize the relevance of these results for cyanobacterial scum formation in the environment and we also suggest that controlling the salinity of the medium (by manipulating the ion concentration) is a potentially efficient method for biomass harvesting in large ponds/tanks.

Abstract

Molecular plant taxonomy methods have helped to introduce new findings to the original concepts of plant evolution in comparison to traditional classification based on morphological, karyological, and ecological characters. The objective of our study was to determine if a new taxonomic concept developed for the Soldanella genus would also change the traditional knowledge of coenological relations within plant communities and distribution patterns of habitats. Taxa in the genus Soldanella sect. Soldanella from the Carpathian Mts and the adjacent region in the North-Eastern Alps and Bohemian Massif were selected as model representatives. This territory includes the largest concentration of study taxa, namely S. carpatica, S. hungarica, S. major, S. marmarossiensis agg., S. montana, S. oreodoxa, and potentially also some others. However, the ecological characteristics published to date are in conflict with our field observations. Two datasets were combined for the purpose of our study, one of which was based on older and published phytocoenological releves that are now widely available through the European Vegetation Archive (EVA), and the other, which is based on our own data, sampled throughout the distribution area, which specifically targeted the type localities as well as peripheral localities. Analysis of phytocoenological releves significantly extended the older knowledge about the habitat preferences of the studied species. Similarly, due to our detailed population sampling, a view of the geographical distribution and expansion of snowbell distribution boundaries has been added, especially for the Eastern and Southern Carpathian taxa. In revising the older knowledge, the altitudinal range of the selected species must be revised as well. In the majority of cases, our findings broadened the existing knowledge on altitudinal divergence, ecological behaviour and the phytogeographical distribution of the study species. Snowbells considered as typical montane elements in forest habitats were also found at much higher alpine altitudes, e.g. S. carpatica, S. hungarica, S. major, and S. marmarossiensis agg., and vice versa, with taxa considered to be exclusively inhabiting the alpine belt growing in contact forest habitats as well. The spectrum of the studied habitats and plant units show wide ecological valence in the majority of Soldanella species; however, some particular preferences for different substrate types, altitudinal belts, or habitat types were indicated.

Abstract

Desmodesmus maximus (West & G.S.West) Hegewald, D. perforatus (Lemmermann) E.Hegewald and D. tropicus (W.B.Crow) E.Hegewald form the series Maximi within the genus Desmodesmus. Desmodesmus tropicus is a rare species although it is widely distributed in tropical regions including South-East Asia, South America and the USA. It is less common in temperate fresh waters, known only from Ukraine. In this study, we report for the first time its presence in the Danube Delta (Puiu Lake), Romania. The morphology and molecular phylogeny of two newly isolated strains were studied in relation to other strains of the genus Desmodesmus, series Maximi. Cell wall structures (rosettes, spines, tubes, honeycomb-shaped mesh with hexagonal units) which are important in the taxonomy of these algae were investigated by light-, scanning- and transmission electron microscopy. The phylogenetic position of the strains in the Algae and Cyanobacteria Culture Collection of the Institute of Biological Research was assessed using 18S rDNA sequences, ITS2 primary and secondary structures and by analysis of Compensatory Base Changes. Morphological traits and measurements of cells, coenobia and spines matched the description of D. tropicus, although some differences from the established morphological key (ridge-like structures resembling fine ribs) were also noticed. Identification as D. tropicus var. longiclathratus (Tell) Jeon & Hegewald was based on the presence of inner spines on four-celled and especially on eight-celled coenobia. The ITS2 sequence and secondary structure phylogeny supported the assignment of both AICB strains to D. tropicus, with no divergence from other D. tropicus sequences to support the identification of var. longiclathratus. Nevertheless, the morphological measurements and the ITS2 primary and secondary structure data indicated two distinct subclusters within D. tropicus, and a new possible taxon within the series Maximi.

Abstract

Extensive biodiversity conservation efforts in Europe resulted in the recent establishment of the ecological network of protected areas Natura 2000. However, it remains unclear how such protected areas reflect the distribution of soil biodiversity, which represents a substantial fraction of terrestrial biodiversity and drives a plethora of ecosystem services. Here we analyzed and compared different metrics of soil nematode taxonomic diversity, i.e., taxon richness, Shannon Diversity Index, Shannon Evenness (all based on supraspecific diversity), and functional diversity, i.e., Maturity Index (environmental disturbance), Structure Index (food web complexity), Enrichment Index (system enrichment), and Channel Index (dominant decomposition pathway of soil organic matter) in 16 grasslands assigned to two Natura 2000 priority habitat types and 14 grasslands assigned to five Natura 2000 non-priority habitat types in Romania. Nematode communities consisted of a total of 123 taxa (115 genera and 8 suprageneric taxa). We found no significant difference in nematode taxonomic and functional diversity between grasslands assigned to Natura 2000 priority and non-priority habitats, suggesting that this categorization does not reflect nematode diversity patterns.

Abstract

We aimed to detect species distribution patterns at landscape level that have arisen following the colonisation of a mine spoil heap (MSH) by macrolichens. All taxa occurring on various substrates and the degree of occupancy by different vegetation patch types were recorded at a resolution of 50 m x 50 m within a regular square grid of 25 ha, which extended over a 60-year-old abandoned MSH and its adjacent agro-pastoral area. The fraction of MSH was the most important predictor of the lichen composition and richness at grid cell level, followed by the terrain slope and the proportion of heathland. Almost all lichen taxa positively correlated with the MSH fraction were terricolous, fruticose, oligotrophilous, acidophilous species that occurred preferentially on the steep, barren slopes. The few corticolous, nitrophilous species were negatively correlated with the MSH fraction. Except for the corticolous and saprophytic species, the proportion of MSH and the elevation range had each a positive effect on both total and terricolous lichen richness. Conversely, taxonomic distinctness displayed an opposite pattern. Such a contrast was determined by the numerous conspecific (Cladonia) lichens occurring on the steeper MSH slopes, with scarce vegetation. A conspicuous nestedness, but no pattern of species turnover, was detected along the main ecological gradient. This was due to both the corticolous/saprophytic species shared with the adjacent, tailings-free habitats and the terricolous/saxicolous lichens dispersed from proximal source-habitats. The MSH studied can be considered a hotspot for lichen species richness but not for taxonomic diversity.

Abstract

The landscape at the Roman Archaeological Site from Moigrad-Porolissum, Romania, is nowadays mostly forested. But how did it look during the Roman period (106-275 AD)? Also, how can multispectral imagery and laser scanning be combined more effectively to detect the signatures of ancient sub-surface archaeological remains? This study employed WorldView2 satellite and LiDAR (Light Detection And Ranging) data to explore current remotely sensed vegetation and terrain proxies. These helped identify past anthropogenic signatures embedded within the landscape for reconstructing the ancient engineered environment. The spectral vegetation and terrain patterns revealed 227 marks (36256.22 m) relevant for the historical landscape, of which 182 correspond to ancient sub-surface features. In open landscapes, the two techniques had equivalent results, while LiDAR provided better detection rates in shrubland patches and forests. Their successive application is an advantageous strategy for optimizing costs. The satellite imagery is employed first, followed by the density analysis of the results, while the more expensive laser-based data collection can be focused on the problematic or promising areas. The vegetation and terrain marks revealed the intricate and extensive ancient defensive system that extended on over 24.5 km(2). Their strategic functions, requiring visibility between and around them, suggest large-scale deforestation (probably over 1 km around the structures). Thus, in contrast to the present forest dominance, it appears that in the 2nd and 3rd centuries AD, at Porolissum there was an anthropogenic open landscape covering over 2158 ha, with urbanization and intense military activity on 198.76 ha.

Abstract

Although diversity-dependent plant–soil feedbacks (PSFs) may contribute significantly to plant diversity effects on ecosystem functioning, the influences of underlying abiotic and biotic mechanistic pathways have been little explored to date. Here, we assessed such pathways with a PSF experiment using soil conditioned for ≥12 yr from two grassland biodiversity experiments. Model plant communities differing in plant species and functional group richness (current plant diversity treatment) were grown in soils conditioned by plant communities with either low- or high-diversity (soil history treatment). Our results indicate that plant diversity can modify plant productivity through both diversity-mediated plant–plant and plant–soil interactions, with the main driver (current plant diversity or soil history) differing with experimental context. Structural equation modeling suggests that the underlying mechanisms of PSFs were explained to a significant extent by both abiotic and biotic pathways (specifically, soil nitrogen availability and soil nematode richness). Thus, effects of plant diversity loss on plant productivity may persist or even increase over time because of biotic and abiotic soil legacy effects. © 2019 The Authors.

Abstract

Ecological communities are increasingly confronted with multiple global change factors, which can have wide-ranging consequences for ecosystem structure and functions. Yet, we lack studies on the interacting effects of multiple global change factors on ecological communities – particularly long-term studies in field settings. Here, using a grassland field experiment in temperate North America, we report the interactive effects of four of the most common and pressing global change factors of the Anthropocene (elevated CO2, elevated nitrogen, warming, and summer drought)on soil microbial and free-living soil nematode communities, which together form an extensive share of terrestrial biodiversity. In addition, we measured microbial mass-specific soil enzyme activities related to carbon, nitrogen, and phosphorus cycles. Our results showed that mass-specific soil enzyme activities and their stoichiometry were strongly affected by higher-order interactions among the global change factors. In particular, the three-way interaction among elevated CO2, reduced precipitation, and warming decreased the ratio of carbon-to phosphorus-acquiring enzymes as well as nitrogen-to phosphorus-acquiring enzymes in the soil, indicating a relative increase in the breakdown of organic phosphorus in the soil. We also found that the three-way interaction among elevated CO2, reduced precipitation, and warming altered the predominant decomposition pathway in the soil (towards a bacterial-dominated energy channel in future environments), indicated by the Channel Index of nematode communities. Further, the three-way interaction among nitrogen fertilization, reduced precipitation, and warming enhanced acid phosphatase (related to the P cycle). Nematode density increased at elevated nitrogen and ambient CO2 as well as at ambient nitrogen and elevated CO2, whereas it did not differ from controls at elevated nitrogen and elevated CO2. Changes in microbial biomass were mainly driven by the additive effects of elevated CO2 and temperature. Our results reveal various ways in which global change factors affect (both additively and interactively)soil biotic responses mainly via altering nutrient demands of soil microorganisms and changing soil community structure and energy channels. © 2019 Elsevier Ltd

Abstract

Desmodesmus maximus (West & G.S.West) Hegewald, D. perforatus (Lemmermann) E.Hegewald and D. tropicus (W.B.Crow) E.Hegewald form the series Maximi within the genus Desmodesmus. Desmodesmus tropicus is a rare species although it is widely distributed in tropical regions including South-East Asia, South America and the USA. It is less common in temperate fresh waters, known only from Ukraine. In this study, we report for the first time its presence in the Danube Delta (Puiu Lake), Romania. The morphology and molecular phylogeny of two newly isolated strains were studied in relation to other strains of the genus Desmodesmus, series Maximi. Cell wall structures (rosettes, spines, tubes, honeycomb-shaped mesh with hexagonal units) which are important in the taxonomy of these algae were investigated by light-, scanning- and transmission electron microscopy. The phylogenetic position of the strains in the Algae and Cyanobacteria Culture Collection of the Institute of Biological Research was assessed using 18S rDNA sequences, ITS2 primary and secondary structures and by analysis of Compensatory Base Changes. Morphological traits and measurements of cells, coenobia and spines matched the description of D. tropicus, although some differences from the established morphological key (ridge-like structures resembling fine ribs) were also noticed. Identification as D. tropicus var. longiclathratus (Tell) Jeon & Hegewald was based on the presence of inner spines on four-celled and especially on eight-celled coenobia. The ITS2 sequence and secondary structure phylogeny supported the assignment of both AICB strains to D. tropicus, with no divergence from other D. tropicus sequences to support the identification of var. longiclathratus. Nevertheless, the morphological measurements and the ITS2 primary and secondary structure data indicated two distinct subclusters within D. tropicus, and a new possible taxon within the series Maximi. © 2019, © 2019 British Phycological Society.

Abstract

The Cypress Jewel Beetle (Lamprodila (Palmar) festiva subsp. festiva (Linnaeus 1767)), is a formerly rare and protected species, present in the red lists of most Western European countries. In Romania, before 2015 it was present only in the South-Western region and less than 10 specimens were collected. The species recently changed its host plants from wild Cupressaceae (Juniperus sp., Cupressus sp.) to cultivated Cupressaceae, the most affected one being Thuja occidentalis. In 2013 the first big invasion was recorded in Budapest, Hungary. In 2015, the species was found in two horticultural seedling stations in Bucharest. More recently, in 2017, it was recorded in Cluj-Napoca, and in 2018, in Timișoara, Oradea, Suceava. The article provides a short description of the adults, larva and the signs of the attacks on the host plants. The potential distribution of the species is discussed based on climate niche modelling. The daily behaviour of the adults and their preferences, based on observations, is also discussed. Equally, the bioethics related to this attack is analysed. Copyright Ruicănescu & Stoica.

Abstract

One specimen of Anthaxia (Anthaxia) suzannae Théry, 1942 was collected on a meadow, near Cluj-Napoca, Romania. Although this species is widely distributed in Europe, this is the first record of its presence in Romania. A short description of the species, and some considerations about the biology and zoogeography are given. © 2018 De Gruyter Open Ltd. All rights reserved.

Abstract

Agrilus guerini Lacordaire is recorded for the first time in Romania, in Southern Transylvania. The occurrence of this species in Romania was expected, as it is present in neighbouring countries. A short description, some aspects of biology and ecology, and a distribution map of this species in Romania are given. © 2018 De Gruyter Open Ltd. All rights reserved.

Abstract

Through litter decomposition enormous amounts of carbon is emitted to the atmosphere. Numerous large-scale decomposition experiments have been conducted focusing on this fundamental soil process in order to understand the controls on the terrestrial carbon transfer to the atmosphere. However, previous studies were mostly based on site-specific litter and methodologies, adding major uncertainty to syntheses, comparisons and meta-analyses across different experiments and sites. In the TeaComposition initiative, the potential litter decomposition is investigated by using standardized substrates (Rooibos and Green tea) for comparison of litter mass loss at 336 sites (ranging from -9 to +26 degrees C MAT and from 60 to 3113 mm MAP) across different ecosystems. In this study we tested the effect of climate (temperature and moisture), litter type and land-use on early stage decomposition (3 months) across nine biomes. We show that litter quality was the predominant controlling factor in early stage litter decomposition, which explained about 65% of the variability in litter decomposition at a global scale. The effect of climate, on the other hand, was not litter specific and explained <0.5% of the variation for Green tea and 5% for Rooibos tea, and was of significance only under unfavorable decomposition conditions (i.e. xeric versus mesic environments). When the data were aggregated at the biome scale, climate played a significant role on decomposition of both litter types (explaining 64% of the variation for Green tea and 72% for Rooibos tea). No significant effect of land-use on early stage litter decomposition was noted within the temperate biome. Our results indicate that multiple drivers are affecting early stage litter mass loss with litter quality being dominant. In order to be able to quantify the relative importance of the different drivers over time, long-term studies combined with experimental trials are needed. (C) 2018 Elsevier B.V. All rights reserved.

Abstract

Understanding how loss of biodiversity affects ecosystem functioning, and thus the delivery of ecosystem goods and services, has become increasingly necessary in a changing world. Considerable recent attention has focused on predicting how biodiversity loss simultaneously impacts multiple ecosystem functions (that is, ecosystem multifunctionality), but the ways in which these effects vary across ecosystems remain unclear. Here, we report the results of two 19-year plant diversity manipulation experiments, each established across a strong environmental gradient. Although the effects of plant and associated fungal diversity loss on individual functions frequently differed among ecosystems, the consequences of biodiversity loss for multifunctionality were relatively invariant. However, the context-dependency of biodiversity effects also worked in opposing directions for different individual functions, meaning that similar multifunctionality values across contrasting ecosystems could potentially mask important differences in the effects of biodiversity on functioning among ecosystems. Our findings highlight that an understanding of the relative contribution of species or functional groups to individual ecosystem functions among contrasting ecosystems and their interactions (that is, complementarity versus competition) is critical for guiding management efforts aimed at maintaining ecosystem multifunctionality and the delivery of multiple ecosystem services.

Abstract

Groundwater is an essential public and drinking water supply and its protection is a goal for global policies. Here, we investigated the presence and prevalence of antibiotic residues, antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), and microbial contamination in groundwater environments at various distances from urban areas. Antibiotic concentrations ranged from below detection limit to 917 ng/L, being trimethoprim, macrolide, and sulfonamide the most abundant antibiotic classes. A total of eleven ARGs (aminoglycoside, beta-lactam, chloramphenicol, Macrolide-Lincosamide-Streptogramin B - MLSB, sulfonamide, and tetracycline), one antiseptic resistance gene, and two MGEs were detected by qPCR with relative abundances ranging from 6.61 x 10(-7) to 2.30 x 10(-1) copies/16S rRNA gene copies. ARGs and MGEs were widespread in the investigated groundwater environments, with increased abundances not only in urban, but also in remote areas. Distinct bacterial community profiles were observed, with a higher prevalence of Betaproteobacteria and Bacteroidetes in the less-impacted areas, and that of Firmicutes in the contaminated groundwater. The combined characteristics of increased species diversity, distinct phylogenetic composition, and the possible presence of fecal and/or pathogenic bacteria could indicate different types of contamination. Significant correlations between ARGs, MGEs and specific taxa within the groundwater bacterial community were identified, revealing the potential hosts of resistance types. Although no universal marker gene could be determined, a co-selection of int1, qacE Delta 1 and still genes, a proxy group for anthropogenic pollution, with the tetC, tetO, tetW resistance genes was identified. As the tet group was observed to follow the pattern of environmental contamination for the groundwater samples investigated in this study, our results strongly support the proposal of this group of genes as an environmental tracer of human impact. Overall, the present study investigated several emerging contaminants in groundwater habitats that may be included in monitoring programs to enable further regulatory and protection measures. (C) 2018 Elsevier Ltd. All rights reserved.

Abstract

The aim of this paper is to describe a new variant of Janthinobacterium lividum - ROICE173, isolated from Antarctic snow, and to investigate the antimicrobial effect of the crude bacterial extract against 200 multi-drug resistant (MDR) bacteria of both clinical and environmental origin, displaying various antibiotic resistance patterns. ROICE173 is extremotolerant, grows at high pH (5.5-9.5), in high salinity (3%) and in the presence of different xenobiotic compounds and various antibiotics. The best violacein yield (4.59 +/- 0.78 mg.g(-1) wet biomass) was obtained at 22 degrees C, on R2 broth supplemented with 1% glycerol. When the crude extract was tested for antimicrobial activity, a clear bactericidal effect was observed on 79 strains (40%), a bacteriostatic effect on 25 strains (12%) and no effect in the case of 96 strains (48%). A very good inhibitory effect was noticed against numerous MRSA, MSSA, Enterococci, and Enterobacteriaceae isolates. For several environmental E. coli strains, the bactericidal effect was encountered at a violacein concentration below of what was previously reported. A different effect (bacteriostatic vs. bactericidal) was observed in the case of Enterobacteriaceae isolated from raw vs. treated wastewater, suggesting that the wastewater treatment process may influence the susceptibility of MDR bacteria to violacein containing bacterial extracts.

Abstract

A limited number of studies have investigated the biodiversity in deep continental hyperthermal aquifers and its influencing factors. Here, we present the first description of microbial communities inhabiting the Pannonian and Triassic hyperthermal aquifers from the Western Plain of Romania, the first one being considered a deposit of fossilized waters, while the latter is embedded in the hydrological cycle due to natural refilling. The 11 investigated drillings have an open interval between 952 and 3432 m below the surface, with collected water temperatures ranging between 47 and 104 A degrees C, these being the first microbial communities characterized in deep continental water deposits with outflow temperatures exceeding 80 A degrees C. The abundances of bacterial 16S rRNA genes varied from approximately 10(5)-10(6) mL(-1) in the Pannonian to about 10(2)-10(4) mL(-1) in the Triassic aquifer. A 16S rRNA gene metabarcoding analysis revealed distinct microbial communities in the two water deposits, especially in the rare taxa composition. The Pannonian aquifer was dominated by the bacterial genera Hydrogenophilus and Thermodesulfobacterium, together with archaeal methanogens from the Methanosaeta and Methanothermobacter groups. Firmicutes was prevalent in the Triassic deposit with a large number of OTUs affiliated to Thermoanaerobacteriaceae, Thermacetogenium, and Desulfotomaculum. Species richness, evenness, and phylogenetic diversity increased alongside with the abundance of mesophiles, their presence in the Triassic aquifer being most probably caused by the refilling with large quantities of meteoric water in the Carpathian Mountains. Altogether, our results show that the particular physico-cheminal characteristics of each aquifer, together with the water refilling possibilities, seem to determine the microbial community structure.

Abstract

Aims Are there trends of increasing/decreasing dispersion of single, categorical traits related to early/late-successional species between stages of community development? If yes, are these trends dependent on species pool extension and habitat scale? Is there a consistent reduction in single trait convergence or divergence in any seral stage when scaling down from ecological to local species pool? Methods Presence of all vascular species rooted within plots of 5 x 5 m was recorded in assemblages of exposed mining spoils (EMS) and heathlands (HTL), which form a chronosequence on two abandoned ore tailing heaps located close to each other in the south-eastern Carpathians (Romania). Fifteen nominal, trait attributes of plant species co-occurring in the two seral assemblages were collected from available databases and subsequently classified as either successionally 'pioneer' or 'mature'. The strength of single trait convergence or divergence was estimated by comparison with null plant assemblages at patch type (meta-community) level by reference to the ecological or local species pool, and at community level. Important Findings At patch type level, all pioneer and mature trait attributes (apart from short life span), with significant variation between the two seral stages, increased and, respectively, decreased in dispersion irrespective of species pool extension. However, these trends were more conspicuous when using the ecological species pool, very likely due to relaxation in abiotic filtering and dispersal limitation. At community level, no consistent trends were observed between EMS and HTL assemblages, probably because most trait attributes were sorted by microenvironmental filters displaying high variation, like topography or habitat patch geometry. In both seral stages, there was a general weakening of trait convergence or divergence at patch type level when scaling down from the ecological to the local species pool, which was due to niche space contraction. At community level, there was a trend of rise in dispersion of pioneer attributes along the observed chronosequence, presumably imputable to increasing competition for light and underground water, but an opposite trend of dispersion drop in mature attributes was not so evident. Based on these findings, we proposed two rules of thumb concerning the expected changes in dispersion of trait attributes at patch level along successions and between levels of species pool extension. In conclusion, trends in the successional dynamics of pioneer and mature trait dispersion are clearly detectable at meta-community level, especially by reference to the ecological species pool. Habitat scale and species pool extension are key factors to consider and report when estimating the magnitude of single trait dispersion.

Abstract

Plant assemblages and successional pathways were studied on large, abandoned ore mining heaps located around the open-cast pits from Rosia Montana., Romania. Four differently aged mining spoils with relatively homogenous substrate and one control plot were investigated using the chronosequence approach. The effects of the waste dump age, slope steepness, position on slope, terrain curvature and potential solar radiation on the plant species composition of different assemblages from spontaneously revegetated primary sites were evaluated. Releves were grouped into floristically similar vegetation types using non-hierarchical cluster analysis (Fuzzy c-Means). The ecological interpretation of the plant assemblages was performed through indicator species values (IndVal) and non-metric multidimensional scaling (NMDS). This study reinforces several important concepts about the deterministic patterns of primary succession. First, the multiple comparisons between plant assemblages reveal that the highest differences are caused by the age of the spoil heap and substrate acidity. Further differences, lower but significant, are determined by terrain curvature and potential solar radiation. Also, environmental factors acting prior to the establishment of the observed plant assemblages (age, substrate pH, slope steepness and position on slope), have subsequently induced a structural differentiation in terms of species richness, vegetation cover and relative cover of the N-fixing species. There are two main possible successional pathways, determined, most likely, by the long term changes in substrate pH under the influence of both abiotic and biotic factors. Two successional series were clearly distinguished: the weakly acidophilous series, comprising communities of Poo compresae-Tussilaginetum farfarae, Festuco rubrae-Agrostietum capillaris and Carpino-Fagetum, and respectively the acidophilous series, comprising plant assemblages of Deschampsietum flexuosae, Pinetum sylvestris sensu lato, Festuco rubrae-Genistetum sagittalis and Vaccinio-Callunetum vulgaris. The spontaneous succession progresses towards woodland and appears to be an ecologically suitable way of restoring the studied disturbed sites, because species typical of natural and semi-natural vegetation have become dominant over time. Within our study area, spontaneous vegetation succession resulted in plant assemblages that resemble the original semi-natural vegetation.

Abstract

Plant assemblages and successional pathways were studied on large, abandoned ore mining heaps located around the open-cast pits from Roşia Montană, Romania. Four differently aged mining spoils with relatively homogenous substrate and one control plot were investigated using the chronosequence approach. The effects of the waste dump age, slope steepness, position on slope, terrain curvature and potential solar radiation on the plant species composition of different assemblages from spontaneously revegetated primary sites were evaluated. Relevés were grouped into floristically similar vegetation types using non-hierarchical cluster analysis (Fuzzy c-Means). The ecological interpretation of the plant assemblages was performed through indicator species values (IndVal) and non-metric multidimensional scaling (NMDS). This study reinforces several important concepts about the deterministic patterns of primary succession. First, the multiple comparisons between plant assemblages reveal that the highest differences are caused by the age of the spoil heap and substrate acidity. Further differences, lower but significant, are determined by terrain curvature and potential solar radiation. Also, environmental factors acting prior to the establishment of the observed plant assemblages (age, substrate pH, slope steepness and position on slope), have subsequently induced a structural differentiation in terms of species richness, vegetation cover and relative cover of the N-fixing species. There are two main possible successional pathways, determined, most likely, by the long term changes in substrate pH under the influence of both abiotic and biotic factors. Two successional series were clearly distinguished: the weakly acidophilous series, comprising communities of Poo compresae-Tussilaginetum farfarae, Festuco rubrae-Agrostietum capillaris and Carpino-Fagetum, and respectively the acidophilous series, comprising plant assemblages of Deschampsietum flexuosae, Pinetum sylvestris sensu lato, Festuco rubrae-Genistetum sagittalis and Vaccinio-Callunetum vulgaris. The spontaneous succession progresses towards woodland and appears to be an ecologically suitable way of restoring the studied disturbed sites, because species typical of natural and semi-natural vegetation have become dominant over time. Within our study area, spontaneous vegetation succession resulted in plant assemblages that resemble the original semi-natural vegetation. © 2018, Springer International Publishing AG, part of Springer Nature.

Abstract

The paper contributes to the knowledge of forest history during the Dacian Civilization, focusing on the mountainous region where the Dacian fortresses of the Orăştie Mountains were located. Some historical and archaeological evidence has been reviewed regarding the use of trees by the Dacians. Emphasis was laid on the analysis of the papers that present indirect evidence in this respect, namely the palynological sequences from the region, belonging to the period of interest, the Subatlantic. On the basis of these, it was possible to reconstruct the natural environment and especially the forest dynamics in the studied region. The palynological analyses performed demonstrate the millennial age of the forests in the area, and aim at further comparisons with the current situation of forests in the region. © 2018, Babes-Bolyai University, "Alexandru Borza" Botanic Garden. All rights reserved.

Abstract

This paper presents, on the basis of floristic and phytocoenotic data from field studies and the literature, the real vegetation map of Molhașul Mare from Izbuc peat bog, in the Apuseni Muntains. This oligotrophic bog, situated at 46°35’29” N and 22°45’43” E, is the most representative from this area and the least impacted by human activities, being therefore declared a Botanical Reserve. On its surface of c.8 ha, there have been identified, described on floristic and ecological grounds and mapped at 1:1000 scale, 9 plant community types that correspond to 4 Natura 2000 habitat types: 7110*, 7149, 7150 and 91D0*. The vegetation map will be useful for monitoring the conservation status of the plant communities and habitats and will facilitate the establishment of suitable conservation measures for the protection of the peat bog. © 2018, Babes-Bolyai University, "Alexandru Borza" Botanic Garden. All rights reserved.

Abstract

This report describes the Romanian Grassland Database (RGD), registered under EU-RO-008 in the Global Index of Vegetation-Plot Databases (GIVD). This collaborative initiative aims to collect all available vegetationplot data (relevés) of grasslands and other open habitats from the territory of Romania to provide them for science, nationally and internationally, e.g. via the European Vegetation Archive (EVA) and the global database "sPlot". The database mainly contains vegetation-plots from not only wet, mesic, dry, saline, alpine and rocky grasslands, but also other vegetation types like heathlands, mires, ruderal, segetal, aquatic and cryptogamdominated vegetation. Currently, 21,685 relevés have mainly been digitised from literature sources (90%), while the remainder comes from individual unpublished sources (10%). We report on the background and history of the RGD, explain its "Data Property and Governance Rules" under which data are contributed and retrieved, and outline how the RGD can contribute to research in the fields of vegetation ecology, macroecology and conservation. © 2018 Gebrüder Borntraeger.

Abstract

Climate warming is predicted to alter the structure, stability, and functioning of food webs(1-5). Yet, despite the importance of soil food webs for energy and nutrient turnover in terrestrial ecosystems, the effects of warming on these food webs-particularly in combination with other global change drivers-are largely unknown. Here, we present results from two complementary field experiments that test the interactive effects of warming with forest canopy disturbance and drought on energy flux in boreal-temperate ecotonal forest soil food webs. The first experiment applied a simultaneous above-and belowground warming treatment (ambient, +1.7 degrees C, +3.4 degrees C) to closed-canopy and recently clear-cut forest, simulating common forest disturbance(6). The second experiment crossed warming with a summer drought treatment (-40% rainfall) in the clear-cut habitats. We show that warming reduces energy flux to microbes, while forest canopy disturbance and drought facilitates warming-induced increases in energy flux to higher trophic levels and exacerbates the reduction in energy flux to microbes, respectively. Contrary to expectations, we find no change in whole-network resilience to perturbations, but significant losses in ecosystem functioning. Warming thus interacts with forest disturbance and drought, shaping the energetic structure of soil food webs and threatening the provisioning of multiple ecosystem functions in boreal-temperate ecotonal forests.

Abstract

Present-day terrestrial analogue sites are crucial ground truth proxies for studying life in geochemical conditions close to those assumed to be present on early Earth or inferred to exist on other celestial bodies (e.g. Mars, Europa). Although hypersaline sapropels are border-of-life habitats with moderate occurrence, their microbiological and physicochemical characterization lags behind. Here, we study the diversity of life under low water activity by describing the prokaryotic communities from two disparate hypersaline sapropels (Transylvanian Basin, Romania) in relation to geochemical milieu and pore water chemistry, while inferring their role in carbon cycling by matching taxa to known taxon-specific biogeochemical functions. The polyphasic approach combined deep coverage SSU rRNA gene amplicon sequencing and bioinformatics with RT-qPCR and physicochemical investigations. We found that sapropels developed an analogous elemental milieu and harbored prokaryotes affiliated with fifty-nine phyla, among which the most abundant were Proteobacteria, Bacteroidetes and Chloroflexi. Containing thirty-two candidate divisions and possibly undocumented prokaryotic lineages, the hypersaline sapropels were found to accommodate one of the most diverse and novel ecosystems reported to date and may contribute to completing the phylogenetic branching of the tree of life.

Abstract

Climate warming is predicted to alter species interactions, which could potentially lead to extinction events. However, there is an ongoing debate whether the effects of warming on biodiversity may be moderated by biodiversity itself. We tested warming effects on soil nematodes, one of the most diverse and abundant metazoans in terrestrial ecosystems, along a gradient of environmental complexity created by a gradient of plant species richness. Warming increased nematode species diversity in complex (16-species mixtures) plant communities (by similar to 36%) but decreased it in simple (monocultures) plant communities (by similar to 39%) compared to ambient temperature. Further, warming led to higher levels of taxonomic relatedness in nematode communities across all levels of plant species richness. Our results highlight both the need for maintaining species-rich plant communities to help offset detrimental warming effects and the inability of species-rich plant communities to maintain nematode taxonomic distinctness when warming occur.

Abstract

Aims Climate warming raises the probability of range expansions of warm-adapted temperate species into areas currently dominated by coldadapted boreal species. Warming-induced plant range expansions could partly depend on how warming modifies relationships with soil biota that promote plant growth, such as by mineralizing nutrients. Here, we grew two pairs of congeneric herbaceous plants species together in soil with a 5-year warming history (ambient, +1.7 degrees C, +3.4 degrees C) and related their performances to plant-beneficial soil biota. Methods Each plant pair belonged to either the mid-latitude temperate climate or the higher latitude southern boreal climate. Warmed soils were extracted from a chamberless heating experiment at two field sites in the temperate-boreal ecotone of North America. To isolate potential effects of different soil warming histories, air temperature for the greenhouse experiment was identical across soils. We hypothesized that soil with a 5-year warming history in the field would enhance the performance of temperate plant species more than boreal plant species and expected improved plant performances to have positive associations with plant growth-promoting soil biota (microbial-feeding nematodes and arbuscular mycorrhizal fungi). Important Findings Our main hypothesis was partly confirmed as only one temperate species performed better in soil with warming history than in soil with history of ambient temperature. Further, this effect was restricted to the site with higher soil water content in the growing season of the sampling year (prior to soil collection). One of the boreal species performed consistently worse in previously warmed soil, whereas the other species showed neutral responses to soil warming history. We found a positive correlation between the density of microbial-feeding nematodes and the performance of one of the temperate species in previously wetter soils, but this correlation was negative at the site with previously drier soil. We found no significant correlations between the performance of the other temperate species as well as the two boreal species and any of the studied soil biota. Our results indicate that soil warming can modify the relation between certain plant species and microbial-feeding nematodes in given soil edaphic conditions, which might be important for plant performance in the temperate-boreal ecotone.

Abstract

Antimicrobial resistance represents a growing and significant public health threat, which requires a global response to develop effective strategies and mitigate the emergence and spread of this phenomenon in clinical and environmental settings. We investigated, therefore, the occurrence and abundance of several antibiotics and antibiotic resistance genes (ARGs), as well as bacterial community composition in wastewater effluents from different hospitals located in the Cluj County, Romania. Antibiotic concentrations ranged between 3.67 and 53.05 mu g L-1, and the most abundant antibiotic classes were beta-lactams, glycopeptides, and trimethoprim. Among the ARGs detected, 14 genes confer resistance to beta-lactams, aminoglycosides, chloramphenicol, macrolide-lincosamide-streptogramin B (MLSB) antibiotics, sulfonamides, and tetracyclines. Genes encoding quaternary ammonium resistance and a transposon-related element were also detected. The sulI and qacE Delta 1 genes, which confer resistance to sulfonamides and quaternary ammonium, had the highest relative abundance with values ranging from 5.33 x 10(-2) to 1.94 x 10(-1) and 1.94 x 10(-2) to 4.89 x 10(-2) copies/16 rRNA gene copies, respectively. The dominant phyla detected in the hospital wastewater samples were Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria. Among selected hospitals, one of them applied an activated sludge and chlorine disinfection process before releasing the effluent to the municipal collector. This conventional wastewater treatment showed moderate removal efficiency of the studied pollutants, with a 55-81% decrease in antibiotic concentrations, 1-3 order of magnitude lower relative abundance of ARGs, but with a slight increase of some potentially pathogenic bacteria. Given this, hospital wastewaters (raw or treated) may contribute to the spread of these emerging pollutants in the receiving environments. To the best of our knowledge, this study quantified for the first time the abundance of antibiotics and ARGs in wastewater effluents from different Romanian hospitals. (C) 2017 Elsevier Ltd. All rights reserved.

Abstract

The magnitude and frequency of extreme weather events are predicted to increase in the future due to ongoing climate change. In particular, floods and droughts resulting from climate change are thought to alter the ecosystem functions and stability. However, knowledge of the effects of these weather events on soil fauna is scarce, although they are key towards functioning of terrestrial ecosystems. Plant species richness has been shown to affect the stability of ecosystem functions and food webs. Here, we used the occurrence of a natural flood in a biodiversity grassland experiment that was followed by a simulated summer drought experiment, to investigate the interactive effects of plant species richness, a natural flood, and a subsequent summer drought on nematode communities. Three and five months after the natural flooding, effects of flooding severity were still detectable in the belowground system. We found that flooding severity decreased soil nematode food-web structure (loss of K-strategists) and the abundance of plant feeding nematodes. However, high plant species richness maintained higher diversity and abundance of higher trophic levels compared to monocultures throughout the flood. The subsequent summer drought seemed to be of lower importance but reversed negative flooding effects in some cases. This probably occurred because the studied grassland system is well adapted to drought, or because drought conditions alleviated the negative impact of long-term soil waterlogging. Using soil nematodes as indicator taxa, this study suggests that high plant species richness can maintain soil food web complexity after consecutive environmental perturbations.

Abstract

In five grasslands and six forests located in the `Natura 2000' protected area Apuseni (Romania) 191 nematode taxa (132 species) were found. Nematode fauna differed according to geographical location of the sampling sites, ecosystems and `Natura 2000' habitat types. Nematode fauna in forests was more diverse than in grasslands. Plant feeders, bacterial feeders and omnivorous nematodes dominated in the samples. General opportunists were more frequent in forests, as opposite to persisters, which were more abundant in grasslands. Maturing and structured conditions of the soil food web were revealed. The differentiation between types of ecosystems and habitats based on prevailing decomposition channel in soil was not possible.

Abstract

This report describes the biodiversity and ecology of microbial mats developed in thermal gradients (20 to 65 degrees C) in the surroundings of three drillings (Chiraleu [CH], Ciocaia [CI], and Mihai Bravu [MB]) tapping a hyperthermal aquifer in Romania. Using a metabarcoding approach, 16S rRNA genes were sequenced from both DNA and RNA transcripts (cDNA) and compared. The relationships between the microbial diversity and the physicochemical factors were explored. Additionally, the cDNA data were used for in silico functionality predictions, bringing new insights into the functional potential and dynamics of these communities. The results showed that each hot spring determined the formation of distinct microbial communities. In the CH mats (40 to 53 degrees C), the abundance of Cyanobacteria decreased with temperature, opposite to those of Chloroflexi and Proteobacteria. Ectothiorhodospira, Oscillatoria, and methanogenic archaea dominated the CI communities (20 to 65 degrees C), while the MB microbial mats (53 to 65 degrees C) were mainly composed of Chloroflexi, Hydrogenophilus, Thermi, and Aquificae. Alpha-diversity was negatively correlated with the increase in water temperature, while beta-diversity was shaped in each hot spring by the unique combination of physicochemical parameters, regardless of the type of nucleic acid analyzed (DNA versus cDNA). The rank correlation analysis revealed a unique model that associated environmental data with community composition, consisting in the combined effect of Na+, K+, HCO3-, and PO43- concentrations, together with temperature and electrical conductivity. These factors seem to determine the grouping of samples according to location, rather than with the similarities in thermal regimes, showing that other parameters beside temperature are significant drivers of biodiversity. IMPORTANCE Hot spring microbial mats represent a remarkable manifestation of life on Earth and have been intensively studied for decades. Moreover, as hot spring areas are isolated and have a limited exchange of organisms, nutrients, and energy with the surrounding environments, hot spring microbial communities can be used in model studies to elucidate the colonizing potential within extreme settings. Thus, they are of great importance in evolutionary biology, microbial ecology, and exobiology. In spite of all the efforts that have been made, the current understanding of the influence of temperature and water chemistry on the microbial community composition, diversity, and abundance in microbial mats is limited. In this study, the composition and diversity of microbial communities developed in thermal gradients in the vicinity of three hot springs from Romania were investigated, each having particular physicochemical characteristics. Our results expose new factors that could determine the formation of these ecosystems, expanding the current knowledge in this regard.

Abstract

This paper presents the method used to efficiently identify and map previously unknown subsurface remains in a steep, forested, and mostly unexplored area, within the archaeological site of Porolissum, Romania. The remains are part of the defensive system of the ancient Roman Empire frontiers (Roman limes). The complementary use of high-resolution airborne laser scanning derived digital terrain model and visualization techniques enabled the detection of 79 new, subsurface archaeological structures, most of which were confirmed by ground inspection to be key elements of the limes. The best performing methods, achieving detection of the maximum visible extent for over 75% of all features were in descending order: principal component analysis, simple local-relief model, sky-view factor, and positive openness. Analytical hill-shading, slope, negative openness, and hill-shading had a larger proportion of partial detections. The position of these ancient remains supports the hypothesis that this area was extensively deforested, for strategic purposes, during the Roman period. Employing one of the latest remote sensing techniques, we have identified the location of previously unknown, buried ancient structures of the Roman limes in Dacia Province, an essential step for compiling a database necessary for enlisting this Roman limes sector on the World Heritage List.

Abstract

In five grasslands and six forests located in the ‘Natura 2000’ protected area Apuseni (Romania) 191 nematode taxa (132 species) were found. Nematode fauna differed according to geographical location of the sampling sites, ecosystems and ‘Natura 2000’ habitat types. Nematode fauna in forests was more diverse than in grasslands. Plant feeders, bacterial feeders and omnivorous nematodes dominated in the samples. General opportunists were more frequent in forests, as opposite to persisters, which were more abundant in grasslands. Maturing and structured conditions of the soil food web were revealed. The differentiation between types of ecosystems and habitats based on prevailing decomposition channel in soil was not possible. © 2017, Rossiiskaya Akademiya Nauk. All rights reserved.

Abstract

This paper focuses on the distribution of habitats in the Natura 2000 ROSCI0086 Găina-Lucina site, as well as on their conservation status and human impacts. The site analyzed is part of the Natura 2000 Network in Romania and is located in the region of Moldova. It has a total area of 848 ha. The habitat types for which the site has been declared are: 7110* - Active raised bogs, 91D0* - Bog woodland and 91E0* - Alluvial forests with Alnus glutinosa and Fraxinus excelsior (Alno-Padion, Alnion incanae, Salicion albae). Aside from the habitat types listed in the standard form, five additional ones of community interest have been identified: 6520 - Mountain hay meadows, 6510 - Lowland hay meadows (Alopecurus pratensis, Sanguisorba officinalis), 9410 - Acidophilous Picea forests of the montane to alpine levels (Vaccinio-Piceetea), 7140 - Transition mires and quaking bogs and 6430 - Hydrophilous tall herb fringe communities of plains and of the montane to alpine levels. The data collected in the field has served to verify and correct the existing Standard Natura 2000 Form of the site. It represents the scientific foundation of the Management Plan, providing information on the distribution of the habitats, their conservation status, current and potential sources of human impact, and conservation measures needed to achieve and maintain a favourable conservation status for these habitats. © 2017, Babes-Bolyai University, "Alexandru Borza" Botanic Garden. All rights reserved.

Abstract

The paper presents the results of the studies performed in the Natura 2000 site Pădurea Bârnova-Repedea (ROSCI0135), in order to identify and map habitat types and plant species of community interest. Palynological and archaeo-botanical studies in the region were reviewed, in order to assess the presence of the ancient forests. This protected area was designed to preserve forests from two habitats types of community interest, namely Asperulo-Fagetum beech forests and Dacian oak-hornbeam forests, and to shelter a species of wild and endangered orchid, Cypripedium calceolus L. During the field work other Natura 2000 habitats of community interest have been identified: mountain hay meadows, Ponto-Sarmatic steppes and Ponto-Sarmatic deciduous thickets. The information obtained provided new data on the habitats and plant species distribution. Field data were correlated with existing topographic maps and aerial photography. The use of the Geographic Information System allowed translating the field distribution of the species and habitat types into accurate maps, which can be used in the future by the managers of this site for implementing adaptive conservation measures. The human activities with potential impact on this Natura 2000 site have been recorded. The map of current pressures on the site was generated based on these impact categories. © 2017, Babes-Bolyai University, "Alexandru Borza" Botanic Garden. All rights reserved.

Abstract

This study confirms the first certain occurrence of Juncus squarrosus L., an Atlantic species, in the Romanian native flora. Characteristic plant communities with J. squarrosus occur in the Apuseni Mts (Western Romanian Carpathians). At these sites J. squarrosus has the southeastern limit of its European distribution. The identified plant communities with J. squarrosus in Romania are devoid of some Atlantic species present in Western and Central European communities and therefore are assigned to the Nardo-Juncetum squarrosi (Nordh. 1920) Bük. 1942 association. This plant community is a new syntaxon for the Romanian vegetation. © by József Pál Frink 2017.

Abstract

This paper explores the opportunities that arise where forest ecosystem management and cultural heritage monuments protection converge. The case study area for our analysis was the landscape surrounding the Moigrad-Porolissum Archaeological site. We emphasize that an Airborne Laser Scanning (ALS or LiDAR-Light Detection and Ranging) approach to both forest management and cultural heritage conservation is an outstanding tool, assisting policy-makers and conservationists in decision making for integrated planning and management of the environment. LiDAR-derived surface models enabled a synoptic, never-seen-before view of the ancient Roman frontiers defensive systems while also revealing the present forest road network. The thorough and accurate road inventory data are very useful for updating and modifying forest base maps and registries and also for identifying the priority sectors for archaeological discharge. The ability to identify and determine optimal routes for forest management and to locate previously unmapped ancient archaeological remains aids in reducing costs and creating operational efficiencies as well as in complying with the legislation and avoiding infringements. The potential of LiDAR to demonstrate the long-term and comprehensive human impact on wooded areas is discussed. We identified a significant historical landscape change, consisting of a deforestation period, spanning over more than 160 years, during the Roman Period in Dacia (106-271 AD). The transdisciplinary analysis of the LiDAR data provides the base for combining knowledge from archaeology, forestry and environmental history in order to achieve a thorough analysis of the landscape changes and history. In the “nature versus culture” dichotomy, the landscape, outfield areas and forests are primarily perceived as nature, while in reality they are often heavily marked by human impact. LiDAR offers an efficient method for broadening our knowledge regarding the character and extent of human interaction with landscapes – forested or otherwise. © 2017, Editura Silvica. All rights reserved.

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Aim In the alpine life zone, plant diversity is strongly determined by local topography and microclimate. We assessed the extent to which aspect and its relatedness to temperature affect plant species diversity, and the colonization and disappearance of species on alpine summits on a pan-European scale. Location Mountain summits in Europe's alpine life zone. Methods Vascular plant species and their percentage cover were recorded in permanent plots in each cardinal direction on 123 summits in 32 regions across Europe. For a subset from 17 regions, resurvey data and 6-year soil temperature series were available. Differences in temperature sum and Shannon index as well as species richness, colonization and disappearance of species among cardinal directions were analysed using linear mixed-effects and generalised mixed-effects models, respectively. Results Temperature sums were higher in east-and south-facing aspects than in the north-facing ones, while the west-facing ones were intermediate; differences were smallest in northern Europe. The patterns of temperature sums among aspects were consistent among years. In temperate regions, thermal differences were reflected by plant diversity, whereas this relationship was weaker or absent on Mediterranean and boreal mountains. Colonization of species was positively related to temperature on Mediterranean and temperate mountains, whereas disappearance of species was not related to temperature. Main conclusions Thermal differences caused by solar radiation determine plant species diversity on temperate mountains. Advantages for plants on eastern slopes may result from the combined effects of a longer diurnal period of radiation due to convection cloud effects in the afternoon and the sheltered position against the prevailing westerly winds. In northern Europe, long summer days and low sun angles can even out differences among aspects. On Mediterranean summits, summer drought may limit species numbers on the warmer slopes. Warmer aspects support a higher number of colonization events. Hence, aspect can be a principal determinant of the pace of climate-induced migration processes.

Abstract

Climate change can alter soil communities and functions, but the consequences are uncertain for most ecosystems. We assessed the impacts of climate change on soil nematodes in a semiarid grassland using a 7-year, factorial manipulation of temperature and [CO2]. Elevated CO2 and warming decreased the abundance of plant-feeding nematodes and nematodes with intermediate to high values on the colonizer-persister scalp (cp3-5), including predators and omnivores. Thus, under futuristic climate conditions, nematode communities were even more dominated by r-strategists (cp1-2) that feed on bacteria and fungi. These results indicate that climate change could alter soil functioning in semiarid grasslands. For example, the lower abundance of plant-feeding nematodes could facilitate positive effects of elevated CO2 and warming on plant productivity. The effects of elevated CO2 and warming on nematode functional composition were typically less than additive, highlighting the need for multi-factor studies. Published by Elsevier Ltd.

Abstract

Cyanobacterialphotosynthesis is a vital process affected by fluctuating environmental parameters. To avoid accumulation of photodamagedphotosystem II (PSII), the core D1 protein, undergoquick turnoverduring high excitation flux. Our study showed how UV-B radiation affects the function of PSII complex and the expression of D1isoforms in Synechococcussp. PCC 7002. None of the D1 isoformsweresigificantly induced or accumulated under UV-B stress. Further, never before recordedchangesin electron flow on the acceptor side ofPSII complex resulting from anincreased redox potential gap between QA andplastoquinone poolwere identified under UV-B stress.

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Zooplankton communities can be strongly affected by cyanobacterial blooms, especially species of genus Daphnia, which are key-species in lake ecosystems. Here, we explored the effect of microcystin/nonmicrocystin (MC/non-MC) producing cyanobacteria in the diet of experimental Daphnia galeata populations composed of eight genotypes. We used D. galeata clones hatched from ephippia 10 to 60 years old, which were first tested in monocultures, and then exposed for 10 weeks as mixed populations to three food treatments consisting of green algae combined with cyanobacteria able/unable of producing MC. We measured the expression of nine genes potentially involved in Daphnia acclimation to cyanobacteria: six protease genes, one ubiquitin-conjugating enzyme gene, and two rRNA genes, and then we tracked the dynamics of the genotypes in mixed populations. The expression pattern of one protease and the ubiquitin-conjugating enzyme genes was positively correlated with the increased fitness of competing clones in the presence of cyanobacteria, suggesting physiological plasticity. The genotype dynamics in mixed populations was only partially related to the growth rates of clones in monocultures and varied strongly with the food. Our results revealed strong intraspecific differences in the tolerance of D. galeata clones to MC/non-MC-producing cyanobacteria in their diet, suggesting microevolutionary effects.

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Botryococcus braunii is a green colonial microalga which produces large quantities of liquid hydrocarbons similar to fossil petroleum. Exploring Botryococcus genus diversity entailed morphological, biochemical and phylogenetic studies. The majority of scientific literature specifies B. braunii as the only species with strains classified in three chemical races (A, B and L) which superpose the phylogenetic clusters built on 18S rDNA sequences. The cohesion of data provided by the three main research directions relies on the integrative analysis of the Botryococcus strains. The present work addresses the diversity of B. braunii race A strains by taking into account the morphology, the hydrocarbon and fatty acid profiles, and the phylogeny of 10 strains, isolated from several Romanian aquatic environments. The newly sequenced B. braunii strains increased the resolution of the analyses and yielded at least two distinct phylogenetic clades within race A cluster. This outcome was sustained by the genetic information coded by the 18S rRNA genes and both sequence-and sequence-structure analysis of ITS2. The Compensatory Base Changes occurrence within the secondary structure of ITS2 and the presence of one intron in the 18S rDNA sequences gave extra credibility to our phylogenetic results. (C) 2016 Elsevier B.V. All rights reserved.

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This study investigates the role of coliforms in the carriage of class 1 integron and biocide resistance genes in a drinking water treatment plant and explores the relationship between the carriage of such genes and the biofouling abilities of the strain. The high incidence of class 1 integron and biocide resistance genes (33.3 % of the isolates) highlights the inherent risk of genetic contamination posed by coliform populations during drinking water treatment. The association between the presence of intI1 gene and qac gene cassettes, especially qacH, was greater in biofilm cells. In coliforms recovered from biofilms, a higher frequency of class 1 integron elements and higher diversity of genetic patterns occurred, compared to planktonic cells. The coliform isolates under the study proved to mostly carry non-classical class 1 integrons lacking the typical qacE Delta 1/sul1 genes or a complete tni module, but bearing the qacH gene. No link was found between the carriage of integron genes and the biofouling degree of the strain, neither in aerobic or in anaerobic conditions. Coliform bacteria isolated from established biofilms rather adhere in oxygen depleted environments, while the colonization ability of planktonic cells is not significantly affected by oxygen availability.

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Botryococcus braunii is a green colonial microalga which produces large quantities of liquid hydrocarbons similar to fossil petroleum. Exploring Botryococcus genus diversity entailed morphological, biochemical and phylogenetic studies. The majority of scientific literature specifies B. braunii as the only species with strains classified in three chemical races (A, B and L) which superpose the phylogenetic clusters built on 18S rDNA sequences. The cohesion of data provided by the three main research directions relies on the integrative analysis of the Botryococcus strains. The present work addresses the diversity of B. braunii race A strains by taking into account the morphology, the hydrocarbon and fatty acid profiles, and the phylogeny of 10 strains, isolated from several Romanian aquatic environments. The newly sequenced B. braunii strains increased the resolution of the analyses and yielded at least two distinct phylogenetic clades within race A cluster. This outcome was sustained by the genetic information coded by the 18S rRNA genes and both sequence- and sequence-structure analysis of ITS2. The Compensatory Base Changes occurrence within the secondary structure of ITS2 and the presence of one intron in the 18S rDNA sequences gave extra credibility to our phylogenetic results. © 2016 Elsevier B.V.

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Aim: In the alpine life zone, plant diversity is strongly determined by local topography and microclimate. We assessed the extent to which aspect and its relatedness to temperature affect plant species diversity, and the colonization and disappearance of species on alpine summits on a pan-European scale. Location: Mountain summits in Europe's alpine life zone. Methods: Vascular plant species and their percentage cover were recorded in permanent plots in each cardinal direction on 123 summits in 32 regions across Europe. For a subset from 17 regions, resurvey data and 6-year soil temperature series were available. Differences in temperature sum and Shannon index as well as species richness, colonization and disappearance of species among cardinal directions were analysed using linear mixed-effects and generalised mixed-effects models, respectively. Results: Temperature sums were higher in east- and south-facing aspects than in the north-facing ones, while the west-facing ones were intermediate; differences were smallest in northern Europe. The patterns of temperature sums among aspects were consistent among years. In temperate regions, thermal differences were reflected by plant diversity, whereas this relationship was weaker or absent on Mediterranean and boreal mountains. Colonization of species was positively related to temperature on Mediterranean and temperate mountains, whereas disappearance of species was not related to temperature. Main conclusions: Thermal differences caused by solar radiation determine plant species diversity on temperate mountains. Advantages for plants on eastern slopes may result from the combined effects of a longer diurnal period of radiation due to convection cloud effects in the afternoon and the sheltered position against the prevailing westerly winds. In northern Europe, long summer days and low sun angles can even out differences among aspects. On Mediterranean summits, summer drought may limit species numbers on the warmer slopes. Warmer aspects support a higher number of colonization events. Hence, aspect can be a principal determinant of the pace of climate-induced migration processes. © 2016 John Wiley & Sons Ltd

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DNA barcoding represents an accurate, fast and automatable tool that enhanced species identification and species delineation. It relies on the use of standardized gene regions as internal species tags. The barcode markers should meet the followings requirements: they must have short length, conserved flanking sites and display significant genetic variability. Due to the complexity of plant genomes, all attempts to find a universal marker failed. For different plant species, different barcode markers or combinations of markers have been reported. In this study, we aimed to discover barcode markers for an efficient differentiation of two close related species from the genus Pulmonaria (Boraginaceae). Pulmonaria rubra Schott. and the Carpathian endemic P. filarszkyana Jáv. share a strong morphological resemblance and controversial taxonomic relationships, the latter being considered either a subspecies or a variety of the former, or a full ranked independent species. We tested fourteen target regions, of which thirteen belonged to the chloroplast and one was nuclear. Most regions lacked polymorphism or did not have a reliable, reproductible amplification. Only three regions displayed genetic variability: ITS1, rpL16 and psbD-trnT. Along the full length of the three sequences, six SNPs were detected, but they proved to be sufficient for a significant delimitation of the two taxa within subsequent phylogenetic analysis. © 2016, Babes-Bolyai University, "Alexandru Borza" Botanic Garden. All rights reserved.

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This paper compares the floodplain forests from Romania to those described from Central and Southeastern Europe from syntaxonomical and ecological perspectives and proposes a clear and ade-quate vegetation classification system that was needed for the Romanian floodplain forests. We per-formed a syntaxonomical analysis and classification of 473 vegetation relevés published from all nine Romanian provinces, between the years 1968 and 2015. The plant communities, established on the basis of character and differential species, were grouped within the alliance Alnion incanae Pawlowski 1928, according to current phytosociological consensus. The floristic structure of each syntaxon is presented in a synoptic table with species constancy expressed as a percentage. Since plant communi-ties specific to intramontane river floodplains are notably different from those in the plains, we grouped the associations within two different suballiances. Within the suballiance Alnenion glutinosae-incanae Oberdorfer 1953, we included the associations Stellario nemorum-Alnetum glutionosae Lohmeyer 1957, Telekio speciosae-Alnetum incanae Coldea 1990, and Carici remotae-Fraxinetum excelsioris Koch ex Faber 1936. In the suballiance Ulmenion Oberdorfer 1953, we included the associations Fraxino pannonicae-Ulmetum glabrae Aszód 1935 corr. Soó 1963, Ulmo campestris-Fraxinetum holotrichae Borza ex Sanda 1970 and Fraxino pallisae-Quercetum pedunculiflorae Oprea 1997. In order to show the distribution of these associations within the territory of Romania, we have generated two maps displaying the provenance of the analyzed relevés. The proposed classification system will facilitate the phytosociological and ecological investigation of floodplain forests and support the activi-ties aiming at their conservation. © 2016, Floristisch - Soziologische Arbeitsgemeinschaft.

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Cypripedium calceolus L. is one of the most spectacular species of orchid and one that suffered a significant decrease in Eurasia in the second half of the past century. After more than 80 years since the last record, we have found a new population of Cypripedium calceolus L. in the environs of Cluj-Napoca city, in Gârbăului Valley. The last record of this species, near Cluj-Napoca area, was reported from a parallel watercourse named Dumbrăvii Valley in 1934 by E. I. Nyárády. However, any attempts to localize again Nyárády’s C. calceolus population have failed. We have identified this orchid species at two new sites that have not been mentioned before. The two different sites are at the edge of Galio-Carpinetum oak-hornbeam forests, Asperulo-Fagetum beech forests and Dacian oak-hornbeam forests from the Natura 2000 site -Făgetul Clujului-Valea Morii. The importance of this discovery stands on the rarity of this orchid that, although it is a criterion species for the declaration of Natura 2000 sites, is not listed in the Standard Form of the Făgetul Clujului-Valea Morii site. The data from this paper aim to contribute to the introduction of Cypripedium calceolus L. on to the list of protected species from the Natura 2000 site in order to ensure the conservation of this population in Romania. © 2016, Babes-Bolyai University, "Alexandru Borza" Botanic Garden. All rights reserved.

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Botryococcus braunii is a green unicellular microalga with a unique potential to produce large quantities of hydrocarbons similar to fossil fuel. Up to now, B. braunii is the most studied species of the Botryococcus genus. The taxonomic affiliation of eight different strains of the genus Botryococcus collected from freshwaters of Transylvania was investigated based on their morphological characteristics and molecular profile using small subunit (SSU) ribosomal RNA (rRNA) genes and internal transcribed spacer 2 (ITS2) sequence-structure analysis. The phylogenetic inference using ITS2 sequence-structure molecular marker, an approach addressed for the first time in the issue of Botryococcus genus phylogeny, generated similar results with the 18S rRNA gene based analysis. In both phylogenetic trees we constructed, the sequences of our strains formed an independent cluster within the B-race clade. Based on the phylogenetic data and the presence of long mucilaginous processes which emerged from the periphery of the colonies, we established the affiliation of our strains to Botryococcus terribilis species. Detailed analyses regarding the growth performances, ultrastructural characteristics, and hydrocarbon and fatty acid profiles were also included in our study. The micrographs obtained in scanning electron, transmission electron, and light microscopies showed a high degree of similarity to other strains affiliated to the B chemical race. Also, gas chromatography-mass spectrometry assay showed for the first time the ability of B. terribilis strains to synthesize C-30-C-32 botryococcenes, which are known to be specific to the B-type Botryococcus strains.

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The percentage compositions of soil herbivorous, bacterivorous and fungivorous nematodes in forests, grasslands and scrubs in Romania was analysed. Percentages of nematode abundance, biomass and metabolic footprint methods were used to evaluate the patterns and relative size of herbivory, bacterial-and fungal-mediated channels in organic and mineral soil horizons. Patterns and magnitudes of herbivore, bacterivore and fungivore energy pathways differed for a given ecosystem type and soil depth according to the method used. The relevance of herbivore energy channel increased with soil depth due to higher contribution of root-feeders. Ectoparasites, sedentary parasites and epidermal cell and root hair feeders were the most important contributors to the total biomass and metabolic footprints of herbivores. Metabolic footprint method revealed the general dominance of bacterial-based energy channel in all five types of ecosystems. The influence of altitude and climatic factors on percentages of abundance, biomass and metabolic footprints of herbivores, bacterivores and fungivores decreased with soil depth, whereas the influence of humus content, cation-exchange capacity and base saturation increased. Vegetation, altitude, climate and soil physico-chemical characteristics are important factors that influenced the abundance, biomass and metabolic footprints of herbivores, bacterivores and fungivores.

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The nematode fauna in eleven localities distributed in forests and grasslands of three Natura 2000 sites (Cheile Turzii, Trascau and Cheile Turenilor) located in the Trascaului Mountains (Romania) was studied. A total of 133 nematode taxa were found, the nematode communities from the hornbeam-sessile oak forest in Cheile Turenilor being the most diverse (69 taxa), as compared to the grasslands located on sunny, steep slopes of Cheile Turzii (32-44). Only 10 taxa with higher proportions of their populations (D >= 10.1) were noted in the nematode communities. Diphtherophora brevicole, Panagrolaimus verrucosus, Trophurus sculptus, Tylencholaimellus striatus and Tylencholaimus minutus are rare records in the Romanian fauna. Dominant nematode taxa and trophic groups differed according to the ecosystems, Natura 2000 habitat types and soil depth. General opportunist nematodes prevailed in forests, whereas persisters were more abundant in calcophilous grasslands, with more mature, complex and stable nematode communities. Proportion of bacterial and fungal decomposition differed between localities, but grouping ecosystems and Natura 2000 habitat types based on the dominant decomposition pathway in soil food web was not possible. Nematode fauna of forests and grasslands was different; nematode community structure also differed in xerophilic and mesophilic grasslands. Nematode fauna is a promising ecological tool in soil-based assessment and monitoring of the conservation status of Natura 2000 habitats.

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Although the Carpathians represent one of the main elements of the European Alpine System and an important area of endemism, only a few phylogeographic studies concerning this region have focused on the detailed intraspecific variation in alpine plant species. Using two molecular marker systems, we (1) aimed to elucidate the controversy concerning the status of the endemic Carpathian taxon Onobrychis transsilvanica Simonk. in relation to the more widespread Onobrychis montana DC. and (2) determined the phylogeographic structure of O. transsilvanica within the Carpathians. For O. transsilvanica, our data suggest either a recent postglacial speciation with incomplete lineage sorting or genetic divergence followed by subsequent continuous gene flow during the glacial period. The genetic structure of the complex does not support O. transsilvanica as a distinct species from O. montana. Within the Carpathians, the extant populations of O. transsilvanica comprise two major allopatric lineages, which have been isolated from each other for a long period of time. Unexpectedly, the major genetic break was not in line with a classical biogeographical boundary in the Carpathians but rather separated a group from the southwestern edge of the mountains. We also discovered an additional divergent haplotype lineage, with weaker genetic support, within the O. transsilvanica populations.

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The nematode fauna in eleven localities distributed in forests and grasslands of three Natura 2000 sites (Cheile Turzii, Trascău and Cheile Turenilor) located in the Trascăului Mountains (Romania) was studied. A total of 133 nematode taxa were found, the nematode communities from the hornbeam-sessile oak forest in Cheile Turenilor being the most diverse (69 taxa), as compared to the grasslands located on sunny, steep slopes of Cheile Turzii (32-44). Only 10 taxa with higher proportions of their populations (D ≥ 10.1) were noted in the nematode communities. Diphtherophora brevicole, Panagrolaimus verrucosus, Trophurus sculptus, Tylencholaimellus striatus and Tylencholaimus minutus are rare records in the Romanian fauna. Dominant nematode taxa and trophic groups differed according to the ecosystems, Natura 2000 habitat types and soil depth. General opportunist nematodes prevailed in forests, whereas persisters were more abundant in calcophilous grasslands, with more mature, complex and stable nematode communities. Proportion of bacterial and fungal decomposition differed between localities, but grouping ecosystems and Natura 2000 habitat types based on the dominant decomposition pathway in soil food web was not possible. Nematode fauna of forests and grasslands was different; nematode community structure also differed in xerophilic and mesophilic grasslands. Nematode fauna is a promising ecological tool in soil-based assessment and monitoring of the conservation status of Natura 2000 habitats. © 2015, Editura Silvica. All rights reserved.

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The paper presents our results in cultivation on soils polluted with heavy metals (Pb, Cd) of Miscanthus sinensis x giganteus, a sterile hybrid, as well as the tests we have performed for the use of the stems cropped after two years. The results are very encouraging and we expect more and more farmers to cultivate this plant, with benefit for them and for environment. © 2014 Vasile Goldis University Press.

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Synechococcus sp. PCC 7002 is known to be tolerant to most of the environmental factors in natural habitats of Cyanobacteria. Gene expression can be easily studied in this cyanobacterium, as its complete genome sequence is available. These properties make Synechococcus sp. PCC 7002 an appropriate model organism for biotechnological applications. To study the gene expression in Cyanobacteria, real-time quantitative PCR (qPCR) can be used, but as this is a highly sensitive method, data standardization is indicated between samples. The most commonly used strategy is normalization against internal reference genes. Synechococcus sp. PCC 7002 has not yet been evaluated for the best reference genes. In this work, six candidate genes were analyzed for this purpose. Cyanobacterial cultures were exposed to several stress conditions, and three different algorithms were used for ranking the reference genes: geNorm, NormFinder, and BestKeeper. Moreover, gene expression stability value M and single-control normalization error E were calculated. Our data provided a list of reference genes that can be used in qPCR experiments in Synechococcus sp. PCC 7002.

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In this study the molecular analysis of 24 potentially toxic cyanobacterial strains of genus Microcystis isolated from Romania is presented. The toxic potential was assessed by Matrix Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS), which indicated that five out of the 24 strains are able to produce microcystins. Beside this, the strains were shown to produce various peptides, including aeruginosins, microginins or cyanopeptolins. Identification of potentially toxic Microcystis strains by PCR was performed using primers described in known literature. These primers occasionally generated amplification products in non-microcystin-producing strains. New primers were designed, and the amplification of a mcyD gene fragment exclusively in microcystin-producing strains certified the high specificity of these new primers for microcystin-producing cells. All of the five microcystin-producing strains were shown to possess four characteristic parts of the gene cluster responsible for microcystin synthesis (mcyA, mcyB, mcyD and mcyE). The 16S-23S rDNA ITS sequence was used to confirm the taxonomic identification of the strains and their relationship to strains from outside Romania.

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The diversity of archaea and bacteria was investigated in two slightly alkaline, mesophilic hot springs from the Western Plain of Romania. Phylogenetic analysis showed a low diversity of Archaea, only three Euryarchaeota taxa being detected: Methanomethylovorans thermophila, Methanomassiliicoccus luminyensis and Methanococcus aeolicus. Twelve major bacterial groups were identified, both springs being dominated by Cyanobacteria, Chloroflexi and Proteobacteria. While at the phylum/class-level the microbial mats share a similar biodiversity; at the species level the geothermal springs investigated seem to be colonized by specific consortia. The dominant taxa were filamentous heterocyst-containing Fischerella, at 45 A degrees C and non-heterocyst Leptolyngbya and Geitlerinema, at 55 A degrees C. Other bacterial taxa (Thauera sp., Methyloversatilis universalis, Pannonibacter phragmitetus, Polymorphum gilvum, Metallibacterium sp. and Spartobacteria) were observed for the first time in association with a geothermal habitat. Based on their bacterial diversity the two mats were clustered together with other similar habitats from Europe and part of Asia, most likely the water temperature playing a major role in the formation of specific microbial communities that colonize the investigated thermal springs.

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Background: We hypothesised that the relative position of surrounding vegetation patches would account for most floristic patterns observed in patches of exposed gold mine spoil (EMS) scattered over a 60-year-old, abandoned waste heap. Aims: We assessed the extent to which the structure of plant species assemblages from 53 EMS patches was related to distance from woodlands, heathlands and grasslands by controlling for the effect of spatial autocorrelation, patch size, slope and aspect. Results: The most discrepant in terms of species composition were the EMS patches located farthest away from heathlands and those embedded in woodlands. Zoochorous species richness declined with distance from the nearest heathland. Anemochorous, competitive-stress tolerant and total species richness increased with proximity to the nearest woodland. Conversely, competitive species richness and total species cover were larger in EMS patches that were farther away from the nearest woodland, but closer to grasslands. Depending on the identity of colonising species, the woodland stands could act as propagule source, ecological filters or seed dispersal amplifiers. Conclusion: The relative importance of proximity to source habitats for plant community assembly can change dramatically under the confounding or contrasting effects of third-party' habitat patches, which are interposed in the landscape.

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We numerically analysed 154 releves of Potentillo chrysocraspedae-Festucetum airoidis in order to review the compositional variability of these grasslands, the main eco-floristic gradients and the representativeness of the lectotype. Apart from 30 small-sized clusters composed of singular or transitional releves (outliers), three distinctive groups of 77, 19 and 12 communities were finally retained and denominated as typical (TP), closed (CL) and open (OP) facies, as they were significantly different in terms of total species cover. The three facies are well separated but do not form distinctive clusters in the non-metric multidimensional scaling (NMDS) ordination space. Juncus trifidus and Agrostis rupestris are the best differential species of OP and TP, respectively, whereas the best discriminator of CL is the higher cover of F. airoides. There are no significant differences between the three facies regarding altitude. The floristic structure of CL indicates poorer but moister soils compared with the other facies. CL may represent either a post-disturbance, recovery phase following sheep overgrazing and intensive trampling, or a late seral stage. OP gathers communities that are little disturbed and mainly occur on ridges and upper, sunny slopes. Although well distinguished floristically, TP is weakly defined in terms of homotoneity and complexity of the core species assemblage. The most representative releve of TP is poorer in character species than the releve lectotype (5 versus 12), the latter being classified as an outlier in terms of normal specific assemblage. Such patterns may reflect the spatio-temporal heterogeneity in alpine grasslands due to uncontrolled, intensive grazing and stochastic natural disturbances.

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Efficient micropropagation and cryopreservation of Hypericum richeri ssp. transsilvanicum, an endemic species in Romania, and Hypericum umbellatum, a rare and endangered Daco-Balkan species, was achieved. The effects of type of explant and cytokinin on in vitro plant regeneration were investigated. Shoot organogenesis was achieved in all explants, but stem nodes regenerated best. Organogenesis from nodal segments was promoted by incubating these explants on Murashige and Skoog (MS) medium in the presence of cytokinins (6-benzyladenine, thidiazuron, kinetin or 6-gamma,gamma-dimethylallylaminopurine), each tested at four concentrations. The best morphogenic response for both Hypericum species (number of shoots per explant, shoot length, axillary branching of shoot, and frequency of shoot organogenesis) was observed when explants were incubated on MS medium containing 0.44 or 1.11 mu M 6-benzyladenine. Root induction was achieved only when regenerated shoots were transferred to fresh medium with or without auxin. Maximum rooting was recorded on MS medium supplemented with 2.45 mu M indole-3-butyric acid. Plantlets grown in vitro were successfully acclimatized in the greenhouse and showed normal development. Shoot tips and axillary buds excised from the in vitro regenerated plants were successfully cryopreserved in liquid nitrogen by the droplet-vitrification method. Following preculture in 0.25 M sucrose, dehydration and cryopreservation, the highest regeneration rates were obtained in both species by using axillary buds (68 % for H. richeri ssp. transsilvanicum and 71 % for H. umbellatum).

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Climate impact studies have indicated ecological fingerprints of recent global warming across a wide range of habitats(1,2). Although these studies have shown responses from various local case studies, a coherent large-scale account on temperature-driven changes of biotic communities has been lacking(3,4). Here we use 867 vegetation samples above the treeline from 60 summit sites in all major European mountain systems to show that ongoing climate change gradually transforms mountain plant communities. We provide evidence that the more cold-adapted species decline and the more warm-adapted species increase, a process described here as thermophilization. At the scale of individual mountains this general trend may not be apparent, but at the larger, continental scale we observed a significantly higher abundance of thermophilic species in 2008, compared with 2001. Thermophilization of mountain plant communities mirrors the degree of recent warming and is more pronounced in areas where the temperature increase has been higher. In view of the projected climate change(5,6) the observed transformation suggests a progressive decline of cold mountain habitats and their biota.

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In mountainous regions, climate warming is expected to shift species' ranges to higher altitudes. Evidence for such shifts is still mostly from revisitations of historical sites. We present recent (2001 to 2008) changes in vascular plant species richness observed in a standardized monitoring network across Europe's major mountain ranges. Species have moved upslope on average. However, these shifts had opposite effects on the summit floras' species richness in boreal-temperate mountain regions (+3.9 species on average) and Mediterranean mountain regions (-1.4 species), probably because recent climatic trends have decreased the availability of water in the European south. Because Mediterranean mountains are particularly rich in endemic species, a continuation of these trends might shrink the European mountain flora, despite an average increase in summit species richness across the region.

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The Convention on Biological Diversity (CBD) aims at the conservation of all three levels of biodiversity, that is, ecosystems, species and genes. Genetic diversity represents evolutionary potential and is important for ecosystem functioning. Unfortunately, genetic diversity in natural populations is hardly considered in conservation strategies because it is difficult to measure and has been hypothesised to co-vary with species richness. This means that species richness is taken as a surrogate of genetic diversity in conservation planning, though their relationship has not been properly evaluated. We tested whether the genetic and species levels of biodiversity co-vary, using a large-scale and multi-species approach. We chose the high-mountain flora of the Alps and the Carpathians as study systems and demonstrate that species richness and genetic diversity are not correlated. Species richness thus cannot act as a surrogate for genetic diversity. Our results have important consequences for implementing the CBD when designing conservation strategies.

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This study investigated whether somatic markers mediate the effect of serotonin transporter genotype on Iowa Gambling Task (IGT) performance. Participants (N = 135) were genotyped for the insertion/deletion and single-nucleotide (rs25531) polymorphisms in the promoter region of the serotonin transporter gene (5-HTTLPR). The results of mediation analyses indicated that skin conductance responses that anticipated IGT card selections partially (i.e. 42% of the total effect) mediated the effect of genotype on IGT performance. In comparison with high-functioning 5-HTTLPR genotypes, the low-functioning genotypes were associated with higher total IGT scores. This suggests that the higher synaptic availability of serotonin, associated with the low-functioning 5-HTTLPR genotypes, may confer differential susceptibility to decision making under risk, and that almost half of this effect is explained by facilitated somatic markers during IGT.

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Even though they are small-scale ecosystems, microbial mats have greatly influenced the development of life on Earth. In order to put together a clear image of bow life was on this planet billions of years ago, one has to look to fossils. To sec how certain conditions influenced the development of the fossils it is very important to look for modem analogues that may have the potential to create sedimentary structures. Such a possible analogue is the cyanobacterial mat associated with the geothermal spring from Belting, Western Plain of Romania. The cyanobacterial diversity was explored by light and electron microscopy, alongside the following culture-independent techniques automated ribosomal intergenic spacer analysis and amplified ribosomal DNA (rDNA) restriction analysis, based on 16S rDNA and 16S-23S internal transcribed spacer markers. Based on the partial 16S rDNA sequences obtained, four cyanobacterial taxons were identified, all belonging to the Oscillatoriales order. Even though the slat started to develop only a few decades ago, its spatial structure and taxon composition are similar to those of modern or fossil sedimentary structures. These observations, coupled with the chemical properties of the water, rich in Ca2+ and HC3-, make the Beltiug mat suitable for the appearance of sedimentary structures.

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Primula intricate: Gren. et Godr. has an unclear taxonomic status: it was originally described as a distinct species but subsequently was considered a subspecies (Primula elatior subsp. intricata) or even a variety (P. elatior var.intricata) of Primula elatior (L.) Hill. No prior genetic studies were performed on this group of Primulaceae, therefore we considered useful to investigate taxonomies boundaries within the P elatior-intricata group. We explored genetic differences between Primula intricate: and Primula elatior group by applying three different types of molecular markers: nuclear ribosomal DNA (ITSI), chloroplast DNA (spacer trnH-psbA and intron trnL) and Amplified Fragment Length Polymorphisms (AFLP). We found a solid differentiation between P intricata and P elatior group, differentiation that was confirmed by all the employed molecular markers. This finding enabled us to propose a valid species rank for Primula intricata, as a separate taxon from the P. elatior group.

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Continental-scale assessments of 21st century global impacts of climate change on biodiversity have forecasted range contractions for many species. These coarse resolution studies are, however, of limited relevance for projecting risks to biodiversity in mountain systems, where pronounced microclimatic variation could allow species to persist locally, and are ill-suited for assessment of species-specific threat in particular regions. Here, we assess the impacts of climate change on 2632 plant species across all major European mountain ranges, using high-resolution (ca. 100 m) species samples and data expressing four future climate scenarios. Projected habitat loss is greater for species distributed at higher elevations; depending on the climate scenario, we find 36-55% of alpine species, 31-51% of subalpine species and 19-46% of montane species lose more than 80% of their suitable habitat by 2070-2100. While our high-resolution analyses consistently indicate marked levels of threat to cold-adapted mountain florae across Europe, they also reveal unequal distribution of this threat across the various mountain ranges. Impacts on florae from regions projected to undergo increased warming accompanied by decreased precipitation, such as the Pyrenees and the Eastern Austrian Alps, will likely be greater than on florae in regions where the increase in temperature is less pronounced and rainfall increases concomitantly, such as in the Norwegian Scandes and the Scottish Highlands. This suggests that change in precipitation, not only warming, plays an important role in determining the potential impacts of climate change on vegetation.

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The biodiversity of a specific cyanobacterial mat associated to a thermomineral spring from the Western Plain of Romania was investigated. Light and electron microscopy, together with molecular tools (denaturing gradient gel electrophoresis-DGGE, automated ribosomal intergenic spacer analysis-ARISA and amplified ribosomal DNA restriction analysis-ARDRA), based on 16S rDNA and 16S-23S internal transcribed spacer markers were used. Based on the partial 16S rRNA fragments sequenced, eight cyanobacterial taxons were identified, all belonging to the Oscillatoriales order, Phormidium and Leptolyngbya being dominant. A significant difference was observed, in comparison with the morphological approach. In certain conditions, DGGE can provide misleading information due to multiple melting domains in the same sequence, to multiple rrn operons in the same genome and due to unspecific hybridization among closely related sequences. This can lead to an overestimated species abundance which can cause incorrect description of the microbial community investigated. Additional techniques, such as ARISA and ARDRA, can improve the microbial biodiversity studies, thus providing optimal results.

Abstract

Alliinase (Alliin lyase EC 4.4.1.4), a pyridoxal phosphate-dependent lyase, represents one of the major protein components of Allium species. The enzyme is a homodimeric glycoprotein and catalyzes the synthesis of allicin (diallyl thiosulfinate, a biologically active compound), pyruvate, and ammonia starting from the specific non-protein sulfur-containing amino acid alliin ((+S)-allyl-L-cysteine sulfoxide). Using newly developed specific primers two new alliinase genes from Allium obliquum and Allium senescens sop. montanum were amplified and sequenced, as well as their homologs, from Allium fistulosum and Allium schoeonoprasum. The G+C content of the alliinase region ranges between that of other dicot plants and that reported in monocot cereal plants, in all four species. Investigations of gene expression revealed a significantly higher enzyme expression level in bulbs than in leaves in all four taxa. The deduced alliinase sequences displayed a, high variability among different species, since the lowest sequence similarity was found to be 55.5% between senescent var. montanum and Allium cepa, while the highest similarity is 77.5%, between ilium senescent var. montanum and Allium fistulosum. Leucine is the most common amino acid in all four alliinases, while cysteine is also more frequent that in other enzymes, suggesting a high stability of the molecules due to the possible disulfide bonds.

Abstract

We investigated the effects of plant growth regulators [6-benzyladenine (BA), kinetin (Kin), 6-gamma,gamma-dimethylallylaminopurine (2iP), thidiazuron (TDZ) and alpha-naphthaleneacetic acid (NAA)], modified Murashige and Skoog (MS) medium containing 10 mM NH4 (+) and 5 mM NO3 (-) and supplemented with 2iP, BA, Kin and NAA (MSM medium), and two elicitors [jasmonic acid (JA), and salicylic acid (SA)], on plant growth and accumulation of hypericins (hypericin and pseudohypericin) and hyperforin in shoot cultures of Hypericum hirsutum and H. maculatum. Our data suggested that culture of shoots on MS medium supplemented with BA (0.4 mg l(-1)) or Kin (0.4 mg l(-1)) enhanced production of hypericins in H. maculatum and hyperforin in H. hirsutum. Hypericins and hyperforin concentrations decreased in both species when TDZ (0.4 mg l(-1)) was added to the MS medium. Also, TDZ induced hyperhydric malformations and necrosis of regenerated shoots. Cultivation of H. maculatum on MSM medium resulted in approximately twofold increased production of hypericins compared to controls, and the growth of H. hirsutum shoots on the same medium led to a 6.16-fold increase in hyperforin production. Of the two elicitors, SA was more effective in stimulating the accumulation of hypericins. At 50 mu M, SA enhanced the production of hypericin (7.98-fold) and pseudohypericin (13.58-fold) in H. hirsutum, and, at 200 mu M, enhanced the production of hypericin (2.2-fold) and pseudohypericin (3.94-fold) in H. maculatum.

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