Dry calcareous grasslands from two neighboring biogeographic regions: relationship between plant traits and rarity

European dry grasslands formed of the Festuco-Brometea type are among the most diverse plant communities within agricultural landscapes. We examined floristic composition, functional trait structure and threatened species occurrence in grasslands of this type from in two distinct biogeographic regions, Dinaric (NW Balkan) and the Central European. In the Central European region this type of grassland is threatened by a decline in traditional extensive management. We tested, if differences in the level of threat between regions are matched by differences in community-weighted means for resource use strategy traits and occurrence of Red List (threatened) species. We then tested if threatened species differed in their traits from other species and if threatened species richness was related to CWM for resource use strategy traits. The communities from the Central European region had significantly higher SLA and lower LDMC, which perhaps reflects an increase in intensive agriculture promoting fast-growing species. Threatened species occurrence did not differ significantly between regions, but threatened species richness was significantly negatively correlated with CWM for height and SLA. This may suggest that threatened species are less likely to occur in high productivity communities where light competition is intense. This study provides initial evidence that changes in CWM for resource use strategy traits may provide a useful means for predicting threatened species loss in dry grassland ecosystems.     

Ecological determinants of butterfly vulnerability across the European continent

In drawing up Red Lists, the extinction risks of butterflies and other insects are currently assessed mainly by using information on trends in distribution and abundance. Incorporating information on species traits may increase our ability to predict species responses to environmental change and, hence, their vulnerability. We summarized ecologically relevant life-history and climatic niche traits in principal components, and used these to explain the variation in five vulnerability indicators (Red List status, Endemicity, Range size, Habitat specialisation index, Affinity for natural habitats) for 397 European butterfly species out of 482 species present in Europe. We also evaluated a selection of 238 species to test whether phylogenetic correction affected these relationships. For all but the affinity for natural habitats, climatic niche traits predicted more variation in vulnerability than life-history traits; phylogenetic correction had no relevant influence on the findings. The life-history trait component reflecting mobility, development rate, and overwintering stage, proved the major non-climatic determinant of species vulnerability. We propose that this trait component offers a preferable alternative to the frequently used, but ecologically confusing generalist-specialist continuum. Our analysis contributes to the development of trait-based approaches to prioritise vulnerable species for conservation at a European scale. Further regional scale analyses are recommended to improve our understanding of the biological basis of species vulnerability.     

Mechanisms driving plant functional trait variation in a tropical forest

Plant functional trait variation in tropical forests results from taxonomic differences in phylogeny and associated genetic differences, as well as, phenotypic plastic responses to the environment. Accounting for the underlying mechanisms driving plant functional trait variation is important for understanding the potential rate of change of ecosystems since trait acclimation via phenotypic plasticity is very fast compared to shifts in community composition and genetic adaptation. We here applied a statistical technique to decompose the relative roles of phenotypic plasticity, genetic adaptation, and phylogenetic constraints. We examined typically obtained plant functional traits, such as wood density, plant height, specific leaf area, leaf area, leaf thickness, leaf dry mass content, leaf nitrogen content, and leaf phosphorus content. We assumed that genetic differences in plant functional traits between species and genotypes increase with environmental heterogeneity and geographic distance, whereas trait variation due to plastic acclimation to the local environment is independent of spatial distance between sampling sites. Results suggest that most of the observed trait variation could not be explained by the measured environmental variables, thus indicating a limited potential to predict individual plant traits from commonly assessed parameters. However, we found a difference in the response of plant functional traits, such that leaf traits varied in response to canopy‐light regime and nutrient availability, whereas wood traits were related to topoedaphic factors and water availability. Our analysis furthermore revealed differences in the functional response of coexisting neotropical tree species, which suggests that endemic species with conservative ecological strategies might be especially prone to competitive exclusion under projected climate change.     

Ellenberg indicator values for macromycetes – a methodological approach and first applications

Ellenberg indicator values (EIVs) describe the realized niche of species and habitat parameters, and are commonly used for vascular plants, bryophytes, and lichens. We provide a methodology for EIVs and an EIV list for nearly 650 species of macromycetes. We propose a new EIV scale, namely substrate openness (O). We also give the results of two applications and compare EIV values related to the Red List classification with those related to lifestyle classification. Mycorrhizal species on average have higher demands on substrate openness and are less tolerant of high nutrient levels than saprotrophic or parasitic species. Critically endangered species have on average distinctly higher demands on openness of habitat and substrate than not threatened or less strongly threatened species, which in turn have higher demands for nutrient availability. This pattern clearly highlights the points of threat for many macromycete species.     

三峡水库消落带植物叶片光合与营养性状特征

自2007年三峡大坝试运行以来,其独特的人工水位调度节律给当地的水库消落带生态系统带来了巨大的负面影响。植物功能性状可以反映某一特殊生境植物的生理生态过程特殊性,是指示生态系统结构与功能的有效指标。因此,在三峡水库消落带形成2a后,于2009年调查了消落带的42种适生植物以及对照带33种植物的6个叶片功能性状:最大净光合速率(Amax)、叶片气孔导度(Gs)、比叶重(LMA)、叶片全氮含量(Nmass)、全磷含量(Pmass)和全钾含量(Kmass)。运用标准化主轴回归分析对消落带植物叶片各功能性状之间关系进行分析,并对照全球尺度叶片功能性状数据库,旨在说明反季节淹水对消落带植物叶片功能性状之间关系与全球尺度对比发生了哪些变化。同时,运用成对方差t检验的分析方法,对比了在消落带和对照带都存在的33个种的叶片光合与营养性状之间的差异,以阐明消落带植物对消落带特殊生境的生理响应。结果表明:(1)消落带植物叶片各性状关系呈现出与全球尺度基本一致的格局,表现出植物叶性状之间关系的趋同性;(2)消落带植物Amass、Nmass、Pmass和Kmass显著高于全球尺度,而LMA则显著低于全球尺度。处于驯化阶段的消落带植物各叶片性状处在全球叶片经济型谱"低投入-快速回收"的一端。(3)消落带植物叶片Amass与对照带相比,有显著提高。表明三峡水库消落带植物叶片光合能力得到显著提高,这可能是其适应消落带特殊生境的关键生理生态对策之一。     

Automated assessment reveals that the extinction risk of reptiles is widely underestimated across space and phylogeny

The Red List of Threatened Species, published by the International Union for Conservation of Nature (IUCN), is a crucial tool for conservation decision-making. However, despite substantial effort, numerous species remain unassessed or have insufficient data available to be assigned a Red List extinction risk category. Moreover, the Red Listing process is subject to various sources of uncertainty and bias. The development of robust automated assessment methods could serve as an efficient and highly useful tool to accelerate the assessment process and offer provisional assessments. Here, we aimed to (1) present a machine learning–based automated extinction risk assessment method that can be used on less known species; (2) offer provisional assessments for all reptiles—the only major tetrapod group without a comprehensive Red List assessment; and (3) evaluate potential effects of human decision biases on the outcome of assessments. We use the method presented here to assess 4,369 reptile species that are currently unassessed or classified as Data Deficient by the IUCN. The models used in our predictions were 90% accurate in classifying species as threatened/nonthreatened, and 84% accurate in predicting specific extinction risk categories. Unassessed and Data Deficient reptiles were considerably more likely to be threatened than assessed species, adding to mounting evidence that these species warrant more conservation attention. The overall proportion of threatened species greatly increased when we included our provisional assessments. Assessor identities strongly affected prediction outcomes, suggesting that assessor effects need to be carefully considered in extinction risk assessments. Regions and taxa we identified as likely to be more threatened should be given increased attention in new assessments and conservation planning. Lastly, the method we present here can be easily implemented to help bridge the assessment gap for other less known taxa.

The Red List of Threatened Species, published by the IUCN, is a crucial tool for conservation decision making, but is subject to various sources of uncertainty and bias. Modelling the threat status of all global reptiles identifies increased threat to many groups of reptiles across many regions of the world, beyond those currently recognized; moreover, it highlights the effects of the IUCN assessment procedure on eventual threat categories.     

An index for measuring functional extension and evenness in trait space

Most existing functional diversity indices focus on a single facet of functional diversity. Although these indices are useful for quantifying specific aspects of functional diversity, they often present some conceptual or practical limitations in estimating functional diversity. Here, we present a new functional extension and evenness (FEE) index that encompasses two important aspects of functional diversity. This new index is based on the straightforward notion that a community has high diversity when its species are distant from each other in trait space. The index quantifies functional diversity by evaluating the overall extension of species traits and the interspecific differences of a species assemblage in trait space. The concept of minimum spanning tree (MST) of points was adopted to obtain the essential distribution properties for a species assembly in trait space. We combined the total length of MST branches (extension) and the variation of branch lengths (evenness) into a raw FEE₀ metric and then translated FEE₀ to a species richness‐independent FEE index using a null model approach. We assessed the properties of FEE and used multiple approaches to evaluate its performance. The results show that the FEE index performs well in quantifying functional diversity and presents the following desired properties: (a) It allows a fair comparison of functional diversity across different species richness levels; (b) it preserves the essence of single‐facet indices while overcoming some of their limitations; (c) it standardizes comparisons among communities by taking into consideration the trait space of the shared species pool; and (d) it has the potential to distinguish among different community assembly processes. With these attributes, we suggest that the FEE index is a promising metric to inform biodiversity conservation policy and management, especially in applications at large spatial and/or temporal scales.     

Functional trait heritability and local climatic adaptation among grasses: a meta-analysis

Variation in climate has been demonstrated to be a powerful driver of selection and local adaptation among plant populations. Variation in functional traits among populations can also be indicative of the drivers of local adaptation. However, it is not clear to what extent species exhibit consistent patterns of local adaptation as revealed by common, heritable trait–environment relationships among populations. To address this, we conducted a meta-analysis of common garden studies of grass populations to quantify the degree of heritability of several commonly measured functional traits, and whether demonstrated heritability was driven by climate. We found that leaf size, specific leaf area (SLA) and total biomass all displayed strong broad-sense of heritability. Both leaf area and SLA decreased significantly with increasing temperature seasonality among populations within species, while total biomass increased with increasing annual and dry season precipitation, and decreased with increasing precipitation seasonality. These results indicate similar, consistent drivers of local adaptation among species of grasses. Further information on trait–environment relationships within species could greatly improve our ability to predict broad scale patterns in functional diversity across multiple levels of ecological organization. Expanding the range of traits and regions incorporated in common garden research, in the present case by incorporating root traits and Southern Hemisphere taxa, will provide even greater benefits to the fields of restoration, conservation, and global change ecology.     

Local climate and cultivation,but not ploidy,predict functional trait variation in <Emphasis Type="Italic">Bouteloua gracilis</Emphasis> (Poaceae)

Efforts to improve the diversity of seed resources for important restoration species has become a high priority for land managers in many parts of the world. Relationships between functional trait values and the environment from which seed sources are collected can provide important insights into patterns of local adaptation and guidelines for seed transfer. However, little is known about which functional traits exhibit genetic differentiation across populations of restoration species and thus may contribute to local adaptation. Here, we report the results of a common garden experiment aimed at assessing genetic (including ploidy level) and environmental regulation of several functional traits among populations of Bouteloua gracilis, a dominant C4 grass and the most highly utilized restoration species across much of the Colorado Plateau. We found that leaf size and specific leaf area (SLA) varied significantly among populations, and were strongly correlated with the source population environment from which seeds were collected. However, variation in ploidy level had no significant effect on functional traits. Leaves of plants grown from commercial seed releases were significantly larger and had lower SLA than those from natural populations, a result that is concordant with the overall relation between climate and these two functional traits. We suggest that the patterns of functional trait variation shown here may extend to other grass species in the western USA, and may serve as useful proxies for more extensive genecology research. Furthermore, we argue that care should be taken to develop commercial seed lines with functional trait values that match those of natural populations occupying climates similar to target restoration sites.     

Using Red List Indices to measure progress towards the 2010 target and beyond

The World Conservation Union (IUCN) Red List is widely recognized as the most authoritative and objective system for classifying species by their risk of extinction. Red List Indices (RLIs) illustrate the relative rate at which a particular set of species change in overall threat status (i.e. projected relative extinction-risk), based on population and range size and trends as quantified by Red List categories. RLIs can be calculated for any representative set of species that has been fully assessed at least twice. They are based on the number of species in each Red List category, and the number changing categories between assessments as a result of genuine improvement or deterioration in status. RLIs show a fairly coarse level of resolution, but for fully assessed taxonomic groups they are highly representative, being based on information from a high proportion of species worldwide. The RLI for the world's birds shows that that their overall threat status has deteriorated steadily during the years 1988-2004 in all biogeographic realms and ecosystems. A preliminary RLI for amphibians for 1980-2004 shows similar rates of decline. RLIs are in development for other groups. In addition, a sampled index is being developed, based on a stratified sample of species from all major taxonomic groups, realms and ecosystems. This will provide extinction-risk trends that are more representative of all biodiversity.     

Differences in the trait compositions of non-indigenous and native plants across Germany

This paper explores the differences in the trait compositions of non-indigenous (neophytic) and native plant species for selected traits in Germany. Our set of functional traits addresses species’ reproductive biology, life history, morphology and ecophysiology. To take account of broad-scale heterogeneity across the country we compared the relative frequencies of neophytes and natives with particular trait attributes at the scale of grid cells (c. 130 km² each). Subsequently, we compared the differences at the grid cell scale to the differences in the corresponding comparisons at the scale of the entire country. Finally, we explored how variation in the trait compositions of the non-indigenous species across the country relates to variation in the trait compositions of the natives. We found remarkable differences in the trait compositions of neophytes and natives at the grid cell scale. Neophytes were over-represented in insect- and self-pollinated species and in species with a later and longer flowering season. Furthermore, the proportions of species with mesomorphic or hygromorphic leaf anatomy, of annual herbs and of trees as well as of non-clonals and polyploids were significantly higher in neophytes than in natives. These differences at the grid cell scale could vary distinctly from the corresponding differences observed at the country scale. This result highlights the complexity of the invasion process and suggests an importance of spatial scale for the comparisons. Correlation analysis indicated, that for traits relating to plant morphology and ecophysiology, the relative frequencies of the non-indigenous species increased with those of the natives. This suggests that favourable environments for natives with particular attributes constitute an increased suitability for neophytes with these attributes as well. Our study provides a step forward towards an integrated understanding of traits in plant invasions across spatial scales and broad-scale heterogeneity and underlines the necessity to understand the role of functional traits in plant invasions with reference to spatial scale and in the context of the environment.     

Measuring global trends in the status of biodiversity: red list indices for birds

The rapid destruction of the planet's biodiversity has prompted the nations of the world to set a target of achieving a significant reduction in the rate of loss of biodiversity by 2010. However, we do not yet have an adequate way of monitoring progress towards achieving this target. Here we present a method for producing indices based on the IUCN Red List to chart the overall threat status (projected relative extinction risk) of all the world's bird species from 1988 to 2004. Red List Indices (RLIs) are based on the number of species in each Red List category, and on the number changing categories between assessments as a result of genuine improvement or deterioration in status. The RLI for all bird species shows that their overall threat status has continued to deteriorate since 1988. Disaggregated indices show that deteriorations have occurred worldwide and in all major ecosystems, but with particularly steep declines in the indices for Indo-Malayan birds (driven by intensifying deforestation of the Sundaic lowlands) and for albatrosses and petrels (driven by incidental mortality in commercial longline fisheries). RLIs complement indicators based on species population trends and habitat extent for quantifying global trends in the status of biodiversity. Their main weaknesses are that the resolution of status changes is fairly coarse and that delays may occur before some status changes are detected. Their greatest strength is that they are based on information from nearly all species in a taxonomic group worldwide, rather than a potentially biased subset. At present, suitable data are only available for birds, but indices for other taxonomic groups are in development, as is a sampled index based on a stratified sample from all major taxonomic groups.     

Trait adaptation promotes species coexistence in diverse predator and prey communities

Species can adjust their traits in response to selection which may strongly influence species coexistence. Nevertheless, current theory mainly assumes distinct and time‐invariant trait values. We examined the combined effects of the range and the speed of trait adaptation on species coexistence using an innovative multispecies predator–prey model. It allows for temporal trait changes of all predator and prey species and thus simultaneous coadaptation within and among trophic levels. We show that very small or slow trait adaptation did not facilitate coexistence because the stabilizing niche differences were not sufficient to offset the fitness differences. In contrast, sufficiently large and fast trait adaptation jointly promoted stable or neutrally stable species coexistence. Continuous trait adjustments in response to selection enabled a temporally variable convergence and divergence of species traits; that is, species became temporally more similar (neutral theory) or dissimilar (niche theory) depending on the selection pressure, resulting over time in a balance between niche differences stabilizing coexistence and fitness differences promoting competitive exclusion. Furthermore, coadaptation allowed prey and predator species to cluster into different functional groups. This equalized the fitness of similar species while maintaining sufficient niche differences among functionally different species delaying or preventing competitive exclusion. In contrast to previous studies, the emergent feedback between biomass and trait dynamics enabled supersaturated coexistence for a broad range of potential trait adaptation and parameters. We conclude that accounting for trait adaptation may explain stable and supersaturated species coexistence for a broad range of environmental conditions in natural systems when the absence of such adaptive changes would preclude it. Small trait changes, coincident with those that may occur within many natural populations, greatly enlarged the number of coexisting species.     

Functional equivalence of morphologies enables morphological and ecological diversity

Diversity in organismal forms among taxa is thought to reflect distinct selection pressures across environments. The central assumption underlying this expectation is that taxa experiencing similar selection have similar response to that selection. However, because selection acts on trait function, taxa similarity in selection response depends crucially on the relationship between function and morphology. Further, when a trait consists of multiple parts, changes in function in response to selection can result from modification of different parts, and adaptation to the same environment might result in functional but not morphological similarity. Here, we address the extent to which functional and morphological diversity in masticatory apparatus of soricid shrews reflects a shared ecological characteristic of their diet type. We examine the factors limiting morphological variation across shrew species by assessing the relative contribution of trait function (biomechanics of the jaw), ecology, and phylogeny to species similarity in mandibular traits. We found that species that shared diet type were functionally but not morphologically similar. The presence of multiple semi-independently varying traits enabled functional equivalence of composite foraging morphologies and resulted in variable response to selection exerted by similar diet. We show that functional equivalence of multiple morphologies enabled persistence of differences in habitat use (e.g., habitat moisture and coverage) among species that specialize on the same diet. We discuss the importance of developmental and functional integration among traits for evolutionary diversification of morphological structures that generate equivalent functions.     

Comparing IUCN and Probabilistic Assessments of Threat: Do IUCN Red List Criteria Conflate Rarity and Threat?

Estimates of threat form an intrinsic element of World Conservation Union (IUCN) Red List criteria, and in the assignment of species to defined threat categories. However, assignment under the IUCN criteria is demanding in terms of the amount of information that is required. For many species adequate data are lacking. Further, many of the terms and parameters used under IUCN criteria are subjective and open to varying interpretations. During the last decade a number of probabilistic statistical models have been developed which use historical sighting data, such as herbarium and museum collections, to generate objective, quantitative inference of threat and extinction without the requirement for extensive formal survey procedures and where little or no other data exists. In this study these statistical models were applied to herbarium data for the genus Guzmania (Bromeliaceae) from Ecuador. The results suggest that, for species for which collection records are adequate, these methods can be of use in strengthening IUCN Red List assessment procedure. Further, these methods present a unique means of prioritising threat when few biological data are available.     

Present day risk of extinction may exacerbate the lower species richness of dioecious clades

Dioecious clades have been observed to have lower species richness than their non‐dioecious sister groups indicating that dioecious species experience higher extinction rates and (or) lower speciation rates. To determine whether current threats to biodiversity may exacerbate this pattern, we examined the threat to exclusively dioecious families of angiosperms among the 13,013 species of threatened plants included in the IUCN Red List of Threatened Species. When examined phylogenetically, dioecious families had proportionally more species listed than their sister groups. We then examined whether ecological traits correlated with dioecy, namely tropical distribution, woody growth form, and fleshy fruits, are associated with having higher proportions of threatened species. Ignoring breeding system, woody growth form was the only trait that was associated with a greater than expected proportion of threatened species per family. Red‐Listed dioecious families were more likely to have a woody growth form than non‐dioecious families. Woody growth habit is likely contributing to the higher incidence of dioecious species being at risk of extinction but is not solely responsible for the pattern because higher risk within dioecious groups was also apparent in a comparison of exclusively woody sister‐group pairs. Our results indicate that dioecious plants may warrant special attention in conservation practices.     

Functional trait differences and the outcome of community assembly: an experimental test with vernal pool annual plants

Functional trait‐based approaches have seen rapid development in community ecology and biogeography in recent years, as they promise to offer a better mechanistic and predictive understanding of community structure. However, several key challenges remain. First, while many studies have explored connections between functional traits and abiotic gradients, far fewer have directly tested the common assumption that functional trait differences influence interspecific interactions. Second, empirical studies often ignore intraspecific trait variation within communities, even though intraspecific variation has been known to have substantial impacts on community dynamics. Here we present an experiment designed to assess the role of functional trait differences in predicting the outcome of interspecific species interactions among a suite of California vernal pool annual plants. Eight species were grown in pairwise combinations in two levels of inundation in a greenhouse and functional traits were measured on all individuals. Nested models predicting focal plant performance were fit to the data. For seven of the eight species in the experiment, the best model included a functional trait difference term that was consistent with a competitive hierarchy, indicating that focal species tended to do better when they had larger leaf size, lower specific leaf area, and greater investment in lateral canopy spread than their neighbors. Models that included individually measured trait values generally performed better than models using species trait averages. We tested if the same trait measurements predicted tolerance of inundation (a feature of vernal pool habitats), and species depth distributions from extensive field surveys, though we did not find strong relationships. Our results suggest that functional traits can be used to make inferences about the outcome of interspecific interactions, and that greater predictive power can come from considering intraspecific variation in functional traits, particularly in low diversity communities.     

Evaluating the predicted extinction risk of living amphibian species with the fossil record

Bridging the gap between the fossil record and conservation biology has recently become of great interest. The enormous number of documented extinctions across different taxa can provide insights into the extinction risk of living species. However, few studies have explored this connection. We used generalised boosted modelling to analyse the impact of several traits that are assumed to influence extinction risk on the stratigraphic duration of amphibian species in the fossil record. We used this fossil‐calibrated model to predict the extinction risk for living species. We observed a high consensus between our predicted species durations and the current IUCN Red List status of living amphibian species. We also found that today's Data Deficient species are mainly predicted to experience short durations, hinting at their likely high threat status. Our study suggests that the fossil record can be a suitable tool for the evaluation of current taxa‐specific Red Listing status.     

桂林岩溶石山青冈群落植物功能性状的尺度变化与关联

研究植物功能性状在不同尺度的变异和关联,对于揭示植物对环境的适应策略和群落构建规律具有重要意义。以岩溶石山青冈群落为研究对象,测量了研究区内20个样方74种木本植物的叶面积、比叶面积和木材密度3个功能性状值,利用性状梯度分析法分析了3个性状在群落内部(α组分)及群落间(β组分)的变异格局及相关性。结果表明:(1)群落内3个植物功能性状的α值范围均大于β值范围,即物种相对于共生物种性状值的变化大于沿着群落平均性状梯度的变化。(2)植物功能性状比叶面积的种内差异引起的变化小于群落水平。(3)叶面积与比叶面积、比叶面积与木材密度、叶面积与木材密度的β组分相关性均最强,而α组分间无相关性或相关性较弱,即叶面积与比叶面积、比叶面积与木材密度、叶面积与木材密度两两性状间的相关性在群落间的依赖程度比群落内共生物种的依赖性要强,暗示物种在群落内和群落间采取不同的生态策略来适应环境。     

Application of the IUCN Red Listing system to setting species targets for conservation planning purposes

Biodiversity targets, or estimates of the quantities of biodiversity features that should be conserved in a region, are fundamental to systematic conservation planning. We propose that targets for species should be based on the quantitative thresholds developed for the Vulnerable category of the IUCN Red List system, thereby avoiding future listings of species in an IUCN Red List threat category or an increase in the extinction risk, or ultimate extinction, of species already listed as threatened. Examples of this approach are presented for case studies from South Africa, including threatened taxa listed under the IUCN Red List criteria of A to D, a species listed as Near Threatened, a species of conservation concern due to its rarity, and one species in need of recovery. The method gives rise to multiple representation targets, an improvement on the often used single representation targets that are inadequate for long term maintenance of biodiversity or the arbitrary multiple representation and percentage targets that are sometimes adopted. Through the implementation of the resulting conservation plan, these targets will ensure that the conservation status of threatened species do not worsen over time by qualifying for higher categories of threat and may actually improve their conservation status by eliminating the threat of habitat loss and stabilizing population declines. The positive attributes ascribed to the IUCN Red List system, and therefore to the species targets arising from this approach, are important when justifying decisions that limit land uses known to be detrimental to biodiversity.