Dengler J.,University of Bayreuth |
Dengler J.,Synthesis Center sDiv |
Janisova M.,Slovak Academy of Sciences |
Torok P.,Debrecen University |
And 2 more authors.
Agriculture, Ecosystems and Environment
This article introduces a Special Issue on biodiversity of Palaearctic grasslands and provides a synthesis of the current knowledge on this topic. Four major categories of grasslands can be distinguished in the Palaearctic biogeographic realm: (a) zonal steppes (in areas too dry for forests), (b) arctic-alpine grasslands (in areas too cold for forests), (c) azonal and extrazonal grasslands (where hydrology, soil conditions, relief or natural disturbances within the forest biomes prevent tree growth locally) and (d) secondary grasslands (which replace natural forests in consequence of human land use). We summarize the present knowledge about species richness patterns (mainly of vascular plants) along abiotic and land use gradients. Further, we highlight the usefulness of diversity measures not based on species richness, namely functional diversity, phylogenetic diversity and within-species diversity. The strong differences observed for diversity patterns according to analyzed biodiversity parameter, spatial scale or taxonomic group call for comparative studies and caution when generalizing results. A particular challenge are the extreme plot-scale species richness values found in grasslands of a few European regions. We propose a conceptual model that explains the findings by an interplay of various factors acting at different levels: (i) The largest species pool is expected for habitats under conditions that prevailed over the last few million years, with a slight shift towards intermediate positions, i.e. for the Palaearctic in open, semi-dry, base-rich situations. (ii) The landscape-level species pool is increased by continuity of a grassland patch in space and time and heterogeneity of the surrounding landscape. (iii) The coexistence of regionally available species at a plot scale is due to reduced competitive exclusion according to Intermediate Disturbance Hypothesis, mowing once a year without fertilization being particularly effective. Ecosystem functions and services of Palaearctic grasslands are often positively connected to their biodiversity. At the same time, these communities and their biota are nowadays highly endangered. The semi-natural (High Nature Value) grasslands of Europe are mainly threatened by agricultural intensification or abandonment on low-productive sites in remote areas, while the natural steppes of the Palaearctic have largely been destroyed by conversion into arable land. Finally, we present some promising conservation and management approaches and call for a strong and comprehensive Convention on Grassland Conservation. © 2013 Elsevier B.V. Source
Kuzemko A.A.,Ukrainian Academy of Sciences |
Steinbauer M.J.,University of Aarhus |
Becker T.,University of Trier |
Didukh Y.P.,Ukrainian Academy of Sciences |
And 7 more authors.
Biodiversity and Conservation
We asked: (i) Which environmental factors determine the level of α-diversity at several scales and β-diversity in steppic grasslands? (ii) How do the effects of environmental factors on α- and β-diversity vary between the different taxonomic groups (vascular plants, bryophytes, lichens)? We sampled nested-plot series ranging from 0.0001 to 100 m2 and additional 10-m2 plots, covering different vegetation types and management regimes in steppes and semi-natural dry grasslands of Central Podolia (Ukraine). We recorded all terricolous taxa and used topographic, soil, land-use and climatic variables as predictors. Richness-environment relationships at different scales and across taxonomic groups were assessed with multimodel inference. We also fitted power-law species-area relationships, using the exponent (z value) as a measure of β-diversity. In general, the richness values in the study region were intermediate compared to those known from similar grasslands throughout the Palaearctic, but for 1 cm2 we found seven species of vascular plants, a new world record. Heat index was the most important factor for vascular plants and bryophytes (negative relation), while lichen diversity depended mainly on stone and rock cover (positive). The explanatory power of climate-related variables increased with increasing grain size, while anthropogenic burning was the most important factor for richness patterns at the finest grain sizes (positive effect). The z values showed more variation at the finest grain sizes, but no significant differences in their mean between scales. The results highlight the importance of integrating scale into ecological analyses and nature conservation assessments in order to understand and manage biological diversity in steppe ecosystems. © 2016 Springer Science+Business Media Dordrecht Source
Meyer C.,University of Gottingen |
Meyer C.,Synthesis Center sDiv |
Weigelt P.,University of Gottingen |
Kreft H.,University of Gottingen
Plants are a hyperdiverse clade that plays a key role in maintaining ecological and evolutionary processes as well as human livelihoods. Biases, gaps and uncertainties in plant occurrence information remain a central problem in ecology and conservation, but these limitations remain largely unassessed globally. In this synthesis, we propose a conceptual framework for analysing gaps in information coverage, information uncertainties and biases in these metrics along taxonomic, geographical and temporal dimensions, and apply it to all c. 370 000 species of land plants. To this end, we integrated 120 million point-occurrence records with independent databases on plant taxonomy, distributions and conservation status. We find that different data limitations are prevalent in each dimension. Different metrics of information coverage and uncertainty are largely uncorrelated, and reducing taxonomic, spatial or temporal uncertainty by filtering out records would usually come at great costs to coverage. In light of these multidimensional data limitations, we discuss prospects for global plant ecological and biogeographical research, monitoring and conservation and outline critical next steps towards more effective information usage and mobilisation. Our study provides an empirical baseline for evaluating and improving global floristic knowledge, along with a conceptual framework that can be applied to study other hyperdiverse clades. © 2016 John Wiley & Sons Ltd/CNRS. Source
Kuzemko A.A.,Ukrainian Academy of Sciences |
Becker T.,University of Trier |
Didukh Y.P.,Ukrainian Academy of Sciences |
Ardelean I.V.,Babes - Bolyai University |
And 13 more authors.
We present the data of the 2nd research expedition of the European Dry Grassland Group (EDGG), which was conducted in 2010 in Central Podolia, Ukraine. The aim was to collect plot data to compare Ukrainian dry grasslands with those of other parts of Europe in terms of syntaxonomy and biodiversity. We sampled 21 nested-plot series (0.0001-100 m2) and 184 normal plots (10 m2) covering the full variety of dry grassland types occurring in the study region. For all plots, we recorded species composition of terrestrial vascular plants, bryophytes and lichens, while for the 226 10-m2 plots we estimated and measured percentage cover of all species, structural, topographic, soil and landuse parameters. The 10-m2 plots were used for phytosociological classification based on iteratively refined TWINSPAN classification as well as for DCA ordination. Differences between the derived vegetation types with respect to environmental conditions and species richness were assessed with ANOVAs. We assigned our plots to nine association-level units but refrained from placing them into formal associations with two exceptions. In the study area, dry grasslands of the Festuco-Brometea were far more common than those of the Koelerio-Corynephoretea. Among the Festuco-Brometea, xeric Festucetalia valesiacae grasslands were more frequent and represented by the Festucion valesiacae (2 associations, including the Allio taurici-Dichanthietum ischaemi ass. nova) and the Stipion lessingianae (1) compared to the Brachypodietalia pinnati with the Agrostio vinealis-Avenulion schellianae (3). The Koelerio-Corynephoretea were represented by three associations, each from a different order and alliance: basiphilous outcrops (Alysso alyssoidis-Sedetalia: Alysso alyssoidis-Sedion?), acidophilous outcrops (Sedo-Scleranthetalia: Veronico dillenii-Sedion albi?) and mesoxeric sandy grasslands (Trifolio arvensis-Festucetalia ovinae: Agrostion vinealis). We discuss the issue of the mesoxeric order Galietalia veri placed within the Molinio-Arrhenatheretea by Ukrainian authors and conclude that the content of that order would probably be better placed in the mesoxeric orders of the Koelerio-Corynephoretea and Festuco-Brometea. Other syntaxonomic questions could not be solved with our geographically limited dataset and await a supraregional analysis, e.g. whether the Ukrainian outcrop communities should be assigned to the same alliances as known from Central Europe or rather represent new vicariant units. The analysis of the biodiversity patterns showed that at a grain size of 10 m2, Podolian Koelerio-Corynephoretea communities were overall richer than Festuco-Brometea communities (46.4 vs. 40.6 species). This difference was due to the Koelerio-Corynephoretea containing twice as many bryophytes and nine times more lichens, while vascular plant species richness did not differ significantly between classes. The orders within the classes showed no real differences in species richness. The richness patterns observed in Podolia were almost the opposite of those usually found in dry grasslands, where Brachypodietalia pinnati are richer than Festucetalia valesiacae, and these richer than stands of the Koelerio-Corynpehoretea - and we do not have a good explanation for these idiosyncrasies. In conclusion, Podolian dry grasslands behave quite unexpectedly regarding biodiversity, and their syntaxonomy is still poorly understood. These knowledge gaps can only be addressed with supra-national analyses based on comprehensive datasets. Source
Berg C.,University of Graz |
Abdank A.,State Agency for Environment |
Isermann M.,University of Bremen |
Jansen F.,Free University of Berlin |
And 4 more authors.
Applied Vegetation Science
Aims: Red Lists of threatened species are a well-established conservation tool throughout the world. In contrast, Red Lists of ecosystems, habitats or plant community types have only recently found interest at the global level, although they have a longer tradition in Central Europe. We contribute to the debate by presenting and discussing a comprehensive conservation assessment methodology for plant communities that was developed within the framework of the project 'The plant communities of Mecklenburg-Vorpommern and their vulnerability'. Location: Mecklenburg-Vorpommern, Northeast Germany (23,174 km2). Approach: Our approach adopts various concepts from modern red listing and prioritization at various organizational levels of biodiversity, and combines them into a methodological framework applicable for regional to continental Red Lists of plant communities. For each distinguished plant community, three steps are carried out, i.e. (1) assessment of endangerment (scientific part, using the three criteria 'past trend', 'current status' and 'prognosis'), (2) assessment of conservation value (normative part, using the three criteria 'degree of naturalness', 'relevance for species conservation' and 'global relevance'), and (3) a combination of (1) and (2) to derive a need for action (conservation prioritization). These steps are all based on the successive aggregation of quantitative criteria via decision matrices, which makes the assessment process transparent, avoids definition gaps and allows easy adjustment of the decision rules. Conclusions: Plant community types derived from well-documented classifications of extensive vegetation-plot databases in combination with a transparent conservation assessment methodology have great potential in nature conservation and environmental monitoring. We suggest that the presented methodology is an improvement on traditional expert judgments as it separates the scientific and normative parts of the evaluation and uses clear, quantitative criteria and explicit rules to connect these into aggregated measures. It worked effectively and yielded meaningful results for a German federal state. By adjusting the scaling of the criteria, the approach can be adapted, as a whole or in part, to other regions or higher levels of ecosystem typology. © 2014 International Association for Vegetation Science. Source