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The floodplain of the rivers Danube, March/Morava and Thaya/Dyje in eastern Austria and western Slovakia harbours a great diversity of meadows, reed swamps and sedge-bed communities. However, the grasslands along the Danube have not been adequately addressed by any study up to now, and a transnational revision of the alluvial grasslands is completely lacking. In this third part of a series focusing on the syntaxonomy of the Pannonian grasslands of Austria, we present a detailed classification of the grassland and marsh vegetation of the Danube and March-Thaya floodplain. We compiled all available relevés from the study area belonging to the classes Phragmito-Magnocaricetea, Molinio-Arrhenatheretea and Festuco-Brometea. In total, our data set comprised 2119 relevés, of which 355 were from Slovakia. We conducted a TWINSPAN classification and, based on a provisional syntaxonomic interpretation of the clusters, assigned all relevés to classes, orders, alliances and associations using the total cover of the diagnostic species in each relevé as the assignment criterion. We identified 42 associations and five provisional communities belonging to 14 alliances. Our revision includes substantial changes to previous overviews, in particular regarding the alluvial grasslands of the March-Thaya floodplain. We merge Lathyro palustris-Gratioletum, Gratiolo-Caricetum suzae, Cnidio-Violetum pumilae, Serratulo-Plantaginetum altissimae and "Silaetum pratensis" into only two associations (Gratiolo-Caricetum suzae and Cnidio-Violetum pumilae, alliance Deschampsion), which are differentiated along the moisture gradient. The Ophioglosso-Caricetum tomentosae is revealed as a geographical vicariant of the Cnidio-Violetum pumilae, replacing the latter along the Danube. The Agropyro-Alopecuretum pratensis is newly reported for Austria. The mesic Festuca rupicola grasslands along the March/Morava (previously named "Serratulo-Festucetum commutatae") are included in the Colchico-Festucetum rupicolae (Cirsio-Brachypodion). Ranunculo bulbosi-Arrhenatheretum, Pastinaco-Arrhenatheretum, Festuco rupicolae-Brometum and Polygalo-Brachypodietum (the latter in a new subass. selaginelletosum helveticae) are confirmed as widespread grassland types in the Danube floodplain, and the Teucrio botryos-Andropogonetum (Festucion valesiacae) is split into two subassociations. Moreover, we report four grassland types dominated by Elymus repens and Calamagrostis epigejos, provisionally treated as rankless communities, which have been neglected by all previous authors. [ABSTRACT FROM AUTHOR]

Species distribution models (SDMs) are used to project how suitable ranges of species shift under a warming climate. Conservation management, however, commonly targets habitat types rather than individual species. Such habitat types are often defined by the co-occurrence of a set of characteristic species. Here, we develop a co-occurrence-based index (CRI); which measures how the representation of habitat types in a particular area may change in a future climate. The index is based on stacking projections of distribution models of characteristic species and accounts for changes both in potential range size of each species individually and in spatial range overlap among characteristic species, i.e. co-occurrence patterns. We illustrate the approach by modelling the changing representation of 68 habitat types in Austria under two different climate scenarios. We base index calculations on SDM projections under either the assumption of unrestricted mobility ('full-dispersal') or of complete immobility ('no-dispersal') of individual species. Moreover, we compare results to those achieved with a simpler occurrence-based index (OI); which only accounts for change in species' range sizes. All three alternative index calculations suggest that most modelled habitat types will lose area (in particular mires, wetlands and siliceous alpine grasslands) and only a minority will profit from a warming climate (in particular forests of dry and warm sites). 'Full-dispersal' CRI and OI are closely, but not perfectly correlated. Importantly, for more than half of the habitat types, accounting for changing co-occurrence patterns amplifies projected losses. The 'no-dispersal' CRI (CRInd) delivers the most alarming projections, indicating considerable spatial turn-over of sites suitable to the habitat types. Taken together, our results suggest that modelling re-distribution of habitat types which are defined by species combinations needs to account for modifications of co-occurrence patterns. Moreover, conservation should acknowledge that novel combinations of species will likely emerge under a warming climate. [ABSTRACT FROM AUTHOR]

Large-scale infrastructure development projects are discussed transdisciplinarily in several domains of society. Critics often claim that environmental impact assessments lack real influence on planning, management, and monitoring. We report herein the evaluation of ecological compensation via biodiversity offsets and technical constructions with a secondary compensation function for a new railway in Austria. We asked: (1) where can ecological restoration success be detected, and (2) is our new method of a composite biotope value calculation representative for all criteria we used? We conducted a vegetation inventory on reference areas and all types of measures that created new habitats. Together with a comprehensive, spatially dense habitat mapping, evaluation of six attributes of restoration success and testing of our new method were carried out. Current threats typical for intensive agriculture have been generally reduced. Ecological compensation measures had the highest connectivity but the lowest plant community diversity. Surprisingly, technical constructions provided significantly more plant communities and hosted most Red List species. The species assemblage characteristics of compensation measures, their biotope type diversity, and their mean biotope values were, although lower, comparable to the reference. Despite the poor performance of technical areas in the final biotope values, our results call for their reconsideration as potential tools for ecological compensation by greening grey infrastructure in the near future. The tested new method provided an overall statement for the ecological restoration evaluation and could also be used for nature evidence inventories and as a valuable decision support tool in landscape planning. [ABSTRACT FROM AUTHOR]

. Question: Are there effects of long-term deposition of airborne nitrogen and sulphur on the forest floor vegetation from permanent plots collected in 1993 compared to 2005. Location: Northern limestone Alps in Austria. Methods: Single species responses were analysed by correlating trends in cover-abundance values, as derived from marginal models, with Ellenberg indicator values. Changes in the species composition of plots were analysed by correlating changes in mean Ellenberg indicator values with the displacement of plots within a multidimensional scaling ordination. Results: Trends in single species abundance were positively correlated with indicator values of soil pH but were independent of nutrient availability. A general trend towards the homogenisation of vegetation, due to convergent time vectors of the relevés, became obvious. Oligotrophic sites previously situated at the distal ends of ordination axes shifted towards the centre since they were enriched by species preferring mesotrophic conditions. The bulk of plots with intermediate site conditions hardly showed any trends. A concomitant analysis demonstrated that temporal changes in species composition exceed the variation in cover abundance estimates among different field botanists. Conclusions: N deposition can lead to a homogenisation of forest floor vegetation. Larger limestone areas with diverse soil conditions, such as the Northern limestone Alps in Austria, as a whole are thus negatively affected by airborne N deposition. Nevertheless, the vegetation was at least as strongly affected by an increase of basiphilous species as a result of decreasing S deposition. [ABSTRACT FROM AUTHOR]

We present a numerical classification of 2145 objectively sampled relevés from the entire forest area of Austria (Central Europe). The sample sites were selected by a combined method involving a systematic matrix and stratified random sampling. A TWINSPAN classification led to 32 clusters which are described in detail. Three main groups can be distinguished: (1) Alpine-dinaric coniferous forests on carbonate soils, (2) Coniferous forests on acid soils and (3) Deciduous forests. These groups correspond with accuracy to the classes Erico-Pinetea, Vaccinio-Piceetea and Querco-Fagetea in the traditional Braun-Blanquet system. Thus, the value of the Braun-Blanquet approach is supported by more or less objective sampling and numerical classification methods. The assumption of the objective existence of ecological species groups is strongly supported, too. Moreover, our results may help to solve some controverse points discussed in the European forest classification regarding the delimination between the three mentioned classes. [ABSTRACT FROM AUTHOR]

We assessed the relationships between site size, habitat quality, landscape factors (fragmentation, landscape diversity) and species richness in communities of Collembola in 50 small dry grassland habitat patches in an agricultural landscape of eastern Austria. Grasslands in that region were once widespread and extensive, but have become increasingly fragmented and isolated. We hypothesized that dry grassland springtails species richness is significantly correlated with site variables (soil properties, habitat quality) and that the size of grassland sites is positively correlated with species richness. We used pitfall traps in 50 dry grasslands in differently structured agricultural landscapes and tested total abundance and three species richness measures: (1) the number of dry grassland specialist species; (2) total number of dry grassland species and (3) overall species richness. In the multivariate correlation models, we found that all species richness measures were significantly related to the plant species richness, a shape parameter of the sites, soil properties such as humus, temperature, sand and gravel content and the landscape variable reflecting isolation (distance to the nearest large dry grassland area). This landscape variable indicates that neighbouring grasslands are influencing the species richness of the sites. This may be a result of passive wind dispersal across the landscape or historic connection of the small sites with much larger dry grasslands. The size of the site did not show any significant correlation with total, dry grassland specialist, dry grassland generalist or generalist species richness. The small size of Collembola might explain these findings, because they have high population densities even in small patches. [ABSTRACT FROM AUTHOR]

Both, agricultural intensification and abandonment caused a strong decline in plant species richness in semi-natural grasslands in Central Europe within the last decades. At a global scale, the Convention on Biological Diversity targeted at halting the decline of biodiversity by the end of 2010. Agri-environmental schemes (AES) have been developed at the national level to reach this biodiversity target in agricultural areas. We evaluated the effectiveness of Austrian agro-environmental schemes on species-rich grasslands within the UNESCO Biosphere Reserve Wienerwald. We found a general decrease of vascular plant species richness at 95 sites, from an average of 43 species in 1990/92 to 31 species in 2011. The average decrease of species classified as threatened according to the national Red List from 12 to 7 and the parallel increase of widespread, nitrophilous species indicates a reduced conservation value of observed meadows. Species losses did not differ between mesic meadows of the Arrhenatherion type (EU habitat type 6510) and more nutrient-poor, semi-dry Brometalia grasslands (EU habitat type 6210), indicating the sensitivity to changes in agricultural management regimes even for more intensively used grassland types. AES decelerated this overall trend but could not stop biodiversity losses over the past two decades. Although the maintenance of grassland management through AES prevented biodiversity loss in areas which otherwise would have been abandoned, adaptations of the Austrian AES are desirable to effectively conserve biodiversity at agricultural sites. [ABSTRACT FROM AUTHOR]

Highlights: [•] Historical patch size is a better species richness predictor than current size. [•] Habitat quality variables are better predictors than size variables. [•] High quality areas in the landscape are more important than extensively used areas. [•] Grassland specialists do not benefit from linear structures in the surroundings. [•] Conservation should achieve a network of high-quality grassland patches. [ABSTRACT FROM AUTHOR]