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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]

• Glacial survival of Astragalus onobrychis within the Pannonian region. • Pleistocene E–W expansion from the Pontics/Caucasus into Pannonian region (8x). • Younger, smaller-scaled postglacial W–E migration across the Pannonian region. • Long-term stable populations in Dobruja, N Balkan & Central Pontic subregions. • High genetic uniqueness of S Pannonian, N Balkan and N Caucasus populations. Steppe grasslands represent important refuges for rare species in the Pannonian region of eastern Central Europe. Nevertheless, little is known about their regional continuity and potential (post)glacial in-situ survival. Biogeographical studies assume potential source areas for the postglacial (re)colonisation of the Pannonian region in the Western and Central Pontics including the Black Sea coast. However, south-exposed slopes surrounding the Hungarian plain may have also played an important role as small-scale refugia. Using cpDNA sequence markers (atpI-H , rpL16, ycf1) and 190 individuals representing 25 populations, we investigated the genetic diversity and biogeographical history of Astragalus onobrychis within different subregions of its European distribution. We aimed at answering questions about the glacial survival, (post)glacial expansion and/or recent decline of the species throughout this area. A TCS network showed 108 haplotypes, which were divided into two unconnected clusters, representing different ploidy levels. We found octoploid populations widely distributed from the Pannonian region and Transylvania to more eastern areas in the Western Pontics and the Northern Caucasus. On the contrary, di- and tetraploid populations occur in the Dobruja and the Northern Balkan Peninsula, but also in the Central Pontic and the Southern Pannonian subregions. Four main cpDNA haplotype groups basically showed a geographical pattern; the Pannonian region being best-defined. We found high haplotype and moderate to high nucleotide diversity within most populations/subregions. Equilibrating these two genetic diversity measures indicates a long-term – probably glacial – (diploid) persistence of A. onobrychis in the Southern Pannonian subregion, areas along the Black Sea coast, the Northern Balkan Peninsula and the Central Pontic subregion. However, the octoploid lineage likely originated more to the east and expanded to Western Pontic areas and the Pannonian Basin probably already during Pleistocene. [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]