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Essl F.,Environment Agency Austria | Rabitsch W.,Environment Agency Austria | Dullinger S.,University of Vienna | Dullinger S.,Vienna Institute for Nature Conservation and Analyses | And 3 more authors.
Global Ecology and Biogeography | Year: 2013

Aim: To analyse if the historical species description process in 10 animal groups differed among widespread and endemic species and to evaluate whether our current knowledge about the diversity of these groups is complete. Location: Sixty-nine terrestrial regions (countries, large islands, archipelagos) covering all of Europe. Methods: Based on data from the Fauna Europaea project, we reconstructed the description histories of four vertebrate groups (amphibians, fish, mammals, reptiles) and six well-studied invertebrate groups (butterflies, grasshoppers, ground beetles, snails, spiders, true bugs) living in terrestrial and freshwater environments. We used accelerated failure time models to test for a possible delay of endemic species detection and to provide conservative estimates of the as yet undescribed proportions of the existing diversity. Results: Our data set includes 24,092 species, of which 7202 (30%) are endemic to one Fauna Europaea region. Species descriptions over time follow different trajectories for endemic and widespread species, with endemic species being described 79 years later than widespread ones, on average. Rates of widespread species descriptions have been low throughout the 20th century despite increasing numbers of active taxonomists, and models indicate that only a minor fraction of extant species is unknown (0.4-3%). By contrast, endemic species accumulation curves do not seem to have levelled off yet. Conservative model predictions suggest that up to 19% of the existing endemic diversity still awaits description in some taxonomic groups. Conclusions: Our results suggest that even for well-studied groups in the world's biogeographically best-known continent, scientific knowledge of species richness is far from complete and is biased towards widespread species. Research and conservation priorities may thus be misdirected, as, for example, regions with high numbers of as yet unrecognized endemics may not be adequately considered when setting conservation priorities. This is particularly problematic as their mostly small populations make endemic species especially vulnerable to human-induced pressures. © 2012 Blackwell Publishing Ltd.

Bieringer G.,University of Vienna | Zulka K.P.,Environment Agency Austria | Milasowszky N.,University of Vienna | Sauberer N.,Vienna Institute for Nature Conservation and Analyses
Biodiversity and Conservation | Year: 2013

Natural steppes in European agricultural landscapes are characterized by high biotic richness but are subject to fragmentation and associated edge effects. Edge effects on species richness were investigated at an ecotone from a pine plantation to a short-grass steppe in Eastern Austria for eleven invertebrate taxa differentiated into habitat guilds based on known live-history strategies of individual species (grassland species, forest species, generalist species), including Red-Listed and non-threatened grassland species. The large size of the studied grassland site provided an opportunity to test edge effects in the absence of confounding factors and to a gradient length of 208 m into the grassland habitat along a clear-cut border to a pine plantation. All sampling was done by pitfall trapping. Species richness of habitat guilds, but not total richness, was effectively explained by biotic variables reflecting the influence of shading in particular (i.e. soil temperature sums). Total species richness showed a bimodal response pattern, with increases towards the habitat edge and interior grassland habitat. Habitat guilds showed diverging responses to distances from the edge, but no saturation in species richness, with a continuum of edge effects across the entire distance of the grassland samples. Our findings contrast those of previous investigations based on samples taken from smaller patches and across shorter distances from the edge. Methodological and conservation implications are discussed. © 2013 Springer Science+Business Media Dordrecht.

Essl F.,Environment Agency Austria | Mang T.,Vienna Institute for Nature Conservation and Analyses | Moser D.,Environment Agency Austria | Moser D.,Vienna Institute for Nature Conservation and Analyses
Biological Invasions | Year: 2012

Temperate forests are relatively little affected by invasions globally. However, it remains unclear if these low invasion levels can be attributed to high invasion resistance, or if particularly long time lags in forests have lead to wide-spread invasion debt at the landscape and habitat scales, thus masking the invasibility of forests. Using linear and generalized linear mixed-effects models, we tested which factors determine the level of invasion of old (archaeophytes, pre-1500 alien species) and new (neophytes, post-1500 alien species) invaders across 30 study sites (5 ha size) and 16 transects in lowland forests in eastern Austria, Central Europe. We analysed the importance of different forest types, adjacent habitats, introduction pathways, species' local residence time and proximity to human settlements as proxy for propagule pressure. We recorded 109 neophyte and 50 archaeophyte species, with significant differences between both groups with respect to region of origin, pathways, and life form. The number of neophyte species per study site varied by more than an order of magnitude and was dependent on both proximity to settlements and residence time in a non-linear manner, with proximity to settlements showing a particularly strong effect for recently introduced neophytes. In contrast, archaeophyte species numbers were only marginally affected by distance to the nearest settlement. Within habitats, transect plots close to the forest edge and adjacent to settlements showed significantly higher numbers and cover of neophyte species, whereas for archaeophytes and native species no such effect could be detected. Our results suggest that time lag phenomena stemming from dispersal limitation (e. g. aggravated by isolation of forest patches), heterogeneity in species' local residence time as well as increases in local levels of propagule pressure (e. g. created by expanding settlements), may result in wide-spread invasion debt at the landscape and habitat scales, hence masking invasibility of forests. Spread of new invaders may ultimately, although possibly only over long time periods, result in increased frequency and impact of neophyte species in temperate forests. © 2011 Springer Science+Business Media B.V.

Kleinbauer I.,Vienna Institute for Nature Conservation and Analyses | Kleinbauer I.,University of Vienna | Dullinger S.,Vienna Institute for Nature Conservation and Analyses | Dullinger S.,University of Vienna | And 3 more authors.
Biological Conservation | Year: 2010

Static networks of nature reserves disregard the dynamics of species ranges in changing environments. In fact, climate warming has been shown to potentially drive endangered species out of reserves. Less attention has been paid to the related problem that a warmer climate may also foster the invasion of alien species into reserve networks. Here, we use niche-based predictive modelling to assess to which extent the Austrian Natura 2000 network and a number of habitat types of conservation value outside this network might be prone to climate warming driven changes in invasion risk by Robinia pseudacacia L., one of the most problematic alien plants in Europe. Results suggest that the area potentially invaded by R. pseudacacia will increase considerably under a warmer climate. Interestingly, invasion risk will grow at a higher than average rate for most of the studied habitat types but less than the national average in Natura 2000 sites. This result points to a potential bias in legal protection towards high mountain areas which largely will remain too cold for R. pseudacacia. In contrast, the selected habitat types are more frequent in montane or lower lying regions, where R. pseudacacia invasion risk will increase most pronouncedly. We conclude that management plans of nature reserves should incorporate global warming driven changes in invasion risk in a more explicit manner. In case of R. pseudacacia, reducing propagule pressure by avoiding purposeful plantation in the neighbourhood of reserves and endangered habitats is a simple but crucial measure to prevent further invasion under a warmer climate. © 2009 Elsevier Ltd. All rights reserved.

Cooper E.J.,University of Tromsø | Dullinger S.,University of Vienna | Dullinger S.,Vienna Institute for Nature Conservation and Analyses | Semenchuk P.,University of Vienna | Semenchuk P.,University Center in Svalbard
Plant Science | Year: 2011

In tundra areas where the growing season is short, any delay in the start of summer may have a considerable effect on plant development, growth and reproductive success. Climate models suggest long-term changes in winter precipitation in the Arctic, which may lead to deeper snow cover and a resultant delay in date of snow melt. In this paper, we investigated the role of snow depth and melt out date on the phenological development and reproductive success of vascular plants in Adventdalen, Svalbard (78°10'N, 16°06'E). Effects of natural variations in snow accumulation were demonstrated using two vegetation types (snow depth: meadow 21. cm, heath 32. cm), and fences were used to experimentally increase snow depth by over 1. m. Phenological delay was greatest directly after snowmelt in the earlier phenological phases, and had the largest effect on the early development of those species which normally green-up early (i.e. Dryas, Papaver, Salix, Saxifraga). Compressed growing seasons and length of the reproductive period led to a reduced reproductive success in some of the study species. There were fewer flowers, fewer plots with dispersing seeds, and lower germination rates. This can have consequences for plant establishment and community composition in the long-term. © 2010 Elsevier Ireland Ltd.

Hulber K.,Vienna Institute for Nature Conservation and Analyses | Hulber K.,University of Vienna | Winkler M.,University of Natural Resources and Life Sciences, Vienna | Grabherr G.,University of Vienna
Functional Ecology | Year: 2010

High alpine plants endure a cold climate with short growing seasons entailing severe consequences of an improper timing of development. Hence, their flowering phenology is expected to be rigorously controlled by climatic factors. We studied ten alpine plant species from habitats with early and late melting snow cover for 2 years and compared the synchronizing effect of temperature sums (TS), time of snowmelt (SM) and photoperiod (PH) on their flowering phenology. Intraseasonal and habitat-specific variation in the impact of these factors was analysed by comparing predictions of time-to-event models using linear mixed-effects models. Temperature was the overwhelming trigger of flowering phenology for all species. Its synchronizing effect was strongest at or shortly after flowering indicating the particular importance of phenological control of pollination. To some extent, this pattern masks the common trend of decreasing phenological responses to climatic changes from the beginning to the end of the growing season for lowland species. No carry-over effects were detected. As expected, the impact of photoperiod was weaker for snowbed species than for species inhabiting sites with early melting snow cover, while for temperature the reverse pattern was observed. Our findings provide strong evidence that alpine plants will respond quickly and directly to increasing temperature without considerable compensation due to photoperiodic control of phenology. © 2009 The Authors. Journal compilation © 2009 British Ecological Society.

Dobes C.,University of Vienna | Luckl A.,University of Vienna | Hulber K.,University of Vienna | Hulber K.,Vienna Institute for Nature Conservation and Analyses | Paule J.,Senckenberg Institute
New Phytologist | Year: 2013

The flow cytometric seed screen allows for identification of reproductive modes of seed formation and inference of the ploidy of contributing gametes. However, the lack of a mathematical formalization to infer male/female genomic contributions, and the prerequisite of a binucleate female contribution to the endosperm limits its applicability. We evaluated this assumption combining a DNA-based progeny survey with a comparison of the cytology of reproductive pathways co-occurring within single individuals representing 14 Potentilleae species from six phylogenetic lineages. A numerical framework valid for sexual and pseudogamous taxa was developed, enabling quantification of female and male genomes contributing to embryo and endosperm independent of gametophyte origins, numbers of sperm involved and ploidy of parents. The inference strongly depended on accurate peak index estimation. The endosperm of Potentilleae species received a binucleate female contribution in five evolutionary lineages whereas endosperm formation remained uncertain in the Tormentillae. A modified flow cytometric seed screen protocol was developed to cope with low endosperm contents. Evolutionary conservation of a binucleate female contribution to the endosperm suggested wide applicability of flow cytometric seed screen - at least in the Potentilleae. However, alternative progeny surveys and precise embryo/endosperm ploidy estimates are required for a comprehensive understanding of the cytology of seed formation. © 2013 New Phytologist Trust.

Willner W.,Vienna Institute for Nature Conservation and Analyses | Sauberer N.,Vienna Institute for Nature Conservation and Analyses | Staudinger M.,AVL ARGE Vegetationsokologie and Landschaftsplanung GmbH | Schratt-Ehrendorfer L.,University of Vienna
Tuexenia | Year: 2013

The Pannonian part of Austria is a diverse landscape situated in the transition zone between the Alps, the Bohemian Massif and the Carpathian Basin. Although the grasslands of this region have been investigated in many botanical and vegetation studies, their phytosociological classification has re-mained confusing. With this paper, we start a series aiming at a developement of a revised, consistent system of the Austrian Pannonian grasslands. Here we present a general overview focusing on the higher syntaxonomic units. We define grasslands as all types of meadows, pastures, fens and primary steppes. We selected all available relevés of Pannonian grasslands from the Austrian Vegetation Database. Additional unpub-lished data were included from the Danube National Park and the Biosphere Reserve Vienna Woods. To account for the comparatively low number of relevés from the northern part of the Pannonian region of Austria (Weinviertel), we included also data from southern Moravia (Czech Republic). This set of 3384 relevés was classified using TWINSPAN. Relevés that were considered as misclassified at the alliance level according to the summarised cover of diagnostic species were manually re-arranged, and the data-set specific fidelity of species to alliances was calculated using the phi coefficient. The first TWINSPAN division largely corresponded to the traditional border between the classes Festuco-Brometea and Molinio-Arrhenatheretea. The conventional alliance concepts were generally well supported. As an exception, the distinction between Diantho-Seslerion and Bromo-Festucion pallentis was not reproduced at all. Therefore, we unite all rocky grasslands on calcareous soils in a single alliance Seslerio-Festucion pallentis. We also advocate the inclusion of all basiphilous semi-dry grasslands of the study area within a single alliance Cirsio-Brachypodion. Each of the corresponding TWINSPAN clusters showed a clear prevalence of Cirsio-Brachypodion species. Moreover, two sepa-rate alliances of semi-dry grasslands would have almost no regional character species.

Hulber K.,Vienna Institute for Nature Conservation and Analyses | Hulber K.,University of Vienna | Bardy K.,University of Vienna | Dullinger S.,Vienna Institute for Nature Conservation and Analyses | Dullinger S.,University of Vienna
Perspectives in Plant Ecology, Evolution and Systematics | Year: 2011

The relative roles of abiotic conditions and competition by grassland plants in restricting the distribution of certain alpine plant species to snowbed habitats (i.e. sites with particular long-lasting snow cover) is still a matter of debate. Here, we set up a five-year field experiment to compare three vital rates (germination from sown seeds, growth and survival of transplanted juveniles) of four calcareous alpine snowbed plants within sparsely and densely vegetated plots along a natural snowmelt gradient from the centre of a snowbed to the margins of the surrounding grasslands. Without a dense canopy, we found germination and juvenile growth to respond homogeneously across species with optimal performance under intermediate snowmelt. Dense vegetation cover reduced these two vital rates for all species, with the strongest effects of competition detectable at intermediate snowmelt times again. Survival patterns were less consistent among species. In particular, two of the four species showed lowest mortality at the grassland margins when the surrounding vegetation cover was sparse, and the effect of a dense canopy on their survival turned from competitive to facilitative towards the snowbed centre. Overall, these results indicate that the distribution limits of the studied snowbed plants are determined by a combination of abiotic and biotic effects with competition further reducing their performance in grassland sites below the already low levels caused by the abiotic conditions. With respect to climate warming, a combined negative effect of reduced snow cover protection and increased competition by encroaching grassland plants seems a worrying, but possible scenario. We concede, however, that care has to be taken when drawing conclusions on cause-effect relationships from experiments along natural gradients and discuss the uncertainties associated with our results as well as with inferences on the possible future of snowbed plants under a warmer climate. © 2011 Perspectives in Plant Ecology, Evolution and Systematics.

Dullinger S.,University of Vienna | Dullinger S.,Vienna Institute for Nature Conservation and Analyses | Hulber K.,University of Vienna | Hulber K.,Vienna Institute for Nature Conservation and Analyses
PLoS ONE | Year: 2011

Background: The distribution and abundance of plants is controlled by the availability of seeds and of sites suitable for establishment. The relative importance of these two constraints is still contentious and possibly varies among species and ecosystems. In alpine landscapes, the role of seed limitation has traditionally been neglected, and the role of abiotic gradients emphasized. Methodology/Principal Findings: We evaluated the importance of seed limitation for the incidence of four alpine snowbed species (Achillea atrata L., Achillea clusiana Tausch, Arabis caerulea L., Gnaphalium hoppeanum W. D. J. Koch) in local plant communities by comparing seedling emergence, seedling, juvenile and adult survival, juvenile and adult growth, flowering frequency as well as population growth rates λ of experimental plants transplanted into snowbed patches which were either occupied or unoccupied by the focal species. In addition, we accounted for possible effects of competition or facilitation on these rates by including a measure of neighbourhood biomass into the analysis. We found that only A. caerulea had significantly lower seedling and adult survival as well as a lower population growth rate in unoccupied sites whereas the vital rates of the other three species did not differ among occupied and unoccupied sites. By contrast, all species were sensitive to competitive effects of the surrounding vegetation in terms of at least one of the studied rates. Conclusions/Significance: We conclude that seed and site limitation jointly determine the species composition of these snowbed plant communities and that constraining site factors include both abiotic conditions and biotic interactions. The traditional focus on abiotic gradients for explaining alpine plant distribution hence appears lopsided. The influence of seed limitation on the current distribution of these plants casts doubt on their ability to readily track shifting habitats under climate change unless seed production is considerably enhanced under a warmer climate. © 2011 Dullinger, Hülber.

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