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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. Source

Cooper E.J.,University of Tromso | 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. Source

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. Source

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. Source

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. Source

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