Time filter

Source Type

Zulka K.P.,University of Vienna | Zulka K.P.,Environment Agency Austria | Abensperg-Traun M.,University of Vienna | Milasowszky N.,University of Vienna | And 17 more authors.
Agriculture, Ecosystems and Environment

According to island biogeography theory, the species richness of patches is determined by their size and spatial isolation, while in conservation practice, it is patch quality that determines protection and guides management. We analysed whether size, isolation or habitat quality are most important for the species richness in a set of 50 dry grassland fragments in agricultural landscapes of eastern Austria. We studied two plant taxa (vascular plants, bryophytes) and 11 invertebrate taxa (gastropods, spiders, springtails, grasshoppers, true bugs, leafhoppers and planthoppers, ground beetles, rove beetles, butterflies and burnets, ants and wild bees). The species richness of three categories was analysed: (1) dry grassland specialist species, (2) all grassland species and (3) all species. We used regression and hierarchical partitioning techniques to determine the relationship between species richness and environmental variables describing patch size and shape, patch quality, landscape configuration and landscape quality. The area-isolation paradigm was only applicable for dry grassland specialists, which comprised 12% of all species. Richness of all grassland species was determined mostly by landscape heterogeneity parameters. Total species richness was highly influenced by spillover from adjacent biotopes, and was significantly determined by the percentage of arable land bordering the patches. When analysing all taxa together, species richness of dry grassland specialists was significantly related to historical patch size but not to current patch size, indicating an extinction debt. At the landscape scale, the variable 'short-grass area' was a better predictor than the less specific variable 'area of extensively used landscape elements'. 'Distance to mainland' was a good predictor for specialists of mobile animal taxa. Plant specialists showed a pronounced dependence on quality measures at the patch scale and at the landscape scale, whereas animal specialists were influenced by patch size, patch quality, landscape quality and isolation measures. None of the taxa benefited from linear structures in the surroundings. In conclusion, high patch quality and a network of high-quality areas in the surrounding landscape should be the best conservation strategy to ensure conservation of dry grassland specialists. This goal does not conflict with the specific demands of single taxa. © 2013 The Authors. Source

Schaider M.,University of Graz | Komposch C.,Institute for Animal Ecology and Landscape Planning | Stabentheiner E.,University of Graz | Raspotnig G.,University of Graz | Raspotnig G.,Medical University of Graz
Journal of Morphology

The morphological organization and functional anatomy of prosomal defensive (scent) glands in Paranemastoma quadripunctatum, a representative of the dyspnoid harvestmen, was investigated by means of histological semithin sections, software-based 3D-reconstruction and scanning electron microscopy. Scent glands comprise large, hollow sacs on either side of the prosoma, each of these opening to the outside via one orifice (ozopore) immediately above coxa I. In contrast to the situation known from laniatorean, cyphophthalmid and some eupnoid Opiliones, ozopores are not exposed but hidden in a depression (atrium), formed by a dorsal integumental fold of the carapace and the dorsal parts of coxae I. Glandular sacs are connected to ozopores via a short duct which is equipped with a specific closing mechanism in its distal part: A layer of modified epidermal cells forms a kind of pad-like tissue, surrounding the duct like a valve. Several muscles attached to the anterior parts of the glandular reservoir and to the epithelial pad may be associated with ozopore-opening. The actual mechanism of secretion discharge seems to be highly unusual and may be hypothesized on the basis of corroborating data from behavioral observations, scent gland anatomy and secretion chemistry as follows: Enteric fluid is considered to be directed towards the ozopores via cuticular grooves in the surface of the coxapophyses of legs I. Then, the fluid is sucked into the anterior part of the scent gland reservoirs by the action of dorsal dilator muscles that widen the reservoir and produce a short-term negative pressure. After dilution/solution of the naphthoquinone-rich scent gland contents, a secretion-loaded fluid is thought to be discharged with the help of transversal compressor muscles. This is the first detailed study on the functional anatomy of scent glands and the mechanisms of secretion discharge in the Dyspnoi. © 2011 Wiley-Liss, Inc. Source

Komposch C.,Institute for Animal Ecology and Landscape Planning

This paper deals with species whose range lies entirely (endemics) or predominantly (subendemics) within the political borders of Austria. The evolution and current distribution of Alpine endemics find their chief cause in the advent of the Pleistocene ice-ages, the destruction of much of the former fauna and in different forms of survival as well as migration from southern refugia. A first overview of endemic and subendemic arachnids of Austria shows 11 harvestman and 46 spider species. One hotspot of arachnological endemisms in the Eastern Alps are the north-eastern Calcareous Alps. The Gesäuse National Park, an exceptional area situated in the Ennstaler Alps (Styria, Austria), contains 6 subendemic harvestman and 12 endemic and subendemic spider species, i.e. 55% and 26% of the Austrian (subendemic) spectrum. Most of these Opiliones are soil-dwelling forms, most Araneae belong to the linyphiid genera Lepthyphantes s. l. and Troglohyphantes. All these species occur from the nival down to the montane zone, and prefer rock habitats, caves, avalanche corridors and natural woodlands. 100% of these harvestman and 57% of these spider species are Critically Endangered up to Vulnerable. So far, there is no legal protection for them. A main threat to those ice-age relicts is climate warming. There is a great need for conservation action on these endemics and for political support for the national park. Intensive basic research is required as well as encouragement for invertebrate specialists, the protection of endemics enshrined in law, conservation programmes and the creation of protected areas based on endemism hotspots, accompanied by public relations activities about these zoological treasures. Source

Drag L.,University of South Bohemia | Drag L.,Academy of Sciences of the Czech Republic | Hauck D.,Academy of Sciences of the Czech Republic | Berces S.,Duna Ipoly National Park Directorate | And 5 more authors.
Biological Journal of the Linnean Society

Knowledge of patterns of genetic diversity in populations of threatened species is vital for their effective conservation. Rosalia longicorn (Rosalia alpina) is an endangered and strictly protected beetle. Despite a marked decline in part of its range, the beetle has recently expanded to the lowlands of Central Europe. To facilitate a better understanding of the species' biology, recent expansion and more effective conservation measures, we investigated patterns of genetic structure among 32 populations across Central and South-east Europe. Eight microsatellite loci and a partial mitochondrial gene (cytochrome c oxidase subunit I) were used as markers. Both markers showed a significant decline in genetic diversity with latitude, suggesting a glacial refugium in north-western Greece. The cluster analysis of the nuclear marker indicated the existence of two genetically distinct lineages meeting near the border between the Western and Eastern Carpathians. By contrast, one widespread mtDNA haplotype was dominant in most populations, leading to the assumption that a rapid expansion of a single lineage occurred across the study area. The genetic differentiation among populations from the north-western part of the study area was, however, surprisingly low. They lacked any substructure and isolation-by-distance on a scale of up to 600 km. This result suggests a strong dispersal capacity of the species, as well as a lack of migration barriers throughout the study area. That the lowland populations are closely related to those from the nearby mountains indicates repeated colonization of the lowlands. Our results further suggest that R. alpina mostly lives in large, open populations. Large-scale conservation measures need to be applied to allow for its continued existence. © 2015 The Linnean Society of London. Source

Discover hidden collaborations