Time filter

Source Type

Horvath Z.,Eotvos Lorand University | Vad C.F.,Eotvos Lorand University | Toth A.,Balaton Limnological Research Institute | Zsuga K.,Facan sor 56 | And 4 more authors.

Salinity represents a major structuring factor in aquatic habitats which strongly affects species richness. We studied the relationships among species richness, density and phylogenetic diversity of zooplankton communities along a natural salinity gradient in astatic soda pans in the Carpathian Basin (Hungary, Austria and Serbia). Diversity and density showed opposing trends along the salinity gradient. The most saline habitats had communities of one or two species only, with maximum densities well above 1000 ind l-1. Similarity of communities increased with salinity, with most of the highly saline communities being dominated by one highly tolerant calanoid copepod, Arctodiaptomus spinosus, which was at the same time the only soda-water specialist. Salinity obviously constrained species composition and resulted in communities of low complexity, where few tolerant species ensure high biomass production in the absence of antagonistic interactions. The pattern suggests that environmental stress may result in highly constrained systems which exhibit high rates of functioning due to these key species, in spite of the very limited species pool. © 2013 The Authors. Source

Toth A.,Balaton Limnological Research Institute | Horvath Z.,WasserCluster Lunz | Vad C.F.,Eotvos Lorand University | Zsuga K.,Facan sor 56 | And 2 more authors.
International Review of Hydrobiology

Despite the high conservation value of intermittent soda pans, these habitats were mostly targeted by small-scale studies and little is known about their microscopic fauna. We sampled all the remaining 110 representatives of this habitat type (including recently restored ones) in Europe in an area covering approximately 125000km2. We analyzed spring and summer zooplankton species composition including rotifers, copepods, and cladocerans. We found 105 Rotifera, 26 Cladocera, and 26 Copepoda taxa, with local species richness ranging between 1 and 38 taxa. Alpha diversity was comparable in the two main groups (Rotifera, Crustacea), while beta and gamma diversity was higher in rotifers. The most frequently occurring zooplankters were crustaceans, while rotifer taxa were rarer as the most frequent species inhabited less than half of the pans. Dominance of the natronophilic Arctodiaptomus spinosus proved to be a reliable indicator for high quality soda pans. We concluded that the most typical soda pan zooplankton communities developed by early summer, in the concentrated pans, thus we would suggest considering this period as a reference for ecological state monitoring, and especially for evaluating the success of soda pan rehabilitations or reconstructions with the help of zooplankton. Based on these criteria, restorations could be considered only moderately successful. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Horvath R.,Debrecen University | Magura T.,Debrecen University | Szinetar C.,University of West Hungary | Eichardt J.,University of West Hungary | And 2 more authors.
Agriculture, Ecosystems and Environment

Previous studies reported that landscape-level factors are vital to support diversity of spiders in strongly modified arable lands and disturbed habitats such as managed semi-natural grasslands. Cropland management (ploughing, fertilization, and pest management) and agricultural practices (mowing and grazing) destroy and/or modify regularly the spider assemblages; thus, continuous recolonization from the surrounding landscape is vital to sustain the species pool. On the contrary, we hypothesized that in unmanaged grasslands, the spider assemblages are stable and the importance of recolonization is limited, the local factors become much more important drivers in shaping spider assemblages than landscape-level factors. We tested the importance of local and landscape-level factors on the abundance and species richness of spiders in unmanaged grasslands. At the landscape-level, we found that only the isolation had significant effect on the total abundance, on the abundance of hunting and habitat specialist species, and on the abundance of a frequent species (. Gnaphosa mongolica). At the local scale, however, four out of five studied factors influenced significantly the species richness and abundance of spider assemblages and the abundance of two frequent species (. Alopecosa psammophila, Berlandia cinerea). Species richness and abundance increased by plant cover, litter cover, and patch size, while decreased by bare ground cover. We found that in unmanaged grasslands, the local factors had vital role in maintaining the spider species richness; this is just the opposite conclusion that was earlier reported for agricultural ecosystems, where landscape-level effects had crucial role providing the species for continuous recolonization. © 2015 Elsevier B.V. Source

The landfill of Nemesnádudvar has been recultivated in 2010. The planning process of the construction works had been significantly influenced by the discovery of a huge population of the endemic long lasting pink (Dianthus diutinus) in 2009. My article aims to explain the nature conservation interventions due to the relevation of the endemic plant. Source

Halmos G.,U For Life | Karcza Z.S.,U For Life | Nemeth A.,Kiskunsag National Park Directorate | Csorgo T.,Eotvos Lorand University
Acta Zoologica Academiae Scientiarum Hungaricae

Studies conducted within the framework of the EURING Swallow Project in the Mediterranean area pointed out that the fattening of Barn Swallows is dependent on the distance they need to cover to pass over ecological barriers, such as sea and desert via their migration route. Our study was conducted at inland sites and we analysed the data in comparison to results previously obtained in the western Mediterraneum. Barn Swallows were captured at two roosting sites in Hungary: Ócsa peat bog and Izsák, at Lake Kolon between 2000-2002 with tape-luring set up each day one and a half hours before sunset. During the study period 7000 adult and 36000 juvenile Barn Swallows were caught. Wing length, 3rd primary length, tail length, body mass and fat score were measured for all adults and for the first 100 juveniles birds each night. Based on the dynamics of fat accumulation the study period was separated to a post-breeding, a transitional and a pre-migratory phase. The observed pattern between years and sites were similar, and there were recaptures during the same autumn between the two roosting sites (60 km from each other) to north and to south direction as well. Our results can not exclude one of the two alternative hypotheses on Barn Swallow migration strategy that is: (1) Barn Swallows build up their fat reserves in Hungary and afterwards they maintain it while slowly reaching the ecological barriers, and (2) Barn Swallows capable of a non-stop migration from Hungary to the southern edge of the Sahara. Efforts to find important refuelling sites in the eastern Mediterranean are needed to support any of the hypotheses. Source

Discover hidden collaborations