Hortobagy National Park Directorate

Debrecen, Hungary

Hortobagy National Park Directorate

Debrecen, Hungary
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Tothmeresz B.,Debrecen University | Mathe I.,Sudan University of Science and Technology | Balazs E.,Piata Majlath Gusztav Karoly | Magura T.,Hortobagy National Park Directorate
Landscape and Urban Planning | Year: 2011

To investigate the impact of urbanization on carabid beetles samples were taken over two years using pitfall traps along a rural-urban forest gradient representing increasing human disturbance in and nearby the city of Sfântu Gheorghe (Romania). We predicted that total number of species should decrease, whereas number of opportunistic and matrix species should increase towards the urban end of the gradient. Both the overall species richness and the number of individuals were significantly the highest in the suburban area followed by the rural area and the lowest in the urban area. These findings contradicted the increasing disturbance hypothesis; the number of species did not decrease by the increasing disturbance. The proportion of the forest specialist individuals and species significantly decreased from the rural towards the urban area, supporting the habitat specialist hypothesis. An opposite pattern was observed in species richness of the generalist carabids, supporting the opportunistic species hypothesis. Both the proportion of matrix species and their density were significantly higher in the urban area, supporting the matrix species hypothesis. Our findings also highlighted that overall diversity is not an appropriate indicator; species with different habitat affinities should be analysed separately to evaluate the real effect of urbanization. © 2011 Elsevier B.V.

Vegvari Z.,Hortobagy National Park Directorate | Bokony V.,University of Pannonia | Barta Z.,Debrecen University | Kovacs G.,Hortobagy National Park Directorate
Global Change Biology | Year: 2010

An increasing number of studies demonstrate that plant and animal phenologies such as the timing of bird migration have been advancing over the globe, likely as a result of climate change. Even closely related species differ in their phenological responses, and the sources of this variation are poorly established. We used a large, standardized dataset of first arrival dates (FAD) of migratory birds to test the effects of phylogenetic relationships and various life-history and ecological traits on the degree to which different species adapt to climate change by earlier migration in spring. Using the phylogenetic comparative method, we found that the advancement of FAD was greater in species with more generalized diet, shorter migration distance, more broods per year, and less extensive prebreeding molt. In turn, we found little evidence that FAD trends were influenced by competition for mating (polygamy or extra-pair paternity) and breeding opportunities (cavity nests). Our findings were robust to several potentially confounding effects. These evolutionary correlations, coupled with the low levels of phylogenetic dependence we found, indicate that avian migration phenology adapts to climate change as a species-specific response. Our results suggest that the degree of this response is fundamentally shaped by constraints and selection pressures of the species' life history, and less so by the intensity of sexual selection. © 2009 Blackwell Publishing Ltd.

Magura T.,Hortobagy National Park Directorate | Lovei G.L.,University of Aarhus | Tothmeresz B.,Debrecen University
Global Ecology and Biogeography | Year: 2010

Aim: We wanted to test whether urbanization has similar effects on biodiversity in different locations, comparing the responses of ground beetle (Coleoptera, Carabidae) assemblages with an urbanization gradient. We also wanted to see if urbanization had a homogenizing effect on ground beetle assemblages. Locations: Nine forested temperate locations in Europe, Canada and Japan. Methods: Published results of the Globenet Project were used. At all locations, three stages were identified: (1) a forested (rural) area, (2) a suburban area where the original forest was fragmented and isolated, and (3) remnants of the original forest in urban parks. These habitats formed an urbanization series. Study arrangements (number and operation of traps) and methods (pitfall trapping) were identical, conforming to the Globenet protocol. Assemblage composition and diversity patterns were evaluated. Diversity relationships were analysed by the Rényi diversity ordering method considering all ground beetles and - separately - the forest specialist species. Taxonomic homogenization was examined by multivariate methods using assemblage similarities. Results: Overall biodiversity (compared by species richness and diversity ordering) showed inconsistent trends by either urbanization intensity or by geographic position. However, when only forest species were compared, diversity was higher in the original rural (forested) areas than in urban forest fragments. Within-country similarities of carabid assemblages were always higher than within-urbanization stage similarities. Main conclusions: Urbanization does not appear to cause a decrease in ground beetle diversity . per se. Forest species decline as urbanization intensifies but this trend is masked by an influx of non-forest species. The rural faunas were more similar to the urban ones within the same location than similar urbanization stages were to each other, indicating that urbanization did not homogenize the taxonomic composition of ground beetle faunas across the studied locations. © 2009 Blackwell Publishing Ltd.

Lovei G.,University of Aarhus | Magura T.,Hortobagy National Park Directorate
Community Ecology | Year: 2011

Sampling effort in pitfall trapping sessions is routinely calculated as a product of trap numbers and time period, expressed in units of trap-days or trap-weeks. This assumes that these two components contribute equally to the catch, so that the catch from 2n traps run for z days should be equivalent to the catch of n traps run for 2z days. We tested this equivalence relationship by comparing two pitfall trapping sessions, representing an identical trapping effort, performed in the same habitat (an apple orchard in Hungary), using the same pitfall trapping arrangement. The Time Series session had 20 traps operating for 20 weeks (400 trap-weeks), while the Spatial Series session had 100 traps operating for 4 weeks (400 trap-weeks). The Time Series session caught 1265 individuals of 44 species, while the Spatial Series session had fewer (757) individuals but 52 species. The virtual structure of the two carabid assemblages was different, although the major species were the same. Rarefaction curves clearly show that the Spatial Series indicated the presence of a significantly more species-rich ground beetle assemblage than the Time Series. The "common currency" for trapping effort needs to be re-examined because its two components, number of traps and length of operation do not contribute to the final catch in the same way. This has an important consequence for the design of biodiversity monitoring: trapping effort allocation for monitoring may be better when the number of traps is at the possible maximum and the time of sampling shortened rather than the other way around.

Horvath R.,Debrecen University | Magura T.,Hortobagy National Park Directorate | Szinetar C.,University of West Hungary | Eichardt J.,University of West Hungary | Tothmeresz B.,Debrecen University
Biodiversity and Conservation | Year: 2013

The role of fragment size, isolation and habitat diversity in the conservation of spider assemblages living in fragmented landscape were studied in dry sandy grasslands (East Hungary, Nyírség). Spiders were collected using pitfall traps at eight dry grassland fragments from 2001 to 2009 from March to October fortnightly. We tested the rules of island biogeography, which suggest that the species richness increases with the size and decreases with the isolation of fragments. The habitat diversity is an important factor for species richness, since large areas usually have more habitats; therefore, the number of species may be higher in these areas. During the 9-year study period, altogether 10,544 individuals belonging to 106 species were collected. Contradicting the classical theory, we found a significant negative relationship between the total number of spider species and the grassland size, while the ratio of sandy grassland specialist spider species increased with fragment size. The relationship between the ratio of generalist species and the fragment size was not significant. The overall species richness and the isolation of studied grasslands did not show a significant relationship. The ratio of sandy grassland specialist species decreased, while the ratio of generalist species increased with the increasing of isolation. The habitat diversity did not show any effect on spider species richness. We concluded that to conserve the habitat specialist species it is recommended to preserve the large and least isolated grassland fragments, furthermore to increase the size of small fragments with the restoration of the adjacent croplands. © 2013 Springer Science+Business Media Dordrecht.

Magura T.,Hortobagy National Park Directorate | Nagy D.,Debrecen University | Tothmeresz B.,Debrecen University
Journal of Insect Conservation | Year: 2013

Effects of urbanization on rove beetles were studied along a rural-suburban-urban forested gradient characterized by increasing human disturbance in and around Debrecen city (Hungary). Three classical and six novel hypotheses regarding the response of species to urbanization were tested. We found that overall species richness increased significantly with decreasing urbanization (i) as it is predicted by the increasing disturbance hypothesis, and contradicting (ii) the intermediate disturbance hypothesis that predicts the highest species richness in the moderately disturbed suburban area. (iii) The number of forest-associated species was significantly lower in the urban area compared to suburban and rural areas, as predicted by the habitat specialist hypothesis. All of the proposed novel hypotheses are about habitat alteration caused by the urbanization were corroborated. The (iv) richness of hygrophilous species was the highest in the rural area (hygrophilous species hypothesis), while (v) the number of thermophilous species was higher in the urban area (thermophilous species hypothesis). The richness of species directly or indirectly feeding on decaying organic materials ((vi) saprophilous, (vii) phytodetriticol, (viii) myrmecophilous, (ix) mycetophilous species hypotheses) was also highest in the rural area compared to the urban one. We stress that overall species richness is not the most appropriate indicator of the impacts of urbanization and accompanying disturbance on these beetles. Instead, habitat affinity and ecological traits of the species give more information about what habitat properties and environmental variables change drastically during urbanization. © 2013 Springer Science+Business Media Dordrecht.

Horvath R.,Debrecen University | Magura T.,Hortobagy National Park Directorate | Tothmeresz B.,Debrecen University
Ecological Research | Year: 2012

We studied ground-dwelling spiders along a rural-suburban-urban forest gradient representing increasing human disturbance using pitfall traps. We tested four known and two novel hypotheses: (1) increasing disturbance hypothesis (species richness is decreasing by disturbance); (2) matrix species hypothesis (the richness of open-habitat species is increasing by disturbance); (3) opportunistic species hypothesis (the richness of generalist species is increasing by disturbance); and (4) habitat specialist hypothesis (the number of the forest specialist species is decreasing by disturbance). As a consequence of urbanization, urban forests become drier and more open; thus, according to the new hypotheses, the number of (5) xerophilous species and (6) light-preferring species are increasing in the urban area. Our result did not support the increasing disturbance hypothesis, as the overall species richness increased from the rural sites to the urban ones. As predicted, the number of both the open-habitat and the generalist species increased towards the urban sites. The number of forest specialist species was higher in the suburban area than in the rural and urban area. Both xerophilous and light-preferring species were the most numerous in the urban area, supporting the xerophilous species and the light-preferring species hypotheses. Canonical correspondence analysis showed that the forest specialist species associated with the rural sites with higher amounts of decaying woods and more herbs or with the suburban sites with higher cover of leaf litter and higher relative humidity. Two generalist species and one open-habitat species were characteristic of urban sites with higher ground surface and air temperature. © 2012 The Ecological Society of Japan.

Magura T.,Hortobagy National Park Directorate | Horvath R.,Debrecen University | Tothmeresz B.,Debrecen University
Landscape Ecology | Year: 2010

Effects of urbanization on ground-dwelling spiders (Araneae) were studied using pitfall traps along an urban-suburban-rural forest gradient in Debrecen (Hungary). We found that overall spider species richness was significantly higher in the urban sites compared to the suburban and rural ones. The increased diversity was due to the significantly more open-habitat species in the assemblages at the urban sites. This suggests that species from the surrounding matrix (grasslands and arable lands) penetrated the disturbed urban sites. The ratio of forest species was significantly higher in the rural sites than in the suburban and urban ones, suggesting that forest species are indeed sensitive to the disturbance caused by urbanization. Canonical correspondence analysis revealed that the species composition changed remarkably along the urbanization gradient. Openhabitat spiders were associated with the urban sites of higher ground and air temperature. Forest spiders were characteristic of the rural sites with higher amount of decaying woods. Our findings suggest that the overall diversity was not the most appropriate indicator of disturbance; species with different habitat affinity should be analyzed separately to get an ecologically relevant picture of the effect of urbanization. © Springer Science+Business Media B.V. 2010.

Torok P.,Debrecen University | Deak B.,Hortobagy National Park Directorate | Vida E.,Debrecen University | Valko O.,Debrecen University | And 2 more authors.
Biological Conservation | Year: 2010

We studied the effect of sowing low-diversity seed mixtures (containing 2-3 competitive grass species) on the regeneration of vegetation on croplands previously used as alfalfa fields. In four permanent plots in 10 restored fields (four with alkali and six with loess seed mixture) the cover of flowering plants was recorded and phytomass was measured between 2006 and 2008. We asked three questions: (i) How fast will weedy, short-lived species decrease in abundance during secondary succession enhanced by sowing low-diversity seed mixtures? (ii) Can weeds be suppressed by sowing competitive native grasses, followed up by management by mowing? (iii) Can succession towards the target native grasslands be accelerated by sowing only low-diversity seed mixtures compared to set-aside old field succession? Our results showed that in just two years a vegetation dominated by perennial grasses has developed, which successfully prevented the establishment of weed species. These results suggested that sowing seeds of two or three competitive grass species is an effective tool to eliminate weed domination and to lead towards the restoration of species poor grasslands with grass domination such as alkali grasslands. However, the developed dense perennial grass cover and the accumulated litter may hamper the immigration of specialist species characteristic to reference grasslands. Therefore, the restoration of species-rich grasslands requires the facilitation of the immigration of grassland specialist species by further management (grazing, mowing and/or hay-transport). © 2009 Elsevier Ltd. All rights reserved.

Toth K.,Debrecen University | Bogyo D.,Hortobagy National Park Directorate | Valko O.,Mta Of Biodiversity And Ecosystem Services Research Group
Plant Ecology | Year: 2016

Recent studies found that endozoochorous seed dispersal by waterfowl is an important dispersal strategy for numerous plants. With a germination experiment, we evaluated the endozoochorous dispersal potential of the endangered Lesser White-fronted Goose (LWfG, Anser erythropus) and larger goose species (A. anser and A. albifrons) in their autumn and spring staging areas (Hortobágy, East Hungary). We tested the following hypotheses: (1) the amount and species composition of germinable seeds in the droppings of the habitat specialist LWfG and generalist larger goose species have a different species composition, (2) droppings contain less germinable seeds and less species in spring than in autumn, when most species disperse their seeds. We collected droppings of LWfG and larger goose species in their feeding habitats in spring and autumn staging areas. Droppings were concentrated and germinated on trays filled with steam-sterilised soil in a greenhouse. LWfG dispersed more species typical to alkali habitats and lower amounts of weeds compared to larger goose species, which confirmed our first hypothesis. We recorded higher total species numbers and species number of annuals, wetland species and weeds in autumn, which supported our second hypothesis. We found that the studied goose species used a wide range of feeding habitats; thus, they can play an important role in dispersing seeds between a range of habitats which they use for feeding. Based on the seed content of the droppings, LWfG is confined to natural habitats; thus, for the effective protection of this vulnerable species, it is crucial to preserve natural feeding habitats in their staging areas. © 2016, Springer Science+Business Media Dordrecht.

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