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.
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.
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.