1,720,988 research outputs found
Insectivorous and open-cup nester bird species suffer the most from urbanization
No full textCapsule Urbanization effects in an Eastern European city depend on feeding and breeding traits of bird communities with stronger negative effects on more specialized traits. Aims To assess how urbanization affects feeding and breeding traits of bird communities in Cluj (Romania). Methods Based on a stratified random sampling we selected 61 study squares of 200 x 200 m for bird surveys representing the following habitats: suburban, residential and apartment complex (representing an increasing urbanization gradient). We carried out bird censuses in both breeding and wintering seasons. The observed bird species were classified according to their feeding guilds and nesting sites. Results Insectivorous and open-cup nesting species were most abundant in suburban areas. Omnivorous species richness was not related to urbanization gradient. Species showed similar patterns of distribution during breeding and winter with respect to feeding habits. However, in case of nesting preferences, species richness of cavity nesters increased with urbanization gradient in winter, but decreased in the breeding season. Conclusions Food and nesting site availability are key drivers in limiting more specialist species in utilizing city centres. Future studies should assess the effect of how green areas can counteract such negative effects of increasing urbanization in the context of such specialist trait limitations.DFG [BA 4438/1-1
Infanticide or interference : Does the great reed warbler selectively destroy eggs?
No full textInfanticide, the killing of offspring by adult conspecifics, has been demonstrated in many insect, mammal and bird species. In contrast to selective pressures influencing infanticide in other species, egg destruction in birds is thought to primarily represent interference competition for food, nest sites or predator-free nesting space. In the case of the great reed warbler, two opposing hypotheses exist for the explanation of its egg destruction behaviour. Our study tested these hypotheses separately by manipulating the presence of real conspecific, familiar and unfamiliar eggs and nests inside polygynous and monogamous great reed warbler territories. Out of 147 experimental nests placed in the vicinity of 49 active great reed warbler nests, only conspecific eggs were preyed upon by great reed warblers. Furthermore, significantly more great reed warbler nests were destroyed in polygynous than monogamous territories. These results support the hypothesis that egg destruction behaviour in this species is motivated intraspecifically and most probably intrasexually
The past and future of farmland birds in Hungary
No full textCapsule Populations of birds on farmland are larger and more stable in Hungary than in the UK and may provide baseline targets when planning population restoration programmes in more intensively farmed regions of Europe. Aims To review the available evidence on farmland bird populations and their changes over the past century in Hungary, and to compare this with similar data for the UK. Methods Published papers and grey literature were searched to determine long-term bird population trends for birds on farmland in Hungary, and for research evidence on the relationship between farmland management and bird diversity in Hungary. Results Population density of common farmland birds is higher and trends are more positive in Hungary compared to the UK. These findings correlate with the recent change to generally less intensive agriculture in Hungary. However, while the birdlife associated with farmland in Hungary can be considered to have high diversity and density, it is still lower than it was in the first half of the 20th century and earlier. The few studies available showed that low-intensity traditional management promotes a rich biodiversity in both grasslands and arable systems in Hungary. Agri-environment schemes were introduced when Hungary joined the EU in 2004; however, their influence on biodiversity has not been systematically monitored. Conclusions Insights emerging from farmland bird research in those European countries which still practice extensive agricultural techniques could be used to set general baseline targets for restoring biodiversity in regions where farmlands are now intensively managed. At the European scale urgent tasks are to: (1) investigate the relationships between management and bird diversity and density on a much wider geographical scale, (2) evaluate the geographical generality of the existing evidence base (which is mainly based on studies conducted in more intensively farmed regions), and (3) enhance the policy impact of conservation research
Infanticide or interference : Does the great reed warbler selectively destroy eggs?
No full textInfanticide, the killing of offspring by adult conspecifics, has been demonstrated in many insect, mammal and bird species. In contrast to selective pressures influencing infanticide in other species, egg destruction in birds is thought to primarily represent interference competition for food, nest sites or predator-free nesting space. In the case of the great reed warbler, two opposing hypotheses exist for the explanation of its egg destruction behaviour. Our study tested these hypotheses separately by manipulating the presence of real conspecific, familiar and unfamiliar eggs and nests inside polygynous and monogamous great reed warbler territories. Out of 147 experimental nests placed in the vicinity of 49 active great reed warbler nests, only conspecific eggs were preyed upon by great reed warblers. Furthermore, significantly more great reed warbler nests were destroyed in polygynous than monogamous territories. These results support the hypothesis that egg destruction behaviour in this species is motivated intraspecifically and most probably intrasexually
Spatial heterogeneity and farmland birds: different perspectives in Western and Eastern Europe
No full textDummy birds in artificial nest studies: an experiment with Red-backed Shrike Lanius collurio
No full textCapsule Dummy birds placed on artificial nests increase nest survival, and their use should be considered in future studies of nest predation.Scientific Grant Agency VEGA [1/3257/06
Different habitat selection by two sympatric Maculinea butterflies at small spatial scale
No full text. 1. Worldwide extinction of species due to habitat loss and habitat degradation can be recognised among butterflies pronouncedly. Therefore, conservation biologists devote special attention to identify the most important ecological factors affecting distribution and survival of butterflies. These efforts have been dominated by landscape-scale studies, although variation in habitat quality at smaller spatial scales may be of crucial importance. This applies for the highly specialised Maculinea species, which usually do not form classic metapopulations. 2. Maculinea nausithous and Maculinea teleius use the same larval food plant and usually occupy the same habitats in Europe. Afforestation of meadows due to abandonment is a major threat for these species. However, few if any studies have assessed the effects that proximity of forest edges may have on the habitat selection by adult butterflies at the scale of local populations. Here, we aimed to test these effects within one habitat fragment based on an intensive mark-release-recapture sampling. 3. Distribution of M. nausithous was aggregated and its density was highly positively influenced by the proportion of afforested meadow edges, while M. teleius showed no preference for afforested edges. Despite their different within-habitat distribution, the movement of both species was restricted to smaller parts of the habitat. 4. Our results suggest that M. nausithous has a narrower niche in the study region, which is most likely due to that its only host ant can find suitable microclimatic conditions at the afforested edges of wet meadows. This implies that habitat patches are not equally used by the two species and hence different management approaches are desirable for their conservation.EC [EVK2-CT-2001-00126]; NKTH [NKFP 3B023-04
Potential metapopulation structure and the effects of habitat quality on population size of the endangered False Ringlet butterfly
No full textThe False Ringlet (Coenonympha oedippus) is a European butterfly species, endangered due to the severe loss and fragmentation of its habitat. In Hungary, two remaining populations of the butterfly occur in lowland Purple Moorgrass meadows. We studied a metapopulation occupying twelve habitat patches in Central Hungary. Our aim was to reveal what measures of habitat quality affect population size and density of this metapopulation, estimate dispersal parameters and describe phenology of subpopulations. Local population sizes and dispersal parameters were estimated from an extensive mark-release-recapture dataset, while habitat quality was characterized by groundwater level, cover of grass tussocks, bush cover, height of vegetation and grass litter at each habitat patch. The estimated size of the metapopulation was more than 3,000 individuals. We estimated a low dispersal capacity, especially for females, indicating a very low probability of (re)colonization. Butterfly abundance and density in local populations increased with higher grass litter, lower groundwater level and larger area covered by tussocks. We suppose that these environmental factors affect butterfly abundance by determining the microclimatic conditions for both larvae and adult butterflies. Our results suggest that the long-term preservation of the studied metapopulation needs the maintenance of high quality habitat patches by appropriate mowing regime and water regulation. Management also should facilitate dispersal to strengthen metapopulation structure with creating stepping-stones or gradually increase habitat quality in present matrix
Effects of grazing, vegetation structure and landscape complexity on grassland leafhoppers (Hemiptera: Auchenorrhyncha) and true bugs (Hemiptera: Heteroptera) in Hungary
No full text1. Agricultural intensification is a major cause of biodiversity loss in European farmlands. Grasslands are particularly important habitats for the conservation of rich insect assemblages of Central and Eastern Europe. Although regular grazing or mowing of these grasslands is required to maintain diversity, there is no information about how such management and other factors influence Hemiptera assemblages. 2. We studied leafhopper and true bug assemblages in semi-natural grasslands in three regions of the Great Hungarian Plain. We investigated how local vegetation factors and landscape complexity influence assemblages and whether they interact with management effects. 3. Seven pairs of intensively (>1 cow/ha) versus extensively (similar to 0.5 cow/ha) grazed pastures were sampled in each region by sweep-netting. 4. Sward height was the most important explanatory factor for leafhoppers (84 species, 27264 individuals), as it increased both species number and abundance, and influenced assemblage composition. The extent of grassland surrounding the sample sites negatively affected leafhoppers, whereas extensive grazing decreased abundance and influenced composition. True bug assemblages (140 species, 6656 individuals) were positively affected only by mean sward height, whereas regional differences determined the community composition of both taxa. 5. We conclude that vegetation structure is the primary factor shaping Hemiptera communities and that the various types of grasslands studied are all important habitats for the taxon. Therefore, cattle grazing in its current form is beneficial for the rich Hemiptera fauna in lowland pastures of Hungary. However, in some cases, local and landscape factors and great regional differences may confound the effects of grazing, and this must be considered in conservation planning in the future
Structure and size of a threatened population of the False Ringlet Coenonympha oedippus (Fabricius, 1787) (Lepidoptera: Nymphalidae) in Hungary
No full textButterfl ies react sensitively to changes in habitat quality. Their diversity has been decreasing in Europe due to habitat degradation, fragmentation, management changes and climate change. The False Ringlet (Coenonympha oedippus) is one of the 59 butterfl y species protected in Hungary. The species occupies marshy meadows dominated by Molinietum vegetation. Besides drainage, inappropriate management can also deteriorate these habitats. Nowadays the butterfl y remains present in a habitat complex in Hungary, at the north-western part of the Hungarian Great Plain and a newly (2009) rediscovered population in north-western Hungary. Mark– release–recapture method was used to estimate the population size and describe population structure in a 0.65 ha habitat patch from 2005 to 2007. The population size did not fl uctuate during the 3 years; the total estimated number of individuals ranged between 130 and 270. The survival probability was 0.81–0.84/day in the case of males, in females 0.70–0.89/day. The catchability was between 0.27–0.53 in males and 0.22–0.38 in females. The structure of the population indicates that the False Ringlet is a sedentary butterfl y species, with low dispersal ability. In the study area, drainage seems to be the main threatening factor for its habitat. The studied population has recently moved to neighbouring lower parts of the habitat patch, because the formerly occupied part of the habitat patch had been desiccated and the vegetation had been changed. For the long-term survival of the species at this habitat patch the drainage should be inhibited, while in other habitat patches around, the control of invasive plant species is inevitable beside habitat restoration
- …
