The urban space is a permanently changing ecosystem, suffering from decreasing biodiversity, but also providing new anthropogenic habitats for some adaptable species. The Eurasian kestrel (Falco tinnunculus) is such an adaptable species, whose dense urban populations are ethologically different from rural populations in Europe. Several studies have indicated that urban kestrels increasingly prey on birds; this study even indicated avian prey as the main prey category in the inner-city habitat. We analyzed the selection of habitat and building structure parameters while controlling for differences in their availability in Vienna, Austria, a city of 1.7 million inhabitants. We then connected the nest-site selection of urban kestrels to their diet choice and annual reproduction rate. Our results indicated a trade-off between higher nest-site availability in the center and longer distances to larger open green space as optimal foraging ground. Between 2010 and 2012, a preference for breeding in close vicinity to green backyards was linked to earlier clutch dates, higher hatching rates and larger fledged brood sizes, but the overall productivity per nest still remained low in the center compared to the suburban area. In a survey of avian prey species, we found comparable abundances of prey-sized bird species in green backyards, parks and surrounding suburban areas. We thus hypothesize that kestrels use the immediate nest-surroundings to hunt, but are not as efficient in hunting avian prey as they are in hunting voles. Changes in modern city architecture and renovation of historical buildings pose conservation related threats to urban predators and prey
Dung beetles are a functionally important component of most terrestrial ecosystems, but communities change with habitat disturbance and deforestation. In this study, we tested if dung beetle ensembles on dung of introduced cattle and of the endemic anoa, a small buffalo, are affected differentially by habitat disturbance. Therefore, we exposed 10 pitfall traps, five baited with anoa and five baited with cattle dung, per site in six habitat types ranging from natural and selectively logged rain forest to three types of agroforestry system (characterized by different management intensity) and open areas (n = 4 replicate sites per habitat type) at the margin of Lore Lindu National Park, Central Sulawesi, Indonesia. We found 28 species, 43% of which were endemic to Sulawesi. Species richness, abundance and biomass declined from natural forest towards open area. Large-bodied species appeared to be more sensitive to habitat disturbance and the ratio of large to small-sized dung beetles declined with land-use intensity. Although selectively logged forest and cocoa agroforestry systems had lower species richness compared with natural forest, they appeared to maintain a high portion of species originally inhabiting forest sites. The similarity of dung beetle ensembles recorded at forest and agroforestry sites reflects the high similarity of some habitat variables (e.g. vegetation structure and microclimate) between both habitat types compared with open areas. Species richness and abundances as well as species composition, which was characterized by decreases in mean body size, changed with land-use intensity, indicating that dung type is less important than habitat type for determining ensemble structure of these Indonesian dung beetles.
Summary: Winter oilseed rape represents an important food source for Great Bustards. Great Bustard surveys during four consecutive winters (2005/2006–2008/2009) were used to identify characteristics of oilseed rape fields, which increase their attractiveness for the species in its West Pannonian wintering area. The study was conducted in study areas in Eastern Austria, around the Austrian–Slovakian–Hungarian border and in the Hungarian Moson Plain. To test for effects of field size and isolation of fields from other rape fields, and the distance to the nearest paved road on occurrence and abundance of Great Bustards (maximum number of birds counted in individual rape fields per winter), we calculated generalized linear mixed models (GLMMs) including all three predictor variables as fixed effects and winter as random effect for each of the three study areas. Field size most strongly affected occurrence and abundance of Great Bustards. The availability of large (>>15 ha) winter rape fields far from paved roads is recommended as a prime conservation measure to improve the quality of rape fields as foraging habitat for Great Bustards during the winter months (November–March).