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Braaker S.,Swiss Federal Institute of forest | Braaker S.,ETH Zurich | Moretti M.,Swiss Federal Institute of forest | Boesch R.,Swiss Federal Institute of forest | And 4 more authors.
Ecological Applications | Year: 2014

The best model revealed spatially explicit connectivity ''pinch points,'' as well as multiple habitat connections. Cross-validation indicated the general validity of the selected connectivity model. The results show that both habitat connectivity and habitat quality affect the movement of urban hedgehogs (relative importance of the two variables was 19.2% and 80.8%, respectively), and are thus both relevant for predicting urban animal movements.To ensure viable species populations in fragmented landscapes, individuals must be able to move between suitable habitat patches. Despite the increased interest in biodiversity assessment in urban environments, the ecological relevance of habitat connectivity in highly fragmented landscapes remains largely unknown. The first step to understanding the role of habitat connectivity in urban ecology is the challenging task of assessing connectivity in the complex patchwork of contrasting habitats that is found in cities.We developed a data-based framework, minimizing the use of subjective assumptions, to assess habitat connectivity that consists of the following sequential steps: (1) identification of habitat preference based on empirical habitat-use data; (2) derivation of habitat resistance surfaces evaluating various transformation functions; (3) modeling of different connectivity maps with electrical circuit theory (Circuitscape), a method considering all possible pathways across the landscape simultaneously; and (4) identification of the best connectivity map with information-theoretic model selection. We applied this analytical framework to assess habitat connectivity for the European hedgehog Erinaceus europaeus, a model species for grounddwelling animals, in the city of Zurich, Switzerland, using GPS track points from 40 individuals.Our study demonstrates that even in the complex habitat patchwork of cities, habitat connectivity plays a major role for ground-dwelling animal movement. Data-based habitat connectivity maps can thus serve as an important tool for city planners to identify habitat corridors and plan appropriate management and conservation measures for urban animals. The analytical framework we describe to model such connectivity maps is generally applicable to different types of habitat-use data and can be adapted to the movement scale of the focal species. It also allows evaluation of the impact of future landscape changes or management scenarios on habitat connectivity in urban landscapes. © 2014 by the Ecological Society of America.

Giavi S.,Swiss Federal Institute of forest | Moretti M.,Swiss Federal Institute of forest | Bontadina F.,Urban Ecology and Wildlife Research | Bontadina F.,ETH Zurich | And 2 more authors.
PLoS ONE | Year: 2014

Migration is adaptive if survival benefits are larger than costs of residency. Many aspects of bat migration ecology such as migratory costs, stopover site use and fidelity are largely unknown. Since many migrating bats are endangered, such information is urgently needed to promote conservation. We selected the migrating Leisler's bat (Nyctalus leisleri) as model species and collected capture-recapture data in southern Switzerland year round during 6 years. We estimated seasonal survival and site fidelity with Cormack-Jolly-Seber models that accounted for the presence of transients fitted with Bayesian methods and assessed differences between sexes and seasons. Activity peaked in autumn and spring, whereas very few individuals were caught during summer. We hypothesize that the study site is a migratory stopover site used during fall and spring migration for most individuals, but there is also evidence for wintering. Additionally, we found strong clues for mating during fall. Summer survival that included two major migratory journeys was identical to winter survival in males and slightly higher in females, suggesting that the migratory journeys did not bear significant costs in terms of survival. Transience probability was in both seasons higher in males than in females. Our results suggest that, similarly to birds, Leisler's bat also use stopover sites during migration with high site fidelity. In contrast to most birds, the stopover site was also used for mating and migratory costs in terms of survival seemed to be low. Transients' analyses highlighted strong individual variation in site use which makes particularly challenging the study and modelling of their populations as well as their conservation. © 2014 Giavi et al.

Rutishauser M.D.,University of Bern | Bontadina F.,University of Bern | Bontadina F.,Urban Ecology and Wildlife Research | Bontadina F.,Swiss Federal Institute of forest | And 5 more authors.
Diversity and Distributions | Year: 2012

Aim: The discovery of cryptic species poses new challenges for species conservation. Species distributions and conservation status have to be re-evaluated, and the ecological requirements within the species complex have to be re-assessed to recommend adequate conservation guidelines. The recent discovery in Central Europe of the cryptic bat species Plecotus macrobullaris (Kuzjakin 1965) calls for a new appraisal of all three Plecotus species in that area. Location: Switzerland. Methods: Using mostly DNA-identified records, we investigated the environmental niches (ecological niche factor analysis) of the three long-eared bat species at the landscape scale and modelled their potential distributions. Discriminant analysis was used for interspecific niche comparisons. Results: The occurrence of all three species was best explained by proximity to rural settlements and warm summer temperature. Plecotus auritus (Linnaeus, 1758) was positively associated with transition zones from forests to other habitats within heterogeneous landscapes; Plecotus austriacus (J. Fischer, 1829) was more frequently found in orchards and vineyards. Plecotus macrobullaris was linked mostly with deciduous forests. P. auritus had the broadest niche, with occurrence predicted in most forested regions throughout Switzerland. The slightly narrower niche of P. macrobullaris mainly encompassed areas in the Central and Southern Alps. P. austriacus showed a very narrow niche and was predicted mainly in the lowlands, with its habitat requirements overlapping those of P. macrobullaris. Although a range overlap was predicted between P. austriacus and P. macrobullaris, current observations suggest a mostly parapatric distribution in Switzerland. Main conclusions: The projected distributions confirm previous knowledge for P. auritus, but shed new light on the other two species. In contrast to the newly discovered P. macrobullaris, which is actually widespread in the Southern Alps of Switzerland, P. austriacus is restricted to warmer cultivated lowlands and thus may have suffered from recent major land use changes. We suggest reclassifying P. austriacus to a higher conservation status. © 2012 Blackwell Publishing Ltd.

Frey-Ehrenbold A.,Swiss Federal Institute of forest | Frey-Ehrenbold A.,University of Bern | Frey-Ehrenbold A.,Urban Ecology and Wildlife Research | Bontadina F.,University of Bern | And 3 more authors.
Journal of Applied Ecology | Year: 2013

Agricultural intensification has caused a decline in structural elements in European farmland, where natural habitats are increasingly fragmented. The loss of habitat structures has a detrimental effect on biodiversity and affects bat species that depend on vegetation structures for foraging and commuting. We investigated the impact of connectivity and configuration of structural landscape elements on flight activity, species richness and diversity of insectivorous bats and distinguished three bat guilds according to species-specific bioacoustic characteristics. We tested whether bats with shorter-range echolocation were more sensitive to habitat fragmentation than bats with longer-range echolocation. We expected to find different connectivity thresholds for the three guilds and hypothesized that bats prefer linear over patchy landscape elements. Bat activity was quantified using repeated acoustic monitoring in 225 locations at 15 study plots distributed across the Swiss Central Plateau, where connectivity and the shape of landscape elements were determined by spatial analysis (GIS). Spectrograms of bat calls were assigned to species with the software batit by means of image recognition and statistical classification algorithms. Bat activity was significantly higher around landscape elements compared to open control areas. Short- and long-range echolocating bats were more active in well-connected landscapes, but optimal connectivity levels differed between the guilds. Species richness increased significantly with connectivity, while species diversity did not (Shannon's diversity index). Total bat activity was unaffected by the shape of landscape elements. Synthesis and applications. This study highlights the importance of connectivity in farmland landscapes for bats, with shorter-range echolocating bats being particularly sensitive to habitat fragmentation. More structurally diverse landscape elements are likely to reduce population declines of bats and could improve conditions for other declining species, including birds. Activity was highest around optimal values of connectivity, which must be evaluated for the different guilds and spatially targeted for a region's habitat configuration. In a multi-species approach, we recommend the reintroduction of structural elements to increase habitat heterogeneity should become part of agri-environment schemes. This study highlights the importance of connectivity in farmland landscapes for bats, with shorter-range echolocating bats being particularly sensitive to habitat fragmentation. More structurally diverse landscape elements are likely to reduce population declines of bats and could improve conditions for other declining species, including birds. Activity was highest around optimal values of connectivity, which must be evaluated for the different guilds and spatially targeted for a region's habitat configuration. In a multi-species approach, we recommend the reintroduction of structural elements to increase habitat heterogeneity should become part of agri-environment schemes. © 2013 British Ecological Society.

Tschanz B.,Urban Ecology and Wildlife Research | Hegglin D.,Urban Ecology and Wildlife Research | Hegglin D.,University of Zürich | Gloor S.,Urban Ecology and Wildlife Research | Bontadina F.,Urban Ecology and Wildlife Research
European Journal of Wildlife Research | Year: 2011

Domestic cats Felis catus, as companion animals provided with supplemental food, are not limited by the availability of wild prey and locally occur at extraordinary high densities. There is growing concern about the potential impact of large cat numbers on native prey populations. In the present study, we quantified the minimum number of animals killed in a rural village in Switzerland by asking owners (1) to estimate the predation rate in advance and (2) to record prey animals returned home by their pets. The frequency distribution of the numbers of prey items was markedly skewed: 16% of the cats accounted for 75% of prey, irrespective of sex, age or breed. A large fraction of owners considerably overestimated their cat's predation, indicating that surveying predation rates by means of a questionnaire alone is not sufficient. The observed average rate of predation within 48 days in spring was 2.29 prey items/cat/month (N = 32 cats); major prey types were rodents (76.1%) and birds (11.1%). The absolute number of prey items taken per area is striking and indicates that cat predation represents an important factor in ecosystems. Its role may be momentous in intensively fragmented urban habitats, where cat densities are especially high. We thus highlight the need to identify the factors determining predation rates of individual cats. Further extended studies, especially in urbanised areas, are needed to quantify the actual impact of cat predation upon the population dynamics of their prey. © 2010 Springer-Verlag.

Kistler C.,University of Zürich | Hegglin D.,Urban Ecology and Wildlife Research | Wurbel H.,Justus Liebig University | Konig B.,University of Zürich
Animal Welfare | Year: 2010

An increasing number of zoos keep their animals in natural-looking enclosures, but it is often unclear whether or not the species' behavioural and ecological needs are being adequately met. For species that suffer predation in the wild, structural enrichment in captivity can play a crucial role in connection with enclosure use. Firstly, we examined the effectiveness of structural enrichment in modifying enclosure use in an opportunistic carnivore, the red fox (Vulpes vulpes). In a test enclosure, we placed both long wooden and cover structures that simulated natural habitat in predetermined sectors. A group of four foxes were exposed to four treatments: (i) structural enrichment in location 1 (LOC1s); (ii) structural enrichment in location 2 (LOC2); (iii) structural enrichment removed (REM); and (iv) structural enrichment again in location 1 (LOC1e). Sectors containing long wooden structures were preferred significantly compared to the rest of the enclosure. Sector use was selectively shifted to those in which cover structures were present. Structural enrichment had no significant effect on activity. Secondly, in a new outdoor enclosure, we compared the use of sectors with cover or elongated structures with that of corresponding sectors without structures. All individuals showed a significant preference for sectors containing structures. In the course of the three-week observation period, there was a significant decline in preference for structures and a significant increase in activity (week 1 < week 2 = week 3). These results suggest that in medium-sized carnivores, structural enrichment is beneficial when natural features with a net-like distribution over the habitat are simulated. © 2010 Universities Federation for Animal Welfare.

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