Fabio Bontadina

The diet of urban foxes (Vulpes vulpes) and the availability of anthropogenic food in the city of Zurich, Switzerland

Summary The diet of urban foxes and the availability of anthropogenic food were studied in the city of Zurich, Switzerland. A stomach analysis of 402 foxes, which were shot or found dead between January 1996 and March 1998, showed a broad variety in the diet of urban foxes, with a dominance of scavenged meat, other scavenge and cultivated fruit and crops. More than half of an average stomach content was anthropogenic. The proportion of anthropogenic food was increased in stomachs from the city centre – mainly due to the increasing proportion of scavenged meat – compared with stomachs from the periurban area. Significant seasonal variations in the diet were found for invertebrates, birds and for cultivated fruit and crops, which were all most frequently consumed in summer. A written survey among the inhabitants of three municipal districts showed that 85% of the households provided anthropogenic food which was accessible to foxes. This food supply consisted of three quarters of rubbish and compost, completed by fruit and berries and, to a lesser extent, food provisions for pets, birds, and other wild animals. In contrast, the anthropogenic food supply of allotment gardens mainly consisted of berries, completed by fruit, compost and birdseed. The anthropogenic food supply in public areas was determined by transects. The overall food supply of households, allotment gardens and public areas would be sufficient to feed a much higher number of foxes than currently present. This overabundance of food resources could explain the continual increase of urban population densities. A possible further exploitation of anthropogenic food sources is discussed considering its specific characteristics and the necessary behavioural adaptations.

Spider, bee, and bird communities in cities are shaped by environmental control and high stochasticity.

Spatially organized distribution patterns of species and communities are shaped by both autogenic processes (neutral mechanism theory) and exogenous processes (niche theory). In the latter, environmental variables that are themselves spatially organized induce spatial structure in the response variables. The relative importance of these processes has not yet been investigated in urban habitats. We compared the variance explained by purely spatial, spatially structured environmental, and purely environmental components for the community composition of spiders (Araneae), bees (Apidae), and birds (Aves) at 96 locations in three Swiss cities. Environmental variables (topography, climate, land cover, urban green management) were measured on four different radii around sampling points (< 10 m, 50 m, 250 m, 1000 m), while Morans eigenvector maps (MEMs) acted as spatial variables. All three taxonomic groups showed weak spatial structure. Spider communities reacted to very fine-scaled environmental changes of lawn and meadow management and climate. Bird community composition was determined by woody plants as well as solar radiation at all radii, the scale of the influence varying among species. Bee communities were weakly explained by isolated variables only. Our results suggest that the anthropogenic structuring of urban areas has disrupted the spatial organization of environmental variables and inhibited the development of biotic spatial processes. The near absence of spatial structure may therefore be a feature typical of urban species assemblages, resulting in urban community composition mainly influenced by local environmental variables. Urban environments represent a close-knit mosaic of habitats that are regularly disturbed. Species communities in urban areas are far from equilibrium. Our analysis also suggests that urban communities need to be considered as being in constant change to adapt to disturbances and changes imposed by human activities.

Landscape connectivity, habitat structure and activity of bat guilds in farmland‐dominated matrices

Summary 1. 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. 2. 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. 3. 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. 4. 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. 5. 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 multispecies approach, we recommend the reintroduction of structural elements to increase habitat heterogeneity should become part of agri-environment schemes.

BAITING RED FOXES IN AN URBAN AREA: A CAMERA TRAP STUDY

Abstract Baiting red foxes (Vulpes vulpes) is an established method of vaccinating foxes against rabies in rural environments. Furthermore, anthelmintic baiting has been demonstrated to reduce the prevalence of the zoonotic tapeworm Echinococcus multilocularis in foxes. The recent invasion of foxes into urban areas on continental Europe represents a considerable health risk that calls for the evaluation of baiting strategies adapted to the urban environment. We investigated bait uptake by urban foxes using camera traps in Zurich, Switzerland. Baits with and without the anthelmintic praziquantel were placed in several arrangements (exposed, covered, buried), at different locations (fox dens, compost heaps, fox tracks) and in different seasons (early summer, summer, winter). Ninety-one of 252 baits (36%) disappeared within 3 days. Most of the baits consumed near cameras were consumed by foxes (44 of 91). The remaining baits were consumed by hedgehogs (Erinaceus europaeus), snails (Arion sp.), dogs, rodents (Apodemus sp.), and unidentified animals. Bait uptake by foxes was significantly higher during summer than winter (P = 0.022), and foxes accepted baits most frequently at fox dens during early summer (52.8%). Burying baits reduced bait removal by species other than foxes (P < 0.01). For rabies control in urban areas, avoiding contact of nontarget species with the rabies vaccine is particularly important. Greater selection of the fox population can be achieved by distributing baits in winter, burying baits, and choosing sites that are less accessible to non-target species. However, with anthelmintic treatment, uptake by nontarget species is of lesser importance; hence, the effort to bury the bait is unnecessary.

Variation of adult survival drives population dynamics in a migrating forest bat

1. Variation of survival across time, between sex and ages strongly affect the population dynamics of long-lived species. Bats are extremely long-lived, but the variation of their survival probabilities is poorly studied with reliable methods. 2. We studied annual local survival probabilities of the migratory Leislers bats Nyctalus leisleri based on capture-recapture data from 1119 individuals sampled in bat boxes over 20 years in eastern Germany. We assessed variation in survival between sex and age classes, estimated the temporal variance of survival and tested whether survival was affected by weather during hibernation or pregnancy. 3. Among females, our analyses revealed two groups of individuals present with different roosting occupancy, survival and/or dispersal. Local survival of locally born females increased with age [first year: 0.45 +/- 0.04 (SE); later: 0.76 +/- 0.04] and the high recapture probabilities indicate regular presence in the roosts. Recapture probabilities and local survival of foreign adult females were significantly lower, indicating less frequent presence in the roosts and stronger dispersal from the study area. 4. In adult males, locally born and foreign individuals were nearly identical regarding survival and recapture, indicating a more homogenous group. Local survival was very low in the first year (0.04 +/- 0.08), most likely caused by strong natal dispersal. It further increased with age (second year: 0.55 +/- 0.20, later: 0.69 +/- 0.07). 5. Survival probabilities of all females varied significantly and in parallel across time, suggesting that a common environmental factor was operating which affected all individuals similarly. Spring temperature and winter North Atlantic Oscillation explained maximally 9% each of the variation in first year and adult female survival. In contrast to our expectations, the temporal variance of first-year survival was lower than that of adult survival. 6. We found evidence of a complicated social population structure of female Leislers bats. Our analyses suggest that their population dynamics are driven to a large amount by variation of survival, in particular by adult survival. The reason for the major temporal variations remains to be identified.

Survey of public knowledge about Echinococcus multilocularis in four European countries: Need for proactive information

BackgroundPublic information about prevention of zoonoses should be based on the perceived problem by the public and should be adapted to regional circumstances. Growing fox populations have led to increasing concern about human alveolar echinococcosis, which is caused by the fox tapeworm Echinococcus multilocularis. In order to plan information campaigns, public knowledge about this zoonotic tapeworm was assessed.MethodsBy means of representative telephone interviews (N = 2041), a survey of public knowledge about the risk and the prevention of alveolar echinococcosis was carried out in the Czech Republic, France, Germany and Switzerland in 2004.ResultsFor all five questions, significant country-specific differences were found. Fewer people had heard of E. multilocularis in the Czech Republic (14%) and France (18%) compared to Germany (63%) and Switzerland (70%). The same effect has been observed when only high endemic regions were considered (Czech Republic: 20%, France: 17%, Germany: 77%, Switzerland: 61%). In France 17% of people who knew the parasite felt themselves reasonably informed. In the other countries, the majority felt themselves reasonably informed (54–60%). The percentage that perceived E. multilocularis as a high risk ranged from 12% (Switzerland) to 43% (France). In some countries promising measures as deworming dogs (Czech Republic, Switzerland) were not recognized as prevention options.ConclusionOur results and the actual epidemiological circumstances of AE call for proactive information programs. This communication should enable the public to achieve realistic risk perception, give clear information on how people can minimize their infection risk, and prevent exaggerated reactions and anxiety.

Trophic niche partitioning of cryptic species of long-eared bats in Switzerland: implications for conservation

Dietary niche partitioning is postulated to play a major role for the stable coexistence of species within a community, particularly among cryptic species. Molecular markers have recently revealed the existence of a new cryptic species of long-eared bat, Plecotus macrobullaris, in the European Alps. We studied trophic niches as well as seasonal and regional variations of diet in eight colonies of the three Plecotus species occurring in Switzerland. Faeces were collected monthly from individuals returning to roost after foraging. Twenty-one arthropod categories were recognized from the faeces. All three species fed predominantly on Lepidoptera, which made up 41%, 87% and 88% (means across colonies) of the diet composition of P. auritus, P. macrobullaris and P. austriacus, respectively. The occurrence of numerous fragments of both diurnal and flightless insects in the diet of P. auritus (but rarely in the diet of the other two species) indicates that this species mostly gleans prey from substrates. P. austriacus and P. macrobullaris are more typical aerial feeders. The latter two species have narrow trophic niches, whilst P. auritus has a much broader diet. Comparison of intraspecific and interspecific niche overlaps in P. auritus and P. macrobullaris in sympatry suggests dietary niche partitioning between these two species. In contrast, the high similarity of the trophic niches of P. austriacus and P. macrobullaris, associated with a typical parapatric distribution, indicates competitive exclusion. The best conservation measures are preservation and restoration of habitats offering a high abundance of moths, the major prey of the three Plecotus species.

Roost selection by non-breeding Leisler's bats (Nyctalus leisleri) in montane woodlands: implications for habitat management

ABSTRACT We investigated roost selection by Leislers bat (Nyctalus leisleri) before and after hibernation in 2005 in a mountain area of southern Switzerland. The study area is dominated by deciduous trees and characterised by the presence of previously managed chestnut (Castanea sativa) orchards that are now partly abandoned. In March–May and August–October, 15 radio-tracked bats (seven males and eight females) used 28 roost trees. We analysed roosts used by N. leisleri at three different levels: (i) micro-scale: features of roost cavities; (ii) meso-scale: characteristics of selected roost trees and (iii) macro-scale: structure of woodland surrounding roost trees. Selection at meso and macro-scales was obtained comparing characteristics of roost trees and surrounding woodland with potentially available trees and woodlands. Bats roosted mainly in live chestnut trees, with large diameter and absence of vegetation near the entrance. Roost trees were located closer to streams, in woodlands with a higher percentage of sweet chestnut trees and a lower tree density than random trees. Multifunctional forest management in abandoned chestnut stands, comprising recreation (chestnut harvesting) and preservation of a semi-natural habitat and its related biodiversity, would recreate the traditional woodland features – in particular an open forest structure with low tree density and presence of ancient chestnut trees – and provide suitable roosting sites to migratory N. leisleri.

Negative consequences of forearm bands that are too small for bats

1Centro Protezione Chirotteri Ticino, CH-6714 Semione, Switzerland 2Swiss Federal Research Institute WSL, Ecosystem Boundaries Research Unit, Insubric Ecosystems Group, Via Belsoggiorno 22, CH-6500 Bellinzona, Switzerland 3Institute of Ecology and Evolution, Division of Conservation Biology, Baltzerstrasse 6, CH-3012 Bern, Switzerland 4SWILD, Urban Ecology and Wildlife Research, Wuhrstrasse 12, CH-8003 Zurich, Switzerland 5Corresponding author: E-mail: fabio.bontadina@swild.ch

Grosse Fledermausvielfalt in den Waldnaturschutzgebieten des Kantons Zug

Grosse Fledermausvielfalt in den Waldnaturschutzgebieten des Kantons Zug In der Schweiz leben 30 Fledermausarten, wovon 80% den Wald als Lebensraum nutzen. Samtliche 22 national prioritaren Fledermausarten werden als Waldarten eingestuft, zwolf davon gelten als Waldzielarten, fur welche spezifische Fordermassnahmen ergriffen werden sollen. Aufgrund der verborgenen Lebensweise der Fledermause ist oft nicht bekannt, welche Arten in welchem Wald vorkommen. Kenntnisse uber die lokale Artenzusammensetzung bilden jedoch die Basis fur Fordermassnahmen. Neue bioakustische Methoden mit Ultraschallaufnahmegeraten erlauben seit wenigen Jahren grosse Fortschritte bei Nachweisen von Fledermausarten im Wald. Ziel der vorliegenden Untersuchung war, mit diesen neuen Methoden die Artenvielfalt von Fledermausen in funf Waldnaturschutzgebieten im Kanton Zug aufzunehmen, zu vergleichen und zu bewerten. Wahrend 258 Aufnahmenachten wurden insgesamt 30 522 Durchfluge von mindestens zwolf Fledermausarten aufgezeichnet. 23.5% der...