Papers by Fabio Bontadina
Bats have evolved migration to escape unfavourable climatic conditions. However, their migratory ... more Bats have evolved migration to escape unfavourable climatic conditions. However, their migratory flyways and the way how they surmount geographical barriers are still unknown. The Jungfraujoch in the Swiss Alps is a mountain covered in permafrost (3460m ASL), known colloquially as the “Top of Europe”. Using broadband ultrasound recorders, we tested the occurrence of bats at the high altitude research station. In 36 nights, we recorded 268 bat call sequences of 8 species, including all European long-distance migrant bats. Since no feeding buzzes were recorded, we assume the bats were on transit. This is the first evidence to show that migrating bats can fly at unprecedented altitudes to cross the Alps. This feat outperforms the spectacular behaviour of the high altitude foraging bat Tadarida brasiliensis. Our findings shed light on the bats’ migratory flyways and demonstrate that the field of aeroecology can still uncover unexpected perspectives on the behaviour of bats.
Emerging Infectious Diseases, 2010
Journal of Zoology, 2002
Over the past 50 years European populations of the lesser horseshoe bat Rhinolophus hipposideros ... more Over the past 50 years European populations of the lesser horseshoe bat Rhinolophus hipposideros have severely declined, probably because of the loss of foraging habitat. To date, studies of the foraging behaviour of this species have been limited as its low mass (4±8 g) precluded the use of radio-telemetry because commercially available radio-transmitters exceeded 10% of its body mass. In this study, radiotransmitters weighing < 0.35 g were built. These increased the body mass of the animals from 4.5% to 8.1%, with no demonstrable adverse effect on their¯ight behaviour. The habitat selection of eight female lesser horseshoe bats was studied in Monmouthshire, U.K. The bats had foraging ranges between 12 and 53 ha (100% kernel). Although one bat foraged 4.2 km from the roost, for 50% of the time tracked bats were recorded within 600 m of the nursery roost. The estimated density within 200 m of the roost was 5.8 foraging bats/ha. This decreased to 0.01 bats/ha at 1200 m. Compositional analysis revealed that this species used woodlands, predominately broadleaf, more than any other habitat. In addition, the bats foraged in areas of high habitat diversity. Conservation management of this species should concentrate on such areas within 2.5 km of the nursery roost.
Journal of Animal Ecology, 2009
1. Variation of survival across time, between sex and ages strongly affect the population dynamic... more 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 Leisler's 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: 0AE45 ± 0AE04 (SE); later: 0AE76 ± 0AE04] 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 (0AE04 ± 0AE08), most likely caused by strong natal dispersal. It further increased with age (second year: 0AE55 ± 0AE20, later: 0AE69 ± 0AE07). 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 Leisler's 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.
In Switzerland urban foxes are a recent phenomenon dating back 15 years. In this study we analyse... more In Switzerland urban foxes are a recent phenomenon dating back 15 years. In this study we analysed attitudes towards the presence of urban foxes using data from a nation-wide survey and questionnaires sent to households and allotment gardeners in a district in Zurich with a high density of urban foxes. 60% of the respondents to the Swiss survey (telephone interviews) were against urban foxes, whereas only 40% of those surveyed in Zurich were against them. 70% of the gardeners, however, spoke out against urban foxes. Negative attitudes towards urban foxes were more frequent in large households (with children), among women, older people and those from small villages. 55% of the gardeners claimed to have experienced damage caused by foxes. This factor negatively correlated with fox acceptance. It seems then that the presence of urban foxes per se is not the reason behind negative attitudes, but those affected by damage caused by urban foxes will be more likely to view the animal negatively.
Landscape and Urban Planning, 2011
Urbanization is a fundamental environmental change, today happening at accelerated speed worldwid... more Urbanization is a fundamental environmental change, today happening at accelerated speed worldwide. Despite the strong and permanent human impact, urban biodiversity has generally proved to be surprisingly high. Quantitative information on the effect of management actions on biodiversity is often lacking but is an indispensable basis for decisions by urban planners and managers. We therefore quantified key urban variables to predict changes in avian biodiversity when their urban habitat is modified. We analysed species richness, diversity (Simpson index) and community composition of 63 bird species with reference to major urban environmental gradients at 96 sampling points in three Swiss cities. Best explanatory models were selected from candidate models following information theory, and their respective predictions were averaged based on AICc-weights. Bird species richness and diversity are negatively affected by increasing fractions of sealed area or buildings, while increasing vegetation structures, in particular trees, show positive effects. Our models predict an increase from 13 species in the absence of trees to 20 species with 46% tree cover (+54%). Coniferous trees help to maximize bird species richness, with the models predicting an increase from 14 species at sites with only deciduous woody plants to 20 species (+43%) at places with equal representation of coniferous and deciduous plants. While the analysis of the Simpson index did not show any influence of the coniferous and broadleaf woody plants mixture, partial redundancy analysis revealed such an influence on bird community composition, highlighting the importance to consider several measures when analyzing biodiversity.
Acta Chiropterologica, 2009
Journal of Wildlife Management, 2004
Baiting red foxes (Vulpes vulpes) is an established method of vaccinating foxes against rabies in... more 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). Ninetyone 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 nontarget species. However, with anthelmintic treatment, uptake by nontarget species is of lesser importance; hence, the effort to bury the bait is unnecessary.
Fuel and Energy Abstracts, 2011
We assessed the effect of abandonment of sylvo-pastoral practices in chestnut orchards (Castanea ... more We assessed the effect of abandonment of sylvo-pastoral practices in chestnut orchards (Castanea sativa) on bats in southern Switzerland to determine practical recommendations for bat conservation. We compared bat species richness and foraging activities between traditionally managed and unmanaged chestnut orchards, testing the hypothesis that managed orchards provide better foraging opportunities and harbour more bat species. Echolocation calls of foraging bats were sampled simultaneously at paired sites of managed and unmanaged orchards using custom made recorders. Vegetation structure and aerial insect availability were sampled at the recording sites and used as explanatory variables in the model. In a paired sampling design, we found twice the number of bat species (12) and five times higher total foraging activity in the managed chestnut orchards compared to the unmanaged ones. Bat species with low flight manoeuvrability were 14 times more common in managed orchards, whereas bats with medium to high manoeuvrability were only 5 times more common than in abandoned orchards. The vegetation structure was less dense in managed orchards. However, management did not affect relative insect abundance. Bats primarily visited the most open orchards, free of undergrowth. As a result of restricted access into the overgrown forests, the abandonment of chestnut orchards leads to a decline in bat species richness and foraging activities. Continued management of chestnut orchards to maintain an open structure is important for the conservation of endangered bat species in the southern Swiss Alps.
Journal of Applied Ecology, 2008
Recognizing the factor(s) that caused a demographic crash is a prerequisite to the development of... more Recognizing the factor(s) that caused a demographic crash is a prerequisite to the development of a tailored population restoration plan. While habitat destruction leaves little scope for population persistence, cryptic habitat deterioration (for example through reduction of food resources) may similarly render an area totally inhospitable, while it still appears to have a suitable habitat configuration.
Journal of Applied Ecology, 2007
1. It is difficult to establish conservation priorities for cryptic species when their ecological... more 1. It is difficult to establish conservation priorities for cryptic species when their ecological requirements are confounded by problems with species identification. In some cases, such as Chiroptera, cryptic taxa may actually consist of both widespread, abundant species and localized, rare species. Discrimination between these species may be facilitated by phenotypic, species-specific traits such as echolocation calls. Echolocation studies supported by genetic data have revealed that one of the most abundant bat species in Europe actually consists of two cryptic species: Pipistrellus pipistrellus and P. pygmaeus . 2. We recorded echolocation calls from both species along road transects in Switzerland to study their distribution and abundance. Using Ecological Niche Factor Analysis and discriminant analysis, we characterized species-specific habitat requirements, built habitat suitability maps and examined interspecific differences in niche parameters. 3. The presence of P. pygmaeus was associated with landscape matrices comprising large rivers and lakes, human settlements and open woodland. P. pipistrellus utilized similar habitat matrices but was far more tolerant to deviations from its optimal habitat. P. pygmaeus occupied a much narrower ecological niche, encompassed mainly within that of its sister taxon. 4. Synthesis and applications. P. pipistrellus is ranked as 'not threatened' in Switzerland. The results from this study indicate an abundance approximately 30 times higher than that of P. pygmaeus . In contrast, P. pygmaeus is distributed patchily and occurs at comparatively low densities. We recommend reclassification of P. pygmaeus as 'rare and potentially threatened'. Conservation of P. pygmaeus should focus on the management of riparian woodland in areas with a high probability of occurrence. This study emphasizes the need to recognize the potential existence of cryptic taxa so that effective conservation management of rare species can be put into place before they are seriously endangered.
European Journal of Wildlife Research, 2011
Domestic cats Felis catus, as companion animals provided with supplemental food, are not limited ... more 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.
Acta Chiropterologica, 2008
We investigated roost selection by Leisler's bat (Nyctalus leisleri) before and after hibernation... more We investigated roost selection by Leisler's 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.
Since 1985 increasingly more foxes have been recorded from cities i n Switzerland. The inquiry of... more Since 1985 increasingly more foxes have been recorded from cities i n Switzerland. The inquiry of town officials showed that foxes are observed i n 28 out of the 30 largest Swiss cities today and breeding dens are known i n 20 of these cities. Urban foxes are observed more often than one would expect in larger cities than i n smaller towns. I n Ziirich, the largest city i n Switzerland, urban foxes were very scarce until the early 1980s. According t o the hunting statistics, from 1985 onwards, there was a drastic increase i n the urban fox population. I n the adjacent rural areas, there was also a clear but less extreme increase i n the fox population from 1984 onwards due t o successful vaccination campaigns against rabies. As an explanation for the presence of foxes i n human settlements we suggest two alternative hypotheses, which focus either on the population pressure i n the rural areas or on the behavioural adaptations of urban foxes. The presence of foxes i n urban areas influences behaviour and attitudes of people towards urban wildlife and it has a consequences for the management of foxes and the treatment of zoonoses such as rabies and the alveolar echinococcosis.
Endangered Species Research, 2009
Relocation has become an important tool in conservation biology. So far little is known about the... more Relocation has become an important tool in conservation biology. So far little is known about the suitability of translocation to restore bat populations. We evaluated the conditions for successful translocations amongst 2 bat species: the greater horseshoe bat Rhinolophus ferrumequinum and the lesser horseshoe bat R. hipposideros. Both species underwent a dramatic decline in Western and Central Europe in the second half of the 20th century, but some populations have recently started to recover. Due to their sedentary habits, natural recolonisation of their formerly vast inhabited range advances only slowly. Translocation could solve this problem. In 2006, we conducted translocation experiments with 11 greater and 7 lesser horseshoe bats within Switzerland. Bats were captured at large colonies, released into relict colonies, radiotracked for up to 10 d and checked for presence during the following years. Ten out of the 13 individuals released at distances < 20 km from the donor roost homed. None of the 5 bats released at distances > 40 km expressed homing tendencies. Within 3 d of release, 1 greater and 3 lesser horseshoe bats died (2 of shock). Lesser horseshoe bats seem to react very sensitively to translocation. Long-distance translocation of 2 greater horseshoe bats led to short-term settlement in the release area; since its translocation, the sole female released at long distance has been regularly observed in the receiver colony. Apparent species-specific differences in tolerance to translocation underline the necessity of studying the focal species instead of surrogate species in translocation projects.
BMC Public Health, 2008
Background Public information about prevention of zoonoses should be based on the perceived probl... more Background Public 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. Methods By 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. Results For 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. Conclusion Our 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.
Parasitology International, 1998
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Papers by Fabio Bontadina