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Minnig S.,University of Fribourg | Angst C.,Center Suisse Of Cartographie Of La Faune Cscf | Jacob G.,University of Fribourg
Russian Journal of Theriology | Year: 2016

Eurasian beaver (Castor fiber) has been reintroduced in Switzerland between 1956 and 1977. Individuals from the refugium population in France (C. f. galliae) were released in the Rhone catchment area and in tributaries of the Rhine catchment area in Western Switzerland. Individuals from the refugium populations from Norway (C. f. fiber) and Russia (C. f. orientoeuropaeus) were released in tributaries of the Rhine catchment in Eastern Switzerland. In the Rhine basin beavers of different origins came into contact. This study provides a first evaluation of the reintroduction program of beaver in Switzerland and gives implications for the post-release genetic management of the Swiss beaver population. We report on the genetic monitoring of the beaver population in Switzerland, based on the analysis of 251 dead found individuals collected from 1998 to 2014 and a combination of mitochondrial and nuclear genetic markers. We found no evidence of the presence of North American beaver (Castor canadensis) and we observed three mitochondrial DNA haplotypes, assigned to the refugium populations in France (C. f. galliae), Norway (C. f. fiber) and Germany (C. f. albicus). Based on the analysis of seven microsatellite loci, we inferred that the beaver population in Switzerland consists of two genetic clusters and we found evidence of a zone of secondary contact. We observed low levels of genetic diversity and we could show that individuals separated by distances up to 50 km were closely related. © RUSSIAN JOURNAL OF THERIOLOGY, 2016.

Bruggisser O.T.,University of Fribourg | Sandau N.,University of Fribourg | Blandenier G.,University of Fribourg | Blandenier G.,Center Suisse Of Cartographie Of La Faune Cscf | And 5 more authors.
Basic and Applied Ecology | Year: 2012

Species abundance in local communities is determined by bottom-up and top-down processes, which can act directly and indirectly on the focal species. Studies examining these effects simultaneously are rare. Here we explore the direct top-down and direct and indirect bottom-up forces regulating the abundance and predation success of an intermediate predator, the web-building spider Argiope bruennichi (Araneae: Araneidae). We manipulated plant diversity (2, 6, 12 or 20 sown species) in 9 wildflower strips in a region of intensive farmland. To identify the major factors regulating the distribution and abundance of A. bruennichi, we quantified three characteristics of vegetation (species diversity, composition and vegetation structure) as well as the spider's prey community and natural enemies. The distribution and abundance of A. bruennichi was regulated by combined bottom-up and top-down processes as well as by direct and indirect interactions between trophic levels. Four main factors were identified: (1) the strong direct effect of vegetation structure, (2) the positive effect of plant species diversity, which affected spider abundance directly and indirectly through increased densities and size of flower-visiting prey species, (3) the positive or negative direct effects of different plant species, and (4) the strongly negative direct effect of predacious hornets. The advantage of taking a global approach to understand the regulation of species abundance is highlighted first by the quantification of the relative importance of factors, with a surprisingly strong effect of hornet predators, and second by the discovery of a direct effect of plant diversity, which raises intriguing questions about habitat selection by this spider. © 2012 Gesellschaft für Ökologie.

The value of wildlife has long been ignored or under-rated. However, growing concerns about biodiversity loss and emerging diseases of wildlife origin have enhanced debates about the importance of wildlife. Wildlife-related diseases are viewed through these debates as a potential threat to wildlife conservation and domestic animal and human health. This article provides an overview of the values we place on wildlife (positive: socio-cultural, nutritional, economic, ecological; and negative: damages, health issues) and of the significance of diseases for biodiversity conservation. It shows that the values of wildlife, the emergence of wildlife diseases and biodiversity conservation are closely linked. The article also illustrates why investigations into wildlife diseases are now recognized as an integral part of global health issues. The modern One Health concept requires multidisciplinary research groups including veterinarians, human physicians, ecologists and other scientists collaborating towards a common goal: prevention of disease emergence and preservation of ecosystems, both of which are essential to protect human life and well-being. © GST | SVS.

Dewas M.,ONCFS | Herr J.,Administration de la Nature et des Forets | Schley L.,Administration de la Nature et des Forets | Angst C.,Center Suisse Of Cartographie Of La Faune Cscf | And 3 more authors.
Mammal Review | Year: 2012

1 The Eurasian beaver Castor fiber suffered a drastic reduction in both geographical range and population size, due to human persecution, until the end of the 19th century. After the adoption of protection measures, natural expansion and reintroductions led to the recovery of this species over much of its European range. 2 We review historical events that led to the recovery of beavers in France, and summarize the status of beavers in various river systems. Beaver establishment in France is a story of overall success: several major river systems are presently occupied, so that the species is no longer at risk in France. 3 However, beaver recolonization took place in parallel with increasing human impacts on the environment. In addition to natural limiting factors, anthropogenic factors impeded beaver settlement in many areas. Today, beavers often occupy suboptimal habitats and, as a consequence, come into conflict with human activities. Effective solutions for preventing beaver damage include the restoration of riparian habitats to discourage crop damage and the provision of physical barriers to protect crops. 4 Beaver populations reintroduced into France all originate from the relict Rhône population. However, in recent years, beavers from populations in neighbouring countries have been expanding into north-eastern France. Therefore, our review of beaver origin and distribution in these countries may contribute to the development of appropriate national management strategies and towards important decisions, e.g. the decision to try to keep Rhône beavers genetically isolated, or to allow populations to mix. 5 The recently discovered presence of North American beavers Castor canadensis in three countries surrounding France has raised an important issue. This species may out-compete C. fiber in places where the species come into contact. A programme based on field-trapping sessions and genetic analyses has recently been initiated in some western countries in order to eradicate this non-native species. © 2011 The Author. Mammal Review © 2011 Mammal Society/Blackwell Publishing.

Kery M.,Swiss Ornithological Institute | Gardner B.,U.S. Geological Survey | Monnerat C.,Center Suisse Of Cartographie Of La Faune Cscf
Journal of Biogeography | Year: 2010

Aim: (1) To increase awareness of the challenges induced by imperfect detection, which is a fundamental issue in species distribution modelling; (2) to emphasize the value of replicate observations for species distribution modelling; and (3) to show how 'cheap' checklist data in faunal/floral databases may be used for the rigorous modelling of distributions by site-occupancy models. Location: Switzerland. Methods: We used checklist data collected by volunteers during 1999 and 2000 to analyse the distribution of the blue hawker, Aeshna cyanea (Odonata, Aeshnidae), a common dragonfly in Switzerland. We used data from repeated visits to 1-ha pixels to derive 'detection histories' and apply site-occupancy models to estimate the 'true' species distribution, i.e. corrected for imperfect detection. We modelled blue hawker distribution as a function of elevation and year and its detection probability of elevation, year and season. Results: The best model contained cubic polynomial elevation effects for distribution and quadratic effects of elevation and season for detectability. We compared the site-occupancy model with a conventional distribution model based on a generalized linear model, which assumes perfect detectability (p = 1). The conventional distribution map looked very different from the distribution map obtained using site-occupancy models that accounted for the imperfect detection. The conventional model underestimated the species distribution by 60%, and the slope parameters of the occurrence-elevation relationship were also underestimated when assuming p = 1. Elevation was not only an important predictor of blue hawker occurrence, but also of the detection probability, with a bell-shaped relationship. Furthermore, detectability increased over the season. The average detection probability was estimated at only 0.19 per survey. Main conclusions: Conventional species distribution models do not model species distributions per se but rather the apparent distribution, i.e. an unknown proportion of species distributions. That unknown proportion is equivalent to detectability. Imperfect detection in conventional species distribution models yields underestimates of the extent of distributions and covariate effects that are biased towards zero. In addition, patterns in detectability will erroneously be ascribed to species distributions. In contrast, site-occupancy models applied to replicated detection/non-detection data offer a powerful framework for making inferences about species distributions corrected for imperfect detection. The use of 'cheap' checklist data greatly enhances the scope of applications of this useful class of models. © 2010 Blackwell Publishing Ltd.

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