KARCH

Neuchâtel, Switzerland
Neuchâtel, Switzerland

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Garner T.W.J.,UK Institute of Zoology | Garner T.W.J.,North West University South Africa | Schmidt B.R.,Karch | Schmidt B.R.,University of Zürich | And 7 more authors.
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2016

Amphibians across the planet face the threat of population decline and extirpation caused by the disease chytridiomycosis. Despite consensus that the fungal pathogens responsible for the disease are conservation issues, strategies to mitigate their impacts in the natural world are, at best, nascent. Reducing risk associated with the movement of amphibians, non-amphibian vectors and other sources of infection remains the first line of defence and a primary objective when mitigating the threat of disease in wildlife. Amphibian-associated chytridiomycete fungi and chytridiomycosis are already widespread, though, and we therefore focus on discussing options for mitigating the threats once disease emergence has occurred in wild amphibian populations. All strategies have shortcomings that need to be overcome before implementation, including stronger efforts towards understanding and addressing ethical and legal considerations. Even if these issues can be dealt with, all currently available approaches, or those under discussion, are unlikely to yield the desired conservation outcome of disease mitigation. The decision process for establishing mitigation strategies requires integrated thinking that assesses disease mitigation options critically and embeds them within more comprehensive strategies for the conservation of amphibian populations, communities and ecosystems. © 2016 The Author(s) Published by the Royal Society. All rights reserved.


PubMed | North West University South Africa, UK Institute of Zoology, Imperial College London, Ghent University and 3 more.
Type: Review | Journal: Philosophical transactions of the Royal Society of London. Series B, Biological sciences | Year: 2017

Amphibians across the planet face the threat of population decline and extirpation caused by the disease chytridiomycosis. Despite consensus that the fungal pathogens responsible for the disease are conservation issues, strategies to mitigate their impacts in the natural world are, at best, nascent. Reducing risk associated with the movement of amphibians, non-amphibian vectors and other sources of infection remains the first line of defence and a primary objective when mitigating the threat of disease in wildlife. Amphibian-associated chytridiomycete fungi and chytridiomycosis are already widespread, though, and we therefore focus on discussing options for mitigating the threats once disease emergence has occurred in wild amphibian populations. All strategies have shortcomings that need to be overcome before implementation, including stronger efforts towards understanding and addressing ethical and legal considerations. Even if these issues can be dealt with, all currently available approaches, or those under discussion, are unlikely to yield the desired conservation outcome of disease mitigation. The decision process for establishing mitigation strategies requires integrated thinking that assesses disease mitigation options critically and embeds them within more comprehensive strategies for the conservation of amphibian populations, communities and ecosystems.This article is part of the themed issue Tackling emerging fungal threats to animal health, food security and ecosystem resilience.


Werner P.,University of Trier | Lotters S.,University of Trier | Schmidt B.R.,KARCH | Schmidt B.R.,University of Zürich
Journal of Zoology | Year: 2014

Parapatry is a remarkable distributional pattern where the ranges of two species come into contact but only narrowly overlap. Theory predicts and empirical data suggest that parapatric range margins are most likely to form along environmental gradients when there is interspecific competition. Here, we study the ecology of the narrow contact zones of two parapatric European land salamanders, Salamandra salamandra and Salamandra atra. Previous research showed that abiotic conditions determine parapatric range margins of these two species. However, in contrast to other parapatric salamander species and theoretical predictions, there is no evidence for competitive interactions in the two Salamandra species. To study whether competition restricts these species' ranges and to understand local syntopic co-occurrence within their contact zones, we used site-occupancy models (1) to assess species-habitat relationships and (2) to test whether there is evidence for competition. We found that the two salamanders show dissimilar species-habitat relationships. The slope of the site positively affected the site-occupancy probability of S.salamandra, while none of the habitat characteristics explained the occupancy probability of S.atra. The local presence of one species had no effect on the occupancy probability of the other, suggesting that there is no effect of competition on local occurrence or that competition does not lead to spatial segregation. To fully understand the mechanisms that determine the parapatric range margins between the salamander species and to unravel the role of interspecific interactions, it is necessary to further study species' functional traits. © 2013 The Zoological Society of London.


Werner P.,University of Trier | Lotters S.,University of Trier | Schmidt B.R.,KARCH | Schmidt B.R.,University of Zürich | And 2 more authors.
Ecography | Year: 2013

Abrupt range limits of parapatric species may serve as a model system to understand the factors that determine species' range borders. Theory suggests that parapatric range limits can be caused by abiotic conditions along environmental gradients, biotic interactions or a combination of both. Geographic ranges of the parapatric salamanders, Salamandra salamandra and S. atra, meet in small contact zones in the European Alps and to date, the cause of parapatry and the restricted range of S. atra remain elusive. We combine multivariate approaches and climatic data analysis to explore niche differentiation among the two salamanders with respect to the available climatic environment at their contact zones. Our purpose is to evaluate whether climatic conditions explain the species' sharp range limits or if biotic interactions may play a role for range delimitation. Analyses were carried out in three contact zones in Switzerland to assess possible geographic variation. Our results indicate that both species occur at localities with different climatic conditions as well as the presence of a strong climatic gradient across the species' range limits. Although the species' climatic niches differ moderately (with a wider niche breadth for S. atra), interspecific niche overlap is found. Comparisons among the contact zones confirm geographic variation in the species' climatic niches as well as in the conditions within the geographically available space. Our results suggest that the change in climatic conditions along the recognized gradient represents a determining factor for species' range limits within contact zones. However, our analyses of geographic variation in climatic conditions reveal that both salamander species can occur in a much wider range of conditions than observed within contact zones. This finding and the interspecific climatic niche overlap within each contact zone provides indirect evidence that biotic interactions (likely competition) between the two species may also determine their range limits. © 2013 The Authors.


Schmidt B.R.,Karch | Schmidt B.R.,University of Zürich | Kery M.,Swiss Ornithological Institute | Ursenbacher S.,Karch | And 4 more authors.
Methods in Ecology and Evolution | Year: 2013

The use of environmental DNA (eDNA) to detect species in aquatic environments such as ponds and streams is a powerful new technique with many benefits. However, species detection in eDNA-based surveys is likely to be imperfect, which can lead to underestimation of the distribution of a species. Site occupancy models account for imperfect detection and can be used to estimate the proportion of sites where a species occurs from presence/absence survey data, making them ideal for the analysis of eDNA-based surveys. Imperfect detection can result from failure to detect the species during field work (e.g. by water samples) or during laboratory analysis (e.g. by PCR). To demonstrate the utility of site occupancy models for eDNA surveys, we reanalysed a data set estimating the occurrence of the amphibian chytrid fungus Batrachochytrium dendrobatidis using eDNA. Our reanalysis showed that the previous estimation of species occurrence was low by 5-10%. Detection probability was best explained by an index of the number of hosts (frogs) in ponds. Per-visit availability probability in water samples was estimated at 0·45 (95% CRI 0·32, 0·58) and per-PCR detection probability at 0·85 (95% CRI 0·74, 0·94), and six water samples from a pond were necessary for a cumulative detection probability >95%. A simulation study showed that when using site occupancy analysis, researchers need many fewer samples to reliably estimate presence and absence of species than without use of site occupancy modelling. Our analyses demonstrate the benefits of site occupancy models as a simple and powerful tool to estimate detection and site occupancy (species prevalence) probabilities despite imperfect detection. As species detection from eDNA becomes more common, adoption of appropriate statistical methods, such as site occupancy models, will become crucial to ensure that reliable inferences are made from eDNA-based surveys. © 2013 British Ecological Society.


Fish are often found in ponds that fish cannot colonize by themselves. A common explanation is that ducks may act as vectors because fish eggs may stick to their feet and ducks may therefore transport fish eggs and may facilitate colonization of ponds by fish. Here I review the evidence for the «duck transport fish» hypothesis. While there is some evidence that ducks might act as vectors and that fish eggs may survive transport, there is no evidence for the duck-mediated colonization of ponds by fish. Other explanations (i.e. vectors such as humans) are much more likely than ducks. © Laurenti-Verlag, Bielefeld.


Tanadini M.,University of Lausanne | Schmidt B.R.,Karch | Schmidt B.R.,University of Zürich | Meier P.,Service de la consommation et des affaires veterinaires | And 2 more authors.
Animal Conservation | Year: 2012

Alteration of natural habitats as a result of agricultural intensification is detrimental for wildlife. There is, however, growing evidence that land use and management can be wildlife friendly. In Europe, agricultural areas cover two-thirds of the land and therefore play a major role in maintaining biodiversity. Agricultural land use is very intense in vineyard-dominated landscapes but there are no refuges for wildlife in the form of ecological compensation areas. In our study, we assessed spatial variation in abundance of salamander (Salamandra salamandra) larvae in relation to land use and stream characteristics in vineyard-dominated landscapes. Abundance of larval salamanders depended positively on weirs, amount of riparian vegetation along the streams and environment-friendly agricultural practice in the vineyards. Surprisingly, road density also had positive effects, presumably through indirect effects (stone walls along roads may serve as refugia). Thus, abundance is determined by characteristics of both the aquatic and terrestrial habitats. Our results suggest that fire salamanders can persist in landscapes dominated by intensive agriculture like viticulture, indicate wildlife-friendly management options and highlight that man-made habitat can be valuable for wildlife. © 2011 The Authors. Animal Conservation © 2011 The Zoological Society of London.


Cruickshank S.S.,University of Zürich | Ozgul A.,University of Zürich | Zumbach S.,karch | Schmidt B.R.,University of Zürich
Conservation Biology | Year: 2016

Accurate trend estimates are necessary for understanding which species are declining and which are most in need of conservation action. Imperfect species detection may result in unreliable trend estimates because this may lead to the overestimation of declines. Because many management decisions are based on population trend estimates, such biases could have severe consequences for conservation policy. We used an occupancy-modeling framework to estimate detectability and calculate nationwide population trends for 14 Swiss amphibian species both accounting for and ignoring imperfect detection. Through the application of International Union for Conservation of Nature Red List criteria to the different trend estimates, we assessed whether ignoring imperfect detection could affect conservation policy. Imperfect detection occurred for all species and detection varied substantially among species, which led to the overestimation of population declines when detectability was ignored. Consequently, accounting for imperfect detection lowered the red-list risk category for 5 of the 14 species assessed. We demonstrate that failing to consider species detectability can have serious consequences for species management and that occupancy modeling provides a flexible framework to account for observation bias and improve assessments of conservation status. A problem inherent to most historical records is that they contain presence-only data from which only relative declines can be estimated. A move toward the routine recording of nonobservation and absence data is essential if conservation practitioners are to move beyond this toward accurate population trend estimation. © 2016 Society for Conservation Biology


Trademark
Karch | Date: 2014-06-03

Electronic cigarette liquid (e-liquid) comprised of propylene glycol; Electronic cigarette liquid (e-liquid) comprised of vegetable glycerin. Electronic cigarette liquid (e-liquid) comprised of flavorings in liquid form used to refill electronic cigarette cartridges.


PubMed | University of Zürich and karch
Type: Journal Article | Journal: Conservation biology : the journal of the Society for Conservation Biology | Year: 2016

Accurate trend estimates are necessary for understanding which species are declining and which are most in need of conservation action. Imperfect species detection may result in unreliable trend estimates because this may lead to the overestimation of declines. Because many management decisions are based on population trend estimates, such biases could have severe consequences for conservation policy. We used an occupancy-modeling framework to estimate detectability and calculate nationwide population trends for 14 Swiss amphibian species both accounting for and ignoring imperfect detection. Through the application of International Union for Conservation of Nature Red List criteria to the different trend estimates, we assessed whether ignoring imperfect detection could affect conservation policy. Imperfect detection occurred for all species and detection varied substantially among species, which led to the overestimation of population declines when detectability was ignored. Consequently, accounting for imperfect detection lowered the red-list risk category for 5 of the 14 species assessed. We demonstrate that failing to consider species detectability can have serious consequences for species management and that occupancy modeling provides a flexible framework to account for observation bias and improve assessments of conservation status. A problem inherent to most historical records is that they contain presence-only data from which only relative declines can be estimated. A move toward the routine recording of nonobservation and absence data is essential if conservation practitioners are to move beyond this toward accurate population trend estimation.

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