Current and historical nephric and hepatic mercury concentrations in terrestrial mammals in Poland and other European countries

The long-term anthropogenic release of mercury (Hg) into the environment has led to contamination of the biosphere, with all forms of Hg showing toxic effects and the ability to accumulate in organisms. Since the 1970s, efforts have been made in Western Europe to reduce Hg emissions and for the economic use of Hg, leading to a reduction in Hg exposure to humans and entire ecosystems. The purpose of this research was to present the total mercury (THg) burden in three mustelids (the piscivorous Eurasian otter and American mink, and the invertebrativorous European badger) inhabiting north-western Poland (mostly floodplains) and other European countries (literature data). Moreover, we wanted to investigate whether reductions in the environmental Hg burden in Europe have resulted in reductions in liver and kidney levels in wild terrestrial mammals (Eurasian otter, wild boar, red deer, roe deer, cervids, leporids, rodents, and ecotrophic groups: piscivorous mustelids, non-mustelids whose diets include aquatic prey, canids and other carnivores, omnivores, herbivores), between samples collected before and after 2000. We revealed significantly higher nephric THg levels in roadkilled than in trapped American minks. As roadkilled piscivorous mustelids from the same floodplain had similar hepatic and nephric THg concentrations, we suggest that the European research on Hg ecotoxicology should more often use alien American mink instead of the protected Eurasian otter. Badgers inhabiting Polish and other European floodplains bioaccumulated higher amounts of THg than those from other areas, and as such, may be recommended as bioindicator of mercury soil contamination. Our analysis of abundant data on mammalian hepatic and nephric THg concentrations (excluding non-piscivores mustelids) showed that in 12 of 21 cases, Hg concentrations had dropped significantly since 2000. This data signals a reduction in Hg contamination in terrestrial mammals, such as the Eurasian otter, and may be reason for cautious optimism.

Altitude shapes the environmental drivers of large-scale variation in abundance of a widespread mammal species

AIM

Habitat quality and heterogeneity directly influence the distribution and abundance of organisms at different spatial scales. Determining the main environmental factors driving the variation in species abundance is crucial to understand the underlying ecological processes, and this is especially important for widely distributed species living in contrasting environments. However, the responses to environmental variation are usually described at relatively small spatial scales. Here, we studied the variation in abundance of a widely distributed mustelid, the European badger (Meles meles), across France.

LOCATION

The whole metropolitan France.

METHODS

We used (a) direct detections of 9,439 dead and living badgers, from 2006 to 2009, to estimate badger relative abundance in 703 small agricultural regions of metropolitan France and (b) a Bayesian modeling approach to identify the main environmental determinants influencing badger abundance.

RESULTS

Despite a continuous distribution of badger in France, we found large variation in badger abundance between regions, explained by environmental factors. Among a set of 13 environmental variables, we demonstrated that badger abundance in lowlands (<400 m a.s.l.) was mostly driven by biotic factors such as potential food resources (earthworm abundance and fruit crops) and forest fragmentation. Conversely, in mountainous areas, abiotic factors (i.e., soil texture and climate) drove the variation in badger relative abundance.

MAIN CONCLUSIONS

These results underline the importance of mapping the abundance of wildlife species based on environmental suitability and highlight the complexity of drivers influencing species abundance at such large spatial scales. Altitude shaped the environmental drivers (biotic vs. abiotic) that most influenced relative abundance of a widespread species. In the case of badger, such abundance maps are crucial to identify critical areas for species management as this mustelid is a main wild vector of bovine tuberculosis in several countries.

Acceptability and consensus for the management of game and non-game crop raiders

Abstract ContextWild boars (Sus scrofa) and European badgers (Meles meles) have been increasingly implicated in crop damage in Greece. The species’ increasing presence on agricultural land has also raised concern about disease transmission to livestock and humans. Greece does not have any plans for the management of these situations, because they have only recently emerged. Understanding public preferences for management strategies is necessary for the successful implementation of management plans. AimsTo survey residents of Eastern Macedonia and Thrace, north-eastern Greece, to understand variation between stakeholder groups in preferences for the management of wild boars and European badgers in different scenarios. MethodsData were collected from on-site face-to-face surveys (n=585), between September and November 2017. Respondents, assigned to one of general public, farmers, hunters and farmer-hunter groups, were asked to rate their acceptability of wild boar and European badger management strategies under four conflict scenarios: wild boars and European badgers raid crops and transfer disease. Key resultsStakeholders preferred less invasive strategies for the management of crop raiders, although they accepted lethal control in the more severe disease-transmission scenarios. Potential for conflict was higher for non-lethal control in the crop-raiding scenarios and for lethal control in the disease-transmission scenarios. Farmers and farmer-hunters were the groups more strongly supporting management strategies in all scenarios. Hunters were more reluctant to accept the reduction in numbers of a game species (i.e. the wild boar) than of a non-game species (i.e. the European badger). ConclusionsVariation in the acceptability of and consensus for wild boar and European badger management strategies was considerable, both among and within groups. ImplicationsFindings are a critical guide for the design of a conflict-management process aimed at reaching consensus for proper management strategies. This would allow for the successful management of human conflicts over wildlife.