Climate and landscape changes as driving forces for future range shift in southern populations of the European badger

Soil δ13C and δ15N baselines clarify biogeographic heterogeneity in isotopic discrimination of European badgers (Meles meles)

Isotopic techniques have been used to study phenomena in the geological, environmental, and ecological sciences. For example, isotopic values of multiple elements elucidate the pathways energy and nutrients take in the environment. Isoscapes interpolate isotopic values across a geographical surface and are used to study environmental processes in space and time. Thus, isoscapes can reveal ecological shifts at local scales, and show distribution thresholds in the wider environment at the macro-scale. This study demonstrates a further application of isoscapes, using soil isoscapes of ¹³C/¹²C and ¹⁵N/¹⁴N as an environmental baseline, to understand variation in trophic ecology across a population of Eurasian badgers (Meles meles) at a regional scale. The use of soil isoscapes reduced error, and elevated the statistical signal, where aggregated badger hairs were used, and where individuals were identified using genetic microarray analysis. Stable isotope values were affected by land-use type, elevation, and meteorology. Badgers in lowland habitats had diets richer in protein and were adversely affected by poor weather conditions in all land classes. It is concluded that soil isoscapes are an effective way of reducing confounding biases in macroscale, isotopic studies. The method elucidated variation in the trophic and spatial ecology of economically important taxa at a landscape level. These results have implications for the management of badgers and other carnivores with omnivorous tendencies in heterogeneous landscapes.

Sett Use, Density and Breeding Phenology of Badgers in Mediterranean Agro-Sylvo-Pastoral Systems

Simple Summary

Understanding carnivores social structure variation is pivotal for properly addressing conservation challenges and solutions. The European badgers is a social carnivore for which most of the available information regarding how this species is socially organized derives from central west populations. This article describes the group composition, den use patterns and breeding phenology of a Mediterranean population of badgers. We showed that badger live in low density, in relatively small groups, composed by 2–4 adult animals and ca. 2 cubs, born in winter. These patterns, representing a variation of what was described for other populations, show that badgers take advantage of the landscape context, where human-related resources and mild environmental conditions allow badger to reach higher densities than in many southern populations, and to reproduce earlier than their northern counterparts.

Abstract

Carnivores social organization varies widely, from strongly social to solitary predators. European badgers are facultative social carnivores that also shows a geographical variation in social structure. These patterns derive mainly from central/west European regions, with an under-representation of Mediterranean populations that face different conservation challenges, especially regarding group composition, sett use patterns and breeding phenology. We addressed these traits topics for a population inhabiting a Portuguese agro-silvo-pastoral system. Based on monthly monitoring of 34 setts and continuous camera-trapping surveys of 12, we showed that setts surrounded by diversified vegetation and located in sandy sites are more used, a pattern probably linked to food availability and ease of sett excavation and maintenance, respectively. Badgers followed a general pattern regarding group size (2–4 adults), but showed an intermediate population density (0.49–0.73 badgers/km²), with values higher than those estimated for other Mediterranean environments, but lower than for central-western populations. This, together with the breeding (November/January) and cub emergence (1.8 cubs/sett; March/April) periods, indicates an ecological adaptation to the landscape context, where human-related resources and mild environmental conditions allow badger to reach higher densities than in many southern populations, and to reproduce earlier than their northern counterparts.

Metapopulation Patterns of Iberian Butterflies Revealed by Fuzzy Logic

Metapopulation theory considers that the populations of many species are fragmented into patches connected by the migration of individuals through an interterritorial matrix. We applied fuzzy set theory and environmental favorability (F) functions to reveal the metapopulational structure of the 222 butterfly species in the Iberian Peninsula. We used the sets of contiguous grid cells with high favorability (F ≥ 0.8), to identify the favorable patches for each species. We superimposed the known occurrence data to reveal the occupied and empty favorable patches, as unoccupied patches are functional in a metapopulation dynamics analysis. We analyzed the connectivity between patches of each metapopulation by focusing on the territory of intermediate and low favorability for the species (F < 0.8). The friction that each cell opposes to the passage of individuals was computed as 1-F. We used the r.cost function of QGIS to calculate the cost of reaching each cell from a favorable patch. The inverse of the cost was computed as connectivity. Only 126 species can be considered to have a metapopulation structure. These metapopulation structures are part of the dark biodiversity of butterflies because their identification is not evident from the observation of the occurrence data but was revealed using favorability functions.

Potentially toxic element accumulation in badgers (Meles meles): a compositional approach

Potentially Toxic Elements (PTEs) in Badgers (Meles meles), otherwise known as heavy metals, are unique amongst environmental pollutants occurring, both naturally and anthropogenically. PTEs have a broad range of negative health and environmental effects, therefore identifying their sources and pathways through the environment is imperative for public health policy. This is difficult in terrestrial systems due to the compositional nature of soil geochemistry. In this study, a compositional statistical approach was used to identify how PTEs accumulate in a terrestrial carnivorous mammal, Eurasian Badgers (Meles meles). Compositional principal component analysis (PCA) was used on geochemical data from the Tellus survey, the soil baseline and badger tissue data to map geo-spatial patterns of PTEs and show accumulative trends measured in time. Mapping PCs identified distinct regions of PTE presence in soil and PTE accumulation in badger tissues in Northern Ireland. PTEs were most elevated in liver, kidney and then muscle tissues. Liver and kidney showed the most distinct geo-spatial patterns of accumulation and muscle was the most depleted. PC1 and 2 for each type were modelled using generalised additive mixed models (GAMM) to identify trends through time. PC1 for the liver and muscle were associated with rainfall and ∂N15 in the liver, showing a link to diet and a bioaccumulation pathway, whilst PC2 for both tissues was associated with mean temperature, showing a link to seasonal activity and a bioaccessibility pathway. However, in kidney tissue these trends are reversed and PC1 was associated with bioaccessibility and PC2 with bioaccumulation. Combined these techniques can elucidate both geo-spatial trends in PTEs and the mechanisms by which they move in environment and in future may be an effective tool for assessing PTE bioavailability in environmental health surveys.

How far from the road should land cover be assessed? A case study on mesopredator mortality on roads

The methods used to assess the significance of land cover in the vicinity of a road for the mortality of mesopredators are diverse. In assessing the effect of land cover along the road on road causalities, scientists use various buffer sizes, or even no buffer along the road. The aim of this study was to verify how results of land cover effects on the mortality of mesopredators on roads may differ when analyzing various buffer sizes from the road. We assessed road causalities in the Warmian-Masurian voivodeship (Poland) from 3 consecutive years: 2015, 2016, and 2017. The roads were divided into equal sections of 2000 m each with buffer size of radius: 10, 250, 500, and 1000 m. We analyzed the number of road kills of red fox and European badger separately in a generalized linear model, whereas explanatory variables we used land cover types (based on the Corine Land Cover inventory) and traffic volume. Mean annual mortality from road collisions amounts to 2.36% of the red fox population and 3.82% of the European badger population. We found that the buffer size determines the results of the impact of land cover on mesocarnivore mortality on roads. The red fox differed from the European badger in response to land cover depending on the buffer size. The differences we have shown relate in particular to built-up areas. Our results indicate a 500-m buffer as best reflecting the land cover effects in road kills of both species. This was confirmed by model evaluation and a tendency to use or avoid the vicinity of human settlements of the analyzed species. We concluded that buffer size will probably affect mostly the significance of cover types that are spatially correlated with roads, positively or negatively. We suggest that the home range size of given species in local conditions should be assessed before determining the size of the buffer for analysis.

Ecological Niche Models Reveal Climate Change Effect on Biogeographical Regions: The Iberian Peninsula as a Case Study

How species are distributed on Earth depends largely on climate factors. Whenever these environmental conditions change, species tend to shift their distributions to reach more favourable conditions. Distinct sets of species similarly distributed (i.e., chorotypes) occur in biogeographical regions with homogeneous environmental conditions. Here, we analysed whether biogeographical regions are unstable over time (from the past to the future). We modelled the realised niche of amphibians and reptiles in the Iberian Peninsula in the present, and several past and future climate scenarios. Then, we used Jaccard’s index and the unweighted pair group method (UPGMA) to define the biogeographical regions. Our results suggest that the biogeographical regions of Iberian amphibians and reptiles changed greatly over time, due to the climatic changes between periods. Biogeographical regions composed of species with Atlantic affinities changed particularly, overall gaining suitable areas in past colder periods and losing suitable areas in warmer periods. The areas of refugia for amphibians over time corresponded to the most humid regions (north-west of the peninsula), while the most important areas for reptiles occur in the south and on the Atlantic coast. The identification of biogeographical patterns considering past climate changes is essential to better apply conservation measures.

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.