Socio-spatial organization of Eurasian badgers (Meles meles) in a low-density population of central Europe

We studied the socio-spatial organization of Eurasian badgers (or European badgers), Meles meles (L., 1758), in a low-density population (estimate 1.8 badgers/km2) inhabiting a semi-rural area of western Switzerland. For this purpose, 8 badgers (5 males and 3 females) were caught at 5 different main setts and were radio-tracked between May 1994 and November 1996. The size of individual home ranges varied from 0.27 to 3.74 km2 (1.69 ± 1.33 km2 (mean ± SD), n = 8, 100% MCP), seemingly according to local variations in habitat productivity. Individual home ranges were spatially stable, but their size decreased significantly during winter (0.26 ± 0.42 km2, n = 7, 100% MCP). Badger social units consisted of 1–5 adults and (or) subadults (2.2 ± 1.5 animals, n = 9) and their yearly offspring. Group-range size varied from 0.57 to 3.74 km2 (2.12 ± 1.30 km2, n = 4) and seemed to be influenced by the spatial distribution pattern of food resources. Indeed, each group range encompassed approximately the same surface of agricultural land (about 0.60 km2). Territories were not well marked, some group ranges partly overlapped. Latrines, which were not numerous and principally located inside rather than along borders of group ranges, were only used irregularly or sporadically. This prompts us to encourage the reconsideration of the role of territorial behaviour in promoting group formation in Eurasian badgers.

Isolation by distance and gene flow in the Eurasian badger (Meles meles) at both a local and broad scale

Eurasian badgers, Meles meles, have been shown to possess limited genetic population structure within Europe; however, field studies have detected high levels of philopatry, which are expected to increase population structure. Population structure will be a consequence of both contemporary dispersal and historical processes, each of which is expected to be evident at a different scale. Therefore, to gain a greater understanding of gene flow in the badger, we examined microsatellite diversity both among and within badger populations, focusing on populations from the British Isles and western Europe. We found that while populations differed in their allelic diversity, the British Isles displayed a similar degree of diversity to the rest of western Europe. The lower genetic diversity occurring in Ireland, Norway and Scotland was more likely to have resulted from founder effects rather than contemporary population density. While there was significant population structure (F ST = 0.19), divergence among populations was generally well explained by geographic distance (P < 0.0001) across the entire range studied of more than 3000 km. Transient effects from the Pleistocene appear to have been replaced by a strong pattern of genetic isolation by distance across western Europe, suggestive of colonization from a single refugium. Analysis of individuals within British populations through Mantel tests and spatial autocorrelation demonstrated that there was significant local population structure across 3-30 km, confirming that dispersal is indeed restricted. The isolation by distance observed among badger populations across western Europe is likely to be a consequence of this restricted local dispersal.