Spatial organization and demography of badgers (Meles meles) in Bialowieza Primeval Forest, Poland, and the influence of earthworms on badger densities in Europe

Abstract

From 1996 to 2001 we studied the spatial organization and demography of Eurasian badgers, Meles meles, in Białowieża Primeval Forest in eastern Poland, one of the best preserved woodlands in temperate Europe. Badger density estimated on the basis of main sett distribution (0.54 sett/10 km2) and group size (3.9 individuals per sett, on average) was 2.11 badgers/10 km2. Average annual productivity of the population was 64% and the mortality rate of badgers >1 year old was 22–38% per annum. The size of territories of badger groups (n = 7), estimated by radio telemetry, varied from 8.4 to 25.5 km2(mean 12.8 km2). Individual home ranges of badgers (n = 13) covered, on average, 9.3 km2, and varied seasonally and among animals of different age and sex classes (from 4.0 to 24.4 km2). Home ranges of adult badgers were significantly larger than those of subadults. Badgers occupied larger home ranges in summer, when earthworm availability was low. The size of both group territories and individual home ranges was influenced by the distribution of oak–lime–hornbeam (OLH) forests, habitats rich in earthworms. Based on our findings and a review of literature, we propose that the standing crop of biomass of earthworms (Lumbricus spp.), the main food of badgers in a large part of their geographic range, and mean annual temperature are crucial factors shaping the densities of badgers in the European temperate and boreal zones. We also suggest that abundance of food resources is the essential factor underlying the great variation in badger sociality (from pairs to large groups).