Natal dispersal of Eurasian lynx (Lynx lynx) in Switzerland

Abstract

Dispersal influences the dynamics and persistence of populations, the distribution and abundance of species, and gives the communities and ecosystems their characteristic texture in space and time. The Eurasian lynx Lynx lynx is a medium-sized solitary carnivore that has been re-introduced in central Europe and currently occurs in rather small populations, where dispersal is believed to play a prominent role for the recolonization of unsettled areas and persistence of subpopulations. Between 1988 and 2001 the spatio-temporal behaviour of sub-adult Eurasian lynx was studied in two re-introduced populations in Switzerland, based on 31 juveniles of which 24 were radio-tagged to find out which factors influence dispersal. Age at independence ranged from 8.1 to 10.7 months and did not differ between populations or sex. Independence began from January to the beginning of May with a peak in April. After independence, sub-adults stayed a few days in the maternal home range. Age at dispersal differed between the areas of origin and was possibly affected by sex and the presence of new progeny. Dispersers of both sexes established transient home ranges; however, only one male in the saturated population established a transient home range. Although only females took over the maternal home range, there was no significant sex bias in the proportion of individuals that dispersed in both populations. Successful dispersers settled in a territory at distances that differed between populations with effects of sex, but not condition. The mean dispersal distance in the high-density population was 25.9 km compared to 63.1 km in the low-density population. Dispersal distances in the high-density population – shorter than those reported in other Eurasian lynx studies but comparable to those observed in an Iberian lynx population – are limited by habitat restrictions hindering connections with a neighbouring population.