Population ecology of the raccoon dog in Finland - a synthesis
Kauhala, K. & Helle, E. 1995: Population ecology of the raccoon dog in Finland - a synthesis. - Wildl. Biol: 3-9.
The population ecology of the raccoon dog Nyctereutes procyonoides was investigated in Finland from 1973 to 1992. Annual mean temperature explained most of the regional variation in the growth rate and present density of the population. Climate explained most of the regional variation in the productivity of the raccoon dog population; the length of the annual snow-free period accounted for most of the regional variation in the weight and fat reserves of young females in late autumn which, in turn, affected the proportion of reproducing females in the population the following spring. Of the independent variables examined, the abundance of wild berries is the dominating factor in explaining the annual variation in density; mortality is highest during the first year of life and the availability of berries probably affects the mortality of juveniles during autumn and winter. The abundance of voles and the population density of raccoon dogs in spring affects the fat reserves of adult females which, in turn, affect their litter size. The productivity of adult females is density dependent, and, thus, regulates population density to some extent. Changes in population size seem to be density dependent after the population peaked around the mid-1980s.
Kaarina Kauhala & Eero Helle, Finnish Game and Fisheries Research Institute, P.O. Box 202, FIN-00151 Helsinki, Finland
Received 9 May 1994, accepted 12 December 1994
Associate Editor: Erik Lindström