Rodent population dynamics in a primeval deciduous forest (Bialowieza National Park) in relation to weather, seed crop, and predation

Abstract

Population dynamics of bank vole Clethrionomys glareolus and yellow-necked field mouse Apodemus flavicollis were studied in 1959-1991 in the pristine mature forest in Bialowieza National Park, E Poland. Rodent numbers were very low in spring (April), then grew through summer due to reproduction. The annually highest numbers of both species were recorded in autumn. Winter mortality was on average 77% of autumn numbers of voles and 86% of mice. Multiannual variations in numbers were large; the combined numbers of voles and mice showed a regular pattern of 2 yr of outbreak-crash (triggered by heavy mast production) and 4-7 yr of moderate, though variable, densities. Heavy seed crops occurred at 6-9-yr intervals and were triggered by warm June-July temperature in the preceding year). -from Authors