Summer food as the factor limiting roe deer population size

Abstract

THE sizes of unexploited populations of roe deer (Capreolus capreolus) are regulated by spring migration. Individuals which have been able to establish a territory (bucks) or home range (does) force all other animals to move out of the habitat. This phenomenon is specific to age class, and if there is no mortality amongst adult animals, most yearlings emigrate to find new forest area¹³. Thus, in order to develop an intensive harvest policy for roe deer population, knowledge of the number of animals which can be supported by the habitat (that is, social carrying capacity) is essential to avoid undesirable population losses through emigration. During 1970–75, an intensive team research study was carried out in various regions throughout Poland⁶. Deer food resources were estimated by the harvest plot method³, and winter population densities were precisely determined by drive census techniques¹¹. Based on these data, several study areas were selected in which hunting and natural mortality were very low, and where it was known that most juvenile animals emigrated each spring. We show here that summer food is a major factor limiting roe deer population size.