Long‐Term Population Development of a Reintroduced Beaver (Castor fiber) Population in Sweden

Abstract

Deliberate reintroductions of locally exterminated animal species to areas within their former ranges is an increasingly important conservation tool. Most reintroductions are fairly recent and still in an initial phase of population development. There are few long‐term studies of reintroduced populations. The aim of this study was to see if the population development of the reintroduced European beaver (Castor fiber) population in Sweden exhibits the same pattern of population development as other introductions, in accordance with general theories, and to discuss possible management consequences. Since the European beaver was reintroduced to Sweden 70 years ago, the population has developed in a way predicted by the Riney‐Caughley model for introduced ungulates, exhibiting an irruption and a subsequent decline. In two study areas, the rate of population increase r turned negative after 34 and 25 years and at densities of 0.25 and 0.20 colonies/km2, respectively. The data suggest that management policy for an irruptive species should allow hunting during the rapid‐increase phase, thus maintaining food resources and avoiding uncontrolled population decline. Copyright © 1994, Wiley Blackwell. All rights reserved