Population Effects of Habitat Change: A Quantitative Assessment

Abstract

Ecological habitat selection theory can project animal population changes from short-term habitat use and availability data. Sitka black-tailed deer (Odocoileus hemionus sitkensis) in a coastal southeastern Alaska forest watershed yield data linking the theory to a typical wildlife management problem. In a model watershed, reducing old growth in favor of young clearcuts and second growth negatively impacts deer, particularly in years of heavy snowfall. J. WILDL. MANAGE. 52(1):41-46 Wildlife habitat may change in space and time. Changed proportions of different habitats in an area can alter the area's overall suitability as wildlife habitat. There is a need for models of habitat relationships to predict wildlife responses to habitat changes (Verner et al. 1986). This paper presents a method for projecting the impacts of habitat change on wildlife from shortterm use and availability data frequently gathered in wildlife management. Ecological habitat selection theory specifies conditions under which population densities indicate habitat quality so that consequences of habitat change can be projected directly from use and availability data. In Alaska and elsewhere in western North America, temperate old-growth forests continue to be logged for timber and pulp. In this paper I indicate some potential impacts of habitat change on wildlife in old-growth forests. I am indebted to J. W. Schoen and M. D. Kirchhoff for unpublished information, permission to cite unpublished technical reports, and critical reviews. R. Flynn kindly checked calculations for the numerical example. I thank M. L. Rosenzweig for insights and discussions that gre ly aided model development.