A Population Dynamics Model of Black Bears in Eastcentral Ontario

Abstract

A population model was developed to estimate demographic parameters and abundance of a black bear (Ursus americanus) population in eastcentral Ontario, using data from a 12-year mark-recapture program. The model enables the separation of natural and hunting mortality and allows for immigration to the study area. Parameter fitting was done by a nonlinear least-squares criterion. Abundance estimates using the 0-truncated Poisson, Petersen, and Jolly-Seber procedures allowed comparison of the different methods. The population growth rate was estimated as 2.9%/year for the female segment. Age-specific reproductive value was calculated, and its significance for black bear conservation is discussed. J. WILDL. MANAGE. 50(4):602-612 The black bear is one of Ontario's most familiar and widely distributed large mammals. Traditionally it was regarded as a predator and a nuisance, and a provincial bounty was paid from 1942 to 1961. In 1961, the species was recognized as a valuable wildlife resource with removal of the bounty and elevation to game animal status (Clarke 1961). During recent years, increased hunter pressure in many areas and invasion of black bear habitat by nonconsumptive users intensified the need for information about population densities and behavior. Although important studies of black bear demography have been conducted in a variety of habitats (Jonkel and Cowan 1971, Poelker and Hartwell 1973, Rogers 1977, Beecham 1980, Lindzey and Meslow 1980, Young and Ruff 1982), none have been carried out in the conifer-deciduous forests of eastern Canada. This paper presents the results of an extensive mark-recapture program carried out in eastcentral Ontario from 1969 to 1980. Objectives of the study were to: (1) estimate population abundance; (2) estimate age-specific natural mortality; (3) estimate immigration into the study area; and (4) use this information, together with reproductive data obtained during the study, to estimate the intrinsic growth rate of the population and the age-specific reproductive value of female bears. This project was supported in part by the Nat. Sci. and Eng. Res. Counc. Can. under Grant A7775.