The optimal timing of reintroducing captive populations into the wild

Abstract

We examine a conservation problem in which the recovery of an endangered species depends on a captive breeding and reintroduction program. The model is applied to the case of the black-footed ferret (Mustela nigripes), an endangered species in North America reliant on captive breeding for survival. The timing of reintroduction is an important concern in these programs as there is a tradeoff between the duration (and therefore the cost) of the captive breeding program and the period the population spends in recovery and in the wild. In this paper, we develop a stylized bioeconomic model to determine the optimal reintroduction time, in which the objective is to minimize the cost of reintroduction while providing a viably-sized population in the wild. Our control variable is the timing of reintroduction, which departs from a large body of work in bioeconomics that focuses on adjustable controls that directly affect the target population. Generally, we find it is optimal to reintroduce ferrets early in a reintroduction program, although this result is contingent on species interactions and provisioning services.