SGER: Monitoring Anacapa Island Deer Mice: Population Bottleneck, Release, and Reestablishment

University Of Illinois At Chicago, Chicago IL

Investigators

Abstract

This project will take advantage of a unique opportunity to monitor the progress of a controlled population bottleneck and its aftermath during a capture, release, and recovery program for a threatened mammal, the Anacapa Island deer mouse (Peromyscus maniculatus anacapae). This deer mouse is an endemic subspecies that occurs only on the three small islets that comprise Anacapa, one of the California Channel Islands. The Channel Islands National Park is currently conducting a program to eradicate the introduced rat, Rattus rattus. Rat eradication is conducted by large-scale poisoning with a potent rodent poison; deer mice as well as rats will be extirpated. Previously Dr. Ashley had conducted a conservation and management study using a combination of approaches that included molecular genetics, morphological measurements and population viability analysis (PVA). As a result, recommendations were made to the Park Service to capture a minimum of 333 mice from each of the islets, hold them in captivity, and use then as stock for reintroduction. According to research, this scenario would produce a population with high probability of persistence that maintained genetic variation, and yet represented a feasible undertaking. This plan is currently being implemented. Here Dr. Ashley proposes to take advantage of this unique opportunity to monitor the recovery of these populations. She will sample and genotype every mouse reintroduced, census the population regularly, and resample biannually. The impact of this research extends well beyond the management of an island endemic. The project will test the outcome of a PVA, compare predictions of population genetic theory to the real world, and will evaluate a captive breeding and reintroduction program. Most species management projects involve one or more of these practices, but outcomes are rarely evaluated or field-tested. By monitoring the numbers, distributions, and genetic variation in deer mice as they are reintroduced and during their recovery, the results of this study will provide important new information that can be directly applied to management and conservation of other endangered vertebrate species.