Using retrospective analyses to adaptively manage conservation breeding of an endangered rodent

Abstract

The conservation of at-risk species increasingly relies on ex situ breeding programs, whose success hinges on producing offspring. Even relatively successful programs can face unseen barriers to reproductive fitness. What may seem like minor choices in husbandry and management can impact reproductive outputs, thereby reducing the effectiveness of recovery efforts. Additionally, given that many endangered species are understudied, there can be unique, fitness-relevant aspects of their reproductive biology which go undetected without further study. Retrospective analyses into long standing conservation breeding programs offer an opportunity to investigate the relative importance of decisions on the reproductive success of at-risk species within an adaptive management framework. We demonstrate the utility of this approach by analyzing the factors driving reproductive stages of copulation, pregnancy, and the production of offspring in a conservation breeding population of the Pacific pocket mouse (Perognathus longimembris pacificus), a U.S. federally endangered subspecies. Our findings not only provide detailed insights into the species' reproductive biology but also reveal previously unknown and potentially unique predictors of reproduction in this subspecies. For example, even small differences in the degree of male reproductive readiness influenced the likelihood of successful copulation and pregnancy that resulted from breeding opportunities. By examining husbandry-related factors influencing reproduction, we identified actionable management improvements that will improve future breeding success and support species recovery.