Genetic rescue, a process that increases a population’s fitness by introducing new genetic variation, can occur naturally, but it can also be facilitated by managers to safeguard at-risk populations and enhance their ability to adapt to environmental changes. Genetic rescue through assisted migration, physically moving species to a different area, is recognized as a management option, but its suitability for various species had been unclear.  

To better understand the role of genetic rescue as a management tool, researchers funded by the Midwest CASC reviewed U.S. Fish and Wildlife Service recovery plans for over 200 vertebrates and counted how often genetic rescue was mentioned. Their findings, detailed in a study published in the Journal of Heredity, reveal that genetic rescue has been used just three times, for the Florida scrub-jay, the Columbia Basin Pygmy Rabbit, and the Florida Panther while only eight other plans considered it. The study goes on to outline a “genetic rescue suitability index” (GR Index) that evaluates whether sufficient natural history and genetic information exists about each species for genetic rescue to be a viable option. After calculating a GR Index for each species, the researchers suggest that two-thirds of the species reviewed are potential candidates for genetic rescue.  

This Midwest CASC-supported research demonstrates the under-use of genetic rescue as a conservation strategy for imperiled vertebrate species in the United States and introduces a quantifiable index that can assist managers assessing the usefulness of genetic rescue for a given species. 

This work is supported by the Midwest CASC Project, “Leveraging Genomic Data to Increase Adaptive Potential and Inform Management Action for the Endangered Mitchell’s Satyr Butterfly Under Climate Change.”