The disappearing northern leopard frog ( L ithobates pipiens ): conservation genetics and implications for remnant populations in western N evada

Global amphibian declines suggest a major shift in the amount and quality of habitat for these sensitive taxa. Many species that were once widespread are now experiencing declines either in part of or across their historic range. The northern leopard frog ( R ana [ L ithobates ] pipiens ] has undergone significant declines particularly in the western U nited S tates and C anada. Leopard frog population losses in N evada are largely due to habitat fragmentation and the introduction of nonnative fish, amphibian, and plant species. Only two populations remain in the T ruckee and C arson R iver watersheds of western N evada which represents the western boundary of this species range. We used sequence data for an 812 base pair fragment of the mitochondrial NADH dehydrogenase 1 ( ND 1) gene to support a native origin for western N evada populations. All frogs had a single haplotype (W07) from the distinct western N orth A merica ND 1 haplotype clade. Data from seven polymorphic microsatellite loci show that T ruckee and C arson R iver populations are highly differentiated from each other and from leopard frogs collected from eastern N evada sites. Lack of gene flow among and distinct color morphs among the western N evada populations likely predates the current geographical isolation. Comparisons with other peripheral L . pipiens populations show western N evada populations have similar levels of gene diversity despite their contemporary isolation ( H E 0.411, 0.482). Restoration of leopard frog populations in these watersheds will be challenging given well‐entrenched nonnative bullfrog populations and major changes to the riparian zone over the past century. Declines of once common amphibian species has become a major conservation concern. Contemporary isolation of populations on a species range periphery such as the leopard frog populations in the T ruckee and C arson rivers further exacerbate extirpation risk as these populations are likely to have fewer genetic resources to adaptively respond to rapidly changing biotic and abiotic environments.