title: Landscape genetics of the nonnative red fox of California.
abstract: Invasive mammalian carnivores contribute disproportionately to declines in global biodiversity. In California, nonnative red foxes (Vulpes vulpes) have significantly impacted endangered ground-nesting birds and native canids. These foxes derive primarily from captive-reared animals associated with the fur-farming industry. Over the past five decades, the cumulative area occupied by nonnative red fox increased to cover much of central and southern California. We used a landscape-genetic approach involving mitochondrial DNA (mtDNA) sequences and 13 microsatellites of 402 nonnative red foxes removed in predator control programs to investigate source populations, contemporary connectivity, and metapopulation dynamics. Both markers indicated high population structuring consistent with origins from multiple introductions and low subsequent gene flow. Landscape-genetic modeling indicated that population connectivity was especially low among coastal sampling sites surrounded by mountainous wildlands but somewhat higher through topographically flat, urban and agricultural landscapes. The genetic composition of populations tended to be stable for multiple generations, indicating a degree of demographic resilience to predator removal programs. However, in two sites where intensive predator control reduced fox abundance, we observed increases in immigration, suggesting potential for recolonization to counter eradication attempts. These findings, along with continued genetic monitoring, can help guide localized management of foxes by identifying points of introductions and routes of spread and evaluating the relative importance of reproduction and immigration in maintaining populations. More generally, the study illustrates the utility of a landscape-genetic approach for understanding invasion dynamics and metapopulation structure of one of the world's most destructive invasive mammals, the red fox.
authors.affiliation: Mammalian Ecology and Conservation Unit Veterinary Genetics Laboratory University of California, Davis One Shields Avenue/Old Davis Road Davis California 95616-8744; Department of Population Health and Reproduction University of California, Davis One Shields Avenue Davis California 95616.
authors.forename: Benjamin N
authors.initials: BN
authors.lastname: Sacks
authors.affiliation: Mammalian Ecology and Conservation Unit Veterinary Genetics Laboratory University of California, Davis One Shields Avenue/Old Davis Road Davis California 95616-8744.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Brazeal
authors.affiliation: Washington Department of Fish and Wildlife 600 Capitol Way N Olympia Washington 98501-1091.
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Lewis
keywords: Invasive species; Vulpes fulva; Vulpes vulpes; landscape genetics; predator control; red fox