Red Fox (Vulpes vulpes) in Great Basin National Park

This article was originally published in The Midden – Great Basin National Park: Vol. 17, No. 2 , Winter 2017.

Figure 1. Comparison of red fox populations across the Great Basin and surrounding
areas using nuclear DNA (microsatellites) with 9 partitions, i.e., presumed number of
populations. Note: Great Basin National Park contains a unique group (purple).

By Preston Alden, University of California-Davis

An evolutionarily distinct lineage of red fox native to the Western United States occurred historically in isolated populations scattered among high-elevation sky islands of the Great Basin and surrounding mountain ranges. These Pleistocene relictual populations are disappearing as their subalpine habitats are lost to climate change and other anthropogenic causes. Great Basin National Park (GBNP) is becoming an increasingly important refuge for these and other relictual sky-island species. Additionally, these native foxes are threatened by introduced nonnative foxes at lower elevation that hybridize with native populations and appear to be increasing in number in recent decades.

Little was known about the current range-wide distribution of remaining native Great Basin red foxes prior to our research in 2015. We verified with genetic scat samples that red fox within GBNP clustered more closely with the Rocky Mountain subspecies of red fox (Vulpes vulpes macroura) and not with the Sierra Nevada red fox population (Vulpes vulpes necator). In addition, comparison of red fox genetics across the greater Great Basin revealed that red fox within GBNP specifically might be remnants of a distinct subspecies of native montane red fox originating within the Great Basin itself (Figure 1).

Once native montane red foxes were identified within GBNP, the next step was to investigate the size of the population in the Park. We performed additional scat collection surveys and used previously collected data to make a population estimate. Using a mark-recapture analysis of 25 DNA scat samples from 10 individuals, we estimated the population to be 11 to 15 individuals. This small population estimate is likely a result of native montane red fox behavior. These foxes tend to persist in small family groups in subalpine habitat.

Future research is needed to better understand the historical and contemporary connectivity of red fox in GBNP to other native and expanding nonnative red fox populations. This research highlights the conservation value for the species both in and out of GBNP and provides an excellent opportunity to better understand how climate change affects population genetics on a large scale.