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Landscape genetics of the nonnative red fox of California

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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.

No MeSH data available.


Related in: MedlinePlus

Distribution of 10 mitochondrial haplotypes from 392 red foxes sampled from central and southern California. Top and left panels each depict a single relatively widespread haplotype, whereas the bottom right panel shows the distribution of seven localized haplotypes. All haplotypes are nonnative except for D‐19, which is endemic to the native Sacramento Valley red fox and found only in the contact zone between these and nonnative red foxes. Asterisks indicate the locations of two red foxes sampled from near Davis, California, in the 1920s.
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ece32229-fig-0002: Distribution of 10 mitochondrial haplotypes from 392 red foxes sampled from central and southern California. Top and left panels each depict a single relatively widespread haplotype, whereas the bottom right panel shows the distribution of seven localized haplotypes. All haplotypes are nonnative except for D‐19, which is endemic to the native Sacramento Valley red fox and found only in the contact zone between these and nonnative red foxes. Asterisks indicate the locations of two red foxes sampled from near Davis, California, in the 1920s.

Mentions: The gene diversity was high for the total sample (0.73) relative to gene diversities within sampling sites (X¯ = 0.37, standard deviation [SD] = 0.23; Table 1). This pattern corresponded to a global estimate of FST = 0.49 (i.e., 1 − 0.37/0.73), and all but three haplotypes were restricted to ≤3 sampling sites, indicating considerable population structure (Fig. 2). Pairwise FST estimates averaged 0.54 (range: 0–1; Table S1). The two most widespread haplotypes were G‐38 and N‐7, which also were found in two specimens (UC Davis, Museum of Wildlife and Fish Biology, Catalog Nos. 10z, 17z) collected in the 1920s in southern Yolo County near an active fur farm (Lewis et al. 1999).


Landscape genetics of the nonnative red fox of California
Distribution of 10 mitochondrial haplotypes from 392 red foxes sampled from central and southern California. Top and left panels each depict a single relatively widespread haplotype, whereas the bottom right panel shows the distribution of seven localized haplotypes. All haplotypes are nonnative except for D‐19, which is endemic to the native Sacramento Valley red fox and found only in the contact zone between these and nonnative red foxes. Asterisks indicate the locations of two red foxes sampled from near Davis, California, in the 1920s.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4979706&req=5

ece32229-fig-0002: Distribution of 10 mitochondrial haplotypes from 392 red foxes sampled from central and southern California. Top and left panels each depict a single relatively widespread haplotype, whereas the bottom right panel shows the distribution of seven localized haplotypes. All haplotypes are nonnative except for D‐19, which is endemic to the native Sacramento Valley red fox and found only in the contact zone between these and nonnative red foxes. Asterisks indicate the locations of two red foxes sampled from near Davis, California, in the 1920s.
Mentions: The gene diversity was high for the total sample (0.73) relative to gene diversities within sampling sites (X¯ = 0.37, standard deviation [SD] = 0.23; Table 1). This pattern corresponded to a global estimate of FST = 0.49 (i.e., 1 − 0.37/0.73), and all but three haplotypes were restricted to ≤3 sampling sites, indicating considerable population structure (Fig. 2). Pairwise FST estimates averaged 0.54 (range: 0–1; Table S1). The two most widespread haplotypes were G‐38 and N‐7, which also were found in two specimens (UC Davis, Museum of Wildlife and Fish Biology, Catalog Nos. 10z, 17z) collected in the 1920s in southern Yolo County near an active fur farm (Lewis et al. 1999).

View Article: PubMed Central - PubMed

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.

No MeSH data available.


Related in: MedlinePlus