A restricted hybrid zone between native and introduced red fox (Vulpes vulpes) populations suggests reproductive barriers and competitive exclusion

Benjamin Sacks, Marcelle Moore, Mark J. Statham, Heiko U. Wittmer

Research output: Contribution to journalArticle

46 Citations (Scopus)

Abstract

Introduced species can threaten native taxa in multiple ways, including competition and hybridization, which can reduce fitness, alter ecological niches or swamp native genomes. Encroachment and hybridization by introduced species also provide opportunities to study the dynamics of invasiveness and hybridization during early stages following contact. We used 33 microsatellites, 51 single nucleotide polymorphisms and a mtDNA marker to characterize the extent and spatial pattern of encroachment and hybridization between a native, endemic subspecies of red fox (Vulpes vulpes patwin) and an introduced red fox population composed of highly admixed, phylogenetically divergent stock, resulting from a century of domestication. Both nuclear and mtDNA markers indicated that hybridization was primarily restricted to a narrow zone where the two populations came into contact. Although a few introgressed genotypes were detected in the interior of the native range, we found no immigrant foxes or F1 or F2 hybrids there, suggesting native foxes excluded introduced individuals. We speculate that the observed interbreeding at the periphery was facilitated by low densities. In total, 98% of mtDNA haplotypes in the native range were native and 96% of the nuclear ancestry was estimated to be native. Although the introduced range had expanded fivefold over the past four decades, native and non-native haplotypes from museum samples collected in and near the native range three decades earlier showed a similar geographic distribution as today, suggesting that the native range and hybrid zone were relatively stable. We hypothesize that the monogamous mating system of red foxes and other wild canids may enhance their resistance to hybridization because of greater fitness consequences associated with mate discrimination.

Original languageEnglish (US)
Pages (from-to)326-341
Number of pages16
JournalMolecular Ecology
Volume20
Issue number2
DOIs
StatePublished - Jan 1 2011

Fingerprint

hybrid zone
competitive exclusion
Vulpes vulpes
hybridization
Population
Mitochondrial DNA
mitochondrial DNA
Introduced Species
foxes
introduced species
haplotypes
fitness
Haplotypes
canid
invasiveness
Canidae
domestication
Museums
swamps
Wetlands

Keywords

  • hybridization
  • introgression
  • invasive species
  • Sacramento Valley red fox
  • Vulpes vulpes
  • Vulpes vulpes patwin

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Genetics

Cite this

A restricted hybrid zone between native and introduced red fox (Vulpes vulpes) populations suggests reproductive barriers and competitive exclusion. / Sacks, Benjamin; Moore, Marcelle; Statham, Mark J.; Wittmer, Heiko U.

In: Molecular Ecology, Vol. 20, No. 2, 01.01.2011, p. 326-341.

Research output: Contribution to journalArticle

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