Genetic structure of Mexican Spotted Owl (Strix occidentalis lucida) populations in a fragmented landscape

George F. Barrowclough, Jeff G. Groth, Lisa A. Mertz, R. J. Gutiérrez

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

We used mitochondrial DNA control-region sequences to investigate the genetic structure of Mexican Spotted Owl (Strix occidentalis lucida) populations in the southwestern United States. This subspecies is federally listed as threatened, and its preferred habitat is naturally fragmented. We found that intrapopulation genetic diversity was high in all but the southeastern Arizona "sky island" populations, where it was variable. Genetic variance partitioning indicated that ∼17% of the variation was distributed among populations and 7.5% was distributed among physiographic regions. Patterns of genetic correlation with geographic distance indicated that gene flow was substantial among populations within the relatively continuous habitat zone of the Mogollon Rim-Upper Gila Mountains in central Arizona and west-central New Mexico. However, there was significant isolation-by-distance elsewhere, and estimates of genetic divergence increased exponentially with geographic distance among fragmented populations on the scale of a few hundreds of kilometers; this implies that gene flow is restricted among those habitat fragments. Genetic heterogeneity among southeastern Arizona populations suggest that they have regularly received immigrants from the central Arizona populations. The Colorado population either was larger than thought or, more likely, has continuously received immigrants from elsewhere and is not a self-sustaining population.

Original languageEnglish (US)
Pages (from-to)1090-1102
Number of pages13
JournalAuk
Volume123
Issue number4
DOIs
StatePublished - Oct 2006

Keywords

  • Gene flow
  • Mexican Spotted Owl
  • Phylogeography
  • Population genetics
  • Strix occidentalis
  • mtDNA

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