Can low densities of carnivores result in genetic depletion? An investigation within French polecat populations.
Carnivores as top predators are commonly found in relatively low densities even in optimal habitats. Despite a lack of empirical studies, it could be suspected that long-term low density could result in genetic depletion. The genetic structure of European polecat Mustela putorius natural populations was investigated by allozyme electrophoresis in five distinct areas. Density estimates significantly differed among sites from 0.17 to 0.83 individuals/km2 with an average of 0.56 individuals per km2, resulting in a scattered distribution. Genetic structure varied among distinct populations both in number of polymorphic loci and heterozygosity. Polecats from Brittany revealed a very low observed heterozygosity (H(O) = 0.028) whereas mean heterozygosity reached H(O) = 0.072 in Brière. That the lowest heterozygosity levels and highest inbreeding coefficient F(IS) were significantly associated with the lowest densities suggests that low densities may affect populations of carnivores. Both the loss of polymorphic loci and the reduction in heterozygosity rates suggest a density-dependent effect and population density can be arguably regarded as a factor affecting genetic diversity in top carnivores.
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Laboratoire d'Ecologie Animale, UMR105 Paysages and Biodiversité, UFR Sciences, Campus Belle-Beille, Université d'Angers, Angers Cedex, France. thierry.lode@univ-angers.fr
D000483:Alleles; D000818:Animals; D002335:Carnivora / Q000235:genetics*; D004798:Enzymes / Q000235:genetics*; D005260:Female; D005289:Ferrets / Q000235:genetics* / Q000502:physiology; D005602:France; D014644:Genetic Variation; D005828:Genetics, Population / Q000379:methods; D006579:Heterozygote; D007178:Inbreeding; D011156:Population Density
D004798:Enzymes