Influence of habitat fragmentation on the genetic structure of Polyommatus coridon (Lepidoptera : Lycaenidae): implications for conservation

摘要

Conservation biologists pay increasing attention to the interdependence between habitat structure and genetic patterns of species and to the importance of conserving genetic diversity. A suitable model species for such a study is Polyommatus coridon, a butterfly of dry calcareous grassland. We studied the population genetic structure of 22 western German populations of this species (874 individuals). We observed no congruence between the observed genetic structure and the geographic arrangement of the studied populations. Genetic diversity was slightly higher in large populations than in small populations. Differentiation among populations was weak or even missing. Populations of an area with high habitat density showed no significant differentiation, whereas areas with low habitat densities showed significant genetic differentiation among populations. At present, hierarchical variance analysis revealed no differentiation between four distinguished limestone areas. The combination of all analytical results allow the definition of management units for P. coridon. Conservation measures are proposed from which a large number of rarer species occurring together with P. coridon will benefit.