Viability of ground beetle populations in fragmented heathlands

摘要: Numbers of ground beetle species that are characteristic for heathlands were negatively associated with area, whereas this relationship was not found the total number or unspecialised species. In particular heathland low dispersal ability strongly related to area. Transplant experiments showed some experienced reduced habitat quality in small habitats, others at least part unoccupied areas sufficient successful reproduction. From presence occupied as well habitats and from knowledge on its possibilities dispersal, it is inferred Pterostichus lepidus lives metapopulations continuously discontinuously patches. Using allozymes, high levels genetic variation P. Agonumericeti large areas. two areas, however, populations P.lepidus had relatively genetically different other populations. As exchange individuals between separate possible, divergent composition probably results founder events. Populations A.ericeti patches concluded dense have remained present since isolation. Genetic erosion could be identified an important process causing extinction Environmental stochasticity most threat survival isolated The presence-absence data beetles various sizes specialized need a more than 50 ha provide substantial chance survive isolation period 25 100 year. For endangered options available reduce rates: enlargement formation corridors habitats.