Metapopulation structure of Carabus problematicus in a fragmented landscape, significance of simulation results for nature conservation
Within an agricultural landscape in Germany in which only a few isolated patches of woodland have remained, the spatial distribution of the eurytopic forest species Carábus problematicus was studied for three years using pitfall traps. In more remote forest patches the species could not be found every year, which is interpreted as an indication of the existence of metapopulation dynamics of this species in this area.
On the basis of GIS-generated maps, stochastic metapopulation models are developed using the standard modelling program RAMAS-GIS. Simulation results obtained correspond well with field data. According to the models created, the spatial arrangement of habitats and distance between suitable neighbouring habitats belong to the most important parameters regulating habitat colonization. Dispersal is a key factor in most metapopulation models, but good data on migration are rare and hard to obtain. Applicability and limitations of simulation models as well as consequences for nature conservation planning are critically discussed.