STOCHASTIC POPULATION-MODELS AND THEIR RELEVANCE FOR THE CONSERVATION OF SPECIES

Stochastic population models are introduced on different levels of ecosystem's description to show their relevance for the conservation of species. First, the problem of demographic extinction in both constant and fluctuating environments is discussed. The minimal size of a viable population and its dependence on internal and external parameters is briefly outlined. Then the randomness of both migration and reproduction is investigated to estimate the range of a species under unfavourable conditions. The next step in hierarchy is the stochastic dynamics of metapopulations and the consideration of fragmentation and connection of habitats. Finally, some relations to the mosaic-cycle theory with habitats of finite size and lifetime are outlined.