Species coexistence in the face of demographic and environmental uncertainty: Part II


主講人:Professor Sebastian Schreiber,University of California, Davis




內容介紹:Environmental stochasticity stems from fluctuations in environmental conditions  which influence survival, growth, and reproduction. These effects on population  and community dynamics can be modeled by stochastic difference or differential  equations. For these models, stochastic persistence corresponds to the weak*  limit points of the empirical measures of the process placing arbitrarily little  weight on arbitrarily low population densities. I will discuss sufficient and  necessary conditions for stochastic persistence. These conditions involve  Lyapunov exponents corresponding to the realized per-capita growth rates of  species with respect to stationary distributions supporting subsets of species.  These results will be illustrated with models of Bay checkerspot butterflies,  coupled sink populations, and rock-paper-scissors dynamics.