NONLINEAR SENSITIVITY ANALYSIS AS A TOOL FOR EXPLAINING POPULATION-DYNAMICS IN A LIFE-SYSTEM CONCEPTUAL-FRAMEWORK

Life-system analysis is the examination of interacting ecological processes affecting population dynamics. The major problem in application of life-system analysis is in developing methods for analysis of ecological processes. I use a non-linear sensitivity analysis of simulation models to evaluate the role of individual ecological processes and their interactions in population dynamics. The method is applied to the problem of population stability. Co-efficients of m- and upsilon-stability characterize stability of the mean and variance of population density, respectively. Contributions of ecological processes and their interactions to m- and upsilon-stability are represented by non-linear sensitivity coefficients. The second application is the analysis of common pine sawfly (Diprion pini L.) population dynamics in Russia. Process interactions are shown to be important in outbreak patterns of this pest.