Ecological Energetics and Spatial Processes in Individual-based Population Models

T.G. Hallam, Q. Deng, and W.M. Holls, III (USA)


physiology, heterogeneous environment, partial differential equation.


A heterogeneous environment can create and maintain physiological and spatial structures in ecological systems. To understand the roles of a spatially heterogeneous envi ronment in structuring populations, we present an analysis and simulation theory of a model of a structured popula tion composed of individuals having both sessile and mo bile life history stages, who utilize energetically-controlled, resource-directed movement and are subjected to random and density dependent diffusion. When phrased in a temporal-spatial setting, this results in a representation that is a nonlinear degenerate parabolic problem with discon tinuous coefficients and nonlocal initial-boundary condi tions. A numerical scheme to solve this spatio-temporally individual-based structured population model with disper sion mechanisms is indicated. This scheme defines ap proximate solutions derived from localization, destructur ization, and linearization techniques. Simulation experi ments for this model suggest that (i) despite a propensity to move to regions of higher resource density, organisms need not concentrate in the vicinity of high levels of resource and (ii) because of energetic need, growth of an individual can induce movement in the spatial domain.

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