Spatial Models of Metapopulations and Benthic Communities in Patchy Environments

摘要

The distribution of organisms in space has important consequences for the function and structure of ecological systems. Such distributions are often referred to as patchy, and a patch-based approach to modeling ecosystem dynamics has become a major research focus. In this dissertation I develop a series of spatial models to study the dynamics of metapopulations and marine benthic communities in patchy environments. In part one, I construct patch-occupancy and cellular automaton models to investigate how habitat destruction affects metapopulation persistence. I explore how the extinction threshold (i.e. the minimum fraction of suitable habitat required for persistence) varies as a function of the fractal dimension of the landscape, and how the expected extinction time varies as a function of the number of suitable patches in a finite landscape. In part two, I construct a series of Markov chain models to investigate the dynamics of marine benthic communities. The models are parameterized using a long-term data set of a rocky subtidal community. I investigate how various successional processes affect diversity and stability, explore the effects of time and space on successional patterns, examine the effects of environmental stochasticity on species abundances, and characterize the effects of density-dependent interactions on community dynamics.