Neighborhood Models of Plant Population Dynamics. I. Single-Species Models of Annuals

We present tractable formulations for neighborhood models of annual plant population dynamic processes. These models are constructed from submodels, termed predictors, of individual plants. Fecundity and survivorship predictors give the fecundity and survivorship of an individual as a function of local population density. Dispersal predictors predict the dispersal pattern of a plant's maternal progeny and the survivorship of plants from seed to seedlings. We develop both computer models and analytically tractable models. Our computer models are designed to determine the population dynamic consequences of specific fecundity, survivorship and dispersal predictors. The analytical models are valid when dispersal is sufficiently large, and are used to explain the predictions of analogous computer models. We show through examples that the predictions of corresponding computer and analytical models may be virtually identical. Empirical tests of these models are practical because all model parameters and functional forms can be estimated with data obtained in a single year. We describe the experiments and statistical methods used to test a neighborhood model. Finally, we describe how neighborhood models can be used to address specific issues in plant ecology and discuss possible extensions of neighborhood theory.