Community structure and patch dynamics in rocky intertidal communities: Linking process and pattern across scales

A major challenge in ecology has been relating macroscopic biogeographic patterns to microscopic patterns and process at the level of individuals. To investigate this relationship, I developed SimApp, a modeling framework that facilitates and standardizes modeling pattern and process at different scales of measurement, and across scales.; Observations from field studies of rocky intertidal communities in the Pacific Northwest suggest an oceanographic gradient from north to south in which the interplay between recruitment and post-recruitment processes plays a major role in determining community structure. In this study, I used SimApp to implement a series of models of benthic communities, evaluating pattern and process in the marine intertidal systems at different spatial scales. The models were developed in conjunction with field experiments conducted at sites on the central Oregon coast. Data from these experiments were used to parameterize the models.; First I introduce an individual-based model (IBM) of sessile organisms competing for space in a mussel bed gap. Using parameters associated with processes at the level of individual organisms, the model produces patterns of community organization and development consistent with those observed in the field. The range of recruitment and growth parameters derived from the field data generate results that reproduce the oceanographic gradient observed on the Oregon coast.; I then introduce an interacting particle system (IPS) model of mussel bed gap dynamics to investigate the particular relationship between oceanographic forcing and community structure at the level of a single mussel bed bench. Output from the IBM simulator is used to constrain the transition probabilities for the IPS model. The IPS model demonstrates that realistic patterns of mussel bed patch dynamics may emerge independent of the full detail of the IBM approach. Together, these models realistically describe the relationship between processes at the level of the individual and the large scale patterns to which they are linked.