Hierarchical Approaches to the Study of Ecological Process and Pattern

摘要

An approach based on hierarchy theory is applied to problems involving the relationships between levels of analysis in ecology. The first problem involves ''emergence'' - the inability to predict the behavior of the whole from its parts. To analyze emergence, a hierarchical conceptual model is developed, which is then used to clarify several controversies involving emergence and to help assess the benefits and pitfalls of higher level analyses. If a taxonomic hierarchy can be assumed to reflect a hierarchy of ecological similarity of species, then higher taxonomic levels may be useful in detecting larger scale ecological patterns. Patterns shown by specific and generic level binary similarity coefficients are compared for chironomid species data from a polluted Ohio stream. The ecological similarity of congenerics is assessed using the trend in the species:genus ratio along the pollution gradient. A hierarchical approach assumes that a hierarchy of pattern reflects a hierarchy of process. Simulation models of New England and Australian rocky intertidal communities were used to show how this assumption may be violated. The model results indicate that three characteristics of the Australian rocky intertidal community may allow small-scale ''stochastic'' processes to have larger scale effects than in the New England community. (ERA citation 12:001778)