Introduction

Abstract

A necessary component in an ecosystem model is the seasonality of the characteristic species in the three trophic levels treated in Part 3. Local species in one trophic level may never interact with those in another trophic level if their periods of activity are different, because separation in time is as absolute as geographic separation. Although modeling of seasonality is too broad a topic for a single session of a symposium, communications could be and was opened between modelers and field biologists. A panel discussion of seasonality modeling, chaired by P. E. Waggoner, showed that phenologists have been modeling perhaps longer than anyone else in ecology. Phenological modeling, however, has been pursued not for the purposes of systems ecology, but for analyzing individual species/phenophase reactions to environmental driving forces. Models presented in this volume are primarily of this type.