From Individuals to Communities: Consequences of Ontogenetic Functional Diversity for Community Structure and Functioning

William Marsh Rice University, Houston TX

Investigators

Abstract

A central challenge in community ecology is to understand the connection between biodiversity and the functioning of ecosystems. The traditional approach in community ecology and particular in food web theory is based on the premise that predictions can be made by treating a species as a homogenous entity. However, no population is truly homogenous and individuals within a species often vary considerably in their ecological function. By far the largest source of this functional variation between individuals stems from differences in size and developmental stage. Indeed, the functional variation across developmental stages within a species often exceeds the variation across species. The unresolved question is how this functional variation within species affects the structure and functioning of natural ecosystems. This question will be answered using a combination of field experiments manipulating the stage-structure in predatory invertebrates in natural pond communities, and development of a new theoretical framework that accounts for functional variation across developmental stages. Together these studies will provide first insight into how the ecological variation across developmental stages within species may alter the structure, dynamics, and functioning of entire ecosystems. Human activities are fundamentally changing ecological systems and natural populations. Our ability to predict how such changes will affect the functioning of ecosystems will critically depend on our understanding of the detailed mechanisms that connect intraspecific diversity to ecosystem functions. The study will permit a new detailed understanding of the mechanisms that determine how individuals scale up to affect entire communities and their functioning. The obtained results will advance our conceptual understanding of whether and what details need to be included in a general predictive framework for community dynamics and ecosystem processes and guide the development of conservation and harvest strategies to assure that vital ecosystem functions are not lost in the future. It will also provide training opportunities for undergraduate and graduate students, including underrepresented groups in science.