A Mass-Balanced Model of Trophic Flows in Prince William Sound: Decompartmentalizing Ecosystem Knowledge

Just as real-world food webs contain complex interactions among species, so too must scientists and others interact to describe food webs in realistic ways. The most useful ecosystem models are constructed through collaboration among a wide range of experts. Collaboration among Prince William Sound (PWS), Alaska, researchers resulted in a mass-balanced Ecopath model of trophic flows including all ecosystem components (explicitly or implicitly). This study was conducted to describe functional interactions among components, and to reveal thermodynamic constraints of these interactions, thus enabling further refinement of contributed estimates as well as dynamic simulations of ecosystem perturbations. Since the 1989 Exxon Valdez oil spill (EVOS) in Prince William Sound, and adjacent areas, research teams focused on the status of particular biological components of the PWS ecosystem, changes to those components, and the effects of EVOS. Some research groups investigated the effects of EVOS on larger segments of the PWS ecosystem, but a systemwide analysis was not undertaken until the current model was constructed. Estimates of basic population parameters were lacking for several biological components of the ecosystem, but the Ecopath approach enables refinement of knowledge of uncertain groups based on the constraints of interrelationships among groups. The whole-system model described herein can be used by managers, schools, or local communities for learning, knowledge refinement, or simulation of environmental disturbances such as oil spills or increased fishing. Ecopath modeling through multiway collaboration is presented as a broadly accessible tool for restoration and resource planning with the potential to be highly community-based. 622 Okey & Pauly — Decompartmentalizing Ecosystem Knowledge Only fluency across the boundaries will provide a clear view of the world as it really is. E.O. Wilson, Consilience: The Unity of Knowledge, 1998