How do we take the pulse of an aquatic ecosystem? Current and historical approaches to measuring ecosystem integrity.

Global environmental monitoring has indicated that the structure and function of some aquatic ecosystems have been significantly altered by human activities. There are many potential causes for these changes, however one major concern is the increasing release of anthropogenic contaminants into aquatic environments. Although toxicological responses of individual organisms are typically well characterized, few studies have focussed on characterizing toxicity at the ecosystem-level. In fact, due to their scale and complexity, changes in ecosystem integrity are rarely considered in assessments of risks to ecosystems. Here we attempt to move the conversation forward by defining integrity of ecosystems, reviewing current and historical approaches to measuring ecosystem integrity status (e.g. structural and functional measurements), and highlighting methods that could significantly contribute to the field of ecosystem toxicology (e.g. keystone species, environmental energetics, ecotoxicological modeling, adverse outcome pathways). Through a critical analysis of current and historical methodologies, this paper offers a comprehensive, conceptual framework for the assessment of risks of contaminant exposure for whole ecosystems and proposes steps to facilitate better diagnoses of the integrity of aquatic systems. This article is protected by copyright. All rights reserved.