Ecosystem health and integrity and the role of aquatic insects

Abstract

In recent years the terms "health" and "integrity" have been applied to ecosystems to convey normative judgements about their state and functioning. This has been criticized on the basis that the health metaphor is invalid since ecosystems are not organisms, they do not have consistent structures from one individual to the next, they do not develop in a predictable manner and they do not have homoeostatic mechanisms. Moreover there are dangers in pursuing ecosystem health as an operational management goal, since it diverts decision makers from a true understanding of the inherent processes. Despite these criticisms many ecologists would agree to maintain the terms health and integrity and use them with caution in a manner that does not imply organismal properties. Under this usage, health refers to the desirable state and functioning (which is normally, although not exclusively, related to the pristine state of the ecosystem). Integrity relates to the degree to which the ecosystem's components (species) are similar to the pristine state. Aquatic insects have been used extensively for the monitoring of aquatic ecosystem health and integrity, achieving, as well, a role in the environmental legislation of certain states and countries. They are used in Rapid Assessment Protocols, in evaluation using indices (metrics and multimetrics) and in multivariate methods.