Conservation of Aquatic Insects: Worldwide Crisis or Localized Threats?

Abstract

An overview is presented on the current worldwide status of aquatic insect conservation. Despite extensive habitat destruction or modification, aquatic insects as a whole do not appear to have suffered as great a proportional loss of species over the last century as members of other groups. In North America, for example, only 204 species are considered at risk out of a total fauna of over 10,000 species, and no species has been documented as having gone extinct. Even so, aquatic insect diversity is subject to a broad spectrum of threats, including chemical pollution of waters from industry and agriculture, physical destruction of habitat from impoundments or drainage, and introduction of alien aquatic biota, primarily sport or aquarium fishes. Adequate legislation exists in the United States and Europe to provide protection to aquatic insect taxa at risk, but the implementation of this legislation is often hampered by a lack of taxonomic and distributional knowledge, and by a concentration of recovery efforts on more highly visible vertebrate taxa. The case of the Ash Meadows Naucorid, the only aquatic species currently protected under the Endangered Species Act, is examined in detail. It is concluded that the listing of this species has had no discernable effect in halting its population decline, partly due to the fact that recovery efforts for endangered fishes have proven deleterious to the insect. It is recommended that future listing efforts be conducted in the context of national biological surveys, and that an ecosystem rather than single species approach be applied to aquatic conservation efforts.