Decline of the giant salmonfly Pteronarcys californica Newport, 1848 (Plecoptera: Pteronarcyidae) in the Provo River, Utah, USA.

摘要

Anthropogenic disturbances are causing many aquatic insect species, including those in Plecoptera, to lose geographic range, and, in some cases, succumb to extinction. One species, Pteronarcys californica Newport, 1848, has declined in several rivers in the western United States during the past century. It has been extirpated from the Arkansas River of Colorado and the Logan River of northern Utah and is now in decline in the Provo River of central Utah. We sampled the Provo River for two years (20162017) to determine the abundance and distribution of P. californica and other stonefly species. In over 300 samples, we found only 17 P. californica individuals. Our study demonstrates that their abundance and distribution have declined dramatically when compared to baseline values obtained from museum records, unpublished data and publications from the past century. Total stonefly species abundance and richness may also be lower compared to historical data. Because Plecoptera are bioindicators of water quality, this decline indicates that the health of the Provo River is deteriorating, especially in the lower reaches where few stoneflies were found. These findings suggest that active steps should be taken to protect the Provo River and its aquatic biodiversity.