Influence of gully erosion control on amphibian and reptile communities within riparian zones of channelized streams

摘要

Riparian zones of streams in northwestern Mississippi have been impacted by agriculture, channelization, channel incision, and gully erosion. Riparian gully formation has resulted in the fragmentation of remnant riparian zones within agricultural watersheds. One widely used conservation practice for controlling gully erosion is the installation of drop pipes. This practice involves placing earthen dams across eroding gullies and embedding a metal standpipe within the dam to convey water from the field to stream level. Installation of this structure halts gully erosion and incidentally replaces eroding gullies with riparian habitats. Previous research evaluating gully erosion control structures have not considered the ecological impacts of these conservation practices on amphibian and reptile communities. We compared amphibian and reptile communities among riparian sites containing actively eroding gullies and four riparian habitat types created by drop pipe installation. Amphibians and reptiles were sampled from four gullies and four sites of each drop pipe-created habitat type from 1994 to 1996. Amphibian and reptile diversity and abundance were the greatest in created habitat types with mean habitat areas ＞ 1000 m~2 and mean pool volumes ＞420 m~3. Amphibian and reptile diversity and abundance within the created riparian habitats were also positively correlated with hydrology. Our results suggest that the use of drop pipes to control gully erosion is capable of creating needed riparian wetlands for amphibian and reptile communities. Additionally, altering the installation design will increase the ecological benefits resulting from this conservation practice.