Affiliation:
1. Odum School of Ecology and River Basin Center University of Georgia Athens GA U.S.A.
2. Odum School of Ecology University of Georgia Athens GA U.S.A.
3. Eastern Ecological Science Center U.S. Geological Survey Athens GA U.S.A.
Abstract
There is inconsistent evidence that stream restoration projects lead to recovery of ecosystem attributes, especially stream biota. While some assessments have documented desired changes in fish community metrics in the first years following restoration, longer‐term studies have not always corroborated these findings. In this study, we used data and monitoring reports submitted to federal regulators by stream mitigation consultants to examine whether in‐stream restoration activities led to changes in fish community attributes at 23 compensatory mitigation projects representing 53 sampling sites in Georgia, United States over 7 years of post‐restoration monitoring. Modeling results indicated that abundance and species richness of fishes generally increased in the first years after restoration before decreasing to baseline levels by the seventh year. This pattern was consistent for models considering sensitive fish taxa, as well as at sites across a range of agricultural and forested land cover percentages. However, the effect of restoration on species richness was dampened in larger streams and at more urbanized locations. A community trajectory analysis supported the findings that fish community change was transitory at most sites. Remote estimation of canopy cover change at restoration sites suggested that the hump‐shaped response may be driven by increased light availability during the immediate‐post restoration period, followed by subsequent re‐shading of stream channels by riparian plantings. Our analysis indicates that reach‐level manipulation of streams should not be expected to induce long‐term changes in fish communities, and that publicly available monitoring reports may be leveraged to address questions of stream restoration efficacy.
Funder
U.S. Army Corps of Engineers
U.S. Geological Survey
Subject
Nature and Landscape Conservation,Ecology,Ecology, Evolution, Behavior and Systematics