Sponsor
This research was funded by the Environmental Professional Program at Portland State University.
Published In
Restoration Ecology
Document Type
Article
Publication Date
3-2024
Subjects
Wetlands -- Conservation, Food chains (Ecology), Sedimentation and deposition, River ecology
Abstract
Streams systems draining upland landscapes provide valuable ecosystem services, but they are vulnerable to incision and channelization caused by anthropogenic disturbance. Restoring a degraded stream to its pre-disturbance condition by reconnecting the channel to its historical floodplain aims to recover lost hydro-morphological processes and functions. Seeking evidence to indicate whether that aim is met in practice, we examined diatoms and the stream macroinvertebrate trophic structures in three reaches of Whychus Creek, Oregon, United States. Two reaches were reconnected to their pre-disturbance floodplains in 2012 and 2016. The third, control reach, was not restored and was selected to represent the degraded stream condition prior to restoration. Ordinations showed that benthic diatom species composition shifted from the control reach to the restored reaches. Compared to the control reach, reconnection decreased the percentages of diatoms with nitrogen (N)-fixing cyanobacterial endosymbionts in the 2012 restored reach and decreased diatoms tolerant to low N conditions in both the restored reaches. δ15N values in both stream macroinvertebrates and tree leaves in the riparian zone were higher in the restored reaches. These findings suggest that floodplain reconnection may modify hydro-morphological processes and ecosystem functions in ways that enhance organic matter retention and hyporheic exchange, resulting in increased nutrient availability, improved nutrient cycling, and greater primary productivity. More generally, our results suggest that characterizing diatom species composition and trophic interactions using stable isotopes provides the basis for identifying and evaluating the beneficial effects of stream restoration on ecosystem functions and the food-web.
Rights
Copyright (c) 2024 The Authors
This work is licensed under a Creative Commons Attribution 4.0 International License.
Locate the Document
DOI
10.1111/rec.14123
Persistent Identifier
https://archives.pdx.edu/ds/psu/41451
Citation Details
Edwards, P. M., Popp, N. C., Pan, Y., Weilhoefer, C. L., Peterman, A. B., Mork, L. A., ... & Popp, B. N. (2024). Reconnecting a stream channel to its floodplain: implications for benthic diatoms and macroinvertebrate trophic structure. Restoration Ecology, e14123.