Monitoring the Removal of Invasive Vegetation from an Urban Creek - A Case Study in Southern California
Abstract
The increasing prevalence of invasive plant species in upland or riparian areas of urban Mediterranean riverine systems due to climate and land use change may affect the ability of streams to achieve important eco-hydrologic, water quality, and biologic functions. Following the February 2016 removal of invasive vegetation from an urban creek in Southern California, this study implemented regular monitoring for three years to evaluate potential disturbance caused by restoration activities as well as the post-restoration re-stabilization processes that may have affected vegetation, geomorphic, hydrologic, and water quality parameters. Vegetation transects were established and monitored throughout the stream reach and topographic surveys and grain size distributions were collected annually. Additionally, water depth and temperature were monitored continuously. Three bio-assessments were also conducted to monitor effects to species diversity and richness of benthic macroinvertebrate and diatom communities. The removal of approximately 163 metric tons of invasive vegetation (predominantly Washintonia spp., Phoenix canariensis , and Arundo donax) allowed native vegetation species to triple in cover from 23.6% to 66.9%. The structure of the vegetation also changed from canopy-dominated to understory-dominated. Restoration efforts resulted in a widening of the channel cross-section and a shift in the grain size distribution of more variation and larger clast sizes. Results from diatom bioassessments showed a decrease in diatom species associated with poor water quality and suggested an improvement in post-restoration conditions. Furthermore, re-stabilization processes were highly variable. These findings help to better understand the complexity that invasive vegetation can introduce to an aquatic urban ecosystem and merit continued research as they are important to the maintenance and control of invasive vegetation in an urban Mediterranean riverine system.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMH032.0010M
- Keywords:
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- 0478 Pollution: urban;
- regional and global;
- BIOGEOSCIENCES;
- 0481 Restoration;
- BIOGEOSCIENCES;
- 0496 Water quality;
- BIOGEOSCIENCES;
- 1879 Watershed;
- HYDROLOGY