Short-Term Stream and Riparian Responses to Beaver Dam Analogs on a Low-Gradient Channel Lacking Woody Riparian Vegetation
| Autor: | Matthew R. Orr, Heather M. Broughton, Wesley N. Noone, Taiontorake M. Oakes, Megan G. Mooney, Nicholas P. Weber |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
0106 biological sciences
Hydrology Beaver geography Biogeomorphology geography.geographical_feature_category biology Floodplain 010604 marine biology & hydrobiology Beaver dam STREAMS Vegetation 010603 evolutionary biology 01 natural sciences Aggradation biology.animal Environmental science Ecology Evolution Behavior and Systematics Riparian zone |
| Zdroj: | Northwest Science. 93:171 |
| ISSN: | 0029-344X |
| DOI: | 10.3955/046.093.0302 |
| Popis: | As ecosystem engineers, beavers (Castor canadensis) influence biogeomorphology and riparian vegetation. Streams with historic beaver removal and grazing often become incised, thereby altering stream and riparian processes. Anthropogenic structures that mimic beaver dams called beaver dam analogs (BDAs) may reverse incision by reintroducing historic processes. To understand BDAs as a process-based restoration tool, monitoring is needed across a range of watershed and stream conditions, but monitoring lags behind implementation. We constructed five BDAs in Central Oregon, on a low-gradient stream to test whether it may transport sufficient sediment to favor streambed aggradation behind BDAs. The stream also lacks woody riparian vegetation, and we examined how water temperatures and restoration plantings respond to BDAs where woody riparian vegetation is absent. We monitored structure integrity, aggradation, water temperature, groundwater, and vegetation for 1–2 yr after structures were installed. BDAs retained flows equally whether they were constructed from on-site juniper or off-site willow. During high flows, three structures failed and were rebuilt using improved design. After one year, aggradation of sediment above the two structures that survived flooding was negligible at one structure and high (33.7 m3) at the other. Groundwater levels rose 18–30 cm up to 135 m upstream of BDAs and 12 m into the floodplain. We found no evidence that BDAs raised stream temperatures. Within six months, willow cuttings planted near BDAs exhibited 1.3 times more growth than those on unimpounded locations. Overall, BDAs promoted a restoration trajectory on a low-gradient stream lacking woody riparian vegetation. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|