Low-tech Riparian Restoration Increases Vegetation Productivity and Resilience across Semi-arid Rangelands
 
Nicholas L. Silverman1*, Brady W. Allred1, John Patrick Donnelly2, Teresa B. Chapman3, Jeremy D. Maestas4, Joseph M. Wheaton5, Jeff White6, and David E. Naugle1
 
1 College of Forestry and Conservation, University of Montana, 32 Campus Way, Missoula, MT 59812
2 Intermountain West Joint Venture, 1001 S. Higgins Avenue, Suite A1, Missoula, MT 59801
3 Colorado Field Office, The Nature Conservancy, 2424 Spruce Street, Boulder, CO 80302
4 Natural Resources Conservation Service, 625 SE Salmon Avenue, Redmond, OR 97756
5 Watershed Science Department, Utah State University, 5210 Old Main Hill, NR 360, Logan, UT 84322
6 Newmont Mining Corporation, 1655 Mountain City Highway, Elko, NV 89801
 
Riparian and wet meadow landscapes make up a small percentage of the overall land area in the Western United States, yet their impacts on wildlife, vegetation, and water resources are profound. When healthy, these areas act as zones of soil water storage allowing for increased plant productivity, groundwater infiltration, and the slow, steady release of surface and sub-surface runoff. When these areas are functioning sub-optimally, the watershed as a whole suffers from increased drought and flood vulnerability, decreased plant productivity, and degraded fish and wildlife habitat. Over the last century unregulated livestock management, drought, non-native invasive weeds, and conifer encroachment have impacted the Intermountain West in ways that we are still recovering from today. Historically, much of the restoration that has taken place in the Intermountain West has largely focused on upland rangeland. It wasn’t until the late 1990s that practitioners began to focus on riparian and wet meadow restoration. While many of these restoration activities have been different in design, the processes they are meant to restore are often the same. Common to all these processes is the dynamic interplay between the hydrology and ecology of the landscape.
 
In this study, we use satellite remote sensing to explore changes in vegetation productivity (NDVI) of three distinct low-tech, riparian restoration projects. The projects range widely in geographic location (Colorado, Oregon, and Nevada), restoration practice (Zeedyk structures, beaver dam analogs, and grazing management), and time since implementation, but are considered “low-cost” and “low-impact” solutions. We evaluate changes in plant productivity, in addition to changes in time above a riparian productivity threshold. We also explore changes in vegetation sensitivity to precipitation over time since restoration. Restoration practices resulted in increased vegetation productivity of up to 25% and increased persistence of productive vegetation–up to six months in some locations. Mesic restoration practices also led to increased resiliency, buffering vegetation productivity from climatic variability.