2013 Annual Report
1a.Objectives (from AD-416):
Techniques for the revegetation of former agricultural lands will become more important as water rights are transferred from agriculture to other uses in the arid western U.S. The US Forest Service has acquired property with abandoned fields at Rosaschi Ranch on the East Walker River in the southern Great Basin. We will conduct factorial experiments testing the roles of (1) first-year irrigation, (2) seed mix functional diversity, and (3) alternative site preparation techniques in the establishment of native species on these abandoned agricultural fields. The experiments will take place over two years, and data collection will occur during years two through four of the project. Subsequently, a full-scale restoration plan for Rosaschi Ranch will be completed, incorporating applied research to maximize restoration success.
1b.Approach (from AD-416):
This project will use experimental restoration projects deployed in two initial years and monitored in years two through four to guide restoration planning and implementation on all bare agricultural fields at Rosaschi Ranch. These experimental projects will result in demonstration plots that could be used to:.
1)illustrate the effectiveness of different seeding techniques and seed mixes;.
2)ask research questions that will inform future efforts to restore agriculture lands; and.
3)build support for the project by demonstrating success. Rigorous analysis of results from these experimental projects will allow for the design of a restoration plan for Rosaschi Ranch that will be successful over the long term. Research plots will examine major factors in a large-scale experimental design, and additional factors in a small-scale experimental design.
This is the final report for this project which was terminated on September 30, 2013. This agreement was established in support of objective 4 of the in-house project, "Develop restoration methodologies to prevent the invasion of annual grasses (such as cheatgrass, medusahead rye, and/or red brome) following destructive events (such as fire) in rangeland ecosystems".
This project concluded a three-year experimental study at Rosaschi Ranch to determine optimal strategies for re-vegetating abandoned agricultural land and rehabiliting these areas semiarid shrub communities. Collaborators on the project include the United States Department of Interior-Fish and Wildlife Service (USDI FWS), USDA Natural Resources Conservation Service (NRCS), USDA Forest Service Rocky Mountain Research Station (RMRS), USDA Forest Service and Humboldt-Toiyabe National Forest (Memorandum of Understanding #08-IA-11041701-065). All collaborators attended a meeting in Carson City, Nevada, in October, 2011, where the USDA ARS and Forest Service RMRS presented their preliminary restoration guidelines report. A final meeting was held in Carson City, Nevada, in March of 2012, where all collaborators agreed on a spatially explicit phased restoration plan for the uplands. On April 1, 2012, the USDA ARS and Forest Service RMRS submitted the final restoration plan to all the collaborators. This plan represents the transfer of restoration technology to the Forest Service management unit of the Humboldt-Toiyabe National Forest. In 2013, a manuscript was sent out for review detailing the experimental results. The experimental results were presented at the Ecological Society of America 97th annual meeting in Portland, Oregon, May 5-10, 2012. Restoration of abandoned agricultural lands typically requires seeding or transplanting native species, improving plant-soil-water relations, and controlling invasive species. This study asked if improving water relations via irrigation or surface mulch would result in negative tradeoffs between native species establishment and invasive species competition and if those tradeoffs could be mitigated with herbicide application. The effects of sprinkler irrigation, straw mulch, and herbicide (2, 4-D) on native seed mixtures planted in two consecutive years in an abandoned agricultural field in southwestern Nevada, USA were examined. Shrubs, grasses and forbs were seeded, but this study found low success of shrubs and forbs and the seeding density of selected grass species should be high to facilitate revegetation success. Precipitation was low during the first growing season and seeded plant density, cover or biomass increased in response to irrigation. Precipitation was relatively high during the second growing season, seeded plant densities and biomass were generally high, and irrigation had inconsistent effects. Mulch increased seeded plant establishment without irrigation during the dry year. Invasive plant biomass and cover also were influenced by growing season, but irrigation increased invasive plants regardless of precipitation. Herbicide application had no effect likely due to differences in invasive species phenology. Positive effects of irrigation on seeded plant density, cover, and biomass outweighed negative tradeoffs of increases in invasive plants, but in ecosystems with highly variable precipitation, restoration strategies should be adaptive.