Grazing Management and Ecosystem Services

Prescribed Grazing to Restore Rangeland Soil Quality, Plant Diversity, Water Quality, and Agricultural Productivity

Partners: Tate, K.W., L.M. Roche, J.D. Derner, V. Eviner, M.N. Lubell, , A.T. O’Geen, M.R. George, B. Cutts, A. Robertson,and D.J. Eastburn.

Funded by USDA Range Research Program and USDA Western Sustainable Agriculture Research and Extension Program

Overview

Rangelands in the western US are at risk due to factors such as weed invasion, improper grazing, energy development, and climate change. Improper livestock grazing can negatively impact various rangeland ecosystem functions and services. Alternatively, grazing practices can enhance plant diversity, carbon storage, suppress weeds, mitigate climate change impacts, and enhance various ecosystem functions. Practical, effective grazing management strategies must be identified, confirmed by research and broad manager agreement, and extended to managers to promote grazing which simultaneously enhances multiple rangeland ecosystem services. Grazing management decisions cannot focus solely on optimizing annual ranch proceeds. Grazing management must sustain ecosystem functions and services necessary for the long-term ecological health of the system and the dependent ranch enterprise.

Determining what constitutes proper prescribed grazing remains problematic largely due, in our opinion, to inadequate exchange of information or perspective about management practices between the range science and ranch management communities. Managers often focus on operational and socio-economic outcomes at the ranch-scale, while researchers emphasize ecological processes of vegetation-soil-herbivore interactions within plant communities and ecological sites. These are both valid scales at which to evaluate grazing management, but we must bridge the gap in scale and communication in order to integrate prescribed grazing research and management expertise to advise ranch managers.The problem is not a lack of management expertise or research results, rather in the integration of this information for application at the ranch enterprise scale.

We are working directly with the ranching communities in Wyoming and California to integrate management expertise, ranch-scale research, and existing research information to identify and extend practical grazing options to optimize interdependent agricultural, economic, and ecological services. Wyoming represents a perennial, summer rangeland system, while California is representative of an annual, winter rangeland system. Perennial rangelands cover 27 million acres in Wyoming where cattle and sheep production exceeds $820 million annually. In California, annual rangelands encompass 16 million acres and state-wide cattle production exceeds $3 billion annually.By working across these two representative agro ecosystems, the information developed from this project will have applicability across millions of acres. California’s 16 million acre annual rangeland ecosystem provides

critical livestock forage to support rural agricultural economies, houses the most diverse plant and animal communities in the state, and supplies drinking water supplies to millions of residents. Restoration efforts in this ecosystem must be based upon a clear understanding of social, ecological, and business factors determining ranch level grazing management decisions and ecosystem response.

Objectives

Objective 1: Determine social-cultural-economic-institutional factors driving grazing decisions; understand how managers receive, assess, and use grazing management information; and identify management perspectives on managing grazing intensity, grazing season, and rest from grazing for restoration of soil, plant, and water functions and other ecosystem services.
Objective 2: Quantify the differential effects of season and intensity of cattle grazing, and associated interactions, on multiple ecosystem services. Compare the response of multiple ecosystem services between a rotational grazing system, which provides alternating seasons of grazing/rest across years, and a continuous grazing system, which provides the same season of grazing/rest every year.
Objective 3: Conduct a ranch-scale, cross-sectional, observational field research survey to determine how field indicators of rangeland health on ranches in each state correlate to grazing management decisions (e.g., stocking rate, season of grazing/rest, rotational strategies) at the plant community, ecological site, and ranch scales.
Objective 4: Develop an online prescribed grazing – restoration management decision support network that allows users to: access research and management derived information about prescribed grazing and restoration; receive assistance in developing grazing management and effectiveness monitoring options for site specific restoration applications; and participate in interactive prescribed grazing – restoration information exchange.

Approach

We will conduct a survey of 1500 rangeland managers in CA and 500 in WY to achieve Objective 1, and provide information to develop the prescribed grazing management decision support tool (Objective 3). The survey will be designed to determine social-cultural-economic-institutional factors driving grazing decisions; to understand how managers receive, assess, and use grazing management information; and to determine their perspectives on managing grazing intensity, grazing season, and rest from grazing for ecosystem restoration. We will also collect information about specific grazing practices adopted, structure of social networks, and participation in outreach activities. The standard Dillman methodology of delivery introductory letter, survey package, reminder, second survey package, and second reminder will be used to encourage response.
Objective two will be based upon establishment of a replicated, management-scale study to investigate prescribed grazing to restore key ecosystem services. The 10-year study will use 200+ commercial-type beef cattle across 33 pastures covering ~1500 hectares of annual rangeland at the UC Sierra Foothill Research and Extension Center. Prescribed grazing treatments will be based upon annual and seasonal forage production, weed species phenology, hydrology, and management constraints typical of annual rangelands. The eleven prescribed grazing treatments to be examined are a combination of: cattle grazing intensity, season of grazing, season of rest, and grazing system. A 10 year ungrazed treatment will be included as a long-term negative control. We will measure the response of biodiversity and resistance to weed invasion; forage production; water quality; and soil retention of N, C and moisture to grazing treatment over the course of the study.
A cross-sectional observational study design will be used to identify associations between rangeland health (soil quality, plant diversity, forage production, etc) and grazing management (e.g., stocking rate, season of grazing, season of rest). This will be a field-based research project conducted on cooperating ranches. Rangeland health, based in part upon USDA Technical Reference 1734-6, will be evaluated at sites across each ranch. Sites will be selected to represent the gradients of grazing management and rangeland health present on each ranch. On-site interviews of manager(s) will be used to quantify grazing management for each site. Multivariate statistical analysis will be used to identify significant correlations between grazing management practices and rangeland health indicator values.
Based upon the results of the survey of grazing managers, the prescribed grazing study, the cross-sectional survey of ranches, and the broader science base we will develop an online prescribed grazing – restoration management decision support tool that allows users to: access information about prescribed grazing and restoration; explore site-specific grazing management and effectiveness monitoring options; and participate in prescribed grazing – restoration information exchange.

For more information please contact Ken Tate, kwtate@ucdavis.edu