A Synoptic Review of U.S. Rangelands A Technical Document Supporting the Forest Service 2010 RPA Assessment Matthew Clark Reeves and John E. Mitchell Reeves, Matthew Clark; Mitchell, John E. 2012. A synoptic review of U.S. rangelands: a technical document supporting the Forest Service 2010 RPA Assessment. Gen. Tech. Rep. RMRS-GTR-288. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 128 p. Abstract: The Renewable Resources Planning Act of 1974 requires the USDA Forest Service to conduct assessments of resource conditions. This report fulfills that need and focuses on quantifying extent, productivity, and health of U.S. rangelands. Since 1982, the area of U.S. rangelands has decreased at an average rate of 350,000 acres per year owed mostly to conversion to agricultural and residential land uses. Nationally, rangeland productivity has been steady over the last decade, but the Rocky Mountain Assessment Region appears to have moderately increased productivity since 2000. The forage situation is positive and, from a national perspective, U.S. rangelands can probably support a good deal more animal production than current levels. Sheep numbers continue to decline, horses and goats have increased numbers, and cattle have slightly increased, averaging 97 million animals per year since 2002. Data from numerous sources indicate rangelands are relatively healthy but also highlight the need for consolidation of efforts among land management agencies to improve characterization of rangeland health. The biggest contributors to decreased rangeland health, chiefly invasive species, are factors associated with biotic integrity. Non-native species are present on 50 percent of non-Federal rangelands, often offsetting gains in rangeland health from improved management practices. Keywords: rangeland health, livestock, remote sensing, rangeland extent, grazing, coterminous United States, Renewable Resources Planning Act Authors Matthew Clark Reeves is a Post Doctoral Research Ecologist in the Human Dimensions program of the USDA Forest Service, Rocky Mountain Research Station in Missoula, Montana. He earned his B.S. degree in Range Management from Washington State University, his M.S. degree in Environmental Resources from Arizona State University, and a Ph.D. in Ecosystem and Conservation Sciences from the University of Montana. He specializes in using remote sensing and spatial analysis to understand the status and trends of natural resources and biospheric processes and is an active participant in the Sustainable Rangelands Roundtable and Society for Range Management. John E. Mitchell is an Emeritus Rangeland Scientist with the Rocky Mountain Research Station in Fort Collins, Colorado. Prior to retiring in 2009, his research supported the rangeland component of the Renewable Resources Planning Act Assessment. Since that time, he has continued to assist with rangeland work for the Assessment and has been an active participant in the Sustainable Rangelands Roundtable and Society for Range Management. Mitchell is a Certified Professional in Rangeland Management. You may order additional copies of this publication by sending your mailing information in label form through one of the following media. Please specify the publication title and number. Publishing Services Telephone (970) 498-1392 FAX (970) 498-1122 E-mail [email protected] Web site http://www.fs.fed.us/rmrs Mailing Address Publications Distribution Rocky Mountain Research Station 240 West Prospect Road Fort Collins, CO 80526 Acknowledgments This work was initiated by John Mitchell, the author of the previous rangeland portion of the RPA Assessment. After the initial planning phase, the assignment was given to Matt Reeves in 2009. Dr. Mitchell provided the impetus to design the program to evaluate the U.S. rangeland base, excellent perspective, and mentoring throughout the development of the document and contributed significantly to Chapter 3: Ecosystem Goods and Services. Staff from a wide range of organizations contributed guidance, review, and data to populate the report. Specifically, we thank John Reitsma, Phil Cooley, and Sherm Karl from the Bureau of Land Management (BLM) National Operations Center for providing interpretation and data describing BLM land dispositions, grazing allotments, rangeland health, and grazing statistics. In a similar manner, USDA Forest Service range management staff provided data describing gross receipts from grazing Forest Service (USFS) lands, grazing statistics, allotment boundaries, and juxtaposition of USFS lands. Shelley Douthett, Kaylene Monson, and Lisa McBride, were all involved in this process. Other members of USDA also contributed: Marisa Capriotti provided data regarding conservation lands and Virginia Harris was instrumental in obtaining and understanding data from the National Agricultural Statistics Survey. In addition to agency personnel, staff from three universities contributed data and information for the report. Adam Moreno, under the direction of Dr. Steve Running, Professor of Forest Ecology, University of Montana developed the forecasts in range- land productivity. Wasantha Kulawardhana and Dr. Robert Washington-Allen, Assistant Professor of Ecosystem Science and Management, Texas A&M University, developed the estimated footprint of livestock herbivory. Finally, Ian Leinwand, under the direc- tion of Dr. Dave Theobald, Research Scientist, at Colorado State University, provided the analysis of human modified rangeland and fragmentation. Acquisition of data describing oil and gas networks and invasive species was performed by Robb Lankston, whose help enabled more timely completion of the document. Impetus for the climate change effects section was provided by Dr. Jack Morgan of the Agricultural Research Service. Dr. Morgan’s expertise on the subject enabled us to complete an overview of climate change effects. Kate Marcille provided editorial suggestions and was responsible for a good deal of formatting and compilation.Lane Eskew, Lindy Larson, and Nancy Chadwick patiently provided editorial assistance. Finally, the RPA specialists and Washington Office management personnel provided continual support, answers, and guidance. Dr. Linda Langner and Margaret Connelly, both from the Washington Office, provided oversight and kept the document as up- to-date as possible. In addition, Dr. Langner provided analysis and written evaluation of the RPA scenarios. Dr. Linda Joyce provided data and support for the downscaled climate data. Dr. Kurt Riitters provided the data and analysis for the rangeland frag- mentation evaluation. i ii Executive Summary Chapter 1: Context, Design, and Impetus for the 2010 RPA Rangeland Assessment The Forest and Rangeland Renewable Resources Planning Act (RPA) of 1974 requires assessments and projections of the Nation’s renewable resources. Successive RPA Range Assessments have exhibited a central theme or context binding the chapters together. The 1989 Range Assessment extensively evaluated the forage supply and demand and relied on an econometric model (now retired) for forecasting purposes. It was generally concluded that the total U.S. forage supply was sufficient to meet projected demands. The 2000 Range Assessment was organized around the concept of criteria and indicators developed by the Sustainable Rangeland Roundtable and, like the 1989 Range Assessment, it concluded that forage quantity was sufficient for current and projected livestock levels. This 2010 Range Assessment addresses topics similar to its predecessors, but focuses on providing more spatially explicit data describing the status and trends of U.S. rangelands. Projections for rangeland resources are not provided here and will instead be available in forthcoming docu- ments supporting this Assessment. As a result, this report focuses on contemporary issues, including rangeland extent and health, forage supply, and livestock numbers, while maintaining linkages with past assessments. Chapter 2: Rangeland Extent and Global Concerns Quantifying rangeland extent provides an area basis for estimating carbon seques- tration and forage availability, serves as a baseline against which future estimates of resources can be compared, and is necessary for developing monitoring and management strategies. Extent of rangelands is also a component of at least three criteria and six indicators of rangeland sustainability. Rangeland area in the cotermi- nous United States is between 511 and 662 million acres, depending on the definition used, and roughly one-third of these lands are protected. Since the pre-settlement era, approximately 34 percent of rangelands have been permanently modified by human activity. However, as reported in the 2000 Range Assessment, the U.S. rangeland base is relatively stable, though further fragmentation due to exurban development, oil and gas exploration, agricultural development and, to a lesser degree, residential development can be expected. Privately owned rangelands will continue a slow decline in area while publically owned rangelands will continue to be stable, and changes will usually result from land exchanges and oil and gas development. While data describing global rangelands are sparse, the worldwide situation appears less favorable than the conditions in the United States. Globally, rangelands occupy nearly one-half of the vegetated surfaces and at least half of these lands are grazed and provide livelihood to millions of people. Since rangelands are not explicitly