October 5, 2010
On Friday, October 1, USDA announced the release of a new study evaluating the health and productivity of non-federal rangelands in the western United States, which make up 21% of the total area of the lower 48 states. Findings indicate that less than 25 percent of non-federal rangelands have significant land degradation, but that non-native grasses and shrubs now occur on nearly 50 percent of all non-federal rangeland.
The study, which was the result of collaboration between USDA’s Agricultural Research Service (ARS) and Natural Resources Conservation Service (NRCS) and the U.S. Geological Survey (USGS), was published last week in Frontiers in Ecology and the Environment.
The study evaluated more than 10,000 field plots across western rangelands using National Resources Inventory (NRI) data, which is a statistical survey designed to help gauge natural resource status, conditions and trends on U.S. non-federal land. Biological and physical characteristics were used to assess three rangeland health attributes that collectively reflect the status of key ecological processes: soil and site stability, hydrologic function, and biotic integrity.
Nearly 80 percent of the nation’s 405 million acres of non-federal rangeland remains productive, but 20.7 percent shows at least moderate departure from reference conditions for at least one of the three rangeland health attributes, and 9.4 percent shows at least moderate departure for all three attributes.
Non-native species are present on nearly half of the nation’s non-federal rangeland, and make up at least 50 percent of the plant cover on 6.6 percent of these lands. While some of these species can be beneficial, many non-native species on rangelands are responsible for displacing desirable species, altering ecological and hydrological processes, reducing wildlife habitat, degrading systems, altering fire regimes, and decreasing productivity (USDA).
The rangeland health assessment is intended to communicate ecological concepts to the public and landowners, help identify possible land monitoring areas for more comprehensive programs, and provide early warnings of potential problems.
“These findings will provide a new tool for addressing how to monitor the vast tracts that stretch across the western United States and ensure that they are used well and remain productive,” said ARS administrator Edward B. Knipling.