UC Berkeley

North America's diverse grassland, savanna, steppe and desert ecosystems evolved in the absence of domesticated livestock. The arrival of cattle, sheep, goats, pigs and horses after 1492 transformed many ecosystems while enabling European soldiers, missionaries and settlers to conquer the continent. The decimation of indige-nous populations by warfare, disease and economic dependency further transformed rangelands by removing Native management practices, especially the use of fire. The history of rangelands since then has been one of recursive efforts to commodify and territorialize rangeland resources-including wildlife, grass, soil fertility and the land itself-for market production and exchange. Many former rangelands have been lost altogether, by conversion to forest cover (due to fire suppression) or to agricultural uses (especially in the Great Plains), and invasive exotic plant species have radically altered large areas of rangelands in California, the Great Basin, and other regions. Nonetheless, North American rangelands remain both vast and invalu-able for wildlife. The Western Range system of public land grazing leases, which emerged from the devastating overgrazing of the late nineteenth century, succeeded in stabilizing range conditions and linking land use and management across large landscapes of mixed ownerships. With accelerating urbanization, the rise of environ-mentalism, and structural shifts in the livestock industry since World War II, however, the Western Range has begun to unravel, exposing rangelands to development and fragmentation. Climatic variability in the form of droughts, floods and extreme fire conditions, more so than aridity per se, has frustrated efforts to extract value from rangelands from the outset, and climate change promises to amplify these phenomena going forward.