Although the era of environmental protection has met with significant interruptions, the overall pattern from 1960 to the present has been toward a more environmentally sustainable pattern of use on public lands. The Multiple Use Sustained Yield Act in 1960 was followed by the public outcry related to Rachel Carson’s publication of Silent Spring in 1962. The ensuing flurry of environmental legislation culminated in 1969 with the National Environmental Policy Act (NEPA), which created the Environmental Protection Agency (EPA) and required that any development on federally owned lands needed to be preceded by an environmental impact statement. Ecological concepts, such as ecosystems and watersheds, provided administrators with a new way of viewing public lands. No longer simply a storehouse of potential resources, each of these sites could now be seen as part of larger, complex natural systems. This awareness crystallized during a serious period of contestation over the use of public lands in the late 20th century.