Geosciences and Environmental Change Science Center
The National Land Change Assessment (NLCA) is a research effort that examines the causes, trends, and implications of United States land change. The project takes a comprehensive approach towards understanding land change by systematically examining land conversion and management across a full range of land use and land cover types and climate and ecological settings. Land change is a key driver of environmental change and has important implications related to climate variability and change, biodiversity, natural resources, and ecosystem services.
Historical and recent land transformations are examined using an innovative multi-scale ecoregion framework . The approach employs a variety of spatial analysis approaches to provide an understanding of the geographically- and temporally-variable processes of land change, focusing on the interactions between humans and their environment. A goal of the project is to provide a scientific basis for land management and policy decisions related to issues of sustainability and resilience.
How are the long-term trends, land change transitions, and historical legacies of land use change affecting social-environmental systems and sustainability? This research examines the spatial-temporal dynamics and implications of US land change within the context of global environmental change.
The results show that an estimated 17.7 percent of the Gulf Coastal Plains and Ozarks Landscape Conservation Cooperative (LCC) land cover had a change during the 27-year period. Cyclic forest dynamics—of timber harvest and regrowth—are the most extensive types of land conversion. Agricultural land had an estimated net decline of 3.5 percent as cropland and pasture were urbanized and developed and converted to forest use. Urban and other developed land covers expanded from 2.0 percent of the LCC in 1973 to 3.1 percent in 2000.
Replacement processes, whereby a land use or cover is supplanted by a new land use, including urbanization and agricultural expansion, accounted for approximately 15 % of the extent of change. Recurrent processes that contribute to cyclical changes in land cover, including forest harvest/replanting and fire, accounted for 83 %. Most forest cover changes were recurrent, while the extents of recurrent silviculture and forest replacement processes such as urbanization far exceeded forest recovery processes. The total extent of landscape recovery, from prior land use to natural or semi-natural vegetation cover, accounted for less than 3 % of change.
Mark Drummond (website): Principal Investigator, USGS Geosciences and Environmental Change Science Center (GECSC), Denver and Fort Collins, Colorado
Roger Auch: USGS Earth Resources and Observation Science (EROS) Center, Sioux Falls, South Dakota
Glenn Griffith: USGS Western Geographic Science Center, Corvallis, Oregon
Dave Hester: GECSC, Denver, Colorado
Jamie McBeth: GECSC, Denver, Colorado
Jodi Riegle: GECSC, Denver, Colorado
Chris Soulard: USGS Western Geographic Science Center, Menlo, California
Mike Stier: GECSC, Denver, Colorado
Janis Taylor: Stinger Ghaffarian Technologies, Contractor to the USGS, Whitefish, Montana