Tracking Natural Community Fragmentation and Changes in Land Use and Land Cover: A case study of Chicago Wilderness

Greater Chicago is home to a surprisingly high concentration of globally significant natural communities. Within the metropolis survive some of the world’s best remaining examples of eastern tallgrass prairies, oak savannas, open oak woodlands, and prairie wetlands. Chicago Wilderness is more than 81,000 ha of protected areas in the urban and suburban matrix, as well as a coalition of more than ninety organizations committed to their survival. The long-term health of these imperiled communities depends on proper management of the more extensive, restorable lands that surround and connect the patches of high quality. Information critical to the success of conservation efforts in the region includes (1) a current vegetation map of Chicago Wilderness, in sufficient detail to make quantitative goal setting possible for the region’s Biodiversity Recovery Plan; (2) quantified fragmentation status of the natural communities; and (3) patterns of land-cover change and their impact on the vitality of communities under threat.

We used multispectral data from the Landsat Thematic Mapper (October 1997) and associated ground truthing to produce the current vegetation map. With multitemporal Landsat remote sensing data (acquired in 1972, 1985, and 1997) we derived land-cover maps of the region at roughly equivalent intervals over the past 25 years. Analyses with GIS models, developed to detect changes and trends in land cover, reveal rapid acceleration of urban and suburban sprawl in the past years. Satellite images provide striking visual comparisons of land use and health, as well as banks of geographically referenced data to make quantitative tracking of trends possible. The data on habitat degradation and fragmentation are the biological foundation of quantitative goals for regional restoration.

This project was funded by the National Aeronautics and Space Administration (Grant No. GP37J). A project publication can be found in Conservation Biology (15(4):835-843). 

Please forward questions to yqwang@uri.edu.