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A National Assessment of Green Infrastructure and Change for the Conterminous United States Using Morphological Image Processing
Citation:
WICKHAM, J. D., K. H. Riitters, T. G. WADE, AND P. Vogt. A National Assessment of Green Infrastructure and Change for the Conterminous United States Using Morphological Image Processing. LANDSCAPE AND URBAN PLANNING. Elsevier Science Ltd, New York, NY, 94(3):186-195, (2010).
Impact/Purpose:
Green infrastructure extends the concept of built-up area needs to conservation of the natural environment (Lewis 1964; Mcharg 1969; Noss and Harris 1986; Benedict and McMahon 2002, 2006; Jongman 1995, Jongman et al. 2004; Fábos et al. 2004). It is a broadly encompassing concept because of its objective to harmonize communities with the natural systems on which they depend (Benedict and McMahon 2006). Development of community parks and recreation trails, stream restoration, storm water management, and land conservation are all within the broad scope of green infrastructure. It is viewed as a conceptual advance in environmental planning (sensu Hoctor et al. 2008) because it integrates natural systems with community well being (see also Nassauer 2006). Though broad in theme and spatial scale, green infrastructure projects all share the common goal of sustainable land management planning (Leitão and Ahern 2002, Weber 2004, Ahern 2007).
Description:
Green infrastructure is a popular framework for conservation planning. The main elements of green infrastructure are hubs and links. Hubs tend to be large areas of ‘natural’ vegetation and links tend to be linear features (e.g., streams) that connect hubs. Within the United States, green infrastructure projects can be characterized as: 1) reliant on classical geographic information system (GIS) techniques (e.g., overlay, buffering) for mapping; 2), mainly implemented by states and local jurisdictions, and; 3) static assessments that do not routinely incorporate information on land-cover change. We introduce morphological spatial pattern analysis (MSPA) as a complementary way to map green infrastructure, extend the geographic scope to the conterminous United States, and incorporate land-cover change information. MSPA applies a series of image processing routines to a raster land-cover map to identify hubs, links, and related structural classes of land cover. We identified approximately 4,000 large networks (> 100 hubs) within the conterminous United States, of which approximately 10 percent crossed state boundaries. We also identified a net loss of up to 3.59 million ha of links and 1.72 million ha of hubs between 1992 and 2001. Our national assessment provides a backbone that states could use to coordinate their green infrastructure projects, and our incorporation of change illustrates the importance of land-cover dynamics for green infrastructure planning and assessment.