EXURBAN DEVELOPMENT: QUANTIFICATION, FORECAST, AND EFFECTS ON BIRD COMMUNITIES
Lookingbill, Todd R
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Rural landscapes in the United States have changed dramatically in recent decades due to the rapid development of private rural lands into low-density residential exurban development. This land conversion is a rising cause of concern due to its potential effects on biodiversity and ecosystem processes. Although exurbanized area is thought to have a significant increase in eastern deciduous forests, a rigorous assessment of exurban trends, drivers, and ecological consequences has yet to be undertaken. First, I develop a novel analytic approach to identify exurban areas and assess how much land has been converted to exurban development in the Mid-Atlantic region. The approach describes mixed pixels containing exurban development as a combination of land covers and uses decision-tree classification and morphological spatial pattern analysis to further separate exurban development from other forest disturbing events. The results indicate that exurban development is a pervasive and fast-growing form of land use in the region. Second, I evaluate the effectiveness of two contrasting modeling approaches in capturing exurban growth at a local and county scale. Exurban growth was effectively captured by the spatially-explicit econometric model at both scales and the pattern-based model only performed well at the county scale. Thus, pattern-based models like SLEUTH can forewarn potential coarse-scale losses of natural resources in exurban areas, but are less useful at finer scale or for assessing potential impacts of implementing land-use policies. Third, I assess whether exurban development degrades avian breeding territories over time and forest birds' response to those changes. I conclude that exurban development is degrading breeding habitats by reducing forest cover and increasing habitat fragmentation. Forest birds exhibited a threshold response to deteriorating breeding habitats in the vicinity of breeding territories and adjacent foraging areas being forest specialists the most sensitive group. To avoid the likelihood of sudden bird population declines amongst further habitat loss and fragmentation, a synergy among land managers, planners, and decision-makers will become increasingly important to mitigate the impacts of exurban development in the Mid-Atlantic region.