Exurbia as Physical and Social Space: Landscape Drivers and Ecological Impacts of Amenity Migration in the New West

Abstract

The American West, once characterized by open spaces, low population densities, and the dominance of primary sector activities, is experiencing high rates of population growth related to amenity migration. Those same natural amenities that attract migration are often degraded by housing growth and associated development; however the extent of impacts and the specific features of the environment that attract amenity migration are poorly understood. This change in land use was investigated by first examining the impacts of exurbanization on three ecosystem indicators (fire hazard, water availability, and distance effects of houses and roads) and secondly by considering the socio-cultural and aesthetic drivers of amenity migration in the Sonoita Plain, Arizona, USA. When the impacts of houses and roads on ecosystem function were considered, 98% of exurban areas were "highly" or "very highly" impacted, compared to 100% for suburban areas and 35% for rural areas. These results were striking because exurban areas have impacts on ecosystem function comparable to those of suburban areas, despite the fact that they support significantly lower population densities. The importance of privacy in the spatial distribution of exurban development was examined through GIS viewshed analysis. Desire for privacy was manifested in the home locations selected by exurbanites, with the large majority of homes located where the inhabitants see few, if any, neighbors. Scenic beauty is a common pull factor for amenity and this study examined three visual quality metrics (naturalness, visual scale and complexity) in relation to the location of exurban houses. Exurban households see significantly more vegetation, more rugged terrain, and a larger viewshed than would be expected if they were randomly distributed. There is evidence that visual complexity throughout the viewshed may be more important than seeing the very highest peaks. These results call into question the use of county-level scales of analysis for the study of landscape preferences, which may miss key landscape aesthetic drivers of preference. Amenity drivers have important implications for the distribution of development and can inform growth strategies designed to minimize negative ecological impacts and protect visual quality of the environment.