Urbanization as a barrier to ecosystem resiliency in the face of climate change

Background/Question/Methods

Human actions on the landscape can limit the effectiveness of robust adaptive cycles in ecosystems. This mediating impact can reduce the ability of certain systems to adapt to changing conditions such as anthropogenic warming of the climate. In the Southeast US urbanization in the form of low density single family residential developments have a large and increasing influence on regional land cover.  Therefore for resource managers and other decision-makers to effectively plan for and adapt to the effects of a changing climate on ecosystems, information is required about how the urban landscape could evolve over time. The goal of this study, as part of the Southeast Regional Assessment Project, is to simulate future patterns of urban growth across the Southeast US over a 50 year period (2011-2060). We use the cellular automata model SLEUTH developed by the US Geological Survey to simulate urban growth based on recent spatio-temporal patterns of urbanization. The model simulates future urbanization according to a set of growth rules related to existing urbanization, transportation patterns, land use planning, and topographic and environmental constraints.  

Results/Conclusions

Model results show large increases in the extent of suburban and exurban areas by 2060 under a business-as-usual development scenario. The results of the simulation show a 71% increase in the urbanized land area compared to 2009. The pattern of urbanization varies depending on proximity to existing urban areas, distance to built-up coastal areas, and current land use features and policies that restrict future urban growth. For decision-makers, model results show that areas that currently place controls on urbanization retain existing habitats but can become isolated and fragmented as urban areas form around them. The number of urban patches decreases by 38% while the size of the largest urban patch increases by 63%, indicating an enlargement of the extent of urban areas that causes a corresponding reduction in habitat patches for the ecosystems of interest. A continuation of current urbanization patterns in this region can limit management options that strive to promote resiliency in the face of climate change.