Suburbanization, Water Use, Nitrogen Cycling, and Eutrophication in the 21st Century: Interactions, Feedbacks, and Uncertainties in a Massachusetts Coastal Zone

Suburbanization in coastal zones can generate severe environmental impacts, such as estuarine eutrophication and the impairment of shellfish beds. Suburbanization can also produce substantial social disruptions, as established populations (and their contributions to society and the economy) are replaced by new populations and their land uses. This process of transforming land cover to support suburban land uses is so multi-dimensional that few research projects have analyzed and modeled the process in a holistic manner. One complicating factor is the conflicting character of human-environment interactions, as environmental processes unfold alongside the promotion of single-family, low-density development, the expansion of affordable housing, and the preservation of a sense of place. Another complicating factor is that a single type of land-cover transformation can be associated with various land uses. For example, because two low-density residential areas may exhibit a high proportion of lawn cover but with different water and fertilizer application rates; the two neighborhoods will exhibit different environmental outcomes. There are few empirically based explanations for linking specific suburban land covers with specific land uses and for predicting the associated social and environmental outcomes. This research project will examine how suburbanization affects the environment within a tightly coupled analytical framework, examining questions fundamental to social, natural, and geographic information sciences. Northeastern Massachusetts is a compelling natural laboratory for examining these dynamics, because metropolitan Boston is sprawling into this coastal area. Data gathered through fieldwork and statistical and process-based modeling will be used to characterize, explain, and model these dynamics in a suburbanizing coupled human-watershed-estuary system in a 26-town Massachusetts study area. The investigators will employ a suite of methods, such as conducting interviews, evaluating primary and secondary statistical data, taking in situ measurements, conducting field experiments, processing high resolution satellite imagery, modeling, and utilizing geographic information systems. The project will produce an integrated social and ecological science analysis incorporating a georeferenced land-use/land-cover change projection model. This project will provide new insights into the processes that govern suburbanization, water use, nitrogen cycling, shellfish productivity, and their interactions. These dynamics constitute a pressing national problem for coastal zone managers, land owners and water managers. The significance of this research is manifest by its products, which will include a set of quantitative estimates of spatial and temporal trends in suburbanization and in three of its consequences: sense of place, water use, and waste and fertilizer management. The project also will result in an assessment of likely human responses to these consequences; advances in quantifying river channel-floodplain connectivity to track changes in nitrogen cycling associated with human activities; and improved modeling of estuarine eutrophication and shellfish productivity in response to upstream changes in nitrogen cycling. Integrating across these subactivities, a set of georeferenced and validated scenarios of future land use and land cover will be generated, thereby enabling the investigators to make statements about the likely future vulnerability of the coupled system to continued status quo suburbanization patterns. These products each represent new contributions to the fields of land-use and land-cover change, aquatic ecosystem ecology, and geographic information science. Together, these products will help advance basic understanding of coupled human-environment vulnerabilities to the effects of multiple, interacting stressors. The researchers will produce results that interest not only scholars but also suburbanizing communities. Results will be conveyed directly to relevant government and planning organizations and advocacy groups in an end-of-project stakeholder symposium. The general public will also be reached by engaging science journalists through an established program. Students will be integrally involved at the pre-college, undergraduate, graduate, and post-doctoral levels. This project is supported by an award resulting from the NSF competition focusing on the Dynamics of Coupled Natural and Human Systems.