Biocomplexity II

UERL Biocomplexity Research Program

Biocomplexity I

Microsimulation of the urban development process

Developing a spatially-explicit land cover change model that represents the dynamic interaction between development and biophysical processes

Impact model to capture the effects of land cover change on bird populations

Biocomplexity II

Nitrogen modeling in urbanizing ecosystems

Climate Variability and Patterns of Residential Water Use in the Seattle Region

Landscape Signatures

Pricing of environmental quality

Urbanization impacts on bird populations

Functions along an urban-to-rural gradient

Modeling Land Use/Land Cover Change and Nitrogen Cycling in Urbanizing Ecosystems

Steven Walters, Marina Alberti, and Lucy Hutyra

Project Description

Broad-scale urban landscape structure and function emerge from the collective, local-scale interactions of adaptive human and biophysical agents. Changes in land use and land cover resulting from the processes of urbanization lead to significant changes in ecosystem dynamics, particularly in the form of increased nutrient exports into watersheds. Though such effects have been previously explored, what has yet to be addressed is how such changes in ecosystem function, resulting in such effects as reduced water quality and diminished forest abundance and/or function, feed back onto decisions of human agents. We are coupling a spatially explicit model of ecosystem and hydrologic dynamics – the Regional Hydro-Ecologic Simulation System (RHESSys) – with an agent-based model (ABM) of local-scale human and biophysical interactions to explore these feedbacks. Using the greater Seattle region as our study area, we are exploring the changes in hydrology and increases in nitrogen export that result from changes in spatial pattern within urbanizing landscapes. Concurrently, we are examining how changes in feedbacks between human and biophysical elements – for example, greater vs. lesser responsiveness of human settlement patterns to habitat fragmentation, reduced water quality and other ecosystem changes – mediate or exacerbate the impacts of urbanization within coupled systems.

figure 1a figure 1b

Figure 1. Human and biophysical functions are inextricably linked in urban landscapes; hydrologic and forest dynamics are altered as a result of human-induced land use/land cover change, and the consequences of those alterations in turn impact human decision-making through such effects as reduced water quality (Figure 1a). By coupling a model of ecosystem and watershed dynamics (RHESSys) with a model of interactions between human and biophysical agents (ABM), we are exploring how alternate scenarios of decision-making strategies impact the structure and function of urban ecosystems (Figure 1b).