PARENT SESSION
Symposium #19: Cities of Resilience: Integrating Ecology into Urban Planning, Design, Policy, and Management .
Organized by: L Musacchio and J Wu
Wednesday, August 7. 8:00 AM to 11:30 AM. Leo Rich Theatre.
Resilience in urban ecosystems: Patterns, process, and ecological change .
ALBERTI, MARINA*,1, MARZLUFF, JOHN2, 1 University of Washington, Seattle, WA2 University of Washington, Seattle, WA
ABSTRACT- Interactions between humans and ecological processes are extraordinarily complex. Urban ecosystems evolve over time and space as the outcome of dynamic interactions between socio-economic and biophysical forces operating over multiple scales. These complex interactions give raise to a unique ecology and distinctive ecological forcing functions in which human patterns and processes are dominant agents. The ecological resilience of urban ecosystems--the degree to which they have to be altered before they reorganize around a new set of structures and processes-is reduced by human action. In cities and urbanizing areas fragmentation of natural habitats, simplification and homogenization of species composition, disruption of hydrological systems, and alteration of energy flow and nutrient cycling reduce cross-scale resilience, leaving systems increasingly vulnerable to biophysical, economic, or social events. We propose a conceptual model that relates patterns, processes, and resilience in urban ecosystems. Because urban development affects the spatial heterogeneity of the landscape and spread of disturbance, we argue that alternative urban patterns (i.e. urban form, land use intensity, and connectivity) generate differential ecological effects. Although many competing models have addressed the relationship between urbanization and ecosystems, few have directly asked the question of how human and ecological patterns emerge from the interactions between socio-economic and biophysical processes. Nor they have investigated how these patterns control the distribution of energy, materials and organisms in urban ecosystems. We do not know for example how clustered versus dispersed and monocentric versus polycentric urban structures emerge and how differently they affect ecological conditions. We propose that ecological resilience in cities is a function of the spatial patterns of human activities and natural habitats, which control and are controlled by both socio-economic and biophysical processes operating at various scales. We discuss the implications of this conceptual model for urban planning and design.
KEY WORDS: urban ecosystems, patterns, processes, resilience