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RESILIENCE AND SUSTAINABILITY IN HUMAN ECOLOGICAL SYSTEMS
Citation:
Mayer**, A, C. W. Pawlowski**, AND C. McCord. RESILIENCE AND SUSTAINABILITY IN HUMAN ECOLOGICAL SYSTEMS. Presented at Workshop on control of distributed systems and environmental applications, Laxenberg, AUSTRIA, March 26 - 27, 2003.
Impact/Purpose:
To inform the public
Description:
Recent ecological research has uncovered examples of ecosystems that suddenly and sometimes catastrophically change in their composition and in their dynamics in response to incremental changes in external pressure. The possibility of such abrupt changes can have dire consequences on human society and thus must be taken into account in ecosystem management and other activities of human society. Resilience is one of several terms ecologists use to characterize the response of an ecosystem to disturbances. Two definitions of resilience have become prominent in the literature, both of which derive from the dynamic systems theory concept of stability. One refers to the speed of return of a system to its prior, undisturbed steady state. The other refers to the magnitude of disturbance an ecosystem can absorb before it falls into the basin of attraction of a fundamentally different steady state. We argue that these conceptualizations of resilience do not adequately capture the interaction between state displacement and disturbance effects on ecosystems because they use state displacement as a proxy for disturbance. Here we suggest a theoretical measure of resilience that measures both the effects of state displacement and the amount of disturbance an ecosystem can tolerate. Presentation of these resilience concepts is made in the context of a simple model of a lake's response to pollution. In addition to the development of the theory, we are looking to dynamic systems for the tools necessary to calculate resilience for more complex models. How to calculate resilience for real systems is an open question.