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Almost thirty years ago, C. S.
Holling introduced the word resilience into the ecological literature
as a way of helping to understand the non-linear dynamics observed in
ecosystems. Ecological resilience was defined as the amount of disturbance
that an ecosystem could withstand without changing self-organized processes
and structure (defined as alternative stable states). Other authors
consider resilience as a return time to a stable state following a perturbation.
Two definitions recognize the presence (or not) of multiple stable states
(or stability domains), and hence resilience is the property that mediates
transition among these states. Transitions among alternative states
have been described for many ecosystems, including semi-arid rangelands
vegetation, wetlands, lakes, coral reefs, and forests. These transitions
appear to have a some similarities, involving interactions among variables
operating at different spatial/temporal scales. The transitions also
occur as human activities erode resilience through mining of natural
capital, changing critical pathways/connections, or through stabilization
of key variables (for management purposes). Ecological resilience provides
an ecological buffer that protects the system from the failure of management
actions that are taken based upon incomplete understanding, and allows
managers to affordably learn and change.