Ecological Resiliency Presentation to Multi-hazard Roundtable Jan. 16, 2008 Susan Bolton, Ph.D., P.E. University of Washington sbolton@u.washington.edu

Ecological Resiliency Emerges from ecosystem features which follow the ‘rules’ of thermodynamics, conservation of mass and energy, natural selection and evolution

Overarching ecological principles Thermodynamics and conservation of mass and energy Energy flows, solar based Materials are reused and recycled Natural selection and evolution Self-organization Disturbance and thresholds

Ecosystem a self-organizing system with no blueprint or design would need a large amount of information to predict final outcome redundancy of function but not necessarily of structure based on solar energy reuse of materials many possible outcomes and pathways current state reflects past history (disturbances) has a tipping point or threshold where a new state is categorically different from previous and cannot return everything is connected

Definitions Engineering resilience Ecological resilience Rate at which a system returns to a single steady state or cyclic state following a disturbance Ecological resilience Amount of change (disturbance) a system can withstand before it changes to a new set of reinforcing processes and structures

Traditional vs. ecological engineering Seeks stability Accepts inevitability of change Resists disturbance Absorbs and recovers from disturbance One equilibrium point Multiple, non-stable equilibria Single acceptable outcome Multiple acceptable outcomes Predictability Unpredictability Fail-safe Safe-fail Narrow tolerances Wide tolerances Rigid boundaries and edges Flexible boundaries and edges Efficiency of function Persistence of function Redundancy of structure Redundancy of function Engineering Resilience Ecological Resilience

Additional information Holling, C.S. 1973. Resilience and stability of ecological systems. Annual Review of Ecology and Systematics. 4:2-23 Gunderson, L.H. 2000. Ecological Resilience – in Theory and Application. Annual Review of Ecological Syst. 31:425-439. Bergen, S.D., S.M. Bolton, and J.L. Fridley 2001. Design principles for ecological engineering. Ecological Engineering 18:201-210. Huggett, A.J. 2005. The concept and utility of ‘ecological thresholds’ in biodiversity conservation. Biological Conservation 124:310-310.