Development of an index of susceptibility to human disturbance for Great Lakes coastal wetlands

We are just beginning to realize the importance of coastal wetlands to the entire Great Lakes ecosystem.  Unfortunately, greater than 50% of coastal wetland area has been lost to, among other things, development and fragmentation.  Coastal wetlands that remain today must be protected from further degradation.  Much of our recent work has been toward developing indices of biotic integrity, but these tools are reactionary.  We are now working toward proactive approaches in protection.  We measured metabolism at 12 sites and collected a suite of accompanying chemical and physical variables.  We used principal components analysis and multiple regression to determine that stem density, sediment organic depth, bay width, and fetch were the best predictors of ecosystem respiration.  Several of our past studies suggested that ecosystem respiration was related to anthropogenic disturbance and fish and invertebrate community composition and that those wetlands with little organic sediment accumulation may be less susceptible to anthropogenic disturbance.  Since measuring ecosystem respiration directly is quite involved, we combined less complex surrogate measures into an index for use by government agencies and managers to inform decisions that potentially impact Great Lakes coastal wetlands.