Evaluating Mitigation Performance: Functional and Condition-Based Assessment Methods

摘要

Noted ecologist A.D. Bradshaw described restoration ecology as the "acid test" of our understanding of how ecosystems work. If the goal of mitigation is to recreate a more natural, self-regulating, and self-sustaining ecosystem, research has shown that wetland mitigation projects often do not meet this goal. In fact, mitigation wetlands are often found to be distinct from natural sites in terms of their structure and function. Patterns in the major differences that have been reported between natural and mitigation sites include: 1.deeper surface water at the mitigation sites; 2.lower overall species diversity in many taxonomic groups; 3.substantially reduced soil nutrient pools at mitigation sites; 4.significantly different patterns of nutrient movement, both in terms of rates and quantities cycling between ecosystem components; and 5.low soil nutrient availability that propagates through mitigation sites (limiting productivity for example) and appears, in some cases, to set a limit on ecosystem development.