A Realistic Role for Reference in Wetland Restoration

Wetland restoration projects are often evaluated for success or failure by comparing attributes of restored ecosystems to undisturbed reference ecosystems. This method of evaluation has several flaws, including site-specific responses of restored ecosystems to topographic and geomorphic changes during degradation and restoration, the substantial differences in structure and function of early (restored) and mature (reference) ecosystems, and the inherent variability that exists for ecosystems that may not be represented in reference systems. We need a better framework for evaluating restoration success. Success could be demonstrated by using ecosystem attributes that indicate ecosystem integrity and maturation over time, such as: stable landforms, native plant community development, internal carbon and nutrient storage and cycling, connectivity within the broader landscape, ecosystem heterogeneity, and increasing complexity in species and community diversity. A more realistic role for reference areas in wetland restoration is useful information on structural and functional attributes of ecosystems and an indication of the natural variability that exists in ecosystems that we hope to emulate. Ultimately though, success in wetland restoration depends on our ability to establish conditions that promote ecosystem maturation and integrity and reference systems may be of limited value to evaluate this success.