PARENT SESSION
Session #22: Observation, manipulation, experimentation and extrapolation: Limitations and opportunities in ecosystem-level studies. Organized by: R.H. Gardner and J.E. Petersen.
Friday, August 10, 2001. Lecture Hall
Limitations and opportunities in ecosystem-level studies: Lessons from wetland restoration.
Zedler, Joy1, 1
ABSTRACT- Restoration ecology offers unique opportunities to evaluate the limitations of ecosystem research. If we can restore ecosystem structure and function within short time periods, we have sufficient understanding, according to A.D. Bradshaw. Several lessons follow from studies of wetland restoration efforts: (1) Restoration of wetlands often takes decades; (2) Some ecosystem properties are unrestorable; (3) Natural recruitment is typically impaired; (4) Restoration outcomes are often species-poor; and (5) An ecosystem with restored structure might still lack critical functions, such as resilience. We can fail Bradshaw's "acid test" if our methods are inadequate, our time frame is too short, or our theory is faulty. All of the above might be true, first because restoration methods rarely attack enough of the problems of hydrology, soil, vegetation and fauna on or off site. Second, 3-5-year timeframes (as in wetland mitigation projects) are unrealistic. And third, theory that we can reverse changes conflicts with theory on irreversible stable states. If, as this symposium purports, we cannot adequately predict the consequences of declining integrity of natural ecosystems, it is understandable that we cannot yet predict their reversal. To make progress in restoration ecology, we need to undertake more ambitious, larger-scale, longer-term experiments, with many more alternative treatments. I advocate the design of restoration projects as experiments, with an understanding of why some approaches are more effective leading to their broader use in a phased, adaptive approach. This "adaptive restoration" model now drives restoration at Tijuana Estuary and the UW-Madison Arboretum.
KEY WORDS: adaptive restoration, wetlands, large experiments