Document: ZED-3-10-1

Adaptive restoration: Large-scale experimentation to improve restoration.

ZEDLER, J.B.*

University of Wisconsin, Madison, WI 53706 USA ¹

Abstract:
At Tijuana Estuary, a costly 200-ha restoration plan relies on governmenetal initiatives to solve large-scale problems, as well as on-site experiments to improve restoration methods (adaptive restoration). The entire estuary has experienced excess sedimentation and reduced tidal action; hence, restoration requires sedimentation control. Before legislators would allocate funding to improve this estuary, they required that raw sewage inflows from Mexico be stopped, and an international treatment plant and ocean outfall were built. In 1999, the removal of ~3m of flood-borne sediment began. At this 8-ha site, we are asking how important is it to include topographic complexity into restoration designs? Six1-ha plots (+tidal creek networks, n=3) are testing the influence of tidal creek networks on trophic structure and community development. Research in natural wetlands shows that the creek networks foster plant species richness and enhance fish feeding 6-fold by providing access to the marsh plain. At a smaller, 0.5-ha restoration site, we are asking, which species and how many need to be planted to restore essential ecosystem functions? There, 87 replicate plots (2x2m) are showing that introducing more species accelerates N accumulation, increases canopy layering, and ensures the presence of the native species pool. At Tijuana Estuary, the large-scale problems had to be solved before restoration was supportable; now, field experimentation is essential to increase chances of restoring biodiversity.

Keywords: restoration, adaptive management

This abstract is being presented at: 1:15 PM in session:
Symposium # 5: Incorporating Landscape Processes in Ecological Restoration.