Diverse wetland restoration approaches under working-lands programs in the Southeastern U.S.: implications for ecosystem services

Background/Question/Methods

Wetland degradation causes loss of ecosystem services such as water storage, water quality improvement, and habitat support. The U.S. Department of Agriculture’s Wetlands Reserve Program (WRP) offers financial incentives to restore converted or degraded wetlands on working agricultural lands. In the Southeast, a region of diverse wetlands, the nature and outcomes of these restorations are largely unknown. Because ecological functions differ among hydrogeomorphic (HGM) types, identifying wetland types and landscape settings is a necessary foundation for estimating the potential services that may be recovered by restoration. WRP projects across the Piedmont and Coastal Plains of South Carolina, Georgia, and eastern Mississippi were evaluated to classify the HGM types restored and to assess if choice of restoration practices favored recovery of original functions. Based on an unbiased selection of >100 wetland projects enrolled in the WRP from 1996 to 2004, this survey provides the first comprehensive picture of working-lands restorations in the Southeast region.

Results/Conclusions

Projects were unevenly distributed geographically, reflecting varying participation by state, but they were diverse in both prior condition and HGM type. Nearly half the projects involved converted wetlands retired from active agriculture, whereas the remainder were vegetated wetlands or bottomlands formerly degraded by ditching or timber harvesting. Restoration methods differed with wetland HGM type. Practices to block artificial drainage and to manage water levels for waterfowl habitat were common on depressional, wet-flat, and low-order riverine wetlands; in the latter, the practices altered riverine hydrologic function to favor enhanced water retention. In contrast, practices to restore mainstem river floodplains focused on removing barriers to water flow and biologic connectivity, principally when the prior condition was degraded timberland. Use of natural revegetation versus planting also differed with prior habitat status. Differing HGM types, wetland sizes, and prior conditions have landscape-level implications for the ecosystem services gained from individual projects. Field surveys of a sub-sample of project wetlands will assess whether installed practices have achieved actual improvements in wetland condition.