WETLANDS, Vol. 16. No. 4, December 1996, pp. 503-511 © 1996, The Society of Wetland Scientists PLANT SUCCESSION AND GREENTREE RESERVOIR MANAGEMENT: IMPLICATIONS FOR MANAGEMENT AND RESTORATION OF BOTTOMLAND HARDWOOD WETLANDS Sammy L. King and James A. Allen ~ National Biological Service Southern Science Center 700 Cajundome Blvd. I_z~fayette, LA 70506 J Current Address: U.S.D.A. Forest Sen, ice Institute of Pacific Islands Forestr:" 1151 PunchbowI Street, Room 323 Honolulu, HI 96813 Abstract: Bottomland hardwood forests are distributed along rivers and streams throughout the central and eastern United States, with the greatest concentration in the Southeast. Past and projected losses of bottom- land hardwoods and degradation of remaining stands suggest that habitat management and/or restoration strategies thut target multiple species and multiple uses will be necessary to maintain, enhance, and restore flora and fauna within bottomland hardwood wetlands. A greentree reservoir is a current management strat- egy that entails manipulating water regimes to provide habitat for wintering waterfowl. We conducted a literature review and synthesis to determine the potential impacts of greentree reservoir management on plant succession within bottomland hardwood wetlands. Greentree reservoirs can impact vegetation establishment through several processes. Despite shortcomings of greentree reservoirs, designs similar to them could be very beneficial in restoring bottomland hardwood plant and animal communities from degraded forests provided water-level control and maintenance are substantially improved. Emulation of natural hydrologic regimes, including natural variability, could produce diverse bottornland hardwood plant communities and provide habitat for a variety of w'ildlife species. Key Words: bottomland hardwoods, forested wetlands, greentree reservoir, hydroperiod, succession, wet- land restoration INTRODUCTION Bottomland hardwood forests (BLH) are distributed along rivers and streams throughout the central and eastern United States with the greatest concentrations occurring in the Southeast (Huffman and Forsythe 1981, Mitsch and Gosselink 1993). The hydroperiod is the major determinant of plant species composition in BLH wetlands (Bedinger 1971, Franz and Bazzaz 1977, Wharton et al. 1982, Theriot 1993). The hydro- period may also directly affect animal distributions by influencing habitat availability (e.g., flooded or not) or indirectly by influencing habitat structure and com- position (Lambou 1963, Wharton et al. 1982, Christ- man 1984, Hunter et al. 1987, Weller 1988, Brody et al. 1989, Hamel 1989). The linear nature of BLH forests and the encroach- ment of agriculture into these systems makes their total area difficult to quantify (Abernathy and Turner 1987, Tansey and Cost 1990); however, only about 2.8 mil- lion ha existed in the Lower Mississippi Alluvial Val- ley of the United States in 1982 of an estimated his- torical 10 million ha (National Research Council 1982, Hefner and Brown 1985). Although the rate of decline has decreased more recently (Tansey and Cost 1990) and area of BLH has actually increased in local areas (Faulkner et al. 1995), during the 1950s-1970s, these wetlands suffered annual losses exceeding 120,000 ha per yr (MacDonald et al. 1979). In addition to direct losses, degradation of existing stands through frag- mentation, hydrologic alteration, pesticide accumula- tion, and poorly conceived timber management prac- tices (e.g.. high-grading--selective removal of the largest, best-formed, and most economically valuable trees) have further impacted the structure and com- position of plant and animal communities within these systems (Harris 1988, Harris and O'Meara 1989, Dol- lar et al. 1992). 503