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5.4 Restoration

Approximately half of the South's forested wetlands have been lost in the last 200 years. Along with this loss in acreage has been the loss of wetland functions and societal benefits, goods and services described in the last section. In an attempt to ameliorate the environmental damage of wetland loss, restoration of former forested wetlands is being attempted throughout the South. Wetland restoration is defined by the Society of Wetland Scientists as, "actions taken in a converted or degraded natural wetland that result in the establishment of ecological processes, functions, and biotic/abiotic linkages and lead to a persistent, resilient system integrated within its landscape." The goal of restoration of wetland ecosystems was expressed by the National Research Council (1992) as, "returning the system to a close approximation of the predisturbance ecosystem that is persistent and self-sustaining (although dynamic in its composition and functioning)." Therefore, since much of the forested wetland loss in the past has been due to agriculture, any national or regional program designed to restore millions of acres of former wetlands will have to focus primarily on wetlands converted to agricultural use (National Research Council 1992). Presumably these agricultural lands would still occupy the same landscape position and have the same or similar hydrology as the original wetlands prior to conversion. An exception to this is in areas where extensive levee systems like those in the Lower Mississippi Valley have restricted flooding on a broad scale.

Although forested wetlands have been lost throughout the South, perhaps the most acute losses have been in the Lower Mississippi Alluvial Valley (LMAV). There, approximately 18 million acres of wetland were lost to agricultural conversions ((King and Keeland 1999)). Such conversions have involved clearing the natural forested wetland vegetation, drainage, and flood control. In the LMAV, the estimated original 25 million acres were reduced to approximately 5 million acres by 1978 (Hefner and Brown 1985). Ninety-six percent of the forested wetland losses in the LMAV were due to agriculture; the remaining losses were due to construction of flood control structures, surface mining, and urbanization (Schoenholtz and others in prep).

In the 1970s and 1980s the U.S. Fish and Wildlife Service recognized the trend in forested wetland loss and associated habitat impacts in the LMAV and began a campaign to reestablish forested wetlands in the LMAV (King and Keeland 1999). The development of the Wetland Reserve Program (WRP) by NRCS as well as smaller projects undertaken by the U.S. Army Corps of Engineers and State Fish and Game agencies has intensified reforestation/restoration in the LMAV making this area the largest reforestation/restoration effort in the South. Figure 3, derived from NRI data from 1982-1992 indicates that 17.5 percent of the watersheds in the South experienced a gain of forested wetland, 31.2 percent experienced a loss, and 51.3 percent experienced no change. However, it is uncertain if the acres reported in the NRI represent actual acres restored versus acres enrolled in WRP.

The Wetland Reserve Program of the 1990 Farm Bill is directed at wetland systems and provides for conservation easements for 10-30 years. The 1990 Farm Bill, which was reauthorized in 1996, established that up to 1 million of the 6 million acres of cropland eligible for the Conservation Reserve Program (CRP) may be wetlands. This program, unlike most others, has the potential to restore large acreages of forested wetlands in the South.

King and Keeland (1999) reported that approximately 195,000 acres have been reforested in the LMAV. Restoration of forested wetland systems in the LMAV involves restoration of the geomorphic, hydrological, and ecological processes that drive these wetland systems. Massive forest clearing, construction of thousands of miles of drainage ditches, broad-scale channelization of streams and rivers, flood prevention, and farming practices have changed hydrology, topography and soils. Restoration of wetland functions is extremely difficult there. Table 5 shows that 64 percent of the WRP acres are in the States of Mississippi, Louisiana, and Arkansas. Presumably, all or a major portion are in the LMAV. Figure 4 shows the number of WRP acres by State in the South. Once again Mississippi, Louisiana, and Arkansas have the greatest number of farmers enrolled. In addition to WRP acres, the U.S. Fish and Wildlife Service has planted approximately 59,000 acres and State Wildlife Management Areas have planted 28,000 acres (Schoenholtz and others in prep). Information could not be found to document restoration efforts in other parts of the South. Programmatic success of restoration is determined by the number of trees surviving (>125/acres) on a WRP site after 3 years. Ecological success is difficult to determine and, due to the protracted nature of forested wetland restoration, will continue to be difficult to determine in the future.

Currently, restoration has attempted to re-establish forested wetland hydrology and vegetation on sites where these two characteristics have been removed. Thus, much of the restoration effort has been directed toward agricultural land. However, some wetland ecosystems, namely mineral soil pine flats, have been ecologically degraded by exclusion of natural disturbances like fire. Restoration of wetland ecologic processes, functions and biotic/abiotic linkages could be achieved if the disturbance regime were re-established. Lorimer (2001) points out the important role fire has historically played in maintaining plant species composition and structure in the South and its effects on wildlife abundance and distribution. Thompson and DeGraaf (2001) suggest that historic disturbance regimes can provide effective models for silviculture by substituting harvesting for fire. In largely forested regions like the Northeastern and Mid-Atlantic United States, harvesting can promote early successional growth and increase biodiversity (Thompson and others 1992, Welsh and Healy 1993, Hagan and others 1997). However, restoration of mineral soil pine flat wetlands can best be achieved by re-establishing frequent fire into these ecosystems.

Section 404 of the Clean Water Act regulations establishes procedures for permitting the discharge of solid fill material into wetlands. This program is administered primarily by the U.S. Army Corps of Engineers with oversight from the Environmental Protection Agency (EPA). If impacts due to these permitted activities are considered to be unavoidable, restoration of former wetlands is typically required to offset losses. Restoration of forested wetlands is a typical requirement of the Section 404 permitting program. Although many small-scale wetland restoration projects have been required in the history of the Section 404 program, the Corps and EPA maintain no systematic accounting of these projects or their success.

Little consistent data are available to track the amount of forested wetland mitigation that has been required or the amount that has actually been completed. It is even more difficult to ascribe success to many of the mitigation efforts that have been undertaken. Two studies in the South found that many of the mitigation projects proposed and carried out under the Section 404 program did not replace the wetlands originally impacted (Pfeifer and Kaiser 1995; Morgan and Roberts 1999). The National Research Council (1992) listed the following as reasons for unsuccessful mitigation in a regulatory context:

(1)Poor design of mitigation projects by individuals lacking sufficient expertise to address the complexities of wetland ecosystems.




(2) Landowners often prepare the least expensive and least time consuming plan acceptable to the regulatory agencies leading to "half-hearted" attempts to restore wetlands.




(3) Wetlands restored in the regulatory context are often small in size, widely separated from other wetlands, and threatened by adjacent landuses.




(4) After initial restoration wetland mitigation sites receive very little management.

For these reasons wetlands restored in the regulatory context may be less likely to achieve restoration goals. A recent report on compensating for wetland losses under the CWA concluded that the goal of no net loss of wetlands is not being met for wetland functions by the Section 404 mitigation program, despite progress over the last 20 years (National Research Council 2001).