Ecological-economic evaluation of wetland management alternatives

A heavily impacted wetland in Jackson County, FL, USA was selected for this study. Several approaches involving different perspectives were initiated to postulate and test possible mechanisms of transport and transformation of Pb in the wetland environment. A macroscopic system analysis was conducted as well to evaluate the benefits of wetland ecosystem restoration. Microcosms containing cypress (Taxodium ascendens) and black gum (Nyssa sylvatica) seedlings were used as a wetland surrogate to assess the ecological effects of Pb and acidity on the wetland community. Three wetland management alternatives were proposed. These included land control, sediment excavation, and wetland restoration by replanting. An 'emergy'-based ecological-economic evaluation revealed that restoration of the wetland was the most beneficial option, with a net benefit of 15.2 x 10(17) and 57.4 x 10(17) solar emjoules (sej) for 20- and 62-year recovery times, respectively. The net benefit of this alternative is calculated to be $756 000 and $2 870 000 for the 20- and 62-year recovery periods, respectively, based on macroeconomic Values for the US economy in 1990 of 2.0 x 10(12) sej/$. (C) 1998 Elsevier Science B.V. All rights reserved.