Mangrove Restoration - Costs and Benefits of
Successful Ecological Restoration
Roy R. Lewis III
President, Lewis Environmental Services, Inc. P.O. Box 5430, Salt Springs, Florida, USA, 32134-5430.

Actual Costs of Restoration

Reported costs of mangrove restoration range from USD$ 225-216,000/ha (Teas 1977, Lewis 1981, Brockmeyer et al. 1997, Lewis 1999. These costs do not include the cost of any land purchase to provide a site for restoration. This three orders of magnitude range reflects the increases in cost associated with construction of sites.

The higher costs are associated with excavation of fill, or backfilling of an excavated area, to achieve a target restored site with the same general slope, and the exact tidal elevations relative to a benchmark as the reference site, to insure that the hydrology is correct (Lewis 1990a).
Another form of this hydrologic restoration, which is much less expensive, is to reconnect impounded mangroves to normal tidal influence (Turner and Lewis 1997, Brockmeyer et al. 1997). In fact the costs quoted by Brockmeyer are the lowest published costs at USD$225/ha. Figure 3 compares this cost with similar estimates by Lewis (1999), King and Bohlen (1994)(recently updated by King 1998) and Teas (1977).
These estimates range over three orders of magnitude! The key differences are: (1) the amount of soil material that needs to be excavated to restore or create the correct hydrology and; (2) the use of natural secondary succession without planting (or modifications such as hand collection and dispersal of seeds or seedlings without planting) versus costly nursery development and hand planting of young seedlings, or worst the use of very expensive 1-2 meter tall older saplings (Teas 1977).

Successful Ecological Restoration
Successful ecological restoration requires the successful creation or restoration by construction of tidal creeks and intertidal wetland platforms frequently inundated by tidal waters (Lewis 1999, 2000a, b). This excavation to restore the normal hydrology of the historical tidal creeks will be similar to efforts described in Roberts (1991), Whitman and Gilmore (1993) and Kurz et al. (1998). All three publications document the rapid recruitment to restored or created tidal marshes or mangrove/marsh plant communities in Florida, (the latter two publications concentrating on such projects in Tampa Bay) of 40 species of adult and juvenile fish species including red drum (Sciaenops ocellatus), spotted seatrout (Cynoscion nebulosus), snook (Centropomus undecimalis), spot (Leiostomus xanthurus), black drum (Pogonias cromis) and tarpon (Megalops atlanticus).

Cost/Benefit Ratios
Barbier (2000) discusses two examples where he estimates the annual benefits of mangrove associated fisheries. The first example is in Surat Thani, Thailand, where the author is working on a large scale (800 ha) mangrove restoration effort to convert abandoned shrimp aquaculture ponds back to there former condition as mangrove forests. Based upon actual costs generated by the Royal Forest Department in doing successful mangrove restoration, these forests can be restored using just hydrologic restoration for USD$200/ha, or USD$700/ha if planted.

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