The introduction of swine (Sus scrofa) has adversely affected the environment of many natural habitats throughout the world. Basin marshes are dwindling ecosystems in Florida that are especially vulnerable to damage by feral swine. In January 2003, the estimated amount of swine damage to the exposed portion of the last remnant of a basin marsh system in Savannas Preserve State Park (SPSP) was 19% (an area of 5 ha). Economic valuations for the swine damage were based on the monetary amounts that wetland regulators have allowed permit applicants to spend in mitigation attempts to replace lost wetland resources. In 2003, the area of natural habitat damaged by swine had a total value of US$ 1 238 760–4 036 290. The SPSP implemented a contract for swine control throughout 2003 in all areas of the Park. The damage to the basin marsh was re-estimated in January 2004, after swine removal. The damage sampling transects remained the same as the 2003 survey, but damage was significantly reduced, with 31% of sampling transects showing damage in January 2004 versus 92% in January 2003. Similarly, the total area of swine damage had decreased to 0.95 ha, and the value of the lost habitat had been reduced to US$ 235 355–766 865, an economic benefit of US$ 1 003 355–3 269 265. The benefit-cost ratio (BCR) relating the economic value of the damage reduction against the swine control costs (not all swine control in the park was carried out in the vicinity of the basin marsh) was conservatively estimated at 134–436. When estimating costs for swine control in the vicinity of the marsh based on the proportional number of swine removed there as compared to the Park as a whole, the BCR increased to 480–1562. Benefits of swine removal are very high relative to the costs of control.