Prevalence and economic value of feral swine damage to native habitat in three Florida state parks

Abstract

Feral swine (Sus scrofa) adversely affect the environment in many of the places where they have been introduced. Such is the case in Florida, but quantification and economic evaluation of the damage can provide objective bases for developing strategies to protect habitats. Swine damage to native wet pine-flatwoods at three state parks in Florida was monitored from winter 2002 to winter 2003. Economic valuations of damage were based on the US dollar amounts that wetland regulators have allowed permit applicants to spend in attempts to replace lost resources. The parks had different swine management histories and the damage patterns differed among them over time. Swine were intensively removed in 2000 from the first park, and it initially had the lowest habitat damage at 1.3%, but as a result of natural and artificial population growth this damage rose to 5.4% by the conclusion of the study, and was valued at US$ 19 193–36 498 ha⁻¹. The second park had no history of swine harvest and, over the monitoring period, damage escalated from 2.6%–6.4%, with an associated value of US$ 22 747–43 257 ha⁻¹. Swine were managed as game animals in the third park prior to its inclusion into the state parks system in 2000. Within this park, the proportion of area damaged decreased from 4.3%–1.5%, valued at US$ 5 331–10 138 ha⁻¹. This decrease may be a result of human activities associated with development of the park's infrastructure causing dispersal of animals conditioned to avoid humans by hunting. Damage was highly scattered in each park, as evidenced by a much higher proportion of sampling sites showing damage than the actual proportion of land area damaged. The dispersed nature of small amounts of damage would increase the effort required to recover habitat and thus damage value estimates are probably conservative. It was also impossible to incorporate values for such contingencies as swine impact to state and federally listed endangered plants in the parks, some of which are found nowhere else in the world.