Feral swine management for conservation of an imperiled wetland habitat: Florida’s vanishing seepage slopes

Abstract

Force Base containing some of the largest tracts. Feral swine damage is one of the greatest threats to this wetland habitat. We conducted a multi-year study to evaluate the impacts of sport hunting and supplemental swine removal on damage to seepage slopes. Prior to initiation of removal in 2003, swine damage to seepage slopes in the portion of the base closed to hunting averaged 25.0%, over twice the 10.9% losses in the portion open to hunting. After less than one year of supplemental removal, damage in the closed-to-hunting area dropped to 7.2%. Although supplemental removal was not applied in the open hunting area, damage dropped significantly to 5.6%, statistically indistinguishable from the swine-controlled (closed) portion. After another year of removal, average damage in the closed hunting area dropped further to 5.6%, while the open hunting area dropped to 4.3%, again statistically indistinguishable. Even though removal was only applied to the area closed to hunting, it also produced damage reductions in the open hunting area, as swine were free to move among areas. Declines in damage following implementation of removal corresponded with large drops in swine population indices for the base. Economic valuations of seepage slope damage losses demonstrated substantial benefit-cost ratios for application of removal.

Monitoring wild pig populations: a review of methods

“…Consider a tracking plot example for collecting data. Many species preferentially use the path of least resistance for travel, which in many areas includes dirt roads or tracks as travel ways, and this has been documented for wild pigs in many areas of the world (Allen and Engeman 1995;Elledge 2011;Engeman et al 2007;Jiang et al 2006;Theurkauf and Rouys 2008).…”

“…For tracking plot observations, the number of intrusions by a species into a tracking plot is commonly used to monitor many wildlife species globally (e.g., Engeman et al 2001Engeman et al , 2007USDA 2011).…”

“…Tracking plots have been successfully used to monitor wild pig abundance in a variety of circumstances using a variety of plot configurations (e.g., Allen et al 1996;Engeman et al 2001Engeman et al , 2002Engeman et al , 2007USDA 2011). In each case, plots were passive (no attractants) and placed on dirt roads or tracks to intercept the normal daily activities of the animals.…”

“…Road segments several meters in length have been effective in Australia (Allen et al 1996), Florida (Engeman et al 2002), and Texas (Engeman et al 2001). For some large monitoring areas, road segments 0.8 to 1.6 km have been used as plots (Engeman et al 2007;USDA 2011). Road surfaces for shorter plots are typically prepared by hand (smoothed with rake or broom), whereas the road surfaces for the longer plots are prepared mechanically by devices towed behind vehicles (chains, weighted chain-link fencing, and many other possibilities).…”

“…The species has a broad native range and even broader range as an exotic invasive species (e.g., Massei et al 2011). The negative impacts of native or invasive wild pigs on human activities range from damage to agricultural crops to livestock predation, reduction of species abundance in plant and animal communities (especially in fragile wetlands habitats), and threats to rare species and to wild pigs being a reservoir for disease transmission to livestock or humans (Choquenot et al 1997;Corn et al 2005Corn et al , 2009Engeman et al 2007Engeman et al , 2010Engeman et al , 2011Massei and Genov 2004;Ruiz-Fons et al 2008;Seward et al 2004). The species was listed as among 100 of the "World's Worst" invaders by the IUCN's Invasive Species Specialist Group (Lowe et al 2004).…”