Type: report

Article abstract: Wild pigs (Sus scrofa) are a large ungulate native to Eurasia and North Africa which are now widely distributed as non-indigenous species in many areas, including California. Because of their adaptability to new environments, reproductive capabilities and foraging behaviors, wild pigs cause numerous damages to natural areas and wildlife throughout the state. To assess these damages we developed and distributed a survey to managers of all identifiable natural areas in California. Our objective was to identify ecological and monetary costs associated with managing natural areas within the current range of wild pigs. Surveys were mailed to 333 representatives of natural areas across California between mid December 2006 and early January 2007, and by July 2007 we had received information on 573 individual natural areas. Survey results indicated that wild pigs were present at 137 natural area units. Managers of most of these natural areas reported moderate to high concern regarding presence of wild pigs related to rooting and other disturbances in grassland, oak woodland areas and riparian habitats. Many visitors to natural areas with wild pigs commented to managers on rooting damage and negative interactions with wild pigs while hiking or camping, while others asked about hunting access. Some adjacent landowners wanted managers of natural areas with wild pigs to reduce pig numbers, whereas other nearby landowners were less bothered and likely benefited by enhanced hunting on their properties. A significant subset of the 137 natural areas with wild pigs reported using some combination of lethal and non-lethal methods to reduce damages from wild pigs. A key trend identified from the survey was that increased numbers of natural areas developed management programs to reduce wild pig damages in recent years compared to in the past. The overall minimum economic costs to all natural area management entities that reported wild pig-related management costs were $11,300,132 over the last 3 years and $18,672,023 overall. However, this was a conservative estimate because the majority of expenditures were associated with exclusion or removal of wild pigs, and not representative of damages incurred to the natural resources themselves. There is a need for reliable methods of assigning monetarily value to undisturbed natural areas and native plants and animals to provide a consistent economic presentation of actual resource damage caused by wild pigs. Non-lethal control metho