Feral swine disturbance at important archaeological sites

Abstract

Feral swine are well known as environmentally destructive invasive animals in many areas around the world, where they degrade native habitats, harm rare plant and animal species, damage agricultural interests, and spread disease. We provide the first quantification of their potential as agents of disturbance at archaeological sites. Our study was conducted in south-central Florida at Avon Park Air Force Range, a base comprising over 40,000 ha and containing many archaeological sites. To determine the identifiable prevalence of feral swine disturbance, we examined 36 sites registered with the Florida State Historic Preservation Office and also eligible for inclusion in the National Register of Historic Places (NRHP). Moreover, we evaluated the extent of swine disturbance at a prehistoric site of extraordinary significance to Florida's prehistory, "Dead Cow." Fifteen of the 36 NRHP-eligible sites (42 %) had some level of swine disturbance, including 14 of 30 (47 %) sites known to have artifacts within 20 cm of the surface (well within swine rooting depths). At the Dead Cow site, we documented disturbance at 74 % of shovel test points. Sites with shallow artifact depositions appeared highly vulnerable to disturbance by feral swine, threatening destruction of artifact stratigraphy and provenience. Our observations likely are a minimal representation of accumulated damage. These irreplaceable sites tell the area's land use story across the millennia. That they are under threat from feral swine should serve broad notice of potential threats that feral swine may pose to archaeological sites globally, making effective swine management imperative for site protection.

Prevalence of feral swine disturbance at important archaeological sites over a large landscape in Florida

“…We were particularly interested in identifying those sites most susceptible to swine disturbance based on artifact depth. Swine are known to root as deep as 1 m18 and easily root to 20 cm in depth121920 and their rooting has been documented in the literature as deep as 45 cm in Florida21. Among the 293 sites we surveyed, 261 (90%) were known to have artifacts within 20 cm of the surface and 247 (85%) were known to have artifacts within 10 cm of the surface (Table 1).…”

“…Because swine rooting commonly exceeds 20 cm in depth (e.g.refs 12, 19, 20 and 22) and 85% of our surveyed archaeological sites had been identified as having artifacts within 10 cm of the surface, and 90% had artifacts within 20 cm of the surface, the 42% rooting prevalence across the base’s archaeological sites revealed that a substantial percentage of sites were at risk for direct swine damage to artifacts, in addition to disturbance of their artifact stratigraphy and provenience. Although feral swine are capable of rooting to a meter in depth (e.g.ref.…”

“…Archaeological sites are similarly vulnerable to swine rooting, which has been well-documented as so directly destructive to sensitive habitats and agriculture412. A wet climate and soft soils make much of the Florida landscape and the archaeological sites within it, vulnerable to disturbance by feral swine.…”

“…Feral swine activity also accelerates erosion, further exacerbating their damage13. The threat for feral swine to disturb archaeological sites has been recognized in various corners of the world12141516. However there has been very little published documentation on the prevalence of feral swine disturbance to archaeological sites across an extensive landscape, nor has there been much published quantification of the scale of swine disturbance within archaeological sites.…”

Policy and Regulation

“…Feral swine have experienced signi cant range expansion over the past 30 years, in part because a subset of the human population wants to hunt them closer to home (Spencer et al 2005;Acevedo et al 2006;Saito et al 2012;Bevins et al 2014). This expansion has increased con icts with agriculture and humans, triggering several assessments of the costs and bene ts of feral swine in different locations (e.g., Higginbotham et al 2008;Campbell and Long 2009;Siemann et al 2009;Ober et al 2011;Engeman et al 2012;Mengak 2012;Campbell et al 2013;Bevins et al 2014). In addition, there has been considerable research on the increasing management con icts stemming from feral swine expansion (e.g., Weeks and Packard 2009;Honda and Kawauchi 2011;Koichi et al 2013;Warner and Kinslow 2013).…”