Evaluation of Soil Erosion and Changes in Plant Communities Resulting from Rooting Behavior of Invasive Wild Pigs on the Kerr Wildlife Management Area

Joshua R. Coward, Ryan S. Luna, Ryan O’Shaughnessy, Bonnie J. Warnock, and John Kinsey (Kerr Wildlife Management Area)

Wild pigs (Sus scrofa) are a destructive invasive species that cause an estimated $1.5 billion in combined costs of control efforts and damage mitigation annually. They exhibit foraging behavior that is destructive to soil structure and morphology and disturb the plant communities they occupy. Little research has been conducted in Texas to evaluate how rooting behavior affects soil composition and plant communities after rooting events.

Our objectives for this project include identifying potential increases in soil erosion after pig rooting occurs; changes in soil texture, moisture content, pH and electrical conductivity, organic and inorganic carbon, nitrogen and bulk densities; and determine how plant communities might change after rooting events. To measure soil erosion, we installed 14 erosion bridges in pig exclosures. In 2018, these bridges were sampled weekly from January-September. To determine how soil components are affected, we sampled pig rooting areas to a depth of 15 cm and conducted bulk density samples using the compliant cavity method.

Soil samples were later analyzed in a laboratory to determine whether soil components were significantly impacted compared to those of control sites. To determine how plant communities were affected, we sampled vegetation to determine cover class estimates and species presence in rooted areas compared to previously conducted transects (2016 and 2017). We also analyzed vegetation cover classes and presence/absence data to determine how plant communities change after a rooting event. This research will help inform land managers about the impacts wild pigs have on soil composition and plant communities during rooting events.

Funding Source: Texas Parks and Wildlife Department, Region 2