Comparison of three indirect methods for density estimation of the wild boar (Sus scrofa) in different habitats in South Korea

Abstract

Increasing human-wild boar conflicts in South Korea have led to a demand for effective management strategies. Absolute abundance, rather than relative indices, is needed for the long-term monitoring and population control of wild boars. Indirect methods for density estimation have become increasingly popular because they are cost-effective and do not have the risk of capture probability bias. We compared three indirect methods, including the non-invasive capture-recapture model (NICRM), random encounter model (REM), and fecal standing crop (FSC), in two different sites characterized by specific habitats (urban and agricultural environments). NICRM and REM reflected population fluctuation and hunting intensity assumptions at both sites; however, FSC did not reflect the latter. While using NICRM, efforts are needed for achieving a low genotyping error rate; this model would achieve more reliable results in low-density areas. REM with accurate parameter information (i.e., daily range, detection zone, and camera placement) could be the most effective density estimation method for long-term monitoring in South Korean environments. Conversely, FSC may not be recommended because of many factors, such as decomposition rate, rainfall, biased distribution of feces that might affect pellet groups. Additionally, the density estimates from this study can provide information for developing effective management strategies in South Korean environments.