Behavioral and demographic response of small Indian mongooses (Urva auropunctata) to experimental population reduction

Abstract

The small Indian mongoose (Urva auropunctata) is a non-native invasive species throughout the Caribbean and the primary terrestrial wildlife rabies reservoir on 4 islands in the region. In the 1970s and 1980s, island-wide attempts to control and eliminate mongoose rabies through culling or poisoning in Cuba and Grenada proved unsuccessful. On some islands, localized population reduction of mongooses is used to mitigate predation on endangered species or to reduce the nuisance and frequency of interactions with humans. However, the short- and medium-term demographic responses of mongooses to local population reduction and the impacts for infectious disease transmission remain unexplored. We conducted an experimental removal of mongooses across a 0.42-km² area of dry forest in St. Kitts. Employing capture-mark-recapture techniques, we quantified the demographic and behavioral responses of mongooses within the study area. We collected individual-level data using an automated radio-telemetry system, monitoring the daily presence of 19 collared mongooses for 7 months before and up to 7 weeks after experimental removals. The mongoose population density rebounded to pre-removal levels within 7 weeks of the removal, primarily because of the influx of reproductively active females. The proportion of juveniles increased from 1–3% before removals to 14% at 7 weeks after removals yet returned to baseline levels at 6 months after removals. The local immigration of mongooses to the site was evident through changes in capture per unit effort, observed as early as the first week after removals. Tagged mongooses that frequented the study area during the pre-removal period increased their daily presence for 5–30 days after removals. Our results indicate that a localized and intensive mongoose removal program targeting a high-density population has short-term but not long-term residual impacts to the population. Further investigation into contact rates among mongooses and space use among resident and immigrating individuals is essential to advance our understanding of the impacts of localized removals on short- and long-term mongoose population disease dynamics.