Evaluating detection and monitoring tools for incipient and relictual non-native ungulate populations

Abstract

Hawai‘i Volcanoes National Park (HAVO) encompasses 1,308 km2 on Hawai‘i Island. The park harbors endemic plants and animals which are threatened by a variety of invasive species. Introduced ungulates have caused sharp declines of numerous endemic species and have converted ecosystems to novel grazing systems in many cases. Local ranchers and the Territorial Government of Hawai‘i had long conducted regional ungulate control even prior to the establishment of HAVO in 1916. In 1995 the park’s hunting team began a new hunt database that allowed managers to review hunt effort and effectiveness in each management unit. Target species included feral pigs (Sus scrofa), European mouflon sheep (Ovis gmelini musimon), feral goats (Capra hircus) and wild cattle (Bos taurus). Hunters removed 1,204 feral pigs from HAVO over a 19-year period (1996‒2014). A variety of methods were employed, but trapping, snaring and ground hunts with dogs accounted for the most kills. Trapping yielded the most animals per unit effort. Hunters and volunteers removed 6,657 mouflon from HAVO; 6,601 of those were from the 468 km2 Kahuku Unit. Aerial hunts yielded the most animals followed by ground hunt methods. Hunters completed eradications of goats in several management units over an 18-year period (1997‒2014) when they removed the last 239 known individuals in HAVO primarily with aerial hunts. There have also been seven cattle and five feral dogs (Canis familiaris) removed from HAVO.