Changes in habitat use and distribution of mouflon in the Kahuku Unit of Hawai‘i Volcanoes National Park

Abstract

European mouflon sheep (Ovis gmelini musimon) were introduced to Kahuku Ranch on Hawai‘i Island in 1968 and 1974 for trophy hunting and have been detrimental to the native ecosystem by trampling, bark stripping, and browsing vegetation. In 2003, Hawai‘i Volcanoes National Park acquired Kahuku Ranch and managers began removing mouflon. The objective of this project was to determine whether hunting has changed the distribution of mouflon in Kahuku, to better understand mouflon behaviour and to expedite eradication efforts. Locations from hunting and GPS telemetry data during 2007–14 were used to determine the effect of hunting on mouflon distribution by examining distance to roads and habitat use. Mouflon seemed to avoid roads after hunting pressure increased and their distribution within vegetation types changed over time. Mouflon without hunting pressure were detected in native shrub habitat in 68% of all observations. Hunted mouflon were encountered less in native shrub habitat and more in other habitats including open forest, closed forest, and areas with no vegetation. These changes suggest that hunting has influenced the distribution of mouflon over time away from native shrub and into other vegetation types where they may be more difficult to control.