Hawai'i conservation alliance

2011 Best Student Oral Presentation

Movement Patterns and Habitat Utilization of Nonnative Feral Goats in Hawaiian Dryland Montane Landscapes.

Mark Chynoweth 1, Christopher Lepczyk1, Creighton Litton1, Susan Cordell2, James Kellner3

1Department of Natural Resources and Environmental Management, University of Hawaii at Manoa, Honolulu, HI, USA, 2Institute of Pacific Islands Forestry, USDA Forest Service, Hilo, HI, USA, 3Department of Geography, University of Maryland, College Park, MD, USA

Large populations of nonnative, feral goats (Capra hircus) are present on five of the eight main Hawaiian Islands where they have been notable components of the landscape for at least a century. However, very little information exists on their spatial and temporal patterns of habitat use. Such an understanding is essential to manage not only the goats, but also the native and nonnative plant communities that they inhabit. We deployed GPS satellite collars (n = 12) to track movement patterns of feral goats every two hours for one year in one of the last remaining montane dry forest habitats on the Island of Hawai‘i in the Pohakoloa Training Area. Movement data from collars were combined with land cover data and remotely sensed imagery (NASA's MODIS sensor; Carnegie Airborne Observatory LiDAR) to quantify how movement patterns are correlated with seasonal changes in vegetation dynamics and plant community composition. Using a Euclidean distance-based analysis, results of this work indicate that feral goats did not use habitat uniformly, but rather showed preference for native-dominated shrublands during the day and barren lava at night. Males generally had larger home ranges (27.8 km2) than females (12.8 km2). Displacement data also suggested that three movement phases ocurr over diel scales: (i) resting; (ii) searching; and (iii) foraging. Ultimately, the results of this study can be used in the context of both the conservation and restoration of native Hawaiian dry forest ecosystems, arguably the most degraded ecosystem in the Hawaiian Islands.