Some environmental indicators related to feral pig activity in a Hawaiian rain forest.

摘要

Thesis begins with a thorough literature review regarding feral pigs, their success as an invasive species and their effects on native ecosystems worldwide and in Hawai'i. The location of the study area, Upper Hana Rain Forest, from 1524 to 2134 m elevation on the northeast outer slope of Haleakala, Maui, Hawai'i is described with detailed maps, and knowledge of its physical setting, vegetation, and feral pig history is summarized. Original research examined the relationship between various measures of feral pig activity and several environmental factors viz., the abundance of plant species used as food, the slope of the terrain, elevation, and density of earthworms--an important component of pig diet. Regression analyses indicated that only earthworm density was significantly related to pig activity. Increases in earthworm density were weakly associated with increased pig digging, but well related to increases in the total amount of pig activity detected.