Vegetation Assessment to Understand the Effect of Feral Goat Populations on Native Flora Composition

A vegetation assessment was conducted to understand the effect of feral goats (Capra hircus) on the vegetation of Isolated Hill Scenic Reserve located in Southern Marlborough. New Zealand forests evolved without the pressure of mammalian herbivores but following human settlement they became subject to intensive browsing following the introduction of exotic mammals. This study focuses on the presence of feral goats. Interest arises from the settlement of other countries and the subsequent liberations of feral goats which are now considered to be responsible for the significant removal of native vegetation as well as playing a dominant role in erosion. Changes in plant communities have occurred with the pressure of goat browsing as well as secondary effects such as habitat degradation The purpose of this research was to investigate the changes in plant species composition since the initial and subsequent research conducted in 1985 and 1994. An analysis of previous work on the diet of multiple introduced ungulate species was also conducted. Previous studies were not limited to only feral goat studies and included other introduced herbivores to provide a broad overview of diets. The New Zealand Forest Service implemented a programme for monitoring the seral forest in Isolated Hill Scenic Reserve using standard Forest Service vegetation quadrants. 32 quadrants were established, including three exclosures, in various locations around the Reserve to allow assessment of feral goat impacts on seral forests (forest whose constituents are of varied age classes). Nine forest service plots, including three exclosures were re-measured and an additional nine plots were measured. Given the progression of vegetation change that has been observed during the course of this study, both analytically and observationally, Isolated Hill Scenic Reserve in its current state, involving the notable presence of feral goats and the vegetation types will continue to diminish in diversity