The vegetation of Maud Island, Marlborough, New Zealand

Abstract

Maud Island (Te Hoiere - "a long paddle or mighty pull") is a moderately sized island of 309 hectares, located in the Pelorus Sound (41°, 02 'S, 173° 54 'E) Marlborough, at the north-east end of the South Island of New Zealand. It has a long history of human modification and impacts since its colonisation by Maori and early Europeans. The vegetation of Maud Island has been studied in the 1980's and again in the early 1990's. The objectives of this study were to (1) describe how the vascular plant communities vary in species composition across Maud Island, (2) determine which environmental factors are important predictors of the variation in species composition of Maud Island plant communities, and (3) describe the pattern of succession of the plant communities on Maud Island over the last twenty years. In this 2001 study, I comprehensively sampled the vegetation on Maud Island using a Reconnaissance Description Procedure in a total of 158 plots across the island and compared these results to previous descriptions. I also retook photos at permanent photo points to provide a visual comparison of vegetation change. In total, 219 plant species were identified; 177 species occurred within the plots and 42 additional species were observed while walking around the coastline and walking tracks. Six dominant plant species occurred in over 70% of the plots. They were Pteridium esculentum, Pseudopanax arboreus, Hebe stricta var. stricta, Melicytus ramiflorus, Ozothamnus leptophylla and Coprosma robusta. Two-Way Indicator Species Analysis resulted in the description of eight different plant communities on the island. Detrended correspondence analysis showed a high degree of turnover in species composition among these communities. Canonical correspondence analysis showed that slope and moisture were particularly important predictors of variation in plant species composition. The environmental factors that best predicted to variation communities were slope, moisture, and a gradient in historical disturbance. Comparisons of present and past vegetation maps and photos (ground and aerial) showed, in terms of the successional pathways of the vegetation on Maud Island, that over time, the vegetation is reverting from short stature grassland and scrub to predominantly forest scrub and young secondary forest.