Vegetation/environment relationships in lowland and montane vegetation of the Kawarau Gorge, Central Otago, New Zealand

Abstract

Abstract Vegetation patterns In the valley of the Kawarau Gorge, Central Otago, were examined using ordination and classification. Two-way Indicator Species Analysis revealed fifteen communities, many of which were dominated by the shrubs Rosa rubiginosa and Discaria toumatou, but which mostly differed in understorey species. Other distinct communities included scabweed, thyme/ brier, pasture, bracken, dense shrubland, and subalpine snow tussock grassland. Classification divisions were correlated to the 21 environmental factors measured at each site by using rank correlation coefficients. Various factors distinguished some of the fifteen communities, while higher level classification divisions were correlated with a number of factors Including position within the valley, altitude, aspect, grazing by rabbits, gravel, soil acidity, soil carbon, and the nutrients potassium and magnesium. Detrended Correspondence Analysis revealed a very clear xeric/mesic vegetation gradient In the first axis, and a poorly de...