EDAPHIC INFLUENCES ON A NEW-ZEALAND ULTRAMAFIC (SERPENTINE) FLORA - ASTATISTICAL APPROACH

Ultramafic (''serpentine'') soils from and adjacent to the Dun Mountai n Ophiolitic Belt, South Island, New Zealand were analysed for 11 elem ents in order to establish to what degree edaphic factors influenced t he character of the overlying vegetation. Using principal components a nalysis with a mutual plot of the first two principal components, invo lving the total elemental concentrations in the soils, it was possible to divide the soils into 6 virtually nonoverlapping fields, each of w hich represented a specific vegetation community. Component 1 was esse ntially an ''ultramafic plot'' with heavy loadings from the elements c hromium, cobalt, iron, magnesium, manganese, and nickel. Component 2 w as a ''non ultramafic'' plot with heavy loadings from aluminium, coppe r and zinc. For elements extracted from the soils at pH 5.9, discrimin ation was somewhat poorer but confirmed the great importance of magnes ium and nickel as controlling elements for the serpentine vegetation. It was concluded that the results indicated the overriding importance of edaphic factors in controlling the serpentine vegetation.