Two threatened plants of the Surville Cliffs

Forest and Bird, Issue 300, 1 May 2001, Page 23

Two threatened plants of the Surville Cliffs

forms is exhibited by a local subspecies of Coprosma spathulata. Elsewhere Coprosma spathulata is an upright shrub reaching two metres tall: here it is a low-growing shrub producing long flexible stems up to five metres long, which occasionally root on coming in contact with soil in crevices. Repeated burning has opened up light levels on the clifftops. This in turn, has changed an environment which would have suited plants such as Coprosma spathulata subsp. "Surville" and the Surville hook grass, close relatives of which which prefer shade. Now Coprosma spathulata subsp. "Surville" is reduced to about 50 plants and the world population of Surville hook grass exists within a site of five square metres. Another blow for Coprosma spathulata subsp. "Surville" is that increased light levels, induced by fire, have created a favourable habitat for other colonising, light-demanding coprosma species such as karamu Coprosma lucida and Coprosma macrocarpa. All coprosmas have wind-borne pollen. This means that when the coprosmas flower, the pollen spectrum of the surrounding area will be dominated by the pollen of the more common light-loving plants. Thus it is possible that Coprosma spathulata subsp. "Surville" may become extinct through hybridisation. T= most extreme and remarkable example of the strange ‘ultramafic growth’