Threats to Ecology

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

Threats to Ecology

— Dean Baigent-Mercer

etween 1968 and 1984, the major threat to Surville Cliffs plants was the quarrying of serpentinite, and associated mining activities. Serpentinite is a mineral which helps create a free-flowing mixture of fertiliser for use in aerial topdressing. When it is removed from the mine, plant recovery there is extremely slow. With cessation of quarrying in 1984, fire, animal-browse and trampling, and the introduction of weeds in stock faeces became the major threats to the reserve. In April 1995, these concerns were significantly reduced by the erection of an electric fence across the North Cape isthmus by the Department of Conservation, to exclude feral animals and human traffic. All visitors need permits to go to the North Cape Scientific Reserve from DoC, and from the Muriwhenua

Corporation through whose land the four-wheel-drive track passes. Ongoing pest control is vital. Now that all the feral horses and cattle have been removed, rabbit and possum removal is in progress. Unfortunately, locals have occasionally liberated wild pigs over the fence. Weeds are the prominent remaining threat, especially South American pampas grass, and Australian prickly

and downy hakea, all of which can thrive on ultramafic rock. An eradication programme for these weeds has begun. Although herbicides are not needed to eliminate the two hakea species, it is a labour-intensive job. All plant material has to be removed from the area, as the seedpods will otherwise dry out, split, and release the winged seeds.