SAVING THE LANDFORMS AND ROCKS

Forest and Bird, Volume 20, Issue 3, 1 August 1989, Unnumbered Page

SAVING THE LANDFORMS AND ROCKS

By

Bruce Hayward

A new thrust is underway to protect important geological sites in New Zealand.

i Be ensure the survival of the best examples of the geological features and processes found in this country — many of which are under threat — the New Zealand earth science societies have begun compiling an inventory of all nationally and regionally important areas. The aim is to identify and then ensure the protection of a full cross-section of the natural landforms, geological features and soil types which best characterise each part of New Zealand.

Urgent Action Needed

Only rarely do most people think of conservation of our landforms, yet like our biotic heritage these have also suffered greatly at the hands of modern technology and increasing population pressure. Many still require vigilance or urgent action to save them. To date a somewhat random group of mostly spectacular landforms have found their way into the protected lands of the Department of Conservation or into local body reserves. Examples include Rangitoto, Waitomo, Ketetahi hot springs, Mt Egmont/ Taranaki, Punakaiki rocks, Fox and Franz Josef glaciers, Milford Sound and Moeraki boulders. Over the past 15 years, ten scientific reserves have also been established — Turakirae Head, Red Rocks (both Wellington), Chancet rocks (Marlborough), White Creek fault (Nelson), Target Gully shellbed and Hutchin-

son's quarry (Oamaru), Curio Bay, Otapiri Stream, Te Anau and Clifden (Southland). Once again the selection and establishment of these reserves has been rather random. The Southland reserves resulted from the actions of a keen enthusiast within the old Lands and Survey Department; several of the others were established after long campaigns to save the sites from immediate threats of destruction by quarrying or fossicking (see insets). By contrast, the new inventory has been divided into a number of categories, each of which is being compiled and assessed on a national basis using the combined experience and knowledge of the New Zealand earth science community. Features selected will illustrate the different stages of New Zealand's geological history and the physical processes which have combined to produce its present landscape. To date over 1,500 sites have been identified, documented and entered in the computerised data base. Categories so far completed are fossil sites, earthquake-related features, geothermal fields and Quartenary volcanoes and volcanic features (younger than two million years). Others underway include sedimentary rocks, older volcanic rocks, caves and karst, soils and geomorphological sites. Each listed site has been given ratings based on its scientific and educational value and its vulnerability to modification or

destruction by human activity. From these ratings a list is being drawn up giving priority for protection. The information from this inventory is formatted so that it can be easily combined with information from the PNA programme, Wetlands Inventory and NZ Archaeological Association site register, when assessing areas of New Zealand for protected status. Because earth science features in New

Zealand cover such a diverse range of types and sizes and are threatened by a vast array of human activities, they require a broad range of management measures.

Wide Range of Features

Features range in size from volcanic mountains (Egmont National Park) to single erratic boulders (Te Anau scientific reserve). They may be glacial cirques at the top of the

Southern Alps or fault scarps beneath Cook Strait; a vast underground cave network beneath Mt Arthur or a few square metres of unmodified soil beside the road in central Hawkes Bay; examples of destructional or constructional landforms (Ruamahunga landslide and Farewell Spit); the oldest fossils in New Zealand (Trilobite Rock, Northwest Nelson) or the type locality of the rare mineral tuhualite (Mayor Island). They are threatened, modified or destroyed

by almost everything we do to the land — forest clearance, afforestation, reclamation, erosion control, ploughing, housing subdivisions, recreational development, mining, agricultural practices, dams, roads, wetlands drainage, flood control and so on. So much has gone that the time has come for us to identify those features and sites we must protect from destruction by these activities. The best form of protection for many of our

landforms is by retention or return of their original natural vegetation, although some smaller landforms will lose much of their educational and scientific value if forest is allowed to return. Similarly, protection of examples of most of our active geological systems and features (eg, sand dunes rivers, glaciers) is best afforded by as little interference by humans as possible. Many geological sites are natural exposures

of rock in bluffs, seacliffs and river banks that rely on a steady rate of natural erosion to retain a fresh face. These sites are threatened by developments that reduce the erosion or river flow rates. Other important geological sites are in man-made exposures of rock, especially in quarries and rail and road cuttings. These often weather rapidly or are quickly obscured by vegetation, often promoted by hydroseeding. Old quarries are also favoured for rubbish

disposal or recreation lakes. Protection of these sites require measures that prevent their obstruction by rubbish or vegetation. There is a clear need to move away from the old path of random protection of sites, selected by pure chance or by their imminent threat of destruction. We also need to review the previous practice of protecting all scientifically important geological sites by Crown purchases and locking them up in scientific reserves. The strict controls that come with such status may suit a few fragile sites but many others are robust enough to withstand normal educational and scientific study without requiring a bureaucratic permit system. These sites merely need protection against modification and destruction by activities such as road widening, farm bulldozing and stock trampling. Conversely others may require management such as sheep grazing, vegetation spraying and periodic bulldozing to retain the sites’ values. Such measures have yet to be accepted practice in scientific reserves in this country, although they are becoming commonplace in other parts of the world. To help promote the concept of earth science conservation, the Nature Conservation Council has recently published an information booklet titled "Landforms and geological features: a case for preservation’’. It is available for $3.50 from the NCC, P O Box 12-200, Thorndon, Wellington.