Tussock grassland reserve design: some practical considerations
- Conservation Commission of the Northern Territory, Darwin, N. T., Australia
- Botany Department, University of Otago, Dunedin
Historically, design of the few tussock grassland reserves has been constrained by individual situations, indifference of the bureaucracy and the lack of generally approved design criteria. Since 1983, the Protected Natural Area Programme (PNAP) has laid the foundation for an adequate representation of tussock grasslands among other ecosystems in the New Zealand reserves system. To retain integrity and long- term viability of reserves Recommended Areas for Protection (RAPs) ideally should embrace whole catchments, include the range of altitudes, aspects, fertilities, etc., in proportion to their original extent, and be of adequate size (c. 1000 ha) and regular shape. The reliability of flora, vegetation and landform to adequately provide for other components of tussock grassland ecosystems that are less often surveyed, particularly soils and invertebrate fauna, requires further scientific assessment.
The subsequent phase of implementation may confront problems of owner-lessee attitudes and effects of large protected natural areas on the management and economics of individual properties. A system of first and second priority RAPs identified as part of the PNAP surveys are relevant in this context.
Research is inadequate as to minimum viable size for various tussock grassland ecosystems as an aid to assess the value of fragments of indigenous grassland which fall short of fulfilling design criteria.
As few if any tussock areas remain unmodified by human, particularly European, influences, decisions on the level of modification acceptable for recognition of an RAP are important and inevitably subjective. The PNAP recognition of pre-European as the relevant bench mark on which to base human impacts is accepted but evaluated.
Since apparently satisfactory RAPs are being identified on areas which have experienced more than a century of extensive pastoralism, arguments for continuation of existing management regimes, given the impracticability of perimeter fencing at higher altitudes, require consideration and evaluation. The principle of full protection for some areas must also be accepted but should be assessed initially with representative exclosures. This should also allay fears of uncontrolled weed growth, particularly at lower altitudes, among managers and some others.
Discussions and negotiations with the affected owner/lessee on implementation of RAPs should cover the full range of options except that QEII Trust covenants are inappropriate on pastoral leasehold land.