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PAPAROA NATIONAL PARK MANAGEMENT PLANNING - THE KARST & CAVE RESOURCE - THE ISSUES AND DRAFT MANAGEMENT POLICIES

Kevan A. Wilde, District Conservator, Department of Conservation, Buller District

ABSTRACT

The following paper presents a brief description of the karst and cave resource of the Paparoa National Park; a summary of the management issues; and draft management policies.

1.0 INTRODUCTION

The main karst feature of the park is the synclinal plateau extending northwards from Punakaiki. This synclinal plateau supports the most extensive unmodified lowland karst landscape in New Zealand.

The karst features of the syncline comprise polygonal depressions, karren, arches, sunken and blind valleys, extensive cave systems, broad low-lying sea-planed Tertiary karst landforms, marine terraces, and coastal blowholes.

Another major feature of the syncline, although strictly speaking not karst by definition, are the deep down-cut limestone canyons formed by westward flowing rivers. These major rivers are the Fox, Punakaiki and Pororari.

Collectively these features form an outstanding, nationally significant lowland karst resource unparalleled elsewhere in New Zealand's system of national parks.

The major issues in respect of the management of the karst of the park are those of protection and maintenance of scientific, environmental and aesthetic values along with public access and recreational use, and adjoining land uses and their compatibility with those values. In order to achieve this 'balance' a pro-active approach must be taken and appropriate policy incorporated into the management plan.

2.0 THE KARST RESOURCE

As previously stated, one of the major features of the park is the limestone syncline that lies parallel with the west of the main range and extends north from the Punakaiki River to the Tiropahi River. The influence of this structure has lead to distinctive drainage patterns, soils and vegetation as well as many significant caves and other features such as depressions (dolines), sunken and blind valleys, and subterranean waterways.

The unmodified nature of the Punakaiki karst is very significant, because the natural operation of hydrological and chemical processes within karst depends upon the integrity of the overlying vegetation.

The importance of an intact vegetation cover is well known with respect to floral and faunal values, but is easily overlooked in the case of natural physical and chemical processes. The karst of the park is therefore of considerable scientific importance because it is the only extensive lowland karst in New Zealand with an almost undisturbed forest cover; thus permitting biological, chemical, and physical processes to operate in an entirely natural manner (Williams, 1982)

The karst landscape is a feature of interest as an entity, but also contains landforms within it that are important. These are:

Gorges: The limestone plateaux are dissected by a series of gorges bounded by white limestone cliffs. These are not strictly karst features because normal river erosion rather than solution has been the dominant process in their formation. Nevertheless, gorges are characteristic of karst areas because of the ability of mechanically strong limestone to support steep slopes. The gorges of the study area are particularly interesting because of the caves which open out into their sides, for example, Fox River Cave and Ananui Cave.

Disappearing and Reappearing Streams: Sinking streams and the springs at which they resurge are characteristic features of the karst of the park. Bullock Creek is the best example of a sinking stream in the district, with its resurgence in Cave Creek South. This system also provides the best example in New Zealand of subterranean river capture, with the waters of Bullock Creek being diverted south to the watershed of the neighbouring Pororari River. Other important examples of sinking streams are Cave Creek North, which drains to the Fox River Cave, and Ananui Creek, which flows through Metro Cave. These streams disappear down 'stream-sinks', or swallow holes, at the end of 'blind valleys' (Williams, 1982).

Caves: The most important caves of the study area are:

  1. Ananui Cave for its subfossil fauna, passage levels, speleothems, and the light it sheds on the rate of uplift of this part of New Zealand. (Williams, 1982)
  2. Bullock Creek Cave system, especially Xanadu, as superb examples of floodwater maze caves (caves formed under the hydrostatic pressure of the invading floodwaters penetrating into complex joint networks) (Williams, 1982)
  3. Cave Creek South cave system, a significant example of a complex river cave, hydrologically related to Bullock Creek and the Bullock Creek Cave system(Williams, 1982)
  4. Armageddon - Fox River Cave system, a fine example of a river cave, particularly notable for a magnificent cylindrical, white, vertical-walled collapse depression above the downstream end of the Armageddon section(Williams, 1982)
  5. Babylon Cave, parallel, and geomorphologically related, to the Armageddon-Fox River system this cave is therefore also a significant example of a large river cave. Of particular interest is the extensive biokarst (karst form developed from the relationship between photosynthetic plants, chemical and physical processes) in the entrance and twilight zone (Wilde, 1989).

Although many caves are known within the area, the densely forested nature of the karst plateaux, which makes exploration difficult, enhances the possibility that further caves exist. As an example, seven new caves and two arches have been discovered during the time of the preparation of this paper (Wood, pers comm).

Dolines: The karst plateaux are honeycombed with adjoining dolines. These bowl-shaped features are up to a few hundred metres across and maybe a hundred metres deep, formed by run-off to a central low point escaping underground (polygonal karst) (Williams, 1982).

Karren: A widespread feature of the park, with the Punakaiki Blowholes being the most notable. The layered effect of this feature was formed by the erosion of thin bands of soft mudstone interbedded with the more erosion resistant limestone (DSIR, 1987).

The following is a summary of the karst features and known associated biological values within the park:

An outlier to the north of the park contains Ananui Caves (Metro or Nile River Cave) which is approximately 7km long and well decorated. Troglobitic invertebrates, a rare cave beetle, glowworms, and subfossil avifauna and tuatara are present (Wilde and Millar, 1989). Entry by permit only.

3.0 THE ISSUES - PROTECTION AND USE

The main issues in relation to the karst and caves of the park are protection of scientific, environmental and aesthetic values, public access, public safety and adjacent land uses.

The biological and physical processes and values of the park's karst ecosystems and associated caves combined with their vulnerability requires sensitive, informed and pro-active management.

Activities within and outside the park may adversely affect the natural condition of the park's karst and cave resources. Of particular importance are the behaviour and quality of water, and the maintenance of existing hydrological regimes.

Karst and cave catchments may often extend beyond known surface catchment boundaries. Activities such as logging, clearance of vegetation, mining, quarrying, hydro-electrical installations, farming, roading, domestic and tourism development can potentially place the resource under stress or cause irreversible damage.

Such activities adjoining (or, where permissible, within) the park unless carefully planned, controlled and monitored, or even excluded may result in one or more of the following unacceptable impacts: increased sedimentation and siltation of waterways and caves; disturbance of natural hydrological regimes; domestic, chemical and agricultural pollution of karst aquifers; and interference with natural chemical, physical and biological processes.

Uncontrolled tourism and recreational use of karst and caves may also cause unacceptable and irreversible damage. Karst soil profiles are often very shallow and moist and cannot withstand excessive or inappropriate use. Plant communities on karst, and in cave entrances and twilight zones, are therefore vulnerable to destruction by trampling and ad hoc development.

It is now accepted that caves, in particular, have no carrying capacity. Speleothems (cave decorations such as stalactites and stalagmites, crystal floors etc) cave fauna habitat (such as floor sediments and streamways, and aquatic substrates) are vulnerable to unintentional damage and vandalism, and once damaged or destroyed have little or no ability to regenerate to their original state (at least in respect of speleothems) other than within geological time frames (e.g. thousands of years), if at all.

Because of the often fragile and vulnerable nature of karst and cave ecosystems, controls on access and types of use need to be addressed by appropriate management policies. Where possible robust caves will be identified for general public inspection.

Apart from protecting karst and caves from damage and inappropriate use, there is the significant issue of controlling use for safety reasons.

Caves by their very nature are often dangerous for the inexperienced, and because of high rainfall and relatively extensive catchments many of the caves in the park are subject to rapid flooding. Management controls and policy relating to access to caves must also therefore take account of public safety.

The issues relating to general public access to caves includes high public expectation to visit caves; very few safe and robust caves are currently known to exist in the park; controls are often controversial and difficult to enforce; and there can be considerable difficulty in differentiating between experienced bona fide cavers (whose safety should be their own responsibility) and others.

Over 30 named caves and cave systems have been identified within the park's karst, and many more undoubtedly remain to be discovered. The park is considered by recreational cavers as one of the three main caving areas in New Zealand. The recreational caving opportunities represented by the park's karst and caves vary considerably in their degree of difficulty, challenge and danger.

With the exception of the Punakaiki Cavern (located immediately adjacent to SH 6) and Ananui (Metro, Nile River) Cave (entry to which is currently controlled by permit), the most accessible and safest cave for general public inspection is the Fox River 'tourist' Cave.

Other caves and karst features which are potentially suitable for development for viewing by the general public are Cave Creek South, Cataract Pot and associated dolines, grykes and karren. It is emphasised that these areas are not considered to be suitable for general public access until information systems, tracks, safety barriers and viewing platforms are established.

Parts of Ananui Caves are particularly suitable for interpretation and guided inspection for the general public. That is, providing adequate management strategies, controls and in situ development are established to protect the cave's environmental and aesthetic values.

Most caves in the park are not considered to be suitable for general public inspection, either because they are physically dangerous to the inexperienced, or because of their fragile, vulnerable and potentially at-risk scientific and/or aesthetic values.

Caving is recognised as a specialist form of recreation, and because bona fide cavers explore, survey, map and document karst and caves as their major recreational interest they are experienced, or at least generally more experienced, in caving techniques that the general public. It is therefore not intended to inhibit or control their access, other than in exceptional circumstances. Any exception to this will conform to the national policy and management guidelines for caves and karst.

It is recognised that all of the known caves of the Park have either been originally explored, or mapped, by recreational cavers. The Department of Conservation values the maps and information made available to it by cavers, and also values the close liaison with the New Zealand Speleological Society and its member clubs and groups.

4.0 THE POLICY

4.1 The caves and karst of the park shall be managed in accordance with the 'General Policy and Guidelines for Cave and Karst Management in Areas Managed by the Department of Conservation' (Wilde and Millar, 1989).

EXPLANATION

The caves and karst of the park should be managed according to accepted international and nationally consistent standards.

4.2 For the purpose of controlling access and use all caves and karst areas will be classified. Classification will conform to the General Policy and Guidelines for Cave and Karst Management.

EXPLANATION

Caves and, in some cases, sensitive karst features are being degraded, or are potentially under threat of degradation, by uncontrolled recreational use, or overuse. Classification and controlled access and use is an effective means of protecting at-risk features of scientific or aesthetic value.

4.3 Detailed management plans will be prepared for caves and karst areas that could be unacceptably damaged, or further unacceptably damaged, by uncontrolled recreational use; and/or are of high scientific or aesthetic value. Such plans will be appended to the park management plan.

EXPLANATION

Caves and karst areas of high scientific and aesthetic value are often susceptible to unacceptable levels of damage by unmanaged recreational use.

4.4 The karst and caves of the northern portion of the Paparoa Syncline (that is the karst surrounding Cave Creek North) shall be managed as near as possible in its natural state. Development will be minimal and shall be confined to management needs to protect any high scientific and aesthetic values associated with the caves or specific karst localities within the area. This area and its caves will be managed as a karst and cave 'wilderness' or 'remote experience' area.

EXPLANATION

This part of the park represents an extensive, outstanding and relatively unmodified area of karst with high wilderness and environmental values. Recreational and other developments will unacceptably impact on these values.

4.5 Only one concession will be granted for any one cave system, or number of cave systems. Potential concessionaires will be expected to show a high degree of competency in respect to recreational caving techniques and skills, safety and cave conservation relative to the degree of difficulty and values of the cave or caves for which the concession is sought.

EXPLANATION

Along with public expectation for cave experiences and as the park's popularity increases, cave guiding concessions and consequently the number of clientele are likely to significantly increase. Potentially, if poorly managed, cave guiding concessions are likely to cause the most significant recreational impacts on caves. A one cave, one concession policy, therefore provides the most effective means of management and protection.

4.6 High priority will be given to preparing individual management plans in respect of the following caves:

Ananui (Metro Nile River) Cave: To be given first priority. High recreational use; concession, high use at-risk biological, physical and aesthetic values, and locality well known.

Bullock Creek-Cave Creek system: High geomorphological and biological values, flash-flood liable, and dangerous to the general public. Bullock Creek system entrances adjacent to Bullock Creek access road affected by farm management regimes (Bullock Creek Farm) and possible downstream imputs of fertilisers and herbicides.

Babylon Cave: Moderately high recreational use, high potentially at-risk physical, biological and aesthetic values and located adjacent to a high use track.

Fox River Caves: The 'tourist' cave has high public use and potentially at-risk physical and aesthetic values. Because of deep rifts and rockfalls the river cave is dangerous to the general public.

Armageddon: Hydrologically related to Fox River Cave. Has significant cave wilderness values. Also hydrologically associated with Cave Creek North which is to be managed in its natural state (See 4.4).

4.7 Such management plans specified in 4.6 (above) will be prepared within two years of the commencement of the park management plan. In the interim the 'General Policy and Guidelines for Cave and Karst Management' will be regarded as appropriate for management planning and concession purposes.

Given that the demand for recreational and concession use is increasing rapidly, it is considered that the preparation of individual cave and karst management plans within a reasonable time is imperative. However in the meantime it is recognised that recreational caving and concessions are a bona fide use of the park's resources.

5.0 FOSSILS AND SUBFOSSILS

The numerous caves and 'tomo' of the park are an important repository of fossil and subfossil material. Fossil bones and teeth have been observed in the caves of the Bullock Creek area, and subfossil birds and reptiles have been found and recorded in several cave systems (Lands and Survey, 1986).

Ananui (Metro or Nile River) Caves held nationally significant bird bone deposits and it is likely that other cave systems within the park may support significant subfossil sites (Lands and Survey, 1986). Similarly the adjoining Tiropahi (Four Mile) area is known to support nationally significant fossil Oligocene whale deposits.

Despite the relative abundance of known fossil sites and subfossil deposits few have been well researched or documented.

5.1 THE ISSUES

Fossil and subfossil sites are vulnerable to accidental damage by recreational cavers and the general public, and to intentional damage by vandalism. Sites are also at risk from 'curio' collecting by amateurs. In the past even scientists have made unnecessarily large collections for exhibits. There is a vital need, however, for bona fide research in respect to fossil and subfossil deposits in the Park.

5.2 THE POLICY

Fossil and subfossil sites will be managed in accordance with the 'General Policy and Guidelines for Cave and Karst Areas Managed by the Department of Conservation'.

Research will be given a high priority and will be conducted in accordance with national research policy, and the national cave and karst management policy.

EXPLANATION

Disturbance to or damage of fossils and subfossil sites can destroy or seriously reduce their scientific or natural and aesthetic value. Palaeontological research is essential for proper specific site and general cave management, and for improving the park's scientific resource database.

6.0 FAUNA

Because of limited research little is known of either the species, distribution or ecology of cave and karst fauna in the park. However, it can be assumed that numerous species are present. Troglobitic invertebrates, including a new species of weta, millipede and a rare cave beetle (Johns, 1979) have been recorded, along with numerous glowworm populations.

6.1 THE ISSUES

The absence of quantitative knowledge in relation to cave and karst ecology and fauna is a serious impediment to developing appropriate policies and in situ management. It is well known that cave fauna occur in low numbers and with low species diversity, and are particularly vulnerable to habitat modification.

6.2 THE POLICY

Known sites of ecological importance will be managed in accordance with the 'General Policy and Guidelines for Cave and Karst Areas Managed by the Department of Conservation'.

Research will be given a high priority and will be conducted in accordance with national research policy, and the national cave and karst management policy.

EXPLANATION

Disturbance and/or damage of habitat can significantly reduce species numbers and ecological values, particularly within caves. Research is essential for proper ecological management, and for improving the park's scientific data base.

7.0 HYDRO - ELECTRICAL POWER

A range of natural factors present fundamental problems for hydro-electric engineering in the park. One of these is the high earthquake risk. The region lies in the most tectonically active part of New Zealand, where the earthquake risk is higher than anywhere else in the country (NFAC, 1979).

Additional problems include the potential loss of water through caves and karst aquifers which would appear to preclude hydro-developments in the limestone canyons and other karst catchments. Steep gradients and detritus transportation in the catchments above the karst may also preclude such development (NFAC, 1979).

One of the most significant factors affecting hydro-electric development, however, is the region's climate. Torrential, short-duration rainstorms release enormous volumes of water on the Paparoa Range, and the rivers will flood almost instantly as runoff pours through steep short gorges (NFAC, 1979) and, in some cases, karst aquifers and caves, to the ocean.

7.1 POLICY

To oppose the construction of hydro-electric power stations and ancillary facilities within the park.

EXPLANATION

It is considered as a general principle, that industrial development is incompatible with the philosophy and natural state of national parks.

REFERENCES

DSIR,(1987) Guide to the Pancake Rocks, Punakaiki, NZ Geo. Survey, DSIR, Wellington

Johns, P.M.,(1978) in Paparoa National Park, Native Forest Action Council, Nelson 1979

Lands and Survey, (1986) Bullock Creek study, Dept Lands and Survey, Nelson

Millar, I. and Wilde, K.A. (1989) General Policy and Guidelines for Cave and Karst Management, Dept Conservation, Wellington

NFAC, (1979) A proposal for a Paparoa National Park, NFAC, Nelson.

Wilde, K.A, (1989) Draft Management Plan, Paparoa National Park, Dept Conservation, Hokitika

Williams, P.W, (1982) Submission to the Director General of Lands. Lands and Survey, Hokitika

PERSONAL COMMUNICATIONS

Philip Wood, Buller Caving Group (NZSS)