Dialogue: Threat to Waitomo Caves a threat to the nation

By CHRIS de FREITAS*

The Herald's recent report on the human impact on the Waitomo Caves deals with an environmental issue of national significance.

Despite the importance of the caves as natural resources and their great sensitivity to damage, there is little or no legislation to protect them. This highlights a serious blind spot in environmental management.

More people visit the Waitomo Caves than any other in Australia or New Zealand. About half a million people visit Waitomo each year just to see them. But the commercial importance of this extends beyond the Waitomo region. The caves play a vital part in the nation's tourist industry.

The Waitomo Caves are probably the best-known in the world where the cave fauna is the main attraction. To large numbers of tourists from both New Zealand and overseas, a visit to the Waitomo Caves is a high point of their holiday. The caves, and the Rotorua thermal areas, have come to symbolise the North Island tourist encounter.

The value of the Waitomo Caves is more than just that derived from tourism. They are an environmental resource of national significance, like native forests, for which the Government, on behalf of the people, has a major custodial responsibility.

But unlike native forests, which are resilient and can grow back from total destruction, most damage to caves is irreversible. Damage to limestone features can take tens of thousands of years to recover.

Increasing cave tourism and the use of more remote caves by recreational cavers present a growing potential for conflict between the dual requirements of presenting the resource and at the same time protecting it.

The infrastructure of tourism has a major affect on the cave system. There are both direct and indirect impacts to consider.

Direct impacts include breakage of delicate stalactites and stalagmites, construction of access routes through caves, alteration of the cave microclimate from entrance modifications and visitor numbers, the build-up of carbon dioxide in the cave from human breath, accumulated lint from clothing, and heat from people and lights.

Many of these impacts are cumulative and often lead to irreversible degradation to the cave ecosystem.

Where rehabilitation is possible, the recovery process is usually slow and often expensive.

The indirect affects are mainly those caused by human activity on the land surrounding and above caves.These result from farming, the construction of car parks, walking tracks, kiosks, toilets, hotels and motels, and may add to the direct underground impacts by affecting sediment and impurities in runoff into cave streams, passages and caverns.

The result is that caves, especially tourist caves, are potentially more sensitive to human impact than most other natural tourist attractions. Small caves and those hosting cave fauna, such as glowworms, are particularly vulnerable. This is the case for most of the caves in the Waitomo area.

The Glowworm Cave is the best-known cave in Waitomo. It has been used continuously as a tourist cave since late last century and over this time several important lessons have been learned.

Most notably, during the 1970s, it was recognised that conditions in the Glowworm Cave were rapidly deteriorating. There was concern that many changes occurring would be irreversible but, at that time, little was known about the factors that controlled conditions in the cave and how this was related to cave management.

The problem peaked in April 1979 when the Glowworm Cave was closed because only 4 per cent of the glowworms had their lights on. The cave reopened in the following July, but concern for its future led to a number of research projects to improve management and conservation.

Part of the problem centred on the concept of cave ownership and on clearly defining obligations of cave owners and commercial operators.

Happily, in the case of the Glowworm Cave, the owners and operators of the cave have adopted a highly responsible approach, going as far as to appoint a scientific advisory committee and specialist staff to guide cave management practices.

The Herald's report shows this has not been the case elsewhere. Some caves in Waitomo and other parts of the country have been extensively damaged. Part of the reason is that it is often not clear who is accountable for the care and maintenance of the caves or what standards are required.

Ultimately, the Government has the responsibility to protect and care for the nation's caves. Legislation to ensure this is long overdue.

* Dr Chris de Freitas, an environmental scientist in the geography department at the University of Auckland, has led research projects on issues related to cave conservation and management at Waitomo.