Chris de Freitas: Precious caves at risk in legislative vacuum

Chris de Freitas

The controversy over permission granted by the Department of Conservation to allow world adventure racers into Te Tahi cave on the West Coast highlights an important environmental issue of national significance that is being stubbornly ignored.

So far, debate over use of Te Tahi cave has centred on safety practices and well-being of competitors. It reflects the popular perception of caves as little more than places for adventure.

Present legislation on caves echoes the view that they are just cavities in the ground owned and controlled by those who own the land above.

In a more enlightened, contemporary view, caves are seen as valuable environmental assets, considered to be non-renewable resources, as damage to cave features may take several human lifetimes to recover, or never recover at all.

To ensure a balance between preservation and use of cave resources, an appreciation of the resource is crucial.

Te Tahi cave contains stunning stalagmites and stalactites thousands of years old. Other caves contain amazing rivers and caverns.

The famous Waitomo caves have all of these attractions and play a vital part in the nation's tourist industry. They are an environmental resource of national significance, for which the Government has a major custodial responsibility.

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

Unlike other environmental assets, such as native forests that are resilient and can grow back from total destruction, most damage to caves and surrounding limestone landscape is irreversible.

There are 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 that combines with moisture to corrode limestone features, accumulated lint from clothing (on which bacteria feed), and heat from people and lights.

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

Indirect impacts are mainly those caused by so-called surface effects resulting from agriculture, the construction of car parking areas, walking tracks, kiosks, toilets, hotels and motels and may add to the direct underground impacts by affecting sediment and impurities in runoff into streams, cave passages and caverns.

Unlike New Zealand, Australia has taken seriously the business of conserving limestone environments and managing tourism. To heighten protection of the precious Jenolan Caves Reserve in New South Wales, an amendment to the National Parks and Wildlife Act in 1997 brought into force legislation that provides the reserve and the Jenolan, Abercrombie and Wombeyan Caves with the same protection as National Parks.

Despite the legislative vacuum in New Zealand, the news is not all bad.

Tourism Holdings Ltd (THL) operates the Glow-worm, Ruakuri and Aranui caves in Waitomo.

More people visit the Glow-worm cave than any other cave in Australia or New Zealand. About half a million people visit Waitomo each year because of the cave.

But the commercial importance of this extends beyond the Waitomo region. The caves play a vital part in the nation's tourist industry.

In recognition of this, an Environmental Advisory Group funded by THL was set up about six years ago to help to preserve the features of the Waitomo caves and manage the regional resource sustainably. The group includes scientists and representatives from the Department of Conservation and THL.

THL's dedication to the well-being of the cave, plus the high technology employed to monitor the cave environment, ensure the cave can be enjoyed by generations to come.

Today's knowledge of the impact of environmental changes in the Glow-worm cave and ways to manage them is based on extensive research carried out over many years. Sophisticated automated monitoring systems check air quality, rock and air temperature, humidity and carbon dioxide.

Data is downloaded to a central computer every three minutes, analysed by specialist staff at the Waitomo Glow-worm Caves Ltd throughout the day, then reviewed regularly by the Environmental Advisory Group.

Using this information, THL manages the cave, including deciding when the upper entrance doors should be opened or closed to control air flows and the number of people who can visit the cave daily.

But for those New Zealanders who care that the cave is preserved intact for future generations, this is simply good luck, as there is no legislation in place to ensure good management, or any guarantee that future owners and managers will be so caring.

The Environmental Advisory Group's success hinges on the balance it allows between conservation of natural and cultural resources with tourism operations. It is a model for New Zealand environmental legislators to consider.

It provides an opportunity for the Government to deal with its dual responsibility for protecting caves and managing tourism.

It also provides an opportunity for dealing with long-standing problems of cave ownership and to clearly define obligations of cave owners and commercial operators of leased caves. Reserve trusts could direct energy towards setting priorities, ensuring decisions are appropriate.

* Chris de Freitas is an associate professor in geography and environmental science at the University of Auckland who has led numerous research projects on issues related to cave conservation and management. He is chairman of the Waitomo Environmental Advisory Group.