Feature

Conservation Values

How do you decide what to conserve and how to conserve it? Conservation managers have to make difficult choices in preserving New Zealand's flora and fauna.

By Vicki Hyde, NZSM

Given the choice, what do you save -- a giant weta, an alpine flower or a forest songbird?

Over the past twenty years, more and more species in New Zealand have been recognised as being in trouble. Conservation ecologist David Towns recalls his time in the old Wildlife Service when all they had to worry about was birds. These days, over 600 organisms in New Zealand are considered threatened, covering a whole host of plants and animals.

Trying to manage the huge range of organisms involved and to develop priorities for their management has become a daunting task.

"It's almost too big to contemplate," says Towns.

Tagging plants and animals as target species provides a means of focusing efforts on those organisms at their most vulnerable. Target species, on whose behalf major efforts have been made in the past, include kakapo and the Chatham Island black robin.

"It's really all-out-effort stuff," says Towns. Flagship species, although not in great danger themselves, can be used as a symbol of a conservation effort, inspiring support and interest. They can also be used to provide a means of piggy-backing other lesser-known creatures into management strategies. Towns points to tuatara as one flagship species which has proved useful in conservation efforts.

The tuatara is not greatly endangered in and of itself, Towns says, hastening to add that we can't afford to ignore the creature, but rather use its management effectively to help both it and other species.

Warm Fuzzies,
Supremely Uglies

Ecologists use a tongue-in-cheek phrase "charismatic mega-vertebrates" to refer to the warm, fuzzy creatures that get the bulk of public attention and support. Pandas are a prime example overseas, while New Zealand versions are birds and the tuatara.

We can use such flagship species to take the heat off disregarded species, Towns says. Funding and support for a creature such as the tuatara can provide flow-on help for other animals and plants. If you need to establish a suitable insect population on which a tuatara can feed, then you have a chance of doing some good for wetas and other threatened native invertebrates, he explains.

Towns has his sympathies for the animals which miss out because they're not warm and fuzzy. These "supremely ugly cryptofauna" are a PR disaster, he says ruefully, and consequently miss out because few people care about them.

Such cryptofauna do have their advocates. Researchers at Victoria University's School of Biological Sciences have a strong interest in the "silent majority" -- the forgotten invertebrate creepy-crawlies that don't get much public support, as one researcher puts it.

In recent years, giant wetas have gained some support through strong efforts to publicise their uniqueness and danger. There remain many other invertebrates, such as weevils, stag beetles and snails, which desperately need attention.

While such creatures may seem insignificant, they can play an important part in an ecosystem, pollinating plants, breaking down litter and providing a major food source for birds and reptiles. Plans to introduce endangered animals to islands where they have not been before have entomologists concerned about the effects on the little-studied endemic invertebrate populations.

Dr Mary McIntyre, an advocate of the giant weta, is concerned about the transfer of tuatara and birds to islands in the Mercury group, with birds being a particular problem.

"Tuatara and wetas have played together for eons. They both play by the same rules," she says in explaining how both slow, cold-blooded creatures can co-exist relatively happily.

Introduce a warm-blooded, aggressive predator, such as saddlebacks, and there is immediate pressure on the ponderous weta. With only a few hundred individuals on some islands, any form of predation could present a major problem.

Plants have an even harder time in gaining priority, as most attention is focused on animals. Overseas this has even led to physical conflict. In one case, several trees, including sole representatives of individual species, were destroyed by animal rights activists in retaliation for the removal of white-tailed deer from the area. The deers' browsing had threatened the plants.

Island Arks

Over the last 100 years, more than 200 attempts at relocating species to islands around New Zealand have occurred, some more successful than others. Within the last decade, the number of such translocations has increased enormously, with many more being proposed.

With each translocation comes conflict between preserving original island ecosystems, using them as refuges for local species under threat, and transplanting new species from the mainland.

"The solution to these conflicts is by no means clear and it may require some change of attitudes before it is resolved," notes DSIR scientist Ian Atkinson, in a paper on ecological restoration of islands.

"Islands are not floating soup bowls (or zoos) into which species can be ladled in or out according to what seems best at the time," he adds.

In deciding to transfer individuals of endangered species to new homes, conservation managers recognise that they are taking risks. Subtle environmental differences can have a major effect on the viability of such transfers, and much remains to be studied in this area. Nevertheless, such transfers have proved successful for saddlebacks, Chatham Island black robins, wetas, skinks and land snails.

Researchers are beginning to regenerate entire ecosystems. On Stanley Island, for example, Whittaker's skink was the first lizard to be brought to the newly cleared island. As the poorest competitor of the lizards targeted for management, it is being given a head-start in establishing itself before other animals are introduced.

Ecologists are wrestling with determining an appropriate order for establishing everything from plants, to insects, to birds. By doing so, they are learning a great deal about how ecosystems function.

"You can study how ecosystems fit together by putting them together," Towns says. The small-scale ecosystems of islands makes such a task manageable.

While island restoration programmes provide some form of miniature arks for this country's endangered flora and fauna, they can't provide everything.

Some of New Zealand's rarest plants are found in an increasingly small number of wetlands -- such habitats are few and far between on the small islands available. Alluvial plains and terraces support a diverse range of plants and animals on the mainland, yet are not found in island habitats.

Towns's own animals of choice, the lizards of New Zealand, also have some awkward habitats. High country tussockland provides the range for a number of endangered species.

"We can't duplicate that anywhere," Towns notes.

Determining Priorities

A whole host of factors other than the purely scientific can have significant impacts on conservation efforts. Political considerations, public reactions, funding problems and the practicalities of conservation management all play a part in determining which species get attention.

"In some cases, it will be the ones you can get the money for," Towns says. "In the past it's basically been on the basis of who had the strongest advocacy. As a lizard person, I try to push my barrow as much as possible."

He adds that he's gone beyond being just a lizard person these days, and is trying to encourage a group approach.

DOC ran a two-day seminar involving conservation groups, research organisations and scientists interested in a variety of plants and animals. The aim was to produce a means of determining priorities for conservation management.

"There's no way one person can sit down and think up the highest priorities," says Janice Molloy, of the policy arm of DOC's Protected Species Division.

Molloy and colleague Alison Davis have just produced a report which enables the formal ranking of organisms, providing a useful set of criteria which can be checked.

Conservationists and ecologists see some benefits in such an approach, but warn that such a ranking system can produce artificial divisions.

"Those sorts of things can be easily misused," notes one. "It's very hard to rank plants against birds, for example."

Molloy argues that the criteria developed do provide a useful means of comparing the needs of plant and animal species. It looks at the chances of extinction for species, how distinctive they are and also evaluates their human value.

Forty plants and 47 animals are in Category A, the highest priority of three main categories. These include kaka beak, takahe, the Canterbury mudfish, various bats, frogs, skinks and snails.

"These are the species which need to be assessed," says Molloy. The priority ranking system gives conservation managers a logical, straightforward means of assessing the organisms involved and their individual needs.

Molloy stresses that it's not a case of moving down the list one by one, but of evaluating the varying needs and the logistics of the recovery programmes.

Outside the three main categories are a number of special categories. Creatures in Category X are ones which haven't been seen for some time, but which may still be out there somewhere. Molloy sees the need to support surveys to help establish the status of these "missing" species.

Tangata Whenua Concerns

One of the trickiest categories, although more in a political than a scientific sense, is Category M, wherein fall species of cultural significance to Maori but which do not feature in the main divisions. These are generally plants or animals which have become rare in certain localities, rather than nationwide, limiting Maori access to traditional resources.

Pingao, a sand-dwelling sedge, is an important resource for traditional weaving and crafts. Introduced plants and animals have pushed pingao from many areas, and supplies can be hard to get. It comes under Category M, as do a variety of named cultivars of harakeke, New Zealand flax.

"We can't look at this from a totally European, scientific perspective," says Molloy.

Management under the Conservation Act requires DOC to take into account the rights of the tangata whenua as provided for by the Treaty of Waitangi.

This has meant some compromises to allow local iwi access to traditional resources, such as albatross, while ensuring that some control is maintained. Other areas remain controversial, whether the taking of wood pigeon or the eradication of kiore from some islands.

"We haven't really solved these problems yet," says one researcher working in this area. "It's a matter of the right kind of communication."

Other concerns relate to the loss of genetic diversity, whether from kiore, which have proved to be interesting biochemically, or from the eradication of other introduced animals.

The clearance of cattle from Enderby Island led to a last-minute expedition to save eggs and sperm of the unique animals. The Rare Breeds Conservation Society hope to restore the animals genetically one day.

Whatever the decisions made and the way in which they are decided upon, it is generally agreed that there is no simple method and no easy solutions.

"It's very hard to make decisions and it's becoming harder," Towns says.

Vicki Hyde is the editor of New Zealand Science Monthly.