Bernie Napp: All not lost in saving moa's ark

COMMENT

Thirty years ago, a child playing outside in summer would have at some time chased a skink - they were everywhere. Now you would be lucky to see even one. Many of our native species are in a similar predicament, among them kiwi, whio (blue duck), bats and frogs.

Last week, the Herald reported alarming figures from the Department of Conservation's annual report, highlighting the challenges DoC faces in preventing further extinction of native species.

Of 847 species at most risk of becoming extinct, 77 per cent are outside DoC work programmes, 12 per cent had security improved for at least some populations, and 4 per cent were species - such as kakapo, takahe and black stilt - for which work had benefited all or almost all individuals. Work was unsuccessful or incomplete on 3 per cent of the highly threatened species.

At stake is the future of moa's ark, the name English botanist David Bellamy coined for New Zealand and its unusual wildlife.

The list includes our large flightless birds (kiwi, kakapo, takahe); wattlebirds (tieke, kokako); the world's only alpine parrot (kea); whio, one of two torrent ducks worldwide; and a honeyeater (stitchbird).

As well, there are weta, tuatara, a diverse lizard and land snail fauna with alpine species among them, native frogs lacking a tadpole stage, and the short-tailed bat.

The good news is that DoC can protect and even strengthen at least some populations of some species, thanks to learning gained in controlling introduced pests.

The annual report said that 113 acutely threatened and 34 chronically threatened species had their security improved during the last financial year.

Take the kiwi. The department is able to protect at least 11 viable populations, representing all nine species, subspecies and genetically distinct varieties, including North Island brown kiwi, great-spotted kiwi (roa), Fiordland and Stewart Island varieties and the little spotted kiwi.

There are about 8000 North Island kiwi in Northland, 1000 in Coromandel, and 16,000 elsewhere in the North Island.

As a rule of thumb, numbers are halving every decade outside managed areas. But, inside DoC's kiwi zones in Northland, Coromandel and Tongariro forest, their numbers are increasing.

Kiwi are doing well at DoC projects in Hawkes Bay, southern Mt Ruapehu, Mt Bruce forest and in the Wanganui conservancy.

However, they suffered in northern Te Urewera last year because of uncontrolled dogs.

As well, there are 50 private kiwi conservation projects in the country, most in the North Island.

Managed populations of North Island brown kiwi are likely to continue to thrive but overall numbers will continue to decrease. It is practically impossible to control stoats in all places where there are kiwi.

The same principle applies to whio, orange-fronted kakariki, mohua (yellowhead) and native frogs. Their numbers may continue to decrease at the same time as representative populations are enhanced. In the future, it may be possible to manage our two bat species in this way.

Black stilt (kaki) is in a different category of difficulty. In the 1970s numbers dropped to a low of 23. There are now more than 200 birds, mainly because we have learned more about breeding and raising them in captivity - for example, by adding iodine to their diet.

The species is still nationally critical, but DoC is improving the species' security. While protecting them in the wild from feral cats and ferrets will continue to be difficult, because they are sparsely distributed, their numbers in the wild are increasing.

Back to the 847 acutely and chronically threatened species. That number breaks down into: flowering plants, conifers and ferns (295 species), land invertebrates (233), mosses and liverworts (89), birds (84), fungi (61), marine life (33), reptiles (24), freshwater fish (16), and a total of 12 for bats, frogs and freshwater invertebrates.

Plants, fungi, marine species and invertebrates - which make up 83 per cent of the list - are very difficult to protect in any targeted way because they are hard to find, reproduce, protect from pests, or study.

Lizards are further examples of species that are sparsely distributed. Even for such cryptic species, however, some hope remains.

DoC's practice of controlling several pest species at the same time at specific sites to protect certain species means that benefits may spill over to at least some non-target species.

Boundary Stream, an 800ha reserve in inland Hawkes Bay, is a good example of integrated conservation management.

There, possums, stoats, weasels, ferrets, feral cats and rats are controlled to low densities, allowing kereru and whitehead to thrive and ensuring stability for robin.

Such results have encouraged DoC to attempt the reintroduction of kiwi, kokako and North Island saddleback (tieke).

Questions remain over how to control hedgehogs and mice and what, if any, their impact is on forest invertebrates.

Boundary Stream is one of six mainland island projects where DoC is developing and testing conservation management methods. That learning has been and will continue to be applied further afield in New Zealand and overseas.

* Bernie Napp is the Department of Conservation's strategic media adviser. He is responding to a Herald report that DoC is failing to stop the slide to extinction of more than half New Zealand's rare plants and wildlife.