The most intensive efforts to save species at risk focus on small areas within the conservation estate, which comprises about 30% of New Zealand. Many such areas are nearshore and offshore islands. Because these have been protected from habitat destruction, predators or weeds, remnant populations of threatened species are still found.
Once a species is recognised as threatened, the next step is not always simple – for example, a bird’s ecology and reproduction may be poorly understood. It often takes years to develop effective recovery plans.
The Department of Conservation has recovery plans for many individual species on the brink of extinction. Methods developed in New Zealand during the 1980s and 1990s are now being used worldwide. Common solutions are:
- island sanctuaries
- controlling or eradicating pests
- captive breeding programmes.
Early conservationists, such as Richard Henry of Resolution Island in Fiordland, realised that many small, nearshore islands still had native species that on the mainland were nearing extinction. Animals were free from predatory mammals, and plants from browsing mammals.
Conservationists began moving birds to islands such as Kāpiti, north of Wellington. Today these sanctuaries form a network that is a key component of New Zealand’s efforts to save threatened native species.
Pest control and eradication
On small islands, pests such as rats, pigs and goats have been eradicated by poisoning and hunting programmes. Helicopters drop poison bait in a grid pattern, using global positioning systems to ensure an even coverage.
‘Mainland islands’ are especially chosen areas on mainland conservation land that are intensively managed with poisoning and trapping programmes. They are not fenced. Some small sanctuaries have predator-proof fences.
Captive breeding programmes have helped raise the numbers of some species.
One success story is the takahē. Once thought to be extinct, it was rediscovered in 1948 in the Murchison Mountains, Fiordland. In the early 1980s, efforts were made to understand the breeding requirements of this dwindling species, and to reduce chick mortality. Eggs were incubated, and the chicks were raised and held in enclosures near Te Anau.
Secondary, captive populations can be started up, often on island sanctuaries. These then form a back-up in case the original population dies out.
Managing the 70% of New Zealand that is not conservation land has major implications for threatened species. Until the 1980s this land was mainly developed for farming and other production. But in 1991 the Resource Management Act changed the focus to the sustainable management of resources. However, this only addresses the negative environmental impact of new developments, rather than restoring already degraded habitats. Still, city councils and regional councils are required to consider conservation values, and many have begun to restore certain habitats.
The New Zealand Biodiversity Strategy, launched in 2000, aimed to conserve New Zealand’s diversity of species, and to include the whole community in the effort. For example, throughout New Zealand there are local schemes to control predators in areas of native bush.
The strategy also recognised that these projects must cut across map boundaries, and should not be the sole responsibility of the Department of Conservation. For example, the black-billed gull, considered to be in serious decline, nests on South Island riverbeds which are not conservation lands. The regional council, Environment Canterbury, is now involved in saving the gull, among other species.