Great Barrier Island - The Future Sanctuary?

After spending eight weeks on the island, June Brookes shares her story and adventure

I have just spent eight weeks on Great Barrier Island renewing my association with familiar tracks and favourite places that I had not been to for quite some years.

My overall feeling is that the environment on Great Barrier Island is in good shape compared with the mainland but a lot more could be being done to enable the island to fulfill its full potential for nature conservation.

About 60% of the island's 27,400 ha is publicly owned and managed by the Department of Conservation. There are about 850 full time residents swelling to several thousand over the summer.

The DOC track system through the interior of the island is now very well maintained. The new wooden steps ascending and descending from Mt Hobson are a great improvement over the previous free-for-all scramble which caused erosion and damaged Black Petrel burrows. Our party was rewarded with an indignant squawk from a Black Petrel chick in its burrow as we descended from Mt Hobson towards the new hut at Mt Heale. New tracks have also been built to the summit of Whitecliffs/Te Ahumata (the mountain Gerry Brownlee wanted to open cast mine) and to Blind Bay, both of a very good standard. Other top quality tracks are the Hot Springs track with its groves of tall arching nikau and the Okiwi to Haratoanga coastal track with outstanding coastal views.

Goats were eradicated from the island by a combined ARC/DOC initiative some years ago and the regeneration of vegetation is accelerating. Land which was disfigured by ugly bare scars is now mostly covered with native vegetation.

Young kauri and tanekaha are pushing up everywhere through the pioneer kanuka and manuka, along with rimu and broadleaf species. The main challenge now is to control wild pigs, wild cats and wilding pines which cause considerable vegetation damage, limit wildlife recovery and destroy natural landscape.

Brown Teal Ducks at Harataonga Recreation Reserve Stream

Great Barrier Island has the huge advantage that it does not have the norway rat, possums, goats or mustelids and DOC works hard to keep it that way. Major predator groups are therefore absent and native bird species which are all but gone from the mainland are holding their own or improving on Great Barrier.

DOC is trapping for wild cats on Mt Hobson to protect the Black Petrel breeding colony there and also at Okiwi to protect Brown Teal Duck (Pateke) which can be readily seen in the streams and estuaries at Okiwi, Haratoanga, Awana and Kaitoke. Banded rail are quite common everywhere. Flocks of raucous Kaka and Kereru are a feature of the island. We had a kereru nest in a puriri tree not 20 metres from our house hopefully due to poisoning for rats. Bellbirds visit from Arid Island (Rakitu) close offshore and about 14 pairs of NZ Dotterel are breeding along Great Barriers east coast beaches.

In addition to the areas intensively trapped by DOC two areas of private land have major conservation initiatives in place to trap rats and wild cats, as does Kaikoura Island (administered by a trust). Individual island residents are also killing cats and rats to encourage birdlife on their properties. One resident has killed over 390 cats from around his house alone. This illustrates the scale of the problem and that improvement is possible and affordable.

The Future:

This island offers a huge potential advantages for the reintroduction of species which cannot exist on the mainland with the presence of mustelids and possums. It is now clear from experience that on Great Barrier, the number of birds from vulnerable species - N I Kaka, Kereru, Banded Rail, Fern Bird, Brown Teal Duck, Black Petrel and other fauna - would increase several fold if active predator and pest control were to be carried out everywhere. Were these remaining major predators - wild cats and ship rats - to be significantly reduced the island would be ideal for the reintroduction of endangered Kiwi species and maybe eventually for Kokako, Saddleback, Stitchbird and other highly endangered species. To achieve this predator and pest populations would have to be reduced to very low levels to allow these vulnerable species to breed successfully. 

The island is too big and too rugged for expensive ground pest control methods and sustainable aerial methods need to be employed. Co-ordinated aerial pest control programmes need to be initiated over the whole island. 

This is a challenge but it cannot be delayed any longer. Even with existing wild cat trapping the Black Petrel breeding colony is only just holding its own after years of decline and all other vulnerable and endangered species could be doing so much better with extensive pest control. Large amounts of money have been spent recently by DOC on tracks, huts and other facilities. Now it is time for the focus to change to getting serious about making the island safe for its vulnerable inhabitants  - the special birds, animals and endangered plants which call it home.

I would urge all Forest and Bird members to visit the island and enjoy its special flora and fauna and to support initiatives to persuade DOC to initiate island wide pest control programmes.

 

June Brookes (Auckland Central Branch Committee)

 

For further reading visit the website for the Great Barrier Island Charitable Trust - Submissions and reports - Great Barrier Island State of the Environment Report March 2010. Also: "Great Barrier Island" Edited Don Armitage , Canterbury University Press, Revised Edition 2004.