Prospectus for the introduction of Kiwi to Great Barrier Island
Environmental News Issue 13
Submission from: The Great Barrier Island Charitable Trust:
by John Ogden and Judy Gilbert
On: KIWI RECOVERY PLAN 2006-2016 – DISCUSSION DOCUMENT.
Advantages of Great Barrier Island as a Kiwi Sanctuary:
1. The absence of Mustelids (stoats and ferrets) and Possums.
2. The presence of extensive areas of suitable habitat over a range of elevations on Hirikimata and elsewhere.
3. The strong likelihood of Iwi support and active cooperation.
4. The existing infra-structure: the Department of Conservation (D.o.C) already manages c. 60% of the island.
5. The growing and strong terrestrial conservation ethic within the local community.
6. The presence of supportive community organizations (e.g.. GBICT, Little Windy Hill-Rosalie Bay Trust, Glenfern Sanctuary, Biocare Aotea Ltd., Awana Catchment Trust) currently employing people on pest control and working actively for habitat restoration.
7. The possibility of controlling dogs through council by-laws. There is already a requirement for bird-aversion training. Auckland City and Regional Councils are supportive of biosecurity control on Great Barrier Island.
Disadvantages:
1. The presence of some endangered species (skinks) which might be detrimentally influenced by kiwi.
2. The lack of evidence that Kiwi were present during historic times.
Discussion of advantages and disadvantages
The absence of Mustelids and the possibility of controlling cats and dogs provides a unique opportunity for the Department of Conservation to create a new Kiwi Reserve on Great Barrier Island. There is prime potential kiwi habitat on Mt Hirikimata and at Little Windy Hill and Glenfern Sanctuaries, which could be intensively managed by the relevant community groups. Kaikoura Island, recently acquired by D.o.C, might also be considered. The geographical separation of these areas provides possibilities for introducing kiwi from different populations and/or other experimental manipulations. The effectiveness of community groups in managing such projects is already proven.
The vegetation of GBI is suitable for brown kiwi, which are quite adaptable. Even the drier Manuka-kanuka scrub, which covers ridges formerly covered by kauri or broadleaf forest, is rapidly reverting to tall forest. Swamps and damp gullies provide moist soils throughout. Although some species present in the Moehau kiwi sanctuary are absent from Great Barrier, the main canopy, sub-canopy and ground-cover species are the same, providing very similar plant communities and potential kiwi habitat.
The above considerations imply that the Department of Conservation estate, and private conservation properties on Great Barrier Island could fulfil the proposed new Recovery Plan goal of “maintaining all kiwi species and sub-species as functioning parts of extensive protected ecosystems”. This aligns also with the New Zealand Biodiversity Strategy (2000), which under Objective 1.5, implies that viable kiwi populations should be established to enhance distributional ranges and maintain populations in ecosytems important for indigenous biodiversity. In view of this (at least in the first instance,) introductions to the significant montane habitats on Great Barrier should be confined to brown kiwi (Apteryx australis sensu lato).
Ecotourism appears to be the most significant future development on Great Barrier Island. In a survey of 125 off-island property owners the most frequently identified valuable feature of the island was given as “the natural environment”. The GBICT is working to promote the vision of a pest-free island attracting national and international visitors with an interest in the unique biotic and cultural heritage of New Zealand. As the country’s icon, the presence of kiwi would enhance that vision and further the cause of conservation. If the island was actively promoted as a kiwi refuge the community would readily support this because they would see the potential economic advantages through increased tourism. The island could become the most accessible wild kiwi population close to Auckland.
The presence of chevron skink on Great Barrier Island might be seen as a disadvantage. It would be useful to experiment with the interactions between these two species, perhaps at the Auckland Zoo, prior to any extensive release on Great Barrier. However, the large size of Great Barrier would ensure that any negative kiwi-skink interactions would not be immediate and could be relatively easily monitored and managed. The lack of evidence for the former presence of kiwi is a purely esoteric consideration, and might be seen as an advantage rather than the opposite. However, kiwi were presumably present during the last glacial (22 – 10 thousand years ago) when sea-level was much lower and the birds could have walked to Rosalie Bay from Te Moehau. There is a local Iwi tradition that kiwi were formerly present. Leg bones (and gizzard stones) of Moa have been found on the island in association with an early Maori habitation site.
Summary
The advantages of Great Barrier Island as a kiwi refuge in future far outweigh any possible disadvantages. The main advantages are (1) absence of Mustelids, (2) presence of extensive areas of suitable habitat, and (3) an existing supportive infra-structure. The latter comprises the Department of Conservation, the Auckland City and Regional Councils and several active community groups. The future benefit to the local community through ecotourism would ensure strong community support.