In 1966 the government announced a plan to raise the level of Lake Manapouri for the generation of hydro-electricity. A survey of the lake in 1969/70 concluded that to raise the level of the lake would result in "almost all the scrub communities [being] totally submerged" (Johnson, 1972) resulting in the fairly rapid death of these submerged forests. Based on this scientific evidence a concerted Save Manapouri campaign was launched. In 1973 the lake was given statutory protection with the proviso the lake be operated within its natural high and low levels. Saving Manapouri has been described as New Zealand's first great conservation success story (Peat, 1994). The lake was saved for the nation and now the Pomona Island Charitable Trust is restoring the two largest islands within the lake to their natural state for the enjoyment of future generations.
At 262 hectares, Pomona Island (Pōhuruhuru) is the largest island in Lake Manapouri and is the largest inland island in New Zealand. The island was named by James McKerrow after the largest island in the Orkneys. Rising 340m above Lake Manapouri, Pomona Island is a round-topped granite hill with steep sides. At its closest it is 500m from the mainland, separated by the aptly named Hurricane Passage. The island is almost completely bush clad with some impressive bluffs. Vegetation is predominantly mixed beech-kamahi with rata and podocarp forest.
Introduced predators and browsing animals - stoats, rats, mice, possums and deer - have had an impact on the island's biodiversity, particularly native birds.
Rona Island (Puhiruru) is the second largest island in Lake Manapouri. It too was named by James McKerrow after an island off the coast of Skye, with Rona being the Gaelic word for seal. At 60 hectares it is only a quarter the size of Pomona Island, however, our baseline ecological research has shown that the vegetation and birdlife on Rona Island was in much better condition than that on near-by Pomona Island. With only stoats and mice present on the island, the damage to the island's biodiversity has been significantly reduced.
Pomona Island Charitable Trust
In 2005, a group of Manapouri and Te Anau residents formed the Trust to enable work to begin on the restoration of the two islands. Working under a Management Agreement with DOC, the Trust put in place a track and trap network in 2006 targeting stoats. In 2007, a combined aerial and ground operation targeted deer, possum, rats and mice. For several years, the islands remained free of all five of the mammalian pests. Bird restoration began in 2008, with DOC wanting to use Rona as a kiwi crèche. Later South Island Robin and Mohua were reintroduced. Bird monitoring has shown that birdlife on both islands has increased over time since 2006. Both islands have been used to assist the recovery of the critically endangered Haast tokoeka (kiwi). Rona is used as a crèche island, and Pomona as a kohanga kiwi site with a population of 19 adult birds. As the islands are close to the mainland, mice have repopulated both islands and rats have returned to Pomona. To keep rat numbers at very low levels, the trap network on Pomona has been improved and a bait station network is in place. This network has reduced rat numbers to low levels in between incursions. The bait station grid on Rona keeps mice at very low levels.
The Trust is grateful to all its sponsors for the financial support they have provided since 2005. We would like to acknowledge the following:
Lottery Grants Board (Environment and Heritage) has provided funds to:
- cut tracks on Pomona
- eradicate possums from Pomona
- the preparation of a pest management plan and social impact assessment.
DOC Community Fund has provided funds for:
- track cutting and rat control on Pomona
- trap upgrade work
- camera monitoring equipment
- communications equipment
The Meridian Manapouri Community Fund has provided funds for:
- Setting up a Friends of Pomona scheme.
- Transfer of mohua to Pomona
- Establishment of a bait station network on Rona
- Purchase and installation of A24 self-setting traps
Kiwis for Kiwi provides ongoing funding to:
- protect Pomona and Rona as a safe habitat for the Haast tokoeka
- determine whether kiwi are breeding successfully on Pomona
Donations from Gary Chisholm have enabled us to expand our trap and bait stations lines on Pomona, Rona and the adjacent mainland.
A Transpower grant helped eradicate possums from Pomona.
A significant donation from Donald Riley with a contribution from the Community Trust of Southland enabled the Trust to undertake an aerial operation to eradicate rodents from both Pomona and Rona Islands.
Baseline research on the islands was funded by the Leslie Hutchins Conservation Foundation.
The Trust would also like to acknowledge the following for their support over the years:
- Department of Conservation
- Forest and Bird Southland Branch
- local family Trusts (that wish to remain anonymous)
- Fiordland Helicopters
- Fiordland Cinema
- Adventure Kayak & Cruise
- Barry Harcourt