Kawau Island
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Kawau Island is an island in the Hauraki Gulf, close to the north-eastern coast of the North Island of New Zealand. It lies 2 km off the coast of the North Auckland peninsula, and shelters Kawau Bay to the north-east of Warkworth. It is 50 km north of Auckland.
[edit] History
The island has a small population of permanent residents and many holiday dwellings, and is a popular destination for pleasure craft cruising the Hauraki Gulf. Most of the land is privately owned and covered in forest. It is 8 km by 5 km at its longest axes, and is almost bisected by the long inlet of Bon Accord Harbour which is geologically a "drowned valley". Kawau is believed to have been the base for seaborne raiding Māori in the early 18th century and was used as a fishing base by Māori when gathering seafood (kai moana).
Manganese and copper were mined in the first years of European ownership until the island was bought by Sir George Grey, Governor of New Zealand, in 1862 as a private retreat. He extended the original copper mine manager's house (built 1845) to create the Mansion House, which still stands, and made the surrounding land into a botanical and zoological park, importing many plants and animals. The house has been restored and furnished in the period of Governor Grey and is now in public ownership in the Kawau Island Historic Reserve, administered by the New Zealand Department of Conservation. The reserve is public land and covers 10% of the Island, and includes the old copper mine, believed to be the site of New Zealand's first underground metalliferous mining venture (1844).
The island is home to kiwi and two thirds of the entire population of North Island weka. Among the animals that Grey introduced were five species of wallabies. Four of the wallaby species remain and do considerable damage to the native vegetation, thus harming the habitat for these flightless birds and other native fauna. The wallabies destroy all emerging seedlings which means that the present native trees are the last generation. The usual understorey forest species are absent due to wallaby browsing and in many cases the ground is bare. Possums, also introduced by Grey, destroy mature native trees. The result has been a considerable loss of biodiversity, with bird numbers plummeting due to loss of both food supply and habitat. Even the surrounding marine environment has been severely compromised by silt carried from the bare ground by rainwater.
[edit] Pōhutukawa Trust New Zealand
Pōhutukawa Trust New Zealand was founded in 1992 by Ray Weaver and other private landowners who own 90% of the island, "to rehabilitate the native flora and fauna of Kawau Island". Until then it was considered hopeless to reverse the considerable ecological damage caused by the introduced animal and plant species, and Kawau was said to be of historical rather than botanical importance. The Trust's plan is to eradicate significant animal pests including wallabies and possums, eradicate certain weed species and control others, and enable sustainable land uses in a restored ecological setting of native flora and fauna. The ongoing program is funded by donations and sponsors. Possum numbers have already been greatly reduced and kept at very low numbers since 1985 through sustained control, saving the coastal pōhutukawa tree, a New Zealand icon. The response to pest control work has been increasing native bird numbers, including increased kiwi calls, brown teal, kākā, Kererū, and bellbirds.
After assisting with capturing all of the rare brushtail rock wallabies that could economically be recovered from the private land for relocation to a successful captive breeding program established by Waterfall Springs Conservation Association in Wahroonga, Australia, the Pōhutukawa Trust New Zealand is now humanely eradicating the remaining feral wallabies from the island, to enable ecological restoration (mainly by natural regeneration). An inventory of the remaining indigenous plants and forest fragments on the island has been compiled and is being progressively enhanced to define the remnant resource still available for restoration, and several rare indigenous plant species have been discovered during the process. Other animal pests the Trust intends to eradicate in stages as resources enable include stoats and ferrets, feral cats, and ship rats. Exotic plants unpalatable to the wallabies have become serious invasive weeds on the island, and the Trust's plans include eradication or control of these also as part of the ecological restoration process. Kawau is an extreme example of the consequences of exotic animals being brought to a place and ecosystems where they do not belong. The serious threat of possums to New Zealand's indigenous forest was first positively identified on Kawau in 1955. Since then possums have become a major animal pest in New Zealand, compromising both forest health and the country's primary industries. Governor Grey introduced possums to Kawau in 1868-69, and the first liberation in New Zealand is believed to have been by Captain Howell at Riverton in the South Island about 1838. Pōhutukawa Trust New Zealand received a Green Ribbon Award from the Ministry for the Environment in 2003 "for outstanding leadership and commitment to environmental protection".
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