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Nicholas Carlile, from the NSW Department of Environment Climate Change and Water, provides an update on the recovery of Broughton Island’s 130 hectare environment and recent surveys of the surrounding islands. Broughton Island, just north of Port Stephens on the mid-north coast of NSW, is very close to the coast and accessible to the public by private and public launches or even sea kayak. A rat and rabbit eradication was carried out on Broughton Island and the smaller Little Broughton Island some two years ago, as a means of protecting breeding seabirds and their vegetative communities. Since then seabird surveys were carried out by the Australasian Seabird Group (ASG) to provide baseline data on the 130 hectare island main island in 2009 and on the 27 hectare Little Broughton Island and two smaller offshore islands Nature Reserves in 2010.
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Above: Looking north-west (image by Margarita Steinhardt) over Little Broughton Island to the summit of Broughton Island and the distant Storm-petrel Nature Reserves. These unique places are now better understood since recent surveys. It is hoped that as they recover from the impacts of feral pests and weeds that they will provide sites for future studies so that we may better manage our island resources.
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| The outer islands have had far less attention, some only being surveyed twice in 100 years. Using detailed aerial photographs accurate surveys for Wedge-tailed, Short-tailed and Sooty Shearwaters and Little Penguins and White-faced Stormpetrels were carried out on Little Broughton Island, North Rock and Inner Rock, in particular looking for breeding penguins which, while seen on North Rock had never been confirmed as breeding there. Four colonies totalling 20-30 pairs of penguins were found on Little Broughton Island and Inner Rock, being the most northerly breeding colonies of that species. None were found on North Rock. More surprising was three small colonies of Goulds petrels discovered on Little Broughton Island, obviously withstanding the presence of rats. This species had, until 2009 when discovered breeding on Broughton Island, been only know from two islands in the world, further south near the entrance to Port Stephens.
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Above: ASG’s Steve Tremont holds a Gould’s Petrel from one of three suspected breeding sites on Little Broughton Island. This brings to four the number of islands where this species is now known to breed in the world.
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Little Broughton Island, where rats but not rabbits had been introduced, show an intriguing variation in its vegetation when compared to the larger Broughton Island. The seabird colonies were dominated by a variety of native plants, where on Broughton Island they supported only Lomandra (a waist high type-sedge). Interestingly a single Cabbage Tree Palm was also discovered, only known from one other offshore island in NSW, the appropriately named Cabbage Tree Island. Indeed, the vegetation on the island was in far better shape than on Broughton Island, with many shrubs and grasses established and only a sprinkling of the invasive weed prickly pear noticeable, probably due to the lack of rabbits that spread their seeds.
Below: Inner Rock launch site in the lee of 40 knot winds shows two reasons why these islands have been seldom visited. Access to these islands is difficult, even in calm conditions, but when the weather is not favourable it takes a degree of boating skills to safely land and extract surveying teams. The ASG is fortunate to have this level of competence within its members.
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| | Right: Common Blue Tongue (image by Steve Tremont). One of the more unusual finds from recent seabird surveys is the population of Blue Tongue Lizard on Little Broughton Island. It is predicted that this species will flourish in the coming years with the removal of rats from the island. A truly remarkable find given that they don’t swim so they must have been isolated on that island for the last 8,000 years.
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 Little Broughton Is.JPG)
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Broughton Island’s recovery is well under way but it is a slow process for such a dry, windswept place. Seedlings, previously eaten by the rabbits, are beginning to establish themselves and the three species of frogs, Green and Golden Bell-frog, Green Tree-frog and the Striped Marsh frog are fairing much better. The efforts being put into Broughton Island will hopefully reap future rewards with new terrestrial bird species establishing. That in itself is a slow process as it has taken ten years for new species to establish on Montague Island, south of Narooma, where an active restoration program of weed removal is in place and rabbit and mice were eradication some four years ago. Nicholas is especially hopeful the storm petrels from the outer islands will re-establish themselves on both Broughton and Little Broughton Islands. This species has been marginalised by weed invasions and the presence of feral animals on their traditional breeding grounds. Restoring them to their former islands will ensure that they will persist into the future, particularly with the predicted impacts of rising sea-levels. The National Parks and Wildlife Service maintains quarantine processes, especially making sure that mice don’t migrate from the mainland to Broughton Island and visitors are advised to do like-wise. Nicholas Carlile was interviewed by Ruby Vincent for A Question of Balance. All images were sourced by Nicholas Carlile. Summary texr prepared by Victor Barry, Jume 2011.
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