Lord Howe Island is a spectacularly beautiful picture postcard island. The lush forested slopes of its majestic mountains overlook a perfect lagoon, numerous beaches, hidden coves and islets. This is reason enough to want to visit the place, but for scientists its beauty is not the main attraction. The island's flora and fauna is exceptionally rich and diverse and has been drawing botanists, zoologists and naturalists of all sorts to its shores since its discovery in 1788.
Many of the animal and plant communities found on Lord Howe Island are unusual and a high proportion of the animals are endemic (found nowhere else). Also, the island is biologically spectacular and unique underwater. Warm currents from the north bring tropical species that mix with species from cooler southern waters. The most southerly coral reef in the world is found just off the island's beaches.
The unique natural heritage of the island and its surrounding waters was recognised as early as 1878 when the New South Wales State Government proclaimed it a Forest Reserve. As more and more scientific work was completed, the island's status has continued to grow and it was listed as a World Heritage site in December 1982.
The Australian Museum has a long association with Lord Howe Island. Since 1882 the Museum has been involved in a wide range of scientific expeditions and surveys, both on the island itself and in the surrounding seas. Currently, scientists from the Museum's Centre for Biodiversity and Conservation Research (CBCR) are studying the island's invertebrate animal populations. The work is part of an ongoing program to fully describe the species that inhabit the island. This information is vital when trying to monitor ecological changes brought about by human influences.
There is no evidence of any human activity on Lord Howe Island before its discovery by Lieutenant Henry Lidgbird Ball in 1788. The next 45 years saw visits from whaling and supply ships but no-one lived on the island until three families settled there in 1834. These days there are around 300 residents and thousands of tourists visit annually. Lord Howe's environment is still relatively pristine in comparison to many islands of the Pacific. However, exotic animals introduced either on purpose, such as pigs and goats or by accident, such as rats, have had a major impact on the island's ecology.
Of all the invading species (if we discount humans) the introduction of Black Rats has had the worst impact. In June 1918 a cargo ship ran aground and was brought up onto the beach. The rats on board escaped into the forests and have caused havoc with the island's ecology ever since. Five species of ground-nesting birds quickly became extinct. The rats also ate the palm seed crops vital to the island's economy. In 1922 a plan to rid the island of rats by introducing owls began. Eighty owls were introduced over the next few years. They have had some effect on the rat population, but an even greater effect on nesting sea birds and the native Boobook Owl, which became extinct from the island in 1950.
Less is known about the impact of the rats on the insect populations, but it is likely to have been great as rats eat anything ground-dwelling they can catch. The Lord Howe Island Land Lobster (Dryococelus australis) is a spectacular stick insect thought to have been one such casualty. Happily, an expedition in 2001 discovered it alive and well on Ball's Pyramid - an inaccessible and rat-free rock pinnacle 23 km south of the main island.
Information gathered by Museum scientists on the existing invertebrate populations will be used to model and monitor the effects of future rat eradication programs. The study will also carry on the theme of work started by the early museum scientists. The origin of many species found on Lord Howe are mysterious. Some species are also found in New Zealand, or New Caledonia and others are more characteristic of the Australian mainland. There is a whole suite of insects only found on Lord Howe or its surrounding islands. By investigating the unique fauna of the island using evolutionary biology techniques, scientists hope to gain an insight into how the island's fauna became established and how new species evolve.
But detailed ecological information is not an easy thing to obtain. It takes time, resources and a great deal of effort. The remoteness of Lord Howe and the inaccessibility of some areas like Ball's Pyramid and the mountain summits make it a particularly daunting task.
The most recent Museum expedition to the summit of Mt Gower, by Chris Reid and Paul Flemons of CBCR, aimed to continue the Museum's invertebrate biodiversity survey work. The peak of Mt Gower is the highest area of land on the island and is usually covered by cloud. As a result, the stunted forests that cover the summit stay wet most of the year. The community of invertebrates is diverse, poorly studied and every expedition to the area turns up new species.
So it was with some excitement the pair of scientists set off up the slopes for their camp, burdened with food, camping gear and a lot of equipment. The trip had been planned for months down to the minutest detail, and the daily schedule of work, collecting, mapping and describing the habitat was to be heavy. Fieldwork is probably the most rewarding, exciting and fun aspect of biologists' work. It can also be the most difficult and sometimes potentially dangerous part of the job.
So this trip proved as, a day after reaching the summit and setting up camp, the weather turned nasty. A mini cyclone descended and lashed the mountain for the remainder of the seven-day period of the expedition. Working conditions in a cloud forest on top of a mountain are difficult enough - dense vegetation hides gullies and cliff edges. Add to this fierce winds and torrential rain and the situation becomes even more interesting.
During the day, Paul and Chris worked along the gullies and ridges of Mt Gower, 800 m above the Pacific Ocean, taking samples and recording the fauna. At night, the pair kept themselves amused by keeping score of the number of leeches they found in the hut. The blood-sucking worms probably live off the many sea birds that nest in the forests, but they seem partial to an occasional supplement of scientist. By climbing the igloo sides and dropping in through the leaking roof the leeches came in search of a meal. Despite their ordeal the two Museum scientists got some valuable results and are looking forward to next years expedition. 'The summit of Mt Gower is like fairyland - all moss, dripping lichens and gnarled twisted trees. It's a spooky place in the cloud or rain. We were wet but happy,' said Chris, adding 'but we were happier to get down'. He'd like to be involved in the beach surveys next time.
Through the current program, the Museum continues to be at the forefront of research into the island's unique biology. There's no doubt Lord Howe Island is one of Australia's many great natural treasures and, with management based on good scientific information, it can hopefully remain so.
Andrew Donnelly
An Australian Museum Website
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