Macquarie Island - a case study
Macquarie Island is an Australian island to the south-east of Tasmania, about midway to Antarctica. It makes for an interesting case study and ties in with the last On the Brink which was about feral cats and the damage they do.
The island was accidentally discovered in 1810 by a sealer who named it for Governor Lachlan Macquarie. He was not the first to the island; he reported seeing an old shipwreck, possibly Polynesian. The island was uninhabited by humans. In the ensuing years the fur and elephant seals were hunted almost to extinction for their furs and oil respectively. The island became an important stopping off place for Antarctic explorers including Wilkes, Scott, Shackleton and Mawson. The Australian National Antarctic Research Expeditions (ANARE) established a permanently occupied research station in 1947. Macquarie Island was declared a wildlife sanctuary in 1933 (largely due to Mawson’s insistence). In 1977 it was declared a Biosphere Reserve by UNESCO and was placed on the World Heritage List in 1997.
No trees grow in the harsh Antarctic conditions. All the vegetation is herbaceous; there are no woody plants. Of particular interest are two megaherbs, the Macquarie Island cabbage (Azorella polaris) and the silver-leaf daisy (Pleurophyllum hookeri), each growing to a metre or more in height. Terrestrial fauna is limited to small invertebrates. Wildlife consists of marine birds and aquatic mammals. Invasive species came to the island with the sealers, some as a food source, others as stowaways. Rabbits, weka, cats, rats and mice all bred prolifically and did great damage to the fragile sub-Antarctic ecosystem. The rabbits and rats ate out large areas of vegetation. The cats not only ate the rabbits, but also the nesting seabirds and their young. Rats and the weka ate bird eggs. It was a disaster.
It became very clear that Australia had to do something and a cat eradication program in the 1970’s, using a combination of poison baits and shooting, often with the use of dogs. It was expensive but successful with the last cat eradicated in 2000. The eradication of cats in turn led to a surge in the rabbit population (300,000 rabbits) and the subsequent extensive damage to vegetation. As most wildlife leave the island over winter, it was decided to bait the island for rabbits and rodents then. Calisi virus was also introduced. Unfortunately, there was a spike in seabird deaths, due to the birds scavenging poisoned carcasses. The baiting program continued with staff scouring the island and removing any poisoned rabbits or rodents. Remaining animals were hunted down, again by using detector dogs. By the end of 2011 rabbits, rats and mice had been eradicated from Macquarie Island.
The programs cost $24 million. It must be pointed out that the Australian and Tasmanian governments have an obligation to preserve this World Heritage Listed site.
Since the eradication programs, the recovery of vegetation on Macquarie Island has been described as “absolutely extraordinary” by researchers. Once bare areas are now covered by vegetation. In places the tussocks are over head height. Seabirds are thriving and breeding in safety.
To protect the biosecurity of Macquarie Island there are strict protocols to be followed by those travelling to the island. All freight sent to the island is checked by detector dogs before it leaves Hobart and again before it is offloaded. Tourism is limited to a few small cruise ships and is subjected to the same restrictions as those travelling to Antarctica. Access is restricted to certain areas. The research station continues to be a base for conducting ecological, geographical and meteorologic research.
Macquarie Island is a testament to Nature’s resilience.
