The mice of Mer

Location:	Mer Island, Torres Strait, Queensland.
National priority area:	Biodiversity and natural icons Community skills, knowledge and engagement NRM in Northern and Remote Australia
Targets:	Improving coastal hotspots, Increasing coastal community engagement
Funding:	$294 900 (from July 2009 - December 2012)
Partners:	Mer island community and the Torres Strait Regional Authority

Eradication of exotic rodents on Mer Island, Torres Strait

Aims to eradicate exotic rodents over three years to protect threatened species on Mer Island in the Torres Strait.

Preventing new invasions of exotic species and eradicating existing ones may be the most important priorities for global biodiversity conservation.* Nowhere is such eradication more feasible than on islands.*

The Torres Strait's Mer Island, covering 411 hectares, is one of three islands in the Murray Group and lies about 100km south of Papua New Guinea, or 20kms from the tip of the Great Barrier Reef. The islands are the home of the famous Mabo Case, which resulted in the Australian High Court decision to grant native title to the Meriam people over Mer Island.

Under a $294 000 Caring for our Country project to eradicate exotic rodents from Mer Island, a strong partnership has grown between the local Meriam people (population 450), Dr Luke Leung from the University of Queensland and environmental officer Doug Passi from the Torres Strait Regional Council.

They are combining Indigenous knowledge with western science to protect the island's threatened species, including the spectacled flying-fox, herald petrel, hawksbill turtle, flatback turtle and an orchid (Dendrobium superbians).

Luke says Indigenous knowledge provides the key to eradicating exotic species while at the same time protecting the island's only native terrestrial mammal, the grassland melomy (Melomys burtoni).

The project started out as an eradication of an introduced rat (Rattus exulans) and has evolved into a fight against the more invasive roof rat (Rattus rattus) and house mouse (Mus musculus).

"A Polynesian rat was first recorded when the American Museum of Natural History expedition team arrived in early 1920," Luke explained, "This species was later replaced by the more invasive roof rat and house mouse.

"The island is still pretty intact in terms of population of the native grassland melomys. It occupies the grassland and forests of the island. Our research indicates it is competitively keeping the roof rat and house mouse from invading this grassland. However, the islander community population is increasing. Development on the island may tip the balance where the native rodent may decline to a tipping point that the exotic rodents will invade native habitats."

Baiting is being used to eradicate the two exotic rodents from the island, however, the co-existence of native melomys posed a major challenge.

When asked how toxic bait was going to be delivered to exotic rodents but not the native, Luke responded, "We used Indigenous knowledge and discovered that exotic rodents can climb smooth surfaces but the native melomys cannot. We used this behavioural difference to develop a bait delivery system - an elevated bait container - to deliver bait to the exotic rodents but not the native."

The project is now in its third round of baiting. Several Indigenous rangers and council workers who have undergone pest management training are assisting. Elders have also provided information on where exotic rodents were found: mainly in and around built-up areas.

The project includes an awareness program to enhance the community's understanding of the rodents and eradication program. To maximise long-term outcomes after eradication, bait stations with long-life wax block bait will be used near the barge landing to monitor and prevent re-invasion.

The project reflects three national priorities: biodiversity and natural icons, community engagement and NRM in northern and remote Australia.

* References: (Clout & Veitch 2002, Turning the tide of biological invasion: the potential for eradicating invasive species); (Courchamp et al. 2003; Pascal et al. 2010, Mammal invaders on island: impact, control and control imact).