cesar’s Wildlife Ecology team has recently returned from an 8 day field trip trekking through the rainforest on Christmas Island in the Indian Ocean.
The team sampled invertebrates with pitfall and sticky traps and took environmental samples as part of a new project for the Director of National Parks Australia.
Christmas island is known in Australia for housing a very high profile detention centre that is often in the news, but it also has some of the most amazing rainforest and wildlife, including a species of red crab (Gecarcoidea natalis) that numbers in the tens of millions and is the dominant species on the forest floor. This species is widely known for its annual migration during the wet season where millions of crabs migrate to the coast for breeding.
cesar was contracted to assess a planned aerial fipronil baiting program undertaken on Christmas Island to combat the highly invasive yellow crazy ant, Anoplolepis gracilipes.
This introduced species forms massive super colonies that are responsible for displacing and killing millions of the islands endemic red crabs and in the process changing the understory of the rainforest.
Aerial baiting is currently the only way to control these invasive ants, which currently occupy approximately 1200 hectares of largely inaccessible rainforest.
Fipronil is known to be toxic to wildlife and can persist in certain environments for long periods of time before being completely broken down.
The Wildlife Ecology team undertook a pre-baiting assessment of invertebrates and environmental samples (soil, water and sediment) to provide a baseline from which to compare after baiting sampling.
The team received great support from staff of Christmas Island National Parks and will be back on Christmas Island immediately after the aerial baiting program (October) to undertake a similar assessment and determine whether there has been non-target species affected by the baiting program.
They will also assess whether there has been any bioaccumulation of fipronil in the environment.
This is the second time that cesar has undertaken an assessment of the fipronil baiting program, with a similar study occurring through the last baiting program in September of 2009.