Document ID: chunk:federal_register_of_legislation:F2007B00391:body:0:p9
Version: federal_register_of_legislation:F2007B00391
Segment Type: other
Provision Reference: 
Character Range: 21709–24677

turn markedly increased their chances of extinction. Avian malaria arrived with the accidental introduction of a new species of mosquito (Hay 1986). Christmas Island is very vulnerable to the accidental introduction of new disease. In 1994 a quarantine barrier was established between the island and Indonesia and Australia and this has reduced that risk.

Habitat Loss
Approximately 25% of the island's original forests have been cleared and replaced by shrublands of ferns on minefields, regrowth vegetation on stockpiles, and roads and housing (Environment Australia 1994). This has meant a loss of their preferred forested habitat and thus a decrease in the total population size of the Christmas Island Hawk-Owl. Regrowth vegetation growing along roadsides and on stockpiles may provide good feeding habitat for Christmas Island Hawk-Owls at least at some times of the year. These small areas of regrowth vegetation may have slightly offset the effect of habitat clearance.

Rainforests on Christmas Island have been fragmented in places by clearing and dissected by roads and old mining 'grid lines'. The grid line system, a series of parallel lines 120 m apart and a bulldozer blade in width, was installed in the 1970's to explore the island's phosphate resources. After 25 years these are mostly overgrown with dense stands of regrowth vegetation. Numerous large trees were undoubtedly knocked over when the grid lines were being put in, and this may have reduced the number of suitable nest sites for owls. It seems unlikely that any clearings are large enough to be a barrier to dispersal.

There are some major development proposals and associated infrastructure in particular the Immigration Centre, Satellite launching station, airport upgrade, and expansion of phosphate mining that have the potential to reduce the area of hawk-owl habitat. One development condition for the satellite launching facility is to develop and implement an environment management plan (EMP), which is currently underway. The EMP will address threatened fauna and their habitat on the sites. The immigration centre is exempt from assessment under the EPBC Act, however, the DEH is being consulted on environmental aspects of the development, including monitoring of habitat for potential impacts. The airport upgrade and phosphate mining expansion proposals are undergoing assessment for environmental impact under the EPBC Act. Survey and monitoring of the Christmas Island Hawk-owl will aid in determining potential impacts of these and future developments on hawk-owl habitat.

Natural Catastrophes
The effect of climatic catastrophes such as cyclones are more severe on small populations. Cyclone frequency may increase with Greenhouse-induced climate change and it would be useful to understand the effects of cyclones on owl populations to help predict the impact of any increase.

Weeds
Weeds, especially newly introduced invasive species, could impact on Christmas