Document ID: chunk:federal_register_of_legislation:F2007B00385:body:0:p10
Version: federal_register_of_legislation:F2007B00385
Segment Type: other
Provision Reference: 
Character Range: 27777–30743

likely the ants kill young animals in the nest, and possibly adults in severely affected areas (as recorded for a Christmas Island Pipistrelle in a harp trap in The Dales area by Lumsden et al. 1999).

A priority conservation management objective of PAN is to control crazy ant supercolonies by aerial baiting. The impact of this on the shrew, both through contact with baits and flow on impacts on prey species, is unknown. In September 2002 all known supercolonies were baited. Results indicate this was successful in controlling supercolonies over 2500ha of Christmas Island. Crazy ants are still present in low densities and PAN staff will continue to monitor any new supercolony formation and treat by hand baiting over the next few years.

Habitat Loss
Although the dramatic decline of the shrews occurred before extensive clearing and prior to the network of bulldozed drill lines, these factors could have contributed to the population not recovering from the initial decline. The unconfirmed 1958 reports were the result of habitat clearance for phosphate mining (Meek 2000). This suggests that, similar to many of the island's endemic avifauna, remaining shrew populations would have been adversely affected by the destruction of about a third of the rainforest for phosphate mining. They may also have been affected by the drill lines resulting in increased predation risk and localised alteration in microhabitat characteristics, such as the loss of ground cover.

New proposals to clear primary rainforest on vacant crown land may apply additional pressure on any remaining shrew populations. These proposals include phosphate mining at sites in the eastern section of the island, and activities associated with developments such as the siting of a mobile phone tower on Limestone Hill, South Point; the Christmas Island airport upgrade; road re-alignment and new port facilities north of the former Christmas Island Resort area.

Habitat Alteration
Alteration of the rainforest habitat due to the extinction of Maclear's Rat and Bulldog Rat R. nativitatis and theorised alteration in crab populations (particularly Red Crab), may have resulted in an adverse change in microhabitats within rainforest critical to the maintenance of shrew populations (Meek 2000).

Predation
No instances of predation have been recorded. However, it is likely that introduced predators (e.g. Feral Cat, Black Rat and Wolf Snake), the naturalised Nankeen Kestrel Falco cenchroides, and endemic predators, such as the Christmas Island Goshawk Accipiter fasciatus natalis and Christmas Island Hawk-Owl Ninox natalis, may opportunistically predate on the Christmas Island Shrew.

Small Population Size
Current evidence strongly suggests that the Christmas Island Shrew occurs in very low densities, compared to early observations made of the species. A small population size increases the risk of extinction through inbreeding depression and stochastic events (Caughley &