National recovery plan for the Christmas Island Pipistrelle Pipistrellus murrayi
Prepared by Martin Schulz and Linda F. Lumsden
Department of the Environment and Heritage, 2004
ISBN 0 642 55012 3
Summary
- Current Status
- Distribution and Habitat
- Known and Potential Threats
- Recovery Plan Objectives
- Biodiversity Benefits
- Cost of Recovery Plan
- Conservation Status
Current Status
The Christmas Island Pipistrelle Pipistrellus murrayi is an endemic bat species that is listed as Endangered under the Environment Protection and Biodiversity Conservation Act 1999. Due to taxonomic uncertainty the phylogenetic relationship of the Christmas Island Pipistrelle with closely related Southeast Asia and northern Australia taxa requires resolution.
Currently there are no estimates of the population size of the species.
Distribution and Habitat
This bat was formerly widespread and common in primary and secondary rainforest on Christmas Island. In the 1990s, however, targeted surveys indicated that a marked reduction in abundance and a westward range contraction had occurred since the initial survey for the species in 1984.
Few roosts have been documented. All have been situated in primary rainforest in a variety of situations, including under exfoliating bark on trunks, under dead fronds, beneath a Strangler Fig against the trunk of a canopy tree and in a tree hollow. No maternity roosts have been found as yet.
The Christmas Island Pipistrelle is an insectivorous bat that preys on a range of flying insects. It is an edge specialist favouring vegetation ecotones, tracks and other small gaps within primary rainforest. Commuting or foraging individuals also range into adjacent habitats, including secondary regrowth, minefield rehabilitation sites and formerly the Settlement area.
Known and Potential Threats
An unidentified threatening process(es) has resulted in, or contributed to, a recent population decline and a westward range contraction of the Christmas Island Pipistrelle. There are likely to be direct and indirect effects resulting from the spread of supercolonies of the Yellow Crazy Ant Anoplolepis gracilipes. A range of predators may be impacting on the conservation of the species: introduced species (e.g. Common Wolf Snake Lycodon aulicus capucinus, Feral Cat Felis catus and Black Rat Rattus rattus); and a naturalised predator, the Nankeen Kestrel Falco cenchroides. Habitat loss and alteration, altered prey availability, vehicle-related mortality, climatic conditions (e.g. cyclones, drought and associated wildfires), disease and decreasing population size may also be potential threats to this species.
Recovery Plan Objectives
The overall objectives of this recovery plan are to:
- determine the threatening processes responsible for the decline in the species,
- maximise the opportunity for the viability of the species in the wild, and
- clarify its taxonomic status.
Specific objectives for the five years of this recovery plan are:
- To assess current population and distribution trends of the Christmas Island Pipistrelle.
- To determine the roosting requirements of the Christmas Island Pipistrelle, including seasonal and distributional differences.
- To assess the potential for the Common Wolf Snake to prey on bats in roosts and if it is considered that they impact on pipistrelles, devise management actions to reduce predation.
- To assess the impact of the Nankeen Kestrel and if found to predate on pipistrelles, devise management actions to reduce impact.
- To identify primary foraging site characteristics in the dry and wet seasons, especially away from ecotones and roadways, within extensive tracts of primary rainforest.
- To examine dietary specialisation as a contributing factor in the species' decline.
- To clarify the taxonomic status of the Christmas Island Pipistrelle.
- To continue active management for the control of Yellow Crazy Ant supercolonies.
- To increase protection of known and potential habitat outside the Christmas Island National Park.
- To assess the potential impact on the Christmas Island Pipistrelle of phosphate stockpile removal within and abutting the Christmas Island National Park.
- To establish guidelines to reduce vehicle-related mortality along roads passing through important foraging areas.
- To review the conservation status of the species.
Biodiversity Benefits
Protection and maintenance of primary rainforest and secondary regrowth, and the control of introduced predators will benefit other endemic rainforest-dependent species.
Cost of Recovery Plan
The cost to implement this recovery plan is $276,000, plus additional funds to ameliorate key threatening processes when identified.
Conservation Status
Recent evidence suggests the Christmas Island Pipistrelle is experiencing an ongoing population decline. As a result a recommended action within the plan is to re-evaluate the conservation status of the species since it potentially meets criteria for Critically Endangered.