The Action Plan for Australian Bats
Environment Australia, 1999
ISBN 0 642 2546 363
Recovery outlines and taxon summaries (continued)
Recovery outline: Pilbara Leaf-nosed Bat
Family: Hipposideridae
Scientific Name: Rhinonicteris aurantius (Pilbara form)
Common Name: Pilbara Leaf-nosed Bat
Conservation status: Vulnerable (A1c, B1, B2c)
Intra-specific Taxa
The Pilbara population is geographically the most isolated population of R. aurantius, being separated from the northern Australian populations by nearly 400 km of sand-ridge desert. It differs from the Northern Australian population in terms of wing-shape indices and echolocation call frequency (N.L. McKenzie unpub., refer Section 2 on taxonomy; Coles and Guppy 1989).
Former distribution
Individual records scattered across Pilbara Region since 1925, and from a single locality in the north-western corner of the adjacent Gascoyne Region (first captured in Barlee Range Nature Reserve by P. Kendrick) in October in 1995.
No historical data on abundance, but 74 individuals were captured, and a colony-size of 350 was estimated, at Klondyke Queen Mine (eastern Pilbara) in 1981 by Churchill et al. (1988).
Current distribution
Known from less than 10 localities in the Pilbara and from one locality in the Gascoyne. In contrast to the Gascoyne region, no natural colony sites are known from the Pilbara.
Currently 2 to 20 individuals occupy each of the 5 known roost sites in the Pilbara, all of which are in the eastern Pilbara (K. Armstrong unpub.). The first Pilbara specimen was captured in the Red Hill copper mine in 1928. When this west Pilbara site was re-visited in 1997 the entire workings had collapsed, and there was no evidence of R. aurantius present. The five surveys of the Klondyke population since Churchill’s 1981 visit, have failed to record more than 20 individuals.
Habitat
Hunts food during slow manoeuvrable flight. Hawks flying prey close to clutter, and gleans from foliage and the ground in riparian vegetation in gorges, and in open hummock grasslands and sparse tree and shrub savanna.
Known colonies in the Pilbara occupy abandoned, deep and partially flooded mines that trap pockets of warm, humid air in the mine’s constant temperature zone (Hall et al. 1997). For at least part of the year, the species is thought to also occupy smaller, less complex mines nearby.
Two natural roosts have been located in the Gascoyne region (K. Armstrong unpub.). One is a cave more than 30m deep, and the other a horizontal fissure beneath an ephemeral waterfall. Both are in the Barlee Range National Park.
Reasons for decline
Unknown. However, roost loss through the collapse and flooding of old mines has been implicated. On current knowledge, the Klondyke and Comet Mines should be treated as important in maintaining the current population-levels in the region. Although both of these old gold mines are deep, complex and partially flooded, available data indicate a population decline in both mines (Hall et al. 1997).
In the Klondyke, Churchill recorded a population of 350 in 1981, whereas the five subsequent surveys have recorded no more than 20 individuals. Like most of the other old mines in the Pilbara, much of the Klondyke Queen has already collapsed, and the remaining areas are unstable.
Data from the Comet Mine also indicate a decline. While a ‘large colony of orange bats’ roosted over the pool in the base of the Comet Mine prior to a percussion-drilling program in 1992/3 (N. Dunlop pers. comm.), survey in July 1995 netted only a single Rhinonicteris male in the entrance drive, and detected only two R. aurantius passes by ultrasound along the main incline immediately above the pool (N. McKenzie unpub.). When last surveyed (by Kyle Armstrong in May 1997), the lower portion of the Comet Mine where the R. aurantius were reported was completely flooded, and there was no indication that they were roosting in other parts of the mine.
Open-cut mining also presents a threat as recent drilling programs have revealed that there are extensions to the ore-bodies beneath both the Klondyke and Comet gold mines.
Recent roadkills near Tom Price (in 1995) and Fortescue Roadhouse (in 1990) suggest that colonies remain to be discovered elsewhere in the Pilbara.
Conservation reserves on which species occurs
Barlee Range Nature Reserve.
Other public land on which species occurs
None known.
Other land on which species occurs
Pastoral leases and mining leases in the Pilbara.
Is knowledge about species adequate for objectives and actions to be defined accurately?
Yes.
Recovery objectives
- Protect known Pilbara colonies, and/or translocate them if necessary.
- Ascertain if colonies in natural roosts in the Barlee Range Nature Reserve are declining.
- Locate and protect natural breeding roost sites in the Pilbara region.
Management and research actions completed or underway
- Population genetics and morphological study on phylogenetic status of the Pilbara population – MSc project by Kyle Armstrong, University of WA.
- Determine environmental conditions of actual roost sites during the year, including the breeding season – MSc project by Kyle Armstrong, University of WA.
- Monitoring Pilbara mine colonies – Opportunistic by CALM (WA) scientists, and as part of a MSc project by Kyle Armstrong, University of WA.
Management and research actions required
- Seek cooperation of relevant mining companies to minimise effect of mining activities on the populations.
- Negotiate code of practice with mining industry at relevant sites to address:
- replacement of supports in old mine tunnels and chambers, and installation of additional re-inforcement as necessary;
- prevention of destruction of old workings during removal of remaining portions of the ore body; and
- installation and maintenance of drainage devices to control flooding.
- Inspect and re-condition/install supports in a selection of collapsing mines.
- Permanently cap any exploratory drill holes that intersect mine chambers so that the pockets of warm humid air required by colonies (Churchill 1991b) are not vented.
- Ensure any essential drilling programmes near occupied mines are designed to minimise disturbance.
- Design, test and install steel mesh gates on relevant mine entrances to minimise disturbance by visitors.
- Carry out surveys in the region for natural breeding roosts.
- Protect any natural breeding roosts found from disturbance.
- Monitor existing colonies in mines to ensure that populations are stabilised.
- Create reserves to protect several breeding roosts in mines.
- Identify and acquire vesting over a suitable, safe mine for translocation (two possibilities have already been identified).
- Begin translocation from the Klondyke Queen mine.
- Ensure that, as a last resort, opportunity to translocate a colony is provided in any plans to develop the relevant mines.
Organisation(s) responsible for conservation of species
Western Australian Department of Conservation and Land Management.
Other organisation(s) / individuals involved
Department of Zoology, University of Western Australia, mining companies
Can recovery be carried out with existing resources?
No. The following is required :
- Replacement of supports in old mines unknown
- Develop code of practice $10,000
- Design and install gates $35,000
- Survey of natural breeding roosts $85,000
- $130,000
(Code of practice based on 1 person for 2 months 10K; design and install gates based on 1 person for 3 months 15K plus materials 20K; survey and monitoring based on 2 people for 6 months 51K; vehicle 12K, equipment 5K, expenses 17K.)
Bibliography
Churchill S.K. 1991a. Distribution, abundance and roost selection of the orange horseshoe-bat, Rhinonycteris aurantius, a tropical cave-dweller. Wildlife Research 18, 343–353.
Churchill S.K. 1991b. The ecology of the orange horseshoe-bat (Rhinonycteris aurantius). M.Sc. thesis. Department of Anatomy, University of Queensland, Brisbane.
Churchill S.K., Helman P.M. and Hall L.S. 1988. Distribution, populations and status of the Orange horseshoe-bat Rhinonycteris aurantius (Chiroptera: Hipposideridae). Australian Mammalogy 11, 27–33.
Coles R.B. and Guppy A. 1989. Echolocation and doppler-shift compensation in Rhinonycteris aurantius and Hipposideros ater. Macroderma 5, 6–7.
Hall L., Richards G.C., McKenzie N. L. and Dunlop N. 1997. The importance of abandoned mines as habitat for bats. pp 326–334 in P. Hale and D. Lamb (Eds) Conservation Outside Nature Reserves. Centre for Conservation Biology, University of Queensland, Brisbane.
Jolly S. and Hand S. 1995. Orange Leafnosed-bat, Rhinonicteris aurantius. Pp. 464-465 in R. Strahan (Ed.) The Mammals of Australia. Reed Books, Chatswood, NSW.
Authors for the species
Norm McKenzie
Kyle Armstrong
Peter Kendrick
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