Threatened species & ecological communities

The Action Plan for Australian Bats

Environment Australia, 1999
ISBN 0 642 2546 363

Recovery outlines and taxon summaries (continued)

Recovery outline: Grey-headed Flying-fox

Family: Pteropodidae

Scientific name: Pteropus poliocephalus Temminck, 1825

Common name: Grey-headed Flying-fox

Conservation status: Vulnerable: (A2c, A2d, A2e)

(See Section 1.5 Disagreements about categories of threat)

Intraspecific taxa

Radio-tracking (Eby 1991), genetic (Webb and Tidemann 1996) and banding studies (Tidemann unpub.) indicate that the species is panmictic.

Former distribution

Collett (1887) and Andersen (1912) recorded specimens from far north Queensland. In 1929-30 camp-sites occupied permanently or regularly were found from Rockhampton in the north to Mallacoota in the south, from the coast to 100 km inland in Queensland and to the eastern edge of the escarpment in New South Wales (Ratcliffe 1931). By including areas used less consistently, a subsequent assessment extended the southern boundary to Warrnambool, Victoria and the inland boundary to the western slopes of New South Wales (Nelson 1965).

Current distribution

P. poliocephalus is no longer found in the Rockhampton area (D. Vavryn and G. Simmonds pers. comm.) and in 1997 P. poliocephalus was not found north of Hervey Bay, Queensland, a southerly contraction of about 300km since Ratcliffe’s study; small numbers may be irregularly present in the Bundaberg region (P. Birt and L. Hall unpub.). The numbers of P. poliocephalus relative to P. alecto in Brisbane have declined markedly over the past ten years (H.E. Luckhoff pers. comm.). In contrast to the situation reported by Nelson (1965), camps in south-east Queensland now tend to be dominated by P. alecto (Birt and Hall unpub.), the range of which has extended south by about 500 km since Ratcliffe’s study (Webb and Tidemann 1995). A permanent colony of P. poliocephalus is now present in Melbourne (Menkhorst 1995).

Habitat

P. poliocephalus requires foraging resources and roosting sites. It is a canopy-feeding frugivore and nectarivore, which utilises vegetation communities including rainforests, open forests, closed and open woodlands, Melaleuca swamps and Banksia woodlands. It also feeds in introduced tree species in urban areas and in commercial fruit crops. The primary food source is blossom from Eucalyptus and related genera, but, in some areas it also utilises a wide range of rainforest fruits (Eby 1998). None of the vegetation communities used by P. poliocephalus produces continuous foraging resources throughout the year, and P. poliocephalus has adopted complex migration traits in response to ephemeral and patchy food resources (Nelson 1965, Spencer et al. 1991, Parry-Jones and Augee 1992, Eby 1996, 1998).

Temporally and spatially reliable resources are restricted to a small number of coastal vegetation communities in northern New South Wales and Queensland (Eby 1996), but these predictable food sources support relatively few animals. The majority of P. poliocephalus either additionally or exclusively feed on the flowers of Eucalyptus which are usually produced as superabundant pulses in seasonal, but annually irregular patterns. Patterns of use of eucalypts are complex and unpredictable and as a result, essential habitat for P. poliocephalus is difficult to define.

P. poliocephalus roosts in aggregations of various sizes on the exposed branches, commonly of emergent trees. Roost vegetation includes rainforest patches, stands of Melaleuca, mangroves and riparian vegetation (Ratcliffe 1931, Nelson 1965), but colonies also use highly modified vegetation in urban areas (Tidemann and Vardon 1997, Birt et al. 1998). P. poliocephalus can maintain fidelity to roost sites for extended periods (Lunney and Moon 1994) and, although new sites have been colonised in recent times (Tidemann and Vardon 1997), roost sites may be limiting over some of the species' range.

Reasons for decline

P. poliocephalus is affected by a number of threatening processes, the most serious of which is loss of foraging and roosting habitat.

Habitat loss

Ratcliffe (1931), on the basis of anecdotal evidence, believed that the species had declined by 50% since pre-European times as a result of clearing of native vegetation (and competition with P. alecto). Clearing of native vegetation for agriculture and forestry operations has accelerated since that time and has been particularly widespread over the range of P. poliocephalus in eastern Australia (State of the Environment Advisory Committee 1996). The loss of native habitat is assumed to have resulted in the destruction or disturbance of roosting and foraging habitats of the species.

The complexity of the habitat requirements of P. poliocephalus, particularly its requirement for multiple, geographically dispersed populations of food trees, mitigate against its conservation within a system of forest reserves leaving the species vulnerable to population declines from land use decisions and management strategies in unreserved forests of various tenures (Parry-Jones 1993, Pressey 1994, Eby 1996, Tidemann and Vardon 1997).

Annually reliable winter resources are limited in distribution to a narrow coastal strip in northern New South Wales and Queensland, and primarily occur on freehold land (Eby 1996, Pressey et al. 1996). These coastal areas are targeted for intensive residential development to cater for a projected 25% increase in the human population over the next ten years (NSW Department of Planning 1995). Substantial tracts of important winter flowering species, particularly Melaleuca quinquenervia and E. robusta have been zoned for urban and rural residential development. Approximately 40% of the extant M. quinquenervia and 36% of the E. robusta within the City of Coffs Harbour, New South Wales are on land targeted for development by 2010 (Coffs Harbour City Council 1996). Seventy percent of the M. quinquenervia swamps between Noosa Heads and Tweed Heads have been lost to urban development (Hall unpublished).

Exploitation

P. poliocephalus destroys commercial fruit in Queensland and New South Wales (Jamieson 1988, Slack 1990, Tidemann et al. 1997). Direct killing of animals on orchards and harassment and destruction of roosts has almost certainly played a role in the species’ decline. The exact number of animals destroyed is unknown, but estimates as high as 100,000 annually have been made (Vardon and Tidemann 1995). The impact is more substantial than direct deaths alone would indicate, for a large proportion of animals shot on orchards are pregnant and lactating females (Parry-Jones 1993, Tidemann et al. 1997). Permit systems in Queensland and New South Wales regulate pest destruction activities, but the impact of this destruction on both the size and structure of the population remains unquantified (although widely believed to be detrimental).

Roost sites have been legally protected since 1986 in New South Wales and 1994 in Queensland (Tidemann and Vardon 1997), but the recent discovery of lyssavirus in Australia may increase the persecution of flying-foxes and their colonies in places where they are known to roost in large numbers and are already regarded by some people as a nuisance (Tidemann et al. 1997).

Competition and hybridization

Competition with P. alecto (and perhaps P. scapulatus) may be a threat to P. poliocephalus. The distribution of P. alecto has undergone a substantial southerly shift since it was first described, extending further into coastal areas inhabited by P. poliocephalus (Webb and Tidemann 1995). The two species share roosts and diet plants, and increasing competition for resources in the northern part of the range of P. poliocephalus is assumed, although it has not been assessed. Hybrids between P. poliocephalus and P. alecto have occurred in captivity (Luckoff pers. comm.).

Pollutants and pathogens

Some urban-dwelling P. poliocephalus accumulate lethal levels of lead from the environment (Hariono et al. 1993) and they are also prone to electrocution which kills disproportionately high numbers of lactating females (Flying-fox Information and Conservation Network, Ku-ring-gai Bat Colony Committee, L.S. Hall unpub., Tidemann unpub.). The effects of the recently discovered pathogens, Australian bat Lyssavirus, Bat Paramyxovirus and Menangle Pig virus (Hoar et al. 1998) on P. poliocephalus are unknown, but may, in concert with other threatening processes, be expected to have an adverse impact on the population. Other miscellaneous threats are detailed by Eby (1995).

Conservation reserves on which species occurs

The species uses most national parks and other protected areas within its range, but none on its own provides the resources necessary to sustain a viable population in the long term.

Other public land on which species occurs

Roosts and foraging resources are contained in many areas including: forests under State ownership in Queensland, New South Wales and Victoria; Crown Lands; and some lands under control of local government.

Other land on which species occurs

Any land supporting food plants or roost habitat (occupied or potential).

Is knowledge about species adequate for objectives and actions to be defined accurately?

A great deal is known about the biology of this species, but knowledge of the population status is inadequate. Two recent estimates have been made. In March 1989 the New South Wales population was estimated to be 570,000 (K. Parry-Jones, C. Palmer and P. Eby unpub.) and in July 1998 the total population was estimated to be 360,000 (P. Birt, G. Richards, P. Eby, K. Parry-Jones and J. Nelson unpub.). These figures, however, must be interpreted with caution because (1) the 1998 count was made at a time of year when the species is dispersed (Nelson 1965) and (2) the counting methodology needs to be validated. Further work needs to be done to (1) validate population estimates (2) define habitat requirements in relation to the protected area system and (2) develop cost-effective methods of protecting fruit crops. Future counts need to be made during the breeding season when populations are aggregated.

Recovery objectives

Management and research actions completed or underway

Management and research actions required

Organisation (s) responsible for conservation of the species

Environment Australia (if species is listed), Queensland Parks and Wildlife Service, New South Wales National Parks and Wildlife Service, Victorian Department of Natural Resources and Environment. Conservation of habitat is additionally the responsibility of: Queensland Department of Natural Resources, New South Wales State Forests, State planning authorities and local government bodies throughout the range. Some habitat is in private ownership.

Other organisation(s)/individuals involved

Wildlife care groups in New South Wales, Queensland and Victoria; private landholders; orchard industry.

Can recovery be carried out with current resources?

No. Current and past levels of funding for research are poor and resources allocated to management by State government bodies is inadequate.

The following is required:

(Validation of methods for estimating population size based on based on 1 person for 12 months 60K plus materials 20K; implement monitoring programme based on 1 person for 3 months 15K plus expenses 10K per annum; document/model foraging habitat based on 1 person for 2 years 120K plus materials and expenses 30K ; develop on-crop control methods based on 2.5 persons for 2 years 175K, plus expenses 23K and materials 107K; facilitate protection of existing camp sites on private land based on 1 person for 12 months 60K plus expenses 20K, and 500K (nominal estimate) to identify camps and negotiate agreements with landowners / purchase land; National recovery plan 20K).

Bibliography

Andersen K. 1912. Catalogue of the Chiroptera in the collection of the British Museum. Volume i: Megachiroptera. Second Edition. Johnson Reprint Company, London.

Birt P., Markus N., Collins L. and Hall L. 1998. Urban flying-foxes. Nature Australia 26 (2), 54–59.

Coffs Harbour City Council. 1996. Coffs Harbour urban development strategy. Coffs Harbour City Council, Coffs Harbour.

Collett R. 1887. On a collection of mammals from central and northern Queensland. Zoologische Jahrbucher 829–940.

Eby P. 1991. Seasonal movements of grey-headed flying-foxes, Pteropus poliocephalus (Chiroptera: Pteropodidae), from two maternity camps in northern New South Wales. Wildlife Research 18, 547–559.

Eby P. 1995. The biology and management of flying foxes in NSW. Species Management Report No. 18, NSW Parks and Wildlife Service, Hurstville.

Eby P. 1996. Interactions between the Grey-headed flying fox Pteropus poliocephalus (Chiroptera: Pteropodidae) and its diet plants – seasonal movements and seed dispersal. PhD Thesis, University of New England, Armidale, NSW (unpublished).

Eby P. 1998. An analysis of diet specialization in frugivorous Pteropus poliocephalus (Megachiroptera) in Australian subtropical rainforest. Australian Journal of Ecology 23, 443–456.

Hariono B., Ng J. and Sutton R.H. 1993. Lead concentrations in tissues of fruit bats ( Pteropus sp.) in urban and non-urban areas. Wildlife Research 20, 315–320

Hoar B.R., Chomel B.B., Rodrigues F.J.A. and Colley P.A. 1998. Zoonoses and potential zoonoses transmitted by bats. Journal of the American Veterinary Medicine Association 212, 1714–1720.

Jamieson G.I. 1988. Fruit losses from flying-foxes in Queensland. Macroderma 4, 34–42

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Lunney D. and Moon C. 1997. Flying foxes and their camps in the remnant rainforests of north-east New South Wales. pp. 247–277 in J. Dargavel (Ed.) Australia’s ever-changing forests III. Proceedings of the Third National Conference on Australian Forest History. Centre for Resource and Environmental Studies, Canberra.

Menkhorst P.W (Ed.) 1995. Mammals of Victoria: distribution, ecology and conservation. Oxford: Oxford University Press.

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Parry-Jones K. A. 1993. The movements of Pteropus poliocephalus in New South Wales. PhD Thesis, University of New South Wales, Sydney (unpublished).

Parry-Jones K.A. and Augee M.L. 1991. The diet of flying-foxes in the Sydney and Gosford areas of New South Wales, based on reported sightings 1989–90. Australian Zoologist 27, 49–54.

Parry-Jones K.A. and Augee M.L., 1992. Movements of the Grey-headed Flying Foxes (Pteropus poliocephalus) to and from a colony site on the central coast of New South Wales. Wildlife Research 19, 331–40.

Pressey R. L. 1994. Land classifications are necessary for conservation planning but what do they tell us about fauna? pp 31–41 in D. Lunney, S. Hand, P. Reed and D. Butcher (Eds) Future of the Fauna of Western New South Wales. Surrey Beatty & Sons, Chipping Norton.

Pressey R.L., Ferrier S., Hager T.C., Woods C.A., Tully S.L. and Weinman K.M. 1996. How well protected are the forests of north-eastern New South Wales? – analyses of forest environments in relation to formal protection measures, land tenure, and vulnerability to clearing. Forest Ecology and Management 85, 311–333.

Ratcliffe F.N. 1931. The Flying-fox (Pteropus) in Australia. CSIR Bulletin No. 53, Melbourne.

Slack J. M. 1990. Flying fox damage in low-chill stone fruit orchards. pp. 56–60 in J. M. Slack (Ed.). Flying fox Workshop Proceedings. NSW Agriculture and Fisheries, Lismore, N.S.W.

Spencer H. J., Palmer C. and Parry-Jones K. 1991. Movements of fruit-bats in eastern Australia, determined by using radio-tracking. Wildlife Research 18, 463–468.

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Tidemann C.R. Kelson S.L. and Jamieson G. 1997. Flying-fox damage to orchard fruit in Australia – incidence, extent and economic impact. Australian Biologist 10, 179–186.

Tidemann C.R. and Vardon M.J. 1997. Pest, pestilence, pollen and pot-roasts: the need for community-based management of flying-foxes in Australian. Australian Biologist 10, 79–85.

Tidemann C., Vardon M., Nelson J., Speare R. and Gleeson L. 1997. Health and conservation implications of Australian bat Lyssavirus. Australian Zoologist 30, 369–376.

Vardon M.J. and Tidemann C.R. 1995. Harvesting of flying-foxes (Pteropus spp.) in Australia: Could it promote the conservation of endangered Pacific Island species. pp 82–85 in G. Grigg, P. Hale and D. Lunney (Eds) Conservation through the sustainable use of wildlife. University of Queensland, Brisbane.

Wahl D.E. 1994. The management of flying-foxes in New South Wales. MSc thesis, University of Canberra (unpublished).

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Webb N.J. and Tidemann C.R. 1996. Mobility of Australian flying-foxes, Pteropus spp. (Megachiroptera): evidence from genetic variation. Proceeding of the Royal Society London Series B 263, 497–502.

Authors for the species

Chris Tidemann
Peggy Eby
Kerryn Parry-Jones
Michael Vardon