Why culling will fail to solve the flying fox problem at Melbourne Botanic Gardens

by Leslie Hall, Greg Richards and Nicki Markus

There is sound scientific information that leads to the indisputable conclusion that the present intention of the MBG to cull flying foxes will not achieve their management objectives (ie a zero tolerance of flying foxes in the MBG). There are also other moral and ethical reasons why flying foxes should not be culled in the MBG. We present the following information to support the scientific case against culling.

Specific facts about the Melbourne Botanic Gardens Colony

· It is the only permanent flying fox camp site in Victoria.^1,2,3

· It is the only breeding camp site for flying foxes in Victoria.^1,2,3

· It is the most southern permanent flying fox camp in the world of any flying fox species (ie it has international and biogeographical significance). ⁴

· Grey-headed flying foxes are endemic (ie not found anywhere else in the world) to south east Queensland, coastal NSW and Victoria. ⁴

· Population counts of Grey-headed flying foxes in south east Queensland and NSW have shown a dramatic decline in numbers. ^4,5,6

· Flying foxes have been visiting Victoria since before 1900. ²

· The MBG became a permanent flying fox roost site in 1980 ². This is about the same time that Rainbow Lorikeets (Trichoglossus haematodus) became numerous around Melbourne which was caused by a decrease in the area covered by forests and the increased planting of nectar producing plants in urban areas ⁷.

· The recent permanency of the MBG flying fox camp could also be the result of progressive climate change and the condition of forests in NSW and south east Queensland ^4,8.

· There is satellite tracking , radio tracking and genetic evidence that Grey-headed flying foxes move throughout their known distribution from south-east Queensland to Victoria ^9,10,11,12. These movements are not strictly seasonal, and are caused by changes in the local abundance and quality of their food ^4,8.

· Satellite tracking ⁹ and the occurrence of sudden influxes of large numbers ^1,2,3. clearly indicate that the MGG camp site is regularly and continually visited by Grey-headed flying foxes from NSW and south-east Queensland.

· Culling has been identified as a significant threatening process to the survival of Grey-headed flying foxes in both the NSW flying fox management plan and the National Bat Action Plan ^4,8,13.

Implications of culling

· Due to decreasing numbers and habitat loss, Grey-headed flying foxes have been recommended to be listed as Vulnerable in the NSW and Victorian legislation, as well as for Federal listing under the Environmental Protection and Biodiversity Conservation Act. The Queensland Government is currently undergoing a review of the status of the Grey-headed flying fox.

· Culling in the MBG would obviously result in the killing of animals from NSW and south east Queensland. Animals killed in the MBG would be replaced by more animals from NSW and south east Queensland. To be successful, the cull would have to continue until all the flying foxes in NSW and south east Queensland were exterminated.

· Because of the continual and regular arrival of interstate flying foxes at the MBG, culling the present population of flying foxes will only ensure that the problem will continue for a very long period of time.

· Flying foxes are the only pollinator capable of linking the fragmented patches of native forests in eastern Australia, and thus ensure a healthy gene flow, and successful regrowth after logging. Therefore, the culling of foxes at the MBG will negatively impact on the pollination of Victorian native hardwood forests, which will affect the Victorian timber industry and related hardwood building activities.

· The MBG has not conducted any relevant studies on their flying fox colony to facilitate the implementation of a proper management program. At present it is impossible to distinguish between permanent residents and migratory flying foxes in these gardens.

· A similar situation with flying foxes exists in the Sydney Botanic Gardens where culling has not been considered necessary for flying fox management, and other options are being trialled.

· There has been no attempt by the MBG for lateral thinking. There are a number of examples where flying foxes camps have been developed as tourist attractions, and have increased local community income as a consequence.

· The MBG’s demonising of flying foxes by negative publicity (eg signs, newspaper articles and pamphlets), apart from being expensive, shows a gross ignorance of current knowledge of flying fox biology and is reminiscent of superstitious and antiquated thinking that is unacceptable in this modern era (eg. incorrect information about Lyssavirus).

· There is no manual or guide "How to manage flying fox colonies": MBG have not tried all management options nor have they contacted all people involved with, and who have experience in flying fox management. Some of the methods supposedly tested at the MBG need to be conducted at specific times of the year to have any chance of being effective. The MBG has not visited managed camps interstate. There are still many more options they could try and new ones are currently being developed.

· The MBG has a very narrow attitude in trying to solve their flying fox problem. The current plan to cull the bats does not make scientific sense and is based on the convenient views of a small number of researchers, against the vast majority of other flying fox researchers. Because the MBG’s parochial attitude and the lack of its appreciation of flying fox biology, the current management strategy of culling as a means of solving the flying fox problem will fail.

References

1. Aston, H. 1987. Influx of the Grey-headed flying fox Pteropus poliocephalus (Chiroptera:Pteropodidae) to the Melbourne area, Victoria, in 1986. Victorian Naturalist, 104,9-13.

2. Menkhorst, P.W., (Ed) 1995. Mammals of Victoria. Oxford University Press, Melbourne.

3. Menkhorst, P.W. and Dickson, J.M. 1985. Influxes of the Grey-headed flying fox Pteropus poliocephalus (Chiroptera:Pteropodidae) to Victoria in 1981 and 1982. Australian Mammalogy, 8, 117-121.

4. Hall, L.S. and Richards, G. 2000. Flying foxes, fruit and blossom bats of Australia. University of New Wales Press, Sydney.

5. Richards, G.C., Eby, P. and Parry-Jones, K. 1998. Estimating the Grey-headed flying fox population: an example of community involvement in bat conservation. Australasian Bat Society Newsletter, 11, 26-28.

6. Eby, P., Richards, G.C., Collins, L. and Parry-Jones, K. 1999. The distribution, abundance and vulnerability to population reduction of a nomadic nectarivore, the Grey-headed flying fox Pteropus poliocephalus in New South Wales, during a period of resource concentration. Australian Zoologist, 31,240-253.

7. Molenaar, J. 1991. City wildlife. Pp.1-17 in Victorian Urban Wildlife, ed J. Wilson. Angus and Robertson, North Ryde.

8. Eby, P. 1995. The biology and management of flying foxes in New South Wales. Species Management Report Number 18. New South Wales National Parks and Wildlife Service, Hurstville.

9. . http://www.sci.monash.edu.au/biolsci/research/flyingfoxes

10. 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.

11. 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.

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

13. Duncan, A., Baker, G.B. and Montgomery, N. 1999. The Action Plan for Australian Bats. Environment Australia, Canberra. Compiled by:

Dr LESLIE S HALL

Senior Lecturer, School of Veterinary Science, University of Queensland, St Lucia. Qld. 4072 (l.hall@mailbox.uq.edu.au)

· Co-author (with Greg Richards) of Flying foxes, fruit and blossom bats of Australia. University of NSW Press.

· Editor, First National Flying fox Symposium, Brisbane 1986. Australian Mammalogy, 10, 73-157.

· Member, Scientific Advisory Board, Bat Conservation International Inc (Texas).

· Member, IUCN Species Survival Commission, Chiropteran Specialist Group.

Wildlife Consultant, PO Box 9, Gungahlin, ACT 2912. (batmanoz@bigpond.com)

· Co-author (with Les Hall) of Flying foxes, fruit and blossom bats of Australia.

· Invited by Zoological Society of London to present a symposium paper to review fruit bat ecology.

· Invited by 12^th International Bat Conference (Malaysia) and 10^th International Bat Conference (Boston) to present symposium papers.

· PhD thesis (submitted) on bat community structure in south-eastern Australian forests.

· Current Secretary and Past-President, Australasian Bat Society.

· Member, Scientific Advisory Board, Bat Conservation International Inc (Texas).

· Member, IUCN Species Survival Commission, Chiropteran Specialist Group.

School of Veterinary Science, University of Queensland, St Lucia, Qld. 4072 (nmarkus30@hotmail.com)

· PhD thesis (submitted) on the ecology and behaviour of the Black flying fox in an urban environment.

· Member, Woodend Flying Fox Management Committee, Ipswich City Council.

· Member, Slack’s Creek Flying Fox Committee, Logan City Council.

· Editor, The Australasian Bat Society Newsletter, 1998-2000.

· Publicity Officer, Australasian Bat Society.

· Author of flying fox information sheets, Ipswich City Council.