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Ecology, management and conservation in natural and modified habitats
RESEARCH ARTICLE

Current and future threats from non-indigenous animal species in northern Australia: a spotlight on World Heritage Area Kakadu National Park

Corey J. A. Bradshaw A E , Iain C. Field A , David M. J. S. Bowman A B , Chris Haynes C and Barry W. Brook A D
+ Author Affiliations
- Author Affiliations

A School for Environmental Research, Institute of Advanced Studies, Charles Darwin University, Darwin, NT 0909, Australia.

B Current address: Department of Plant Science, University of Tasmania, Private Bag 05, Hobart, Tas. 7001, Australia.

C School for Social Policy and Research, Institute of Advanced Studies, Charles Darwin University, Darwin, NT 0909, Australia.

D Research Institute for Climate Change and Sustainability, School of Earth and Environmental Sciences, University of Adelaide, SA 5005, Australia.

E Corresponding author. Email: corey.bradshaw@cdu.edu.au

Wildlife Research 34(6) 419-436 https://doi.org/10.1071/WR06056
Submitted: 23 May 2006  Accepted: 3 August 2007   Published: 2 November 2007

Abstract

Non-indigenous animal species threaten biodiversity and ecosystem stability by damaging or transforming habitats, killing or out-competing native species and spreading disease. We use World Heritage Area Kakadu National Park, northern Australia, as a focal region to illustrate the current and potential threats posed by non-indigenous animal species to internationally and nationally recognised natural and cultural values. Available evidence suggests that large feral herbivores such as Asian swamp buffalo, pigs and horses are the most ecologically threatening species in this region. This may reflect the inherent research bias, because these species are highly visible and impact primary production; consequently, their control has attracted the strongest research and management efforts. Burgeoning threats, such as the already established cane toad and crazy ant, and potentially non-indigenous freshwater fish, marine invertebrates and pathogens, may cause severe problems for native biodiversity. To counter these threats, management agencies must apply an ongoing, planned and practical approach using scientifically based and well funded control measures; however, many stakeholders require direct evidence of the damage caused by non-indigenous species before agreeing to implement control. To demonstrate the increasing priority of non-indigenous species research in Australia and to quantify taxonomic and habitat biases in research focus, we compiled an extensive biography of peer-reviewed articles published between 1950 and 2005. Approximately 1000 scientific papers have been published on the impact and control of exotic animals in Australia, with a strong bias towards terrestrial systems and mammals. Despite the sheer quantity of research on non-indigenous species and their effects, management responses remain largely ad hoc and poorly evaluated, especially in northern Australia and in high-value areas such as Kakadu National Park. We argue that improved management in relatively isolated and susceptible tropical regions requires (1) robust quantification of density–damage relationships, and (2) the delivery of research findings that stimulate land managers to develop cost-effective control and monitoring programs.


Acknowledgements

We thank C. Crossing for assistance in preparing the manuscript. Three anonymous reviewers provided helpful comments to improve the manuscript. Funding was provided to CJAB, DMJSB and BWB by Parks Australia. The opinions expressed are our own and do not represent those of Parks Australia, the Department of Environment and Water Resources or the Commonwealth of Australia.


References

Aizen, M. A. , and Feinsinger, P. (1994). Habitat fragmentation, native insect pollinators, and feral honey bees in Argentine “chaco serrano”. Ecological Applications 4, 378–392.
Crossref | GoogleScholarGoogle Scholar | Animal Health Australia (2001). Disease Strategy: Foot-and-Mouth Disease (Version 3.0), Australian Veterinary Emergency Plan (AUSVETPLAN) Edition 3. Animal Health Australia, Canberra, ACT.

Arthington A. H., and Blühdorn D. R. (1995). Improved management of exotic aquatic fauna: R&D for Australian rivers. Occasional Paper No. 4/95. Land and Water Resources Research and Development Corporation, Canberra.

Arthington A. H., and Mitchell D. S. (1986). Aquatic invasive species. In ‘Ecology of Biological Invasions: An Australian Perspective’. (Eds R. H. Groves and J. J. Burdon.) pp. 34–53. (Australian Academy of Science: Canberra.)

Atkinson, I. A. E. (1977). A reassessment of factors particularly Rattus rattus that influenced the decline of endemic forest birds in the Hawaiian Islands. Pacific Science 31, 109–133.
Australian National Parks and Wildlife Service (1991). Kakadu National Park Plan of Management. Commonwealth of Australia, Canberra.

Baker, R. , Cannon, R. , Bartlett, P. , and Barker, I. (2005). Novel strategies for assessing and managing the risks posed by invasive alien species to global crop production and biodiversity. Annals of Applied Biology 146, 177–191.
Crossref | GoogleScholarGoogle Scholar | Baskin Y. (2002). ‘A Plague of Rats and Rubber.’ (Vines Island Press: Washington.)

Bayliss, P. , and Yeomans, K. M. (1989). The distribution and abundance of feral livestock in the Top End of the Northern Territory (1985–1986), and their relation to population control. Australian Wildlife Research 16, 651–676.
Crossref | GoogleScholarGoogle Scholar | Braysher M. (1993). ‘Managing Vertebrate Pests: Principles and Strategies.’ (Australian Government Publishing Service: Canberra.)

Brockwell S., Levitus R., Russell-Smith J., and Forrest P. (1995). Aboriginal heritage. In ‘Kakadu: Natural and Cultural Heritage and Management’. (Eds A. Press, D. Lea, A. Webb, and A. Graham.) pp. 15–63. (Australian Nature Conservancy Agency & North Australian Research Unit, Australian National University: Darwin.)

Brook, B. W. , Sodhi, N. S. , Soh, M. C. K. , and Lim, H. C. (2003). Abundance and projected control of invasive house crows in Singapore. Journal of Wildlife Management 67, 808–817.
Crossref | GoogleScholarGoogle Scholar | Catton T. (1997). ‘Inhabited Wilderness: Indians, Eskimos, and National Parks in Alaska.’ (University of New Mexico Press: Albuquerque, NM.)

Caughley J., Bomford M., Parker B., Sinclair R., Griffiths J., and Kelly D. (1998). ‘Managing Vertebrate Pests: Rodents.’ (Australian Government Publishing Service: Canberra.)

Chapman, A. (1981). Habitat preference and reproduction of feral house mice, Mus musculus, during plague and non-plague situations in Western Australia. Australian Wildlife Research 8, 567–579.
Chatty D. (2002). Animal reintroduction projects in the Middle East: conservation without a human face. In ‘Conservation and Mobile Indigenous Peoples: Displacement, Forced Settlement and Sustainable Development’. (Eds D. Chatty and M. Colchester.) pp. 227–243. (Berghahn Books: New York.)

Cheke A. S. (1987). ‘An Ecological History of the Mascarene Islands, with Particular Reference to Extinctions and Introductions of Land Vertebrates.’ (Cambridge University Press: Cambridge.)

Cheng, A. C. , and Currie, B. J. (2005). Melioidosis: epidemiology, pathology and management. Clinical Microbiology Reviews 18, 383–416.
Crossref | GoogleScholarGoogle Scholar | PubMed | Chibeba A. (2003). Nesting ecology of the Australian freshwater crocodile, Crocodylus johnstoni, on the McKinlay River: setting a baseline for assessing the potential impact of the exotic cane toad, Bufo marinus. M.Sc.Trop.Env.Man. Thesis, Charles Darwin University, Darwin.

Choquenot, D. (1993). Growth, body condition and demography of wild banteng (Bos javanicus) on Cobourg Peninsula, northern Australia. Journal of Zoology 231, 533–542.
Choquenot D., and Dexter N. (1996). Spatial variation in food limitation: distribution and abundance of feral pigs. In ‘Frontiers of Population Ecology’. (Eds R. B. Floyd, A. W. Sheppard, and P. J. De Barro.) pp. 531–546. (CSIRO Publishing: Melbourne.)

Choquenot, D. , and Ruscoe, W. A. (2003). Landscape complementation and food limitation of large herbivores: habitat related constraints on the foraging effiency of wild pigs. Journal of Animal Ecology 72, 14–26.
Crossref | GoogleScholarGoogle Scholar | Clout M. N., and Veitch C. R. (2002). Turning the tide of biological invasion. In ‘Turning the Tide: the Eradication of Invasive Species’. (Eds C. R. Veitch and M. N. Clout.) pp. 1–2. (World Conservation Union: Auckland, New Zealand.)

Cogger H. G. (2000). ‘Reptiles and Amphibians of Australia.’ (Reed New Holland: Sydney.)

Colautti, R. I. , and MacIsaac, H. J. (2004). A neutral terminology to define ‘invasive’ species. Diversity and Distributions 10, 135–141.
Crossref | GoogleScholarGoogle Scholar | Communicable Diseases Unit (2005). Vaccination Against Japanese Encephalitis. http://www.health.qld.gov.au/phs/Documents/cdu/9397.pdf (Communicable Diseases Unit: Brisbane.)

Cook, G. D. , Setterfield, S. A. , and Maddison, J. P. (1996). Shrub invasion of a tropical wetland: implications for weed management. Ecological Applications 6, 531–537.
Crossref | GoogleScholarGoogle Scholar | Corbett L. K. (1995a). Bali banteng. In ‘The Mammals of Australia’. (Ed. R. Strahan.) pp. 726–728. (Reed New Holland: Sydney.)

Corbett L. K. (1995b). ‘The Dingo in Australia and Asia.’ (University of New South Wales Press: Sydney.)

Corbett L. K. (2001). The conservation status of the dingo Canis lupus dingo in Australia, with particular reference to New South Wales: threats to pure dingoes and potential solutions. In ‘A Symposium on the Dingo’. (Eds C. R. Dickman and D. Lunney.) pp. 10–19. (Royal Zoological Society of New South Wales: Sydney.)

Cowie, I. D. , and Werner, P. A. (1993). Alien plant species invasive in Kakadu National Park, tropical northern Australia. Biological Conservation 63, 127–135.
Crossref | GoogleScholarGoogle Scholar | Cronin J. P., and Frazer P. T. (2004). Swine Brucellosis. http://www.dpi.qld.gov.au/pigs/4471.html (Department of Primary Industries and Fisheries, Queensland Government: Brisbane.)

Cross, P. C. , and Getz, W. M. (2006). Assessing vaccination as a control strategy in an ongoing epidemic: bovine tuberculosis in African buffalo. Ecological Modelling 196, 494–504.
Crossref | GoogleScholarGoogle Scholar | Database on Introductions of Aquatic Species (2007). Available from www.fao.org/fi/website/FISearch.do?dom=introsp. (Food and Agriculture Organization of the United Nations: Rome.)

Davies J., Higginbottom K., Noack D., Helen R., and Young E. (1999). ‘Sustaining Eden: Indigenous Community Wildlife Management in Australia.’ (International Institute for Environment and Development: London.)

De Poorter M., Browne M., Lowe S., and Clout M. N. (2005). The ISSG Global Invasive Species Database and other aspects of an early warning system. In ‘Invasive Alien Species: A New Synthesis’. (Eds H. A. Mooney, R. N. Mack, J. A. McNeeley, L. E. Neville, P. J. Schei, and J. K.Waage.) pp. 59–83. (Island Press: Washington.)

De Stoppelaire, G. H. , Gillespie, T. W. , Brock, J. C. , and Tobin, G. A. (2004). Use of remote sensing techniques to determine the effects of grazing on vegetation cover and dune elevation at Assateague Island National Seashore: impact of horses. Environmental Management 34, 642–649.
Crossref | GoogleScholarGoogle Scholar | PubMed | Department of Environment and Heritage (2004a). The feral buffalo (Bubalus bubalis). Australian Government: Canberra.

Department of Environment and Heritage (2004b). Feral horse (Equus caballus) and feral donkey (Equus asinus). Australian Government, Canberra.

Department of Environment and Heritage (2005). Review of progress on invasive species. Natural Resource Management Policy Branch, Canberra.

Department of Health and Ageing (2004). Japanese encephalitis fact sheet. Commonwealth of Australia, Canberra. Available at http://www.health.gov.au/internet/wcms/publishing.nsf/Content/health-arbovirus-pdf-fsjapanese.htm [checked 2 September 2007]

Dexter, N. (2003). Stochastic models of foot and mouth disease in feral pigs in the Australian semi-arid rangelands. Journal of Applied Ecology 40, 293–306.
Dickman C. R. (1996). ‘Overview of the Impacts of Feral Cats on Australian Native Fauna.’ (Australian Nature Conservation Agency: Canberra.)

Doody, J. S. , Green, B. , Sims, R. , Rhind, D. , West, P. , and Steer, D. (2006). Indirect impacts of invasive cane toads (Bufo marinus) on nest predation in pig-nosed turtles (Carettochelys insculpta). Wildlife Research 33, 349–354.
Crossref | GoogleScholarGoogle Scholar | East T. J. (1990). ‘Erosion and Sediment Processes in the Kakadu Conservation Zone, South Alligator River Catchment, Northern Territory.’ (Australian Government Publishing Service: Canberra.)

Ebenhard, T. (1988). Introduced birds and mammals and their ecological effects. Swedish Wildlife Research 13, 1–107.
English A. W. (2001). report on the management of feral horses in national parks in New South Wales. NSW National Parks and Wildlife Service, Sydney.

Fairfax, R. , Fensham, R. , Wager, R. , Brooks, S. , Webb, A. , and Unmack, P. (2007). Recovery of the red-finned blue-eye: an endangered fish from springs of the Great Artesian Basin. Wildlife Research 34, 156–166.
Crossref | GoogleScholarGoogle Scholar | Field I. C., Bradshaw C. J. A., and Hayes C. (Eds.) (2007). Feral animals in Kakadu National Park: a management strategy for the future. Report submitted to the Department of Environment and Water Resources, Parks Australia North. School for Environmental Research, Charles Darwin University, Darwin.

Fleming P., Corbett L. K., Harden R., and Thomson P. (2001). Managing the impacts of dingoes and other wild dogs. Bureau of Rural Sciences, Canberra.

Fordham, D. , Georges, A. , Corey, B. , and Brook, B. W. (2006). Feral pig predation threatens the indigenous harvest and local persistence of snake-necked turtles in northern Australia Biological Conservation 133, 379–388.
Crossref | GoogleScholarGoogle Scholar | Furze B., de Lacy T., and Birckhead J. (1996). ‘Culture, Conservation and Biodiversity.’ (John Wiley & Sons: New York.)

Garnett S., and Crowley G. M. (2000). ‘Action Plan for Australian Birds 2000.’ (Environment Australia: Canberra.)

Global Invasive Species Database (2007). Available from www.issg.org. (World Conservation Union Species Survival Commission, Invasive Species Specialist Group: Auckland, New Zealand.)

Graham A., Raskin S., McConnell M., and Begg R. (1982). An aerial survey of feral donkeys in the VRD. Conservation Commision of the Northern Territory, Darwin.

Graham A., Johnson K., and Graham P. (1986). An aerial survey of horses and other large animals in the Alice Springs and Gulf regions. Technical Report. Conservation Commission of the Northern Territory, Alice Springs.

Grice, A. C. (2004). Weeds and the monitoring of biodiversity in Australian rangelands. Austral Ecology 29, 51–58.
Crossref | GoogleScholarGoogle Scholar | Griffiths A. D., Holland D. C., and Whitehead P. J. (2004). Impact of the exotic cane toad (Bufo marinus) on the survival of lowland Varanus species in Kakadu National Park. Kakadu National Park and Department of Environment and Heritage, Jabiru, NT.

Hamilton, M. A. , Murray, B. R. , Cadotte, M. W. , Hose, G. C. , Baker, A. C. , Harris, C. J. , and Licari, D. (2005). Life-history correlates of plant invasiveness at regional and continental scales. Ecology Letters 8, 1066–1074.
Crossref | GoogleScholarGoogle Scholar | Hone J. (1986). An evaluation of helicopter shooting of feral pigs. Report to the Conservation Commission of the Northern Territory, Darwin, Northern Territory, Australia.

Hone, J. (2002). Feral pigs in Namadgi National Park, Australia: dynamics, impacts and management. Biological Conservation 105, 231–242.
Crossref | GoogleScholarGoogle Scholar | IUCN (2000). Guidelines for the prevention in biodiversity loss caused by alien invasive species. Gland, Switzerland.

Izac, A.-M. N. , and O’Brien, P. H. (1991). Conflict, uncertainty and risk in feral pig management: the Australian approach. Journal of Environmental Management 32, 1–18.
Crossref | GoogleScholarGoogle Scholar | King D., and Green B. (1993). ‘Goanna: The Biology of Varanid Lizards.’ (New South Wales University Press: Sydney.)

Krebs, C. J. , Chitty, D. , Singleton, G. , and Boonstra, R. (1995). Can changes in social behaviour help to explain house mouse plagues in Australia? Oikos 73, 429–434.
Crossref | GoogleScholarGoogle Scholar | Letts G. A. (1979). ‘Feral Animals in the Northern Territory.’ (Department of Primary Production: Darwin.)

Leung, B. , Lodge, D. M. , Finnof, D. , Shogren, J. F. , Lewis, M. A. , and Lamberti, G. (2002). An ounce of prevention or a pound of cure: bioeconomic risk analysis of invasive species. Proceedings of the Royal Society of London. Series B. Biological Sciences 269, 2407–2413.
Crossref | GoogleScholarGoogle Scholar | Lever C. (2001). ‘The Cane Toad: The History and Ecology of a Successful Colonist.’ (Westbury Academic and Scientific Publishing: West Yorkshire, UK.)

Levett, P. N. , Walton, D. , Waterman, L. D. , Whittington, C. U. , Mathison, G. E. , and Edwards, C. O. R. (1998). Surveillance of leptospiral carriage by feral rats in Barbados. West Indian Medical Journal 47, 15–17.
Long K., and Robley A. (2004). Cost effective feral animal exclusion fencing for areas of high conservation value in Australia. Australian Government Department of Environment and Heritage, Canberra.

Lonsdale, W. M. (1994). Inviting trouble: introduced pasture species in northern Australia. Australian Journal of Ecology 19, 345–354.
Crossref | GoogleScholarGoogle Scholar | Marshall A. J., Cribb H. N., and Thompson M. J. (2003). Exotic marine pests: what is being done about preventing their introduction. Darwin Harbour Plan of Management Workshop. Available at: http://kakadu.nt.gov.au/pls/portal30/docs/folder/dbird_f/aquatic/marine_pests/exotic_marine_pests.pdf

Martin, J.-L. , Thibault, J.-C. , and Bretagnolle, V. (2000). Black rats, island characteristics, and colonial nesting birds in the Mediterranean: consequences of an ancient introduction. Conservation Biology 14, 1452–1466.
Crossref | GoogleScholarGoogle Scholar | Matthews D., Bryan R., and Edwards G. (2001). Recovery of the black-footed rock-wallaby following horse removal on Finke Gorge National Park, Northern Territory. In ‘Twelfth Australasian Vertebrate Pest Conference’. (Natural Resources and Environment: Melbourne.)

McCool, C. J. , and Newton-Tabrett, D. A. (1979). The route of infection in tuberculosis in feral buffalo. Australian Veterinary Journal 55, 401–402..
McLaren G., and Cooper W. (2001). ‘Distance, Drought and Dispossession: A History of the Northern Territory Pastoral Industry.’ (Northern Territory University Press: Darwin.)

McLeod R. (2004). ‘Counting the Cost: Impact of Invasive Animals in Australia 2004.’ (Cooperative Research Centre for Pest Animal Control: Canberra.)

Mooney H. A., and Hobbs R. J. (Eds.) (2000). ‘Invasive Species in a Changing World.’ (Island Press: Washington, DC.)

Moritz, C. , Richardson, K. S. , Ferrier, S. , Monteith, G. B. , Stanisic, J. , Williams, S. E. , and Whiffin, T. (2001). Biogeographical concordance and efficiency of taxon indicators for establishing conservation priority in a tropical rainforest biota. Proceedings of the Royal Society of London. Series B. Biological Sciences 268, 1875–1881.
Crossref | GoogleScholarGoogle Scholar | Moyle P. B., and Leidy R. A. (1992). Loss of biodiversity in aquatic ecosystems: evidence from fish faunas. In ‘Conservation Biology: The Theory and Practice of Nature Conservation, Preservation and Management’. (Eds P. L. Fiedler and S. K. Jain.) pp. 127–169. (Chapman and Hall: New York.)

Mulrennan, M. E. , and Woodroffe, C. D. (1998). Saltwater intrusion into the coastal plains of the lower Mary River, Northern Territory, Australia. Journal of Environmental Management 54, 169–188.
Crossref | GoogleScholarGoogle Scholar | Mulvaney J., and Kamminga J. (1999). ‘Prehistory of Australia.’ (Allen & Unwin: Sydney.)

Mutze, G. J. (1991). Mouse plagues in South Australian cereal-growing areas. III. Changes in mouse abundance during plague and non-plague years, and the role of refugia. Wildlife Research 18, 593–603.
Crossref | GoogleScholarGoogle Scholar | National Introduced Marine Pest Information System (2002). Available from www.marine.csiro.au/crimp/nimpis. CSIRO Marine Research, Hobart.

National Office of Animal and Plant Health (2000). ‘Wild Animal Management Manual: Strategic and Operational Guidelines, Australian Veterinary Emergency Plan (AUSVETPLAN), Edition 2.’ (Ministry of Agriculture, Fisheries and Forestry: Canberra.)

O’Brien, P. H. (1987). Socio-economic and biological impact of the feral pig in New South Wales: an overview and alternative management plan. The Rangeland Journal 9, 96–101.
Crossref | GoogleScholarGoogle Scholar | Oakwood M. (2004). The effect of cane toads on a marsupial carnivore, the northern quoll, Dasyurus hallucatus. Department of Environment and Heritage, Darwin.

Oldroyd, B. P. (1998). Controlling feral honey bee, Apis mellifera L. (Hymenoptera: Apidae), populations in Australia: methodologies and costs. Australian Journal of Entomology 37, 97–100.
Crossref | GoogleScholarGoogle Scholar | Olsen P., Silcocks A., and Westin M. (2006). ’ The State of Australia’s Birds – Invasive Species.’ (Birds Australia: Melbourne.)

Ortega, Y. K. , and Pearson, D. E. (2005). Weak vs. strong invaders of natural plant communities: assessing invasibility and impact. Ecological Applications 15, 651–661.
Crossref | GoogleScholarGoogle Scholar | Parsons W. T., and Cuthbertson E. G. (2001). ‘Noxious Weeds of Australia.’ (CSIRO Publishing: Melbourne.)

Paton D. C. (1996). Overview of feral and managed honeybees in Australia: distribution, abundance, extent of interactions with native biota, evidence of impacts and future research. Australian Nature Conservation Agency, Canberra.

Pell, A. S. , and Tidemann, C. R. (1997). The impact of two exotic hollow-nesting birds on two native parrots in savannah and woodland in eastern Australia. Biological Conservation 79, 145–153.
Crossref | GoogleScholarGoogle Scholar | Pest Animal Control CRC (2004). The mouse: a major threat to grain producers. Pest Animal Control Co-operative Research Centre, Canberra. Available at www.pestanimal.crc.org.au/research/mouse_fact_sheet.pdf

Petty, A. M. , Werner, P. A. , Lehmann, C. E. R. , Riley, J. E. , Banfai, D. S. , and Elliot, L. P. (2007). Savanna responses to feral buffalo in Kakadu National Park, Australia. Ecological Monographs 77, 441–463.
Crossref | GoogleScholarGoogle Scholar | Rae J., Arab G., and Nordblom T. (2002). Customs excised: arid land conservation in Syria. In ‘Conservation and Mobile Indigenous Peoples: Displacement, Forced Settlement and Sustainable Development’. (Eds D. Chatty and M. Colchester.) pp. 212–226. (Berghahn Books: New York.)

Ramanamanjato, J. B. , and Ganzhorn, J. U. (2001). Effects of forest fragmentation, introduced Rattus rattus and the role of exotic tree plantations and secondary vegetation for the conservation of an endemic rodent and a small lemur in littoral forests of southeastern Madagascar. Animal Conservation 4, 175–183.
Crossref | GoogleScholarGoogle Scholar | Riley J. (2005). An assessment of the impact of a managed buffalo population on woody vegetation in a tropical wetland area. M.Trop.Env.Manag. Thesis, Charles Darwin University, Darwin.

Robinson, C. J. , and Whitehead, P. (2003). Cross-cultural management of pest animal damage: a case study of feral buffalo control in Australia’s Kakadu National Park. Environmental Management 32, 445–458.
Crossref | GoogleScholarGoogle Scholar | PubMed | Robinson T., Hyatt A., and Pallister J. (2006). The development of a cane toad biological control. Australian Government Department of Environment and Heritage, Canberra.

Root, T. L. , Price, J. T. , Hall, K. R. , Schneider, S. H. , Rosenzweig, C. , and Pounds, J. A. (2003). Fingerprints of global warming on wild animals and plants. Nature 421, 57–60.
Crossref | GoogleScholarGoogle Scholar | PubMed | Rose B. (1995). Land managment isues: attitudes and perceptions amongst Aboriginal people of central Australia. Central Land Council, Alice Springs.

Rossiter, N. A. , Setterfield, S. A. , Douglas, M. M. , and Hutley, L. B. (2003). Testing the grass-fire cycle: alien grass invasion in the tropical savannas of northern Australia. Diversity & Distributions 9, 169–176.
Crossref | GoogleScholarGoogle Scholar | Russell-Smith J. (1995). Flora. In ‘Kakadu: Natural and Cultural Heritage and Management’. (Eds A. Press, D. Lea, A. Webb and A. Graham.) pp. 127–166. (Australian Nature Conservancy Agency & North Australian Research Unit, Australian National University: Darwin.)

Saalfeld W. K. (1999). Aerial survey of large vertebrates in Arnhem Land, 1998. Parks and Wildlife Commission of the Northern Territory, Darwin.

Saunders, G. R. , and Giles, J. R. (1977). A relationship between plagues of the house mouse, Mus musculus (Rodentia: Muridae) and prolonged periods of dry weather in south-eastern Australia. Australian Wildlife Research 4, 241–247.
Crossref | GoogleScholarGoogle Scholar | Shine R. (1991). ‘Australian Snakes: A Natural History.’ (Reed Books: Sydney.)

Short, J. , Turner, B. , Risbey, D. A. , and Carnamah, R. (1997). Control of feral cats for nature conservation. II. Population reduction by poisoning. Wildlife Research 24, 703–714.
Crossref | GoogleScholarGoogle Scholar | Singleton G. R. (2002). House mouse. In ‘The Mammals of Australia’. (Ed. R. Strahan.) pp. 646–647. (Reed New Holland: Sydney.)

Skeat A. J., East T. J., and Corbett L. K. (1996). Impact of feral water buffalo. In ‘Landscape and Vegetation Ecology of the Kakadu Region, Northern Australia’. (Eds C. M. Finlayson and I. V. Oertzen.) pp. 155–177. (Kluwer Academic Publishers: The Netherlands.)

Smith C. W. (1998). Impact of alien plants on Hawai’i’s native biota. University of Hawaii, Honolulu.

Stevens S. (Ed.) (1997). ‘Conservation Through Cultural Survival.’ (Island Press: Washington, DC.)

Strahan R. (Ed.) (1995). ‘The Mammals of Australia.’ (Reed New Holland: Sydney.)

Sugden, E. A. , and Pyke, G. H. (1991). Effects of honeybees on colonies of Exoneura asimillima, an Australian native bee. Australian Journal of Ecology 16, 171–181.
Crossref | GoogleScholarGoogle Scholar | Taylor J. A., and Edwards G. (Eds.) (2005). review of the impact and control of cane toads in Australia with recommendations for future research and management approaches. Vertebrate Pests Committee, National Cane Toad Taskforce, Canberra.

Taylor, J. A. , and Friend, G. R. (1984). Ground surface features attributable to feral buffalo, Bubalus bubalis. I. Their distribution relative to vegetation structure and plant lifeform. Australian Wildlife Research 11, 303–309.
Crossref | GoogleScholarGoogle Scholar | Tisdell C. A. (1982). ‘Wild Pigs: Environmental Pest or Economic Resource?’ (Pergamon Press: Sydney.)

Tulloch, D. G. , and Cellier, K. M. (1986). Grazing behaviour of feral buffaloes on a native pasture in the northern portion of the Northern Territory. Australian Wildlife Research 13, 433–439.
Crossref | GoogleScholarGoogle Scholar | U.S. Congress Office of Technology Assessment (1993). Harmful non-indigenous species in the United States. US Government Printing Office, Washington, DC.

van Dam R. A., Walden D. J., and Begg G. W. (2002). preliminary risk assessment of cane toads in Kakadu National Park. Supervising Scientist Report 164. Environmental Research Institute of the Supervising Scientist, Jabiru.

Vaughton, G. (1996). Pollination disruption by European honeybees in the Australian bird-pollinated shrub Grevillea barklyana (Proteaceae). Plant Systematics and Evolution 200, 89–100.
Crossref | GoogleScholarGoogle Scholar | Wager R., and Jackson P. (1993). The action plan for Australian freshwater fishes. Environment Australia, Canberra.

Wanless, R. M. , Angel, A. , Cuthbert, R. J. , Hilton, G. M. , and Ryan, P. G. (2007). Can predation by invasive mice drive seabird extinctions? Biology Letters 3, 241–244.
Crossref | GoogleScholarGoogle Scholar | PubMed | Watson M., and Woinarski J. (2003). preliminary assessment of impacts of cane toads on terrestrial vertebrate fauna in Kakadu National Park. Kakadu Research Advisory Committee, Darwin.

Watts C. H. S. (2002). Black rat. In ‘The Mammals of Australia’. (Ed. R. Strahan.) pp. 659–660. (Reed New Holland: Sydney.)

West, P. , Igoe, J. , and Brockington, D. (2006). Parks and peoples: the social impact of protected areas. Annual Review of Anthropology 35, 251–277.
Crossref | GoogleScholarGoogle Scholar | Whitehead P. J., Storrs M., McKaige M., Kennett R., and Douglas M. (2000). ‘Wise Use of Wetlands in Northern Australia: Indigenous Use.’ (Northern Territory University: Darwin)

Williams D. F. (1994). ‘Exotic Ants: Biology, Impact and Control of Introduced Species.’ (Westview Press: Boulder, CO.)

Wilson, G. R. , and O’Brien, P. H. (1989). Wildlife and exotic animal disease emergencies in Australia: planning an effective response to an outbreak. Disaster Management 1, 30–35.
Wittenberg R., and Cock M. J. W. (Eds.) (2001). ‘Invasive Alien Species. How to Address One of the Greatest Threats to Biodiversity: A Toolkit of Best Prevention and Management Practices.’ (CAB International: Wallingford, UK.)

Woinarski, J. C. Z. , Hempel, C. , Cowie, I. , Brennan, K. , Kerrigan, R. , Leach, G. , and Russell-Smith, J. (2006). Distributional pattern of plant species endemic to the Northern Territory, Australia. Australian Journal of Botany 54, 627–640.
Crossref | GoogleScholarGoogle Scholar |

Wyatt, A. S. J. , Hewitt, C. L. , Walker, D. I. , and Ward, T. J. (2005). Marine introductions in the Shark Bay World Heritage property, Western Australia: a preliminary assessment. Diversity & Distributions 11, 33–44.
Crossref | GoogleScholarGoogle Scholar |

Young, G. R. , Bellis, G. A. , Brown, G. R. , and Smith, E. S. C. (2001). The crazy ant Anoplolepis gracilipes (Smith) (Hymenoptera: Formicidae) in east Arnhem Land, Australia. Australian Entomologist 28, 97–104.