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

Feral pigs: predicting future distributions

Brendan D. Cowled A F , Fiona Giannini B , Sam D. Beckett C , Andrew Woolnough D , Simon Barry E , Lucy Randall B and Graeme Garner A
+ Author Affiliations
- Author Affiliations

A Office of the Chief Veterinary Officer, Department of Agriculture, Fisheries and Forestry, GPO Box 858, Canberra, ACT 2601, Australia.

B Bureau of Rural Sciences, Department of Agriculture, Fisheries and Forestry, Canberra, ACT 2601, Australia.

C Broadleaf Capital International Pty Ltd, Gundaroo, NSW 2620, Australia.

D Department of Agriculture and Food Western Australia, Locked Bag 4, Bentley Delivery Centre, WA 6983, Australia.

E CSIRO Mathematical and Information Science, GPO Box 664, Canberra, ACT 2601, Australia.

F Corresponding author. Email: brendan.cowled@daff.gov.au

Wildlife Research 36(3) 242-251 https://doi.org/10.1071/WR08115
Submitted: 30 July 2008  Accepted: 6 February 2009   Published: 15 April 2009

Abstract

Feral pig populations are expanding in many regions of the world following historically recent introductions. Populations are controlled to reduce damage to agriculture and the environment, and are also a recreational hunting resource. Knowledge of the area over which feral pigs may expand in the future could be used regionally to assist biosecurity planning, control efforts and the protection of biodiversity assets. The present study sought to estimate the future distribution of a recently introduced, expanding feral pig population in the remote Kimberley region of north-western Australia. An existing survey of feral pig distributions was enhanced and remote-sensing and weather data, reflecting or correlated with factors that may affect feral pig distributions, were collated and analysed. Relationships between feral pig distributions and these data were identified by using a generalised additive modelling approach. By the use of the model, the distribution of favourable habitat was estimated across the study region (89 125 km2). The potential future distribution of feral pigs in the Kimberley was then estimated, assuming only natural dispersal of feral pigs from areas of known feral pig status (cf. hunter-assisted movements or escape of domestic pigs). The modelling suggests that feral pigs could expand their distribution by realistic natural dispersal in the future (to 61 950 km2). This expansion possibility contains several strategically important areas (such as sea ports and biologically significant wetlands). This approach has the potential to improve biosecurity planning for the containment of the feral pig in the Kimberley and may have utility for other recently introduced invasive species in other regions. These results may also be used to improve pest-management programmes and contingency planning for exotic-disease incursions.


Acknowledgements

E. Lawrence provided helpful statistical advice. D. Goddard, M. Everett and C. Richards helped refine the distribution of feral pigs. P. Caley provided useful comments on a draft manuscript and assistance on statistical analyses. The Australian Biosecurity Cooperative Research Centre provided financial assistance.


References

Afialo F. G. (1896). ‘A Sketch of the Natural History of Australia with Some Notes on Sport.’ (Macmillan and Co. Ltd: London.)

Anon. (2007). ‘Pest Distribution Maps from Qld PESTINFO.’ Available at http://www.nrm.qld.gov.au/pests/maps/pest_distribution/index.html [Accessed September 2007].

Artois, M. , Depner, K. R. , Guberti, V. , Hars, J. , Rossi, S. , and Rutili, D. (2002). Classical swine fever (hog cholera) in wild boar in Europe. Revue Scientifique et Technique, Office International des Épizooites 21, 287–303.
CAS | Bassett P. A. , and Bishop G. (2007). ‘Generalized Additive Models: Smart Module.’ Available at http://www.bioss.ac.uk/smart/unix/mgam/slides/frames.htm [Accessed 1 November 2007].

Brotons, L. , Thuiller, W. , Arau’jo, M. B. , and Hirzel, A. H. (2004). Presence–absence versus presence-only modelling methods for predicting bird habitat suitability. Ecography 27, 437–448.
Crossref | GoogleScholarGoogle Scholar | Bureau of Meteorology (2003 a). Mean monthly and annual rainfall data (base climatological data set). Bureau of Meteorology, Melbourne. Available at http://www.bom.gov.au/climate/averages/climatology/gridded-data-info/metadata/md_ave_rain_1961-90.shtml

Bureau of Meteorology (2003 b). Mean monthly and mean annual temperature data (base climatological data sets). Bureau of Meteorology, Melbourne. Available at http://www.bom.gov.au/climate/averages/climatology/gridded-data-info/metadata/md_ave_temp_1961-90.shtml

Bureau of Rural Sciences (2007). ‘National Forest Inventory (Preliminary Forest Type and Extent).’ (Bureau of Rural Sciences: Canberra.) Available at http://www.daff.gov.au/brs/forest-veg/nfi [Accessed 1 July 2007].

Bureau of Rural Sciences (2008). ‘Land Cover Productivity.’ (Bureau of Rural Sciences: Canberra.) Available at http://adl.brs.gov.au/mapserv/landuse/land_use_prod.html [Accessed 1 July 2007].

Caley, P. (1993). Population dynamics of feral pigs (Sus scrofa) in a tropical riverine habitat complex. Wildlife Research 20, 625–636.
Crossref | GoogleScholarGoogle Scholar | Choquenot D. , McIlroy J. , and Korn T. (1996). ‘Managing Vertebrate Pests: Feral Pigs.’ (Bureau of Resource Sciences, Australian Government Publishing Service: Canberra.)

Cowled, B. D. , Aldenhoven, J. A. , Odeh, I. O. A. , Garrett, T. , Moran, C. , and Lapidge, S. (2008). Feral pig population structuring in the rangelands of eastern Australia: applications for designing adaptive management units. Conservation Genetics 9, 211–224.
Crossref | GoogleScholarGoogle Scholar | Department of Environment and Heritage (2006). ‘Australia – Present Major Vegetation Groups – NVIS Stage 1, Version 3.0 (100 m Vector Product).’ Canberra. Available at http://www.environment.gov.au/erin/nvis/index.html and http://www.environment.gov.au/erin/nvis/data-products.html [Accessed 14 March 2007].

Dexter, N. (1998). The influence of pasture distribution and temperature on habitat selection by feral pigs in a semi-arid environment. Wildlife Research 25, 547–559.
Crossref | GoogleScholarGoogle Scholar | Geoscience Australia (2006). ‘Geodata Topo250K Series 3: Tab Files Format.’ (Geoscience Australia: Canberra.) Available at http://www.bmr.gov.au/nmd/products/digidat/250k.htm

Giles J. R. (1980). The ecology of the feral pig in western New South Wales. Ph.D. Thesis, University of Sydney.

Gipson, P. S. , Hlavachick, B. , and Berger, T. (1998). Range expansion by wild hogs across the central United States. Wildlife Society Bulletin 26, 279–286.
Green D. M. , and Swets J. M. (1966). ‘Signal Detection Theory and Psychophysics.’ (John Wiley and Sons Inc.: New York.)

Hampton, J. O. , Higgs, T. , Knight, T. , and Spencer, P. B. S. (2005). DNA-based detection of free-ranging pigs of domestic origin, in Western Australia. Ecological Management & Restoration 6, 76–78.
Crossref | GoogleScholarGoogle Scholar | Kohavi R. (1995). A study of cross-validation and bootstrap for accuracy estimation and model selection. In ‘Proceedings of the Fourteenth International Joint Conference on Artificial Intelligence’. (Ed. C. S. Mellish.) pp. 1137–1143. (Morgan Kaufmann Publishers, Inc.: Montreal.)

Lobo, J. M. , Jiménez-Valverde, A. , and Real, R. (2008). AUC: a misleading measure of the performance of predictive distribution models. Global Ecology and Biogeography 17, 145–151.
Crossref | GoogleScholarGoogle Scholar | Long J. L. (2003). ‘Introduced Mammals of the World: Their History, Distribution and Influence.’ (CSIRO Publishing: Melbourne.)

Madin B. (2005). Modelling the spread of foot-and-mouth disease in the Kimberley. M.Sc. Thesis, The University of Sydney.

McClain, B. J. , and Porter, W. F. (2000). Using satellite imagery to assess large-scale habitat characteristics of Adirondack Park. Environmental Management 26, 553–561.
Crossref | GoogleScholarGoogle Scholar | PubMed | McDonald R. C. , Isbell R. F. , Speight J. G. , Walker J. , and Hopkins M. S. (1990). ‘Australian Soil and Land Survey Field Handbook.’ 2nd edn. (Inkata Press: Melbourne.)

McInerney, J. , Small, K. J. , and Caley, P. (1995). Prevalence of Mycobacterium bovis infection in feral pigs in the Northern Territory. Australian Veterinary Journal 72, 448–451.
Crossref | GoogleScholarGoogle Scholar | CAS | PubMed | OIE (2007). Immediate notification: foot and mouth disease – Turkey. Available at http://www.oie.int/wahis/reports/en_imm_0000004954_20070228_122554.pdf [Accessed 5 June 2007].

Phillips, B. L. , Chipperfield, J. D. , and Kearney, M. R. (2008). The toad ahead: challenges of modelling the range and spread of an invasive species. Wildlife Research 35, 222–234.
Crossref | GoogleScholarGoogle Scholar | ProMED-mail (2007). ‘Reprint No.: 2862A, Foot & Mouth Disease, Wild Boar – Israel (North & Northeast) 17 May: 20070517.1571.’ Available at http://www.promedmail.org [Accessed 1 June 2007].

Pullar, E. M. (1953). The wild (feral) pigs of Australia: their origin, distribution and economic importance. Memoirs of the National Museum, Melbourne 18, 7–23.
Semon R. (1899). ‘In the Australasian Bush and on the Coast of the Coral Sea, Being the Experiences and Observations of a Naturalist in Australia, New Guinea and the Moluccas.’ (Macmillan and Co. Ltd: London.)

Spencer, P. B. S. , and Hampton, J. O. (2005). Illegal translocation and genetic structure of feral pigs in Western Australia. Journal of Wildlife Management 69, 377–384.
Crossref | GoogleScholarGoogle Scholar | West P. , and Saunders G. (2003). Pest animal survey 2002. An analysis of pest animal distribution and abundance across NSW and the ACT. NSW Agriculture, Orange.

Wilson G. , Dexter N. , O’Brien P. , and Bomford M. (1992). ‘Pest animals in Australia: a survey of introduced wild animals.’ (Bureau of Rural Resources and Kangaroo Press: Kenthurst, NSW.)

Woolnough, A. P. , West, P. B. , and Saunders, G. R. (2004). Institutional knowledge as a tool for pest animal management. Ecological Management & Restoration 5, 226–228.
Woolnough A. P. , Gray G. S. , Lowe T. J. , Kirkpatrick W. E. , Rose K. , and Martin G. R. (2005). Distribution and abundance of pest animals in Western Australia: a survey of institutional knowledge. Unpublished report. Vertebrate Pest Research Section, Department of Agriculture, Forrestfield, Western Australia.