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Biological Invasions

, Volume 15, Issue 7, pp 1523–1535 | Cite as

Modelling habitat preferences of feral pigs for rooting in lowland rainforest

  • Amanda E. Elledge
  • Clive A. McAlpine
  • Peter J. Murray
  • Iain J. Gordon
Original Paper

Abstract

Feral pigs (Sus scrofa) occupy many different habitats worldwide. Their rooting foraging behaviour poses a serious threat to biodiversity as the resulting soil disturbance alters ecosystem structure and function. Understanding what characteristics are important in selecting rooting locations can be used to predict the impact of pigs on ecosystems. We investigated patch selection for rooting by feral pigs at two spatial scales: (1) habitat variables at a site level, and (2) dependency between observations in a spatial context. Seasonal influences on the modelled environmental variables were also examined. We applied a generalised linear modelling approach and model-averaging to explain the relative importance of variables, as measured by the standardised parameter estimates and unconditional variance. Soil texture, rock cover, soil compaction and sand texture were important explanatory variables in the presence of pig rooting. Soil compaction and distance to roads had a negative influence. The highest ranking model included seven explanatory variables with a 41 % chance that this is the Kullback–Leibler best model. Six of the 128 candidate models were in the 95 % confidence set indicating low model uncertainty. Although no differences in pig rootings were detected between seasons, most rooting (65.7 %) occurred during the dry season with soil and sand texture having the strongest effect. This study highlights how pig control programmes can focus limited resources on either the strategic positioning of control devices (e.g., traps and baits) to either reduce the number of pigs or help prioritise habitats of high conservation value for protection (e.g., exclusion fencing).

Keywords

Foraging Generalised linear modelling Habitat preferences Model averaging Rooting Sus scrofa 

Notes

Acknowledgments

This study was funded by the Invasive Animals Cooperative Research Centre (IA-CRC) and the Commonwealth Scientific and Industrial Research Organisation (CSIRO). The authors are grateful to the Kuku Yalanji Traditional Owners and Queensland Parks and Wildlife Service for access to the study sites. We thank Bilyana Miroak, Elizabeth ‘Ceinwen’ Edwards, Victoria Lake and Michiel Steenhauer for assistance with fieldwork; Greg Keith (Queensland Parks and Wildlife Service), Paul Nelson (James Cook University, JCU), Suzanne Berthelsen (JCU, formerly CSIRO) and Peter Logan (Cairns Regional Council, formerly Douglas Shire Council) for their contribution and support. We also thank Renee Treml (The University of Queensland, UQ) for GIS maps; Michael Liddell (JCU) for use of climatic data collected at the Australian Canopy Crane Research Facility in Cape Tribulation; and Bronwyn Price (UQ), Michiala Bowen (UQ) and Jonathan Rhodes (UQ) for assistance with R scripts. David Westcott (CSIRO), Dan Metcalfe (CSIRO) and two other anonymous reviewers provided helpful comments on an earlier draft.

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Copyright information

© Springer Science+Business Media Dordrecht 2012

Authors and Affiliations

  • Amanda E. Elledge
    • 1
    • 2
    • 3
    • 4
    • 5
  • Clive A. McAlpine
    • 3
  • Peter J. Murray
    • 4
  • Iain J. Gordon
    • 1
    • 2
    • 6
  1. 1.CSIRO Ecosystem SciencesTownsvilleAustralia
  2. 2.Invasive Animals Cooperative Research CentreCanberraAustralia
  3. 3.School of Geography, Planning and Environmental ManagementThe University of QueenslandSt LuciaAustralia
  4. 4.School of Animal StudiesThe University of QueenslandGattonAustralia
  5. 5.Department of Natural Resources and MinesRockhamptonAustralia
  6. 6.James Hutton InstituteInvergowrie, DundeeUK

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