Sympatric predator odour reveals a competitive relationship in size-structured mammalian carnivores
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Interspecific competition between sympatric carnivores can have a profound effect on the structure, function and composition of ecosystems. Interspecific competition is often asymmetrical and the smaller carnivore is usually affected the most. We investigated the behavioural responses of two native species, the larger Tasmanian devil (Sarcophilus harrisii) and the smaller spotted-tailed quoll (Dasyurus maculatus) to each other’s odour and to that of an introduced predator, the feral cat (Felis catus), in north-west Tasmania, Australia. We used an experimental array of camera traps, in which carnivore scats were added as treatments. Behavioural responses exhibited by devils and quolls are indicative of a dominant predator-mesopredator relationship and suggest the potential for interspecific competition. The larger predator, the devil, was as vigilant at quoll odour as at control camera traps, but showed decreased vigilance at cat odour and did not avoid cat or quoll odours. The smaller predator, the spotted-tailed quoll, increased its vigilance near devil odour compared to control camera traps but did not avoid it. This experiment shows that assessing the behavioural responses of sympatric carnivores to each other’s odour can help understand predator interactions and reveal the potential for interspecific competition. Understanding these interactions is crucial in managing and conserving carnivores.
Animals navigate through an environment full of faecal odours left by predators, competitors and conspecifics. These odours provide information on both the immediate presence and the indirect risk of encountering a predator or an aggressive competitor. Tasmania’s largest predator, the Tasmanian devil, coexists with the smaller spotted-tailed quoll and the introduced feral cat. We tested the behavioural responses of Tasmanian devils and spotted-tailed quolls to each other’s faecal odour and to cat faecal odour. Behavioural patterns exhibited by predators in this experiment are indicative of a dominant predator-mesopredator relationship and suggest the potential for interspecific competition. Knowledge of the ecological interactions amongst sympatric carnivores can aid managers in making more informed decisions when trying to achieve specific conservation goals.
KeywordsInterspecific competition Behavioural response Predator odour Predator interactions Tasmanian devil Spotted-tailed quoll
We are grateful to Tasmanian Parks and Wildlife Service for permission to work in the Arthur-Pieman Conservation Area. We are also grateful to Van Diemen’s Land Company and Hydro Tasmania for permission to work at Woolnorth. We thank all the volunteers that assisted with field work and Leon Barmuta for statistical advice. We also thank the two anonymous reviewers for their helpful feedback.
Compliance with ethical standards
All applicable international, national and/or institutional guidelines for the care and use of animals have been followed. This research was funded by grants from the Australian Research Council Discovery Scheme grant (DP110103069), the Holsworth Wildlife Research Endowment (grant number not available) and a Dr Eric Guiler Tasmanian Devil Research grant from the Save the Tasmanian Devil Appeal (grant number not available). The authors declare that they have no competing interests. All procedures performed in this study were in accordance with the ethical standards of the Animal Ethics Committee, University of Tasmania (Approval number A12361). This article does not contain any studies with human participants performed by any of the authors.
- Abbott I (2008) The spread of the cat, Felis catus, in Australia: re-examination of the current conceptual model with additional information. Conserv Sci W Aust 7:1–17Google Scholar
- Albone ES, Shirley SG (1984) Mammalian semiochemistry: the investigation of chemical signals between mammals. Wiley, ChichesterGoogle Scholar
- Australian Bureau of Meteorology (2016) Australian Bureau of Meteorology. 2016. http://www.bom.gov.au/. Accessed 2 Apr 2016
- Banks PB, Nordstrom M, Ahola M, Salo P, Fey K, Korpimäki E (2008) Impacts of alien mink predation on island vertebrate communities of the Baltic Sea Archipelago: review of a long-term experimental study. Boreal Environ Res 13:3–16Google Scholar
- Beauchamp G (2015) Animal vigilance: monitoring predators and competitors. Academic, LondonGoogle Scholar
- Bitterlich W (1984) The relascope idea. relative measurements in forestry. Commonwealth Agricultural Bureaux, NorwichGoogle Scholar
- Brown RE, Macdonald DW (1985) Social odours in mammals. Clarendon, OxfordGoogle Scholar
- Burnham KP, Anderson DR (2002) Model selection and multi-model inference: a practical information-theoretic approach, 2nd edn. Springer, New YorkGoogle Scholar
- Dickman CR (1996) Overview of the impacts of feral cats on Australian native fauna. Australian Nature Conservation Agency, CanberraGoogle Scholar
- Gosling LM, Roberts SC (2001) Scent-marking by male mammals: cheat-proof signals to competitors and mates. In: Slater PJB, Rosenblatt JS, Snowdon CT, Roper TJ (eds) Adv Stud Behav 30:169–217Google Scholar
- Hollings T (2013) Ecological effects of disease-induced apex predator decline. Dissertation, University of TasmaniaGoogle Scholar
- Johnson CN (2006) Australia’s mammal extinctions: a 50,000 year history. Cambridge University Press, Port MelbourneGoogle Scholar
- Jones M (1995) Guild structure of the large marsupial carnivores in Tasmania. Dissertation, University of TasmaniaGoogle Scholar
- Kats LB, Dill LM (1998) The scent of death: chemosensory assessment of predation risk by prey animals. Ecoscience 5:361–394Google Scholar
- Lazenby B (2012) Do feral cats affect small mammals? A case study from the forests of southern Tasmania. Dissertation, University of SydneyGoogle Scholar
- Leo V, Reading RP, Letnic M (2015) Interference competition: odours of an apex predator and conspecifics influence resource acquisition by red foxes. Oecologia:1–8Google Scholar
- Lowe S, Browne M, Boudjelas S, De Poorter M (2000) 100 of the world’s worst invasive alien species. Invasive Species Specialist Group, AucklandGoogle Scholar
- Nudds TD (1977) Quantifying the vegetative structure of wildlife cover. Wildl Soc Bull 5:113–117Google Scholar
- Pemberton D (1990) Social organisation and behaviour of the Tasmanian devil, Sarcophilus harrisii. Dissertation, University of TasmaniaGoogle Scholar
- Quenette PY (1990) Functions of vigilance behaviour in mammals—a review. Acta Oecola 11:801–818Google Scholar
- R Core Team (2015) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna. www.r-project.org/
- Van Dyck S, Strahan R (2008) The mammals of Australia, 3rd edn. Reed New Holland, SydneyGoogle Scholar