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Trained Dogs Outperform Human Surveyors in the Detection of Rare Spotted Knapweed (Centaurea stoebe)

  • Kim M. Goodwin (a1), Rick E. Engel (a1) and David K. Weaver (a1)

Invasive plants have devastating effects on ecosystems and biodiversity that early intervention can prevent. Eradication or containment of new invasions is difficult to achieve because of constraints posed by the low density and detectability of individuals. Domestic dogs trained to cue on distinctive scents might provide an effective method to detect spotted knapweed. The objective of this study was to compare the accuracy and detection distances of dogs to humans in locating new spotted knapweed (Centaurea stoebe) invasions. Three dogs, trained to detect knapweed using scent discrimination and tracking techniques, were compared with human surveyors. Seven sampling units (0.5 ha [1.2 ac]) were delineated in a grazed dryland pasture. Dogs, with their handlers, and human surveyors performed line-transect surveys in fall 2005 and spring, summer, and fall 2006. Dog accuracy for large-size knapweed targets (infestations 0.52 m3 [18.4 ft3]) was similar to human accuracy and better than humans (94 vs. 78%) for medium-size targets (infestations 0.13m3). Dog accuracy (67%) was greater (> 81% probability) than humans (34%) for small targets (plants; 0.02 m3). Overall dog accuracy (81%) and F-measure scores (86%) were better than human scores, 59% and 74%, respectively. Human precision was greater (100%) than dogs at 94%. Dogs detected a larger percentage of small targets (80%) at distances greater than 7.9 m (26 ft) compared with humans at only 20%. Our results indicate dogs are more accurate than humans are, especially at critical detection of small spotted knapweed plants, and from greater distances. Invasive plant monitoring using detection dogs can provide greater overall accuracy of plant detection.

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Anderson D. R., Laake J. L., Crain B. R., and Burnham K. P. 1979. Guidelines for line transect sampling of biological populations. J. Wild. Manag 43:7078.
Bach H. and Phelan J. 2003. Canine-assisted detection. Pages 285299. in MacDonald J., Lockwood J. R., McFee J., et al. eds. Alternatives for Landmine Detection. Santa Monica, CA RAND Institute. 336.
Braithwaite R. W., Lonsdale W. M., and Estbergs J. A. 1989. Alien vegetation and native biota in tropical Australia: the impact of Mimosa pigra . Biol. Conserv 48:189210.
Buck L. 1996. Information coding in the vertebrate olfactory system. Ann. Rev. Neurosci 19:517544.
Buck L. and Axel R. 1991. A novel multigene family may encode odorant receptors: a molecular basis for odor recognition. Cell 65:175187.
Cablk M. E. and Heaton J. S. 2006. Accuracy and reliability of dogs in surveying for desert tortoise (Gopherus agassizii). Ecol. Appl 16:19261935.
Cablk M. E., Sagebiel J. C., Heaton J. S., and Valentin C. 2008. Olfaction-based detection distance: a quantitative analysis of how far away dogs recognize tortoise odor and follow it to source. Sensors 8:22082222.
Cain W. S. and Drexler M. 1974. Scope and evaluation of odor counteraction and masking. Ann. N. Y. Acad. Sci 237:427439.
Callaway R. M. and Vivanco J. M. 2007. Invasion of plants into native communities using the underground information superhighway. Allelopath. J 19:143152.
Dukes J. S. and Mooney H. A. 2004. Disruption of ecosystem processes in western North America by invasive species. Rev. Chil. Hist. Nat 77:411437.
Egan J. P. 1975. Signal Detection Theory and ROC-Analysis. New York Academic.
Fawcett T. 2006. An introduction to ROC analysis. Pattern Recognit. Lett 27:861874.
Gaston K. J. 1997. What is rarity? 3047. in Kunin W. E. and Gaston K. J. eds. The Biology of Rarity: Causes and Consequences of Rare–Common Differences. London Chapman and Hall. 280.
Good P. I. 2005. Permutation, Parametric and Bootstrap Tests of Hypotheses. 3rd ed. New York Springer. 5861.
Green D. M. and Swets J. A. 1966. Signal Detection Theory and Psychophysics. New York Wiley. 455.
Grzymala-Busse J. W. 2002. Discretization of numerical attributes. Pages 218225. in Klösgen W. and Zytkow J. eds. Handbook of Data Mining and Knowledge Discovery. New York Oxford University Press. 980.
Gutzwiller K. J. 1990. Minimizing dog-induced biases in game bird research. Wildl. Soc. Bull 18:351356.
Han J. and Kamber M. 2006. Data Mining: Concepts and Techniques. 2nd ed. San Francisco Morgan Kaufmann. 614628.
Higgins S. I., Richardson D. M., and Cowling R. M. 2000. Using a dynamic landscape model for planning the management of alien plant invasions. Ecol. Appl 10:18331848.
Hobbs R. J. and Humphries S. E. 1995. An integrated approach to the ecology and management of plant invasions. Conserv. Biol 9:761770.
Killam E. W. 1990. The Detection of Human Remains. Springfield, IL Charles C. Thomas. 263.
Laurent G. 1999. A systems perspective on early olfactory coding. Science 286:723728.
Liberman D. A. 1999. Learning: Behavior and Cognition. 3rd ed. Belmont, CA Wadsworth. 624.
MacKenzie D. I., Nichols J. D., Lachman G. B., Droege S., Royle J. A., and Langtimm C. A. 2002. Estimating site occupancy rates when detection probabilities are less than one. Ecology 83:22482255.
Macmillan N. A. and Creelman C. D. 2005. Detection Theory: A User's Guide. 2nd ed. Mahwah, NJ Lawrence Erlbaum. 492.
McLean I. G. 2003. Mine Detection Dogs: Training, Operations and Odour Detection. Geneva, Switzerland International Centre for Humanitarian Demining.
Mombaerts P., Wang F., Dulac C., Chao S. K., Nemes A., Mendelsohn M., Edmondson J., and Axel R. 1996. Visualizing an olfactory sensory map. Cell 87:675686.
Moody M. E. and Mack R. N. 1988. Controlling the spread of plant invasions: the importance of nascent foci. J. Appl. Ecol 25:10091021.
Musil C. F. 1993. Effect of invasive Australian acacias on the regeneration, growth and nutrient chemistry of South African lowland fynbos. J. Appl. Ecol 30:361371.
O'Connell R. J. and Akers R. P. 1989. Responses of insect olfactory receptor neurons to biologically relevant mixtures. Pages 4964. in Laing D. G., Cain W. S., McBriode R. L., and Ache B. W. eds. Perception of Complex Smells and Tastes. Sydney Academic.
Palmer M. E. 1987. A critical look at rare plant monitoring in the United States. Biol. Conserv 39:113127.
Panetta F. D. 2007. Evaluation of weed eradication programs: containment and extirpation. Divers Distrib 13:3341.
Panetta F. D. and Timmins S. M. 2004. Evaluating the feasibility of eradication for terrestrial weed incursions. Plant. Protect. Q 19:511.
Phelan J. M. and Webb S. W. 2003. Chemical sensing for buried landmines: fundamental processes influencing trace chemical detection. Pages 209285. in McLean I. G. ed. Mine Detection Dogs: Training, Operations and Odour Detection. Geneva, Switzerland International Centre for Humanitarian Demining.
Rebmann A., David E., and Sorg M. H. 2000. Cadaver Dog Handbook: Forensic Training and Tactics for the Recovery of Human Remains. Boca Raton, FL CRC. 232.
Reindl-Thompson S. A., Shivik J. A., Whitelaw A., Hurt A., and Higgins K. F. 2006. Efficacy of scent dogs in detecting black-footed ferrets at a reintroduction site in South Dakota. Wildl. Soc. Bull 34:14351439.
Rinberg D., Koulakov A., and Gelperin A. 2006. Speed-accuracy tradeoff in olfaction. Neuron 51:351358.
Smith D. A., Ralls K., Hurt A., Adams B., Parker M., Davenport B., Smith M. C., and Maldonado J. E. 2003. Detection and accuracy rates of dogs trained to find scats of San Joaquin kit foxes (Vulpes macrotis mutica). Anim. Conserv 6:339346.
Syrotuck W. G. 1972. Scent and the Scenting Dog. Rome, NY Arner.
Tanner W. P. and Swets J. A. 1954. A decision-making theory of visual detection. Psychol. Rev 61:401409.
Tomley A. J. and Panetta F. D. 2002. Eradication of the exotic weeds Helenium amarum (Rafin) H. L. and Eupatorium serotinum Michx. from south-eastern Queensland. Pages 293296. in Spafford Jacob H., Dodd J., and Moore J. H. eds. Proceedings of the 13th Australian Weeds Conference. Perth, Australia Plant Protection Society of Western Australia.
Tou J. and Gonzalez R. 1974. Pattern Recognition Principles. Reading, MA Addison-Wesley. 9497.
Waggoner L. P., Jones M., Williams M., Johnston J. M., Edge C., and Petrousky J. A. 1998. Effects of extraneous odors on canine detection. Pages 355362. in DePersia A. T. and Pennella J. J. eds. Proceedings of the Conference on Enforcement and Security Technologies. Volume 3575. Bellingham, WA SPIE.
Williams M. and Johnston J. M. 2002. Training and maintaining the performance of dogs (Canis familiaris) on an increasing number of odor discriminations in a controlled setting. Appl. Anim. Behav. Sci 78:5565.
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Invasive Plant Science and Management
  • ISSN: 1939-7291
  • EISSN: 1939-747X
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