Wildlife Research Wildlife Research Society
Ecology, management and conservation in natural and modified habitats
RESEARCH ARTICLE

Comparisons through time and space suggest rapid evolution of dispersal behaviour in an invasive species

Ross A. Alford A , Gregory P. Brown B , Lin Schwarzkopf A , Benjamin L. Phillips B and Richard Shine B C

A School of Marine and Tropical Biology, James Cook University, Townsville, Qld 4811, Australia.

B School of Biological Sciences A08, University of Sydney, NSW 2006, Australia.

C Corresponding author. Email: rics@bio.usyd.edu.au

Wildlife Research 36(1) 23-28 http://dx.doi.org/10.1071/WR08021
Submitted: 5 February 2008  Accepted: 2 June 2008   Published: 21 January 2009

Abstract

During a biological invasion, we expect that the expanding front will increasingly become dominated by individuals with better dispersal abilities. Over many generations, selection at the invasion front thus will favour traits that increase dispersal rates. As a result of this process, cane toads (Bufo marinus) are now spreading through tropical Australia about 5-fold faster than in the early years of toad invasion; but how have toads changed to make this happen? Here we present data from radio-tracking of free-ranging cane toads from three populations (spanning a 15-year period of the toads’ Australian invasion, and across 1800 km). Our data reveal dramatic shifts in behavioural traits (proportion of nights when toads move from their existing retreat-site to a new one, and distance between those successive retreat-sites) associated with the rapid acceleration of toad invasion. Over a maximum period of 70 years (~50 generations), cane toads at the invasion front in Australia apparently have evolved such that populations include a higher proportion of individuals that make long, straight moves.


References

Alford R. A. , Cohen M. P. , Crossland M. R. , Hearnden M. N. , James D. , and Schwarzkopf L. (1995). Population biology of Bufo marinus in northern Australia. In ‘Wetland Research in the Wet–Dry Tropics of Australia’. (Ed. M. Finlayson.) pp. 173–181. Supervising Scientist Report No. 101. (Office of the Supervising Scientist: Canberra.)

Brown G. P. Phillips B. L. Webb J. K. Shine R. 2006 Toad on the road: use of roads as dispersal corridors by cane toads (Bufo marinus) at an invasion front in tropical Australia. Biological Conservation 133 88 94 doi:10.1016/j.biocon.2006.05.020

Brown G. P. Shilton C. M. Phillips B. L. Shine R. 2007 Invasion, stress, and spinal arthritis in cane toads. Proceedings of the National Academy of Sciences of the United States of America 104 17698 17700 doi:10.1073/pnas.0705057104

Caughley G. (1977). ‘Analysis of Vertebrate Populations.’ (John Wiley & Sons: Chichester.)

Lee C. E. 2002 Evolutionary genetics of invasive species. Trends in Ecology & Evolution 17 386 391 doi:10.1016/S0169-5347(02)02554-5

Lever C. (2001). ‘The Cane Toad. The History and Ecology of a Successful Colonist.’ (Westbury Scientific Publishing: Otley, West Yorkshire.)

Mehta C. R. 1994 The exact analysis of contingency tables in medical research. Statistical Methods in Medical Research 3 135 156 doi:10.1177/096228029400300203

Parmesan C. 2006 Ecological and evolutionary responses to recent climate change. Annual Review of Ecology and Systematics 37 637 669 doi:10.1146/annurev.ecolsys.37.091305.110100

Parmesan C. Yohe G. 2003 A globally coherent fingerprint of climate change impacts across natural systems. Nature 421 37 42 doi:10.1038/nature01286

Pearson R. G. 2006 Climate change and the migration capacity of species. Trends in Ecology & Evolution 21 111 113 doi:10.1016/j.tree.2005.11.022

Phillips B. L. Brown G. P. Webb J. Shine R. 2006 Runaway toads: an invasive species evolves speed and thus spreads more rapidly through Australia. Nature 439 803 doi:10.1111/j.1442-9993.2007.01664.x

Phillips B. L. Brown G. P. Greenlees M. Webb J. K. Shine R. 2007 Rapid expansion of the cane toad (Bufo marinus) invasion front in tropical Australia. Austral Ecology 32 169 176 doi:10.1111/j.1442-9993.2007.01664.x

Phillips B. L. Brown G. P. Travis J. M. J. Shine R. 2008 Reid’s paradox revisited: the evolution of dispersal kernels during range expansion. American Naturalist 172 S34 S48 doi:10.1086/588255

Pimentel D. Lach L. Zuniga R. Morrison D. 2000 Environmental and economic costs of nonindigenous species in the United States. Bioscience 50 53 65 doi:10.1641/0006-3568(2000)050[0053:EAECON]2.3.CO;2

Sax D. F. , Stachowicz J. J. , and Gaines S. D. (Eds) (2005). ‘Species Invasions: Insights Into Ecology, Evolution, and Biogeography.’ (Sinauer Associates: Sunderland, MA.)

Schwarzkopf L. Alford R. A. 1996 Desiccation and shelter-site use in a tropical amphibian: comparing toads with physical models. Functional Ecology 10 193 200 doi:10.2307/2389843

Schwarzkopf L. Alford R. A. 2002 Nomadic movement in tropical toads. Oikos 96 492 506 doi:10.1034j.1600-0706.2002.960311.x doi:10.2307/2389843

Shilton C. M. Brown G. P. Benedict S. Shine R. 2008 Spinal arthropathy associated with Ochrobactrum anthropi in free-ranging cane toads (Chaunus [Bufo] marinus) in Australia. Veterinary Pathology 45 85 94 doi:10.1354/vp.45-1-85

Simmons A. D. Thomas C. D. 2004 Changes in dispersal during species’ range expansions. American Naturalist 164 378 395 doi:10.1086/423430

Smith M. A. Green D. M. 2005 Dispersal and the metapopulation paradigm in amphibian ecology and conservation: are all amphibian populations metapopulations? Ecography 28 110 128 doi:10.1111/j.0906-7590.2005.04042.x

Travis J. M. J. Dytham C. 2002 Dispersal evolution during invasions. Evolutionary Ecology Research 4 1119 1129

Urban M. C. Phillips B. L. Skelly D. K. Shine R. 2007 The cane toad’s (Bufo marinus) increasing ability to invade Australia is revealed by a dynamically updated range model. Proceedings of the Royal Society of London. Series B. Biological Sciences 274 1413 1419
doi:10.1098/rspb.2007.0114

Urban M. Phillips B. L. Skelly D. K. Shine R. 2008 A toad more traveled: the heterogeneous invasion dynamics of cane toads in Australia. American Naturalist 171 E134 E148 doi:10.1086/527494

Wilcove D. S. Rothstein D. Dubow J. Phillips A. Losos E. 1998 Quantifying threats to imperiled species in the United States. Bioscience 48 607 615 doi:10.2307/1313420

Zar J. (1999). ‘Biostatistical Analysis.’ (Prentice-Hall: New Jersey.)



Export Citation