TY - JOUR
T1 - Abiotic and biotic influences on the dispersal behavior of metamorph cane toads (Bufo marinus) in tropical Australia
AU - Child, Travis
AU - Phillips, Benjamin L.
AU - Shine, Richard
PY - 2008/4/1
Y1 - 2008/4/1
N2 - A mechanistic understanding of factors influencing the dispersal behavior of metamorph cane toads (Bufo marinus) has direct conservation relevance in Australia. These invasive anurans are toxic to native predators, and if we can predict their distribution across the landscape, we can also predict (and perhaps, manage) the scale of their impact. We propose that the major drivers of metamorph distribution are the risk of dehydration (restricting the young toads to moist substrates near pond margins) and biotic advantages to dispersal away from the pond (especially, less risk of cannibalism). To test this model, we investigated the influence of abiotic and biotic cues on the behavior of individual toads in the laboratory. Substrate moisture levels strongly influenced metamorph activity levels and habitat selection: dry substrates induced most metamorphs to remain near water. The only biotic cue to influence metamorph dispersal was proximity of a larger (cannibalistic) conspecific; a cannibal's presence at the pond margin caused most metamorphs to spend less time there, and as a consequence, to dehydrate more rapidly. Our results suggest that the spatial and temporal distribution of metamorph cane toads reflects a trade-off between competing risks: the danger of desiccation tends to keep young toads close to the pond margin in dry conditions, whereas the danger of cannibalism stimulates dispersal.
AB - A mechanistic understanding of factors influencing the dispersal behavior of metamorph cane toads (Bufo marinus) has direct conservation relevance in Australia. These invasive anurans are toxic to native predators, and if we can predict their distribution across the landscape, we can also predict (and perhaps, manage) the scale of their impact. We propose that the major drivers of metamorph distribution are the risk of dehydration (restricting the young toads to moist substrates near pond margins) and biotic advantages to dispersal away from the pond (especially, less risk of cannibalism). To test this model, we investigated the influence of abiotic and biotic cues on the behavior of individual toads in the laboratory. Substrate moisture levels strongly influenced metamorph activity levels and habitat selection: dry substrates induced most metamorphs to remain near water. The only biotic cue to influence metamorph dispersal was proximity of a larger (cannibalistic) conspecific; a cannibal's presence at the pond margin caused most metamorphs to spend less time there, and as a consequence, to dehydrate more rapidly. Our results suggest that the spatial and temporal distribution of metamorph cane toads reflects a trade-off between competing risks: the danger of desiccation tends to keep young toads close to the pond margin in dry conditions, whereas the danger of cannibalism stimulates dispersal.
UR - http://www.scopus.com/inward/record.url?scp=45149127060&partnerID=8YFLogxK
U2 - 10.1002/jez.450
DO - 10.1002/jez.450
M3 - Article
C2 - 18288694
AN - SCOPUS:45149127060
SN - 1932-5223
VL - 309A
SP - 215
EP - 224
JO - Journal of Experimental Zoology Part A: Ecological Genetics and Physiology
JF - Journal of Experimental Zoology Part A: Ecological Genetics and Physiology
IS - 4
ER -