Rates of dispersal of cane toads during their global invasion

Invasions often accelerate through time, as dispersal-enhancing traits
accumulate at the expanding range edge. How does the dispersal behaviour
of individual organisms shift to increase rates of population spread? We
collate data from 44 radio-tracking studies (in total, of 650 animals) of
cane toads (Rhinella marina) to quantify distances moved per day, and the
frequency of displacement in their native range (French Guiana) and two
invaded areas (Hawai’i and Australia). Here we show that toads in their
native-range, Hawai’i and eastern Australia are relatively sedentary,
while toads dispersing across tropical Australia increased their daily
distances travelled from 20 to 200 m per day. That increase reflects an
increasing propensity to change diurnal retreat sites every day, as well
as to move further during each nocturnal displacement. Daily changes in
retreat site evolved earlier than did changes in distances moved per
night, indicating a breakdown in philopatry before other movement
behaviours were optimised to maximise dispersal.