Why cane toads give us a small hope for climate change

How much ugly you want?
Credit: The Conversation

Studies of invasive cane toad populations in Australia show that at the advancing front of the invasion, the individuals move much faster than in stable populations: as much as one kilometer in a night. This is not just a behavioral change, the animals on the advancing front have longer, stronger legs which allow them to jump further at a single jump & continue jumping longer.

What this tells us is that, at the advancing front, there are different selective pressures, producing these more athletic pioneering individuals.

Once the advancing front has passed, the selective pressures change to those which produce the cane toads typical of a stable population. Result: the population evolves back to its static, less athletic form.

What does any of this tell us about climate change?

As climate change progresses, environments gradually change. There comes a point where the native flora & fauna reach the limit of their tolerance & must migrate or perish. A concern is that if a population can't move quickly enough, it will be destroyed by an incompatible environment. Cane toad studies give some hope that species may be able to migrate faster than previously thought.

http://theconversation.com/why-cane-toads-give-us-small-hope-for-climate-change-16455 / cane toads toad Bufo marinus Australia’s Australia most serious invasive species feral introduced species pest killing predators goannas quolls crocodiles tropical north toads advancing Queensland Kimberley new research shows toads evolve spread faster new environments good news animals move because climate change toads climate hopping ecological theory assumption population animals stable space individuals their offspring live same general area year after year reality messier many populations are not stable invasive species expand range spread long term long-term study University of Sydney Sydney-based Team Bufo Greg Brown radio track tracking tracker tracked radio-tracked invasive cane toads first arrived at an area near Darwin continued track newly arriving arrive arrival newly-arriving toads next several years Tom Lindstrom’s Lindstrom mathematical analysis radio-tracking results revealed dramatic shift published today in the journal PNAS first toads arrived near Darwin incredibly mobile often moving more than one kilometer kilometre within a single night but within a couple of years that rate had more than halved super-speediness seen at the invasion front probably driven by evolutionary forces that come into play only at an expanding range edge, and are not seen in stable populations earlier studies toad front had revealed these mechanisms current work shows just how spectacular the acceleration can be rapid decrease mobility after the invasion front passes through normal cane toads animals from long-established long established populations would underestimate potential rate movement want predict how quickly species can expand its range we need look right expanding range edge unfortunately logistically difficult most data animal dispersal rates come from long established long-established stable populations population result may be underestimating potential rates of population spread adapting adaptation adapt changing world problem doesn’t just relate invasive species Many species shift ranges range other reasons climate change rendering many areas unsuitable animal plant animals plants that currently live there becoming too hot or too dry creating those conditions somewhere nearby area that previously may have been too cold too wet species caught in this situation survive individuals either must rapidly adapt new conditions move area offers suitable conditions fast pace climate change makes both options very tough to achieve but not impossible species where individuals generally do not move about very much very far process expanding their range into new newly suitable newly-suitable area create evolutionary pressure faster dispersal end result many species will manage shift their distributions distribution more quickly from the movement rates measure existing stable populations provides glimmer of hope /