EPOW - Ecology Picture of the Week

Alien Invasion

Cane Toad (Bufo marinus), Family Bufonidae
Northern Territory, Australia

Explanation:  It is the alien among us.  Introduced to Queensland, Australia, from the Americas in 1935, this voracious, poisonous, and seemingly indestructible amphibian has spread throughout most of the northeastern and northern part of the country.

Why were they introduced?  At the time, it seemed like a good idea ... in the hope that cane toads would rid the land of another pest, cane beetles, that were devastating much of the sugar cane crops.  

I encountered this most unwary specimen at night at Wangi Falls in
Litchfield National Park in Northern Territory, Australia.

The problem is that the toad had little effect on the cane beetle, and the toad then swelled to millions and spread across the land, feeding on native species such as skinks, birds, small mammals, snakes, and frogs, and stealing pet food left outside.  

This is a classic (and terribly destructive) example of an invasive and injurious species that had gone through all phases of the invasion process:

     introduction  -->  survival  -->  establishment  -->  spread  -->  impact
  

To date, control has largely consisted of direct capture ... and prevention of further spread (such as the sign, to the left here, at a boat launch site).

However, new approaches may include use of parasites that apparently affect only the cane toad and not native toads or frogs, and by tricking the toad by using its own attractant pheromone to lure them into traps.  

  

Flatter than a doormat is this road-killed cane toad in northern Australia.
For many Australians, this is the only good cane toad.