Organisms can have positive or negative impacts on the ecosystem they live in. the cane toad, or rhinella marina, was introduced to the hawaiian islands in 1932 by sugar cane farmers. farmers released the toads in their crops to control pests that were damaging the sugar cane. the cane toad has few natural predators, as it secretes a poisonous toxin from its skin that deters larger organisms from eating it. as a result, the cane toad population thrived and grew to number hundreds of thousands by 1935.