Scientific consensus is now emerging to show these animals are crucial to the functioning of a healthy ecosystem. Food chain effects caused by adding or removing a top species are known as “trophic cascades,” and evidence is accumulating:
-overhunting of sea otters caused the collapse of kelp forests, as without predation by otters, the sea urchin population exploded and the feed on kelp
-when jaguars and pumas fled a valley flooded by construction of a dam in Venezuela, howler monkeys multiplied out of control and went mad as the plants they ate increased toxins in self defense
-the wolf’s return to Yellowstone National Park and their predation on elk gave willow and other trees the chance to grow along streams, cooling water temperatures for trout and encouraging the return of the beaver, whose ponds are vital for songbirds and amphibians
-a reduction of lion and leopard populations in Ghana led to an explosion of baboons that attacked livestock, damaged crops and spread internal parasites to the human population
It’s not just the loss of the large predators that can have an effect on human health. Small wild cats, birds of prey, coyotes and other carnivores feed on mice and rats that destroy crops and spread disease.
In spite of all the scientific evidence, governments in many countries – among them Canada and the USA (wolves) and Argentina (puma) – are still adamant that predators be wiped out. They are still the scapegoats for anything that goes wrong in nature, and their removal is the first knee-jerk reaction taken by officials.
It’s time governments started acknowledging the scientific evidence showing we have to pay attention to the well being of predators if we want healthy ecosystems, and a healthy planet.