Reintroducing New Species: Yes Or No?
It's a tricky call to make, whether or not the introduction or even reintroduction of a species is a good move or not. Despite all the scientific data and research that are available to us, it always throws up surprises and problems that no amount of planning revealed. There are just as many examples of great success in reintroduction as there are failures. Let's look at some, analyse and interpret them and try to come to a definitive answer.
One of the main arguments for the introduction of animals is often that, if it wasn't for human beings, they wouldn't be needing reintroduction in the first place. Through poaching or the expansion of human territories or even previously failed attempts, the finger of blame usually ends up point back at us. Still, surely there's merit in trying to right a wrong, right?
The poster child for re/introduction which must be Yellow Stone National Park. Back in 1995, Grey Wolves were set free in an attempt to re-establish the species in the area again. It's safe to say that no-one expected quite the success that was achieved by it. The wolves hunted and changed behaviour of the elk, which allowed the trees and vegetation to recover from decades of uncontrolled elk feasting. The resurging vegetation allowed birds to come back and beavers to expand which allowed fish, reptile, amphibian and further bird species to flourish too as a result of the beaver's work. The wolf presence kept the population of coyotes stable too, allowing rabbits and mice to flourish which allowed eagles and weasels and foxes to flourish. Feeding on the wolf leftover carrion, other bird and bear populations improved. The bears also benefitted from the flourishing vegetation as they fed on the increased number of berries once emerging from hibernation. The last big domino to fall was the stabilizing of the rivers. Yes, introducing wolves helped out the rivers. Thanks to the regenerated vegetation the river banks stabilized, meandered and eroded less. River channels narrowed and more pools formed. All from just reintroducing the Grey Wolf.
That's a lot to take in, admittedly, but it does give a great example of the benefits of introduction or reintroduction. Of course, this whole ecosystem wouldn't have needed it if wolves hadn't been hunted to extinction in the park in the 1920's, but that's another debate. The point is, it can work and it can work well.
Some of the numerous examples of animal introduction that haven't played out so well include the Burmese Pythons in Florida, our own Grey Squirrel in Britain and the Cane Toad epidemic in Australia. Each of these has had disastrous effects in one capacity or another.
In Florida, the accidental introduction (yes, ACCIDENTAL) of the Burmese Python has started to make life very difficult for the natives. The pythons eat all sorts of different animals but have no natural predator, inhabit huge areas and are difficult to find, making containing them very difficult. They feast on rare birds, animals and even alligators and it's estimated that there are 30,000 now living in the Everglades National Park alone. Keep your dog on a lead.
The Grey Squirrel is a well-known irritating import here in the U.K. Introduced in the 1870's, it was brought over and released as it was thought to be a nice and fashionable addition to lordly country estates. However, the population grew rapidly and dominated the native Red Squirrel which has since become extremely rare. Being more aggressive and fitter than their red cousins, Grey Squirrels had a natural advantage and took over.
The biggest example of this comes from Australia as conservationists have started to push back against the non-native animals. The toads, introduced with the hope they'd keep the crop eating insect population of sugar plantations down didn't take to its new diet so the problem persisted. In addition, the Cane Toed secretes a toxin from its skin, making any natural predators wary of it or suffers the fatal consequences. As a result, the population has grown at an alarming rate. Local rare species like the Quoll and three different species of lizard have been pushed to the brink thanks to their fondness for toxic toad.
In an effort to stop the bleeding, one of the great examples of how to deal with a non-native species has taken place. Over a 5 year study, conservationists have put into practice the training of Quolls, Bluetongue Lizards and even different species of Snake to teach them to avoid eating Cane Toads. The animals are given tiny portions of a nausea inducing chemical whenever they are fed toad meant until eventually they avoid the toad meant altogether and try something else on the menu. In the case of the Quolls, being a marsupial means that they have then passed down that trait to their offspring so that they avoid them too and on and on it goes. In more good news, the tiny portions of Cane Toad were distributed in the form of sausages thrown from helicopters, isn't that a great image.
So it's not all doom and gloom. Despite on many occasions when the reintroduction of animals has had disastrous effects, efforts are in progress to turn the tables. The key seems to be tackling each situation on its own merits as the right situation can work wonders for the natural world and in this age of downward spiralling environment talk, a positive story now and again is very welcome.