Monday, March 16, 2009

Is it worth it?

I have been hearing a lot about invasive species and how this should be introduced and that be eradicated. Here on the North Carolina coast there has been some controversy about the help that the Outer Banks Wild Horses should receive.

When is an invasive species no longer invasive? The horses here have been around for over 400 years. They are more local than even the oldest locals, but they will not be protected by the FWS.

...physiological features of present day horses, and historical data lead strongly to the conclusion that the ancestors of these horses were escapees from Spanish stock brought to the Outer Banks of North Carolina in the first part of the 16th century.

These horses were left here by some of the original Spanish explorers who either became shipwrecked or who deserted their horses and left. In the absence of large predators and other large mammals with which to compete, the horses thrived. They have become successful, and the herd needs to be periodically thinned. So if these large mammals are this successful, when are they no longer considered exotic?

Red Fox have been in this country since the English imported them, Wild boar were brought from Russia, nutria from South America, all horses came from somewhere else. The process of change has increased exponentially since humans began moving animals from one place to another.

Over at Cool Green Science they write about the same thing tossing around the research of Darwin.

that is exactly how evolution works. The ancestral Darwin’s Finches once landed, completely exhausted, on one of the Galapagos Islands. They thrived, adapted, evolved and probably displaced quite a few of the species that had arrived before them.

Here in Southeast Asia, I see the same. Every few hundred thousand years, a wave of new species has arrived in the lands that now make up Indonesia and Malaysia, often driven by climatic change. They displaced the original species, which either died out or survived on mountain tops, offshore islands or other unusual places, where they are now rare endemics.

In conservation we are trying to change this. We are eradicating or controlling the invaders, and protect the natives. But that introduces a paradox.

Of course, things are happening much faster now that humans have come onto the scene. We are not talking about millennia or even centuries anymore. Our changes happen in a few years. And few species can adapt to that speed.

Still, there seem to be a disconnect between conservation and natural evolution. Come to Borneo in a few thousand years from now, and quite likely the tree sparrows here will have started to develop some useful traits that allows them to exploit new resources.

When does a species stop being a dangerous invasive and become a wonder of nature worth protecting?

Of course, being an educator, I have to be careful of what I say. Here in North Carolina, I still get a lot of flack about teaching evolution. I can only teach it as a theory, never really proven. Even though the evidence is all around us.

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