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Archive for February 23rd, 2012

We get pretty steeped around here in energy and policy and what Kara had for breakfast. But every once in a while we like to go outside. Especially this time of year – and specifically during a freakishly warm winter – when the weather warms and we SpinachHeads get to leave the cannery and spend more time in the fields, if you will.

Today’s topic: wildlife corridors, and whether or not they actually work to unite populations of species despite development of roads and highways and ongoing growth of cities. The idea is a brainchild of friend-of-the-blog (in our dreams) E.O. Wilson, who hypothesized back in the 60s that the biggest threat to species survival was habitat isolation, and the more we cut off major parts of habitat, the more dire some species’ peril becomes.

So do they work? That’s the question Fred Pearce at New Scientist asked earlier this week. And it got us thinking. There really isn’t much academic evidence we’ve come across to show that corridors indisputably work as intended.

There is, Pearce points out, lots of proof that species like to travel through tunnels (do they hold their breath?!) and travel. But there’s little to show that these things show genetic diversity across geographic distances. It’s a question of time and breeding. Is the population expanding faster than lone animals are using the corridors? If so separate populations won’t become united. The reverse is that animals of different populations are interbreeding faster than the overall population expands. That second scenario would make the corridors effective.

Problem is, it’s looking more and more to be the first scenario. One of the most comprehensive studies on the topic looked at marsupials in a narrow forest corridor in Queensland, Australia. Despite the expensive engineering, researchers found that genetically distinct populations had persisted. Ergo, over time, the populations would continue to grow apart.

The $64,000 question – and don’t worry, we can hear you asking it – is why the heck does this matter? Surely we have more important environment and wildlife issues to consider than whether a bunch of moose use tunnels, right?

Only partly true (and don’t call me Shirley). Corridors have long been the key argument by developers and contruction companies for continued growth. They nip at the core of how we reconcile our growth with the broader health of the environment are our terrestrial counterparts. As long as we keep habitat protected and allow species to roam wild and free, we can do whatever we want to the planet, the thinking goes. Yet this series of studies seems to offer a rather firm rebuke of that rationale.

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