Tentacles of destruction

5 04 2012

This last post before Easter is something I’ve thought more and more about over the last few years. I wouldn’t have given it much time in the past, but I’m now convinced roads are one of the humanity’s most destructive devices. Let me explain.

Before I had a good grasp of extinction dynamics, I wouldn’t have attributed much import to the role of roads in conservation. I mean, really, a little road here and there (ok, even a major motorway) couldn’t possibly be a problem? It’s mostly habitat destruction itself, right?

Not exactly. With our work on extinction synergies, I eventually came to realise that roads are some of the first portals to the devastation to come. Read the rest of this entry »





Sink to source – the loss of biodiversity’s greatest ecosystem service

29 02 2012

I’ve mentioned this idea before, but it’s nice when some real data support a prediction (no matter how gloomy that prediction might have been). It’s what drives scientists toward discovery (or at least, it’s what I find particularly appealing about my job).

Several years ago, my colleagues (Navjot Sodhi† and Ian Warkentin) and I wrote a major review in TREE about the fate of the world’s ‘second’ lung of the planet, the great boreal forests of Russia, Canada & Scandinavia. We discussed how fragmentation was increasing at an alarming rate, and that although most species there are still relatively intact, we stand to lose a lot of its biodiversity if we don’t halt the fragmenting processes soon. We wrote more on the subject in a paper to appear imminently in Biological Conservation.

Another component though that we raised in the TREE paper was the boreal forests were very much in danger of turning into a net carbon producer. You see, the ‘lung’ analogy is very pertinent because on average, the growth of the massive expanse of the vegetation in the forest generally takes up much more atmospheric carbon that it exudes through decay and burning (for as we all know, plants take up carbon dioxide to produce sugars during photosynthesis, and produce oxygen as a ‘waste’ product). However, as we fragment, cut down and burn the forest, it can end up producing more than it takes up (i.e., turning from a ‘sink’ to a ‘source’). We highlighted several studies indicating how insect outbreaks and human-exacerbated fire intensities and frequencies could conceivably do this.

Now Zhihai Ma and colleagues have just compiled a paper in PNAS indicating that the danger is well on the way to becoming reality in Canada. The paper entitled Regional drought-induced reduction in the biomass carbon sink of Canada’s boreal forests reports the results from 96 long-term permanent sampling plots spread right across southern Canada – from British Columbia in the far west, to Newfoundland in the far east. Read the rest of this entry »





Slicing the second ‘lung of the planet’

12 12 2011

© WWF

Apologies for the slow-down in postings this past week – as many of you know, I was attending the International Congress for Conservation Biology in Auckland. I’ll blog about the conference later (and the stoush that didn’t really occur), but suffice it to say it was very much worthwhile.

This post doesn’t have a lot to do per se with the conference, but it was stimulated by a talk I attended by Conservation Scholar Stuart Pimm. Now, Stuart is known mainly as a tropical conservation biologist, but as it turns out, he also is a champion of temperate forests – he even sits on the science panel of the International Boreal Conservation Campaign.

I too have dabbled in boreal issues over my career, and most recently with a review published in Trends in Ecology and Evolution on the knife-edge plight of boreal biodiversity and carbon stores. That paper was in fact the result of a brain-storming session Navjot Sodhi and I had one day during my visit to Singapore sometime in 2007. We thought, “It doesn’t really seem that people are focussing their conservation attention on the boreal forest; how bad is it really?”.

Well, it turns out that the boreal forest is still a vast expanse and that there aren’t too many species in imminent danger of extinction; however, that’s where the good news ends. The forest itself is becoming more and more fragmented from industrial development (namely, forestry, mining, petroleum surveying and road-building) and the fire regime has changed irrevocably from a combination of climate change and intensified human presence. You can read all these salient features here.

So, back to my original thread – Stuart gave a great talk on the patterns of deforestation worldwide, with particular emphasis on how satellite imagery hides much of the fine-scale damage that we humans do to the world’s great forests. It was when he said (paraphrased) that “50,000 km2 of boreal forest is lost each year, but even that statistic hides a major checkerboard effect” that my interest was peaked. Read the rest of this entry »