To study evolution, Jason Munshi-South has tracked elephants in central Africa and proboscis monkeys in the wilds of Borneo. But for his most recent expedition, he took the A train.

To those of you unfamiliar with the NYC subway, this would be the A train to upper Manhattan. Zimmer notes:

Cities attract only a small fraction of evolutionary biologists, who often work in lusher places like the Amazon. But urban evolution is attracting more research these days, because cities are fast-growing, and the urban environment is quickly taking over large areas of the Earth’s surface.

As I recently discussed, this trend is part of an evolution in ecological thinking. And it’s long past due. After all, if neighborhood gardens and green markets can thrive in cities, then so can all manner of wildlife. The unruly biodiversity of society at large is also reflected in the urban landscape, a point unintentionally made in Zimmer’s article:

Biologists find a mixture of native and non-native in all the life forms they study in New York, from the trees in Central Park to the birds of Jamaica Bay.

Speaking of Jamaica Bay, here’s a great article in yesterday’s NYT about “the city’s largest open space”:

A giant salt water puddle, pooled over 20,000 acres beneath the leaky eaves of southern Queens and Brooklyn, the bay lies at the far end of the Rockaways A line. And to ride that line from Times Square to Canal Street to Broadway Junction, and then through Ozone Park to Howard Beach and Broad Channel, where suddenly there are marshes offshore and ibises and egrets in the sky, is to understand that with a simple 90-minute trip one can find a wilderness within the city limits.

The notion that “wilderness” can exist within a metropolis–something that probably would have been deemed nuts several decades ago–suggests that our views of nature have matured and expanded, just like those of the scientists now discovering and cataloguing urban biological diversity.

I don’t think so. More environmentalists need to realize that the boundaries between pristine nature and civilization grow fuzzier by the day. The latest example is a new, intriguing study on pre-Columbian agriculture in the Amazon, published last week in PNAS.

This is the kind of stuff that makes my geeky heart flutter: interdisciplinary research on how ancient farmers engineered their environment in a part of the world that most people today consider primordial nature. Additionally, these findings hold important contemporary ecological lessons, as the study’s abstract explains:

The profound alteration of ecosystem functioning in these landscapes coconstructed by humans and nature has important implications for understanding Amazonian history and biodiversity. Furthermore, these landscapes show how sustainability of food-production systems can be enhanced by engineering into them fallows that maintain ecosystem services and biodiversity. Like anthropogenic dark earths in forested Amazonia, these self-organizing ecosystems illustrate the ecological complexity of the legacy of pre-Columbian land use.

In a nice write-up of the study, New Scientist interviews Doyle McKey, the lead researcher, who says:

Human actions cannot always be characterised as bad for biodiversity. Some might be good.

That’s one of those inconvenient truths that purists who subscribe to the human/nature dualism don’t like to hear. But science has come a long way since the publication of George Perkin Marsh’s seminal text.  The increasing collaboration between archaeologists and ecologists is revealing an ancient world that discomfits doctrinaire environmentalists. (In the American Southwest, I’ve written about one such collaboration here.)

Moreover, as the New Scientist article puts it:

The new study is bound to further fuel the debate over whether most of the Amazon rainforest and the associated savannahs are pristine ecosystem.   “To my mind, the debate has been too black-and-white,” says McKey. “Nature and culture are interacting to produce interesting things, and maybe that is the way this debate should go.”

Seems like good advice to me.

“Now, writes Borrell, “being green is all about greenhouse gases:

Neighborhood moms are more apt to fret over food miles than felled forests; organic cattle farmers are more interested in offsetting the methane coming from cow burps than pondering squished tadpoles in hoof prints. Even scientists have grown bored with question of habitat loss, tweaking their grant proposals to emphasize the climate angle no matter how tenuous the connection. Saving the Amazon is so 1980s.

So far, so good. Borrell then moves on to his essential point:

Climate change has the potential to displace the most impoverished human populations and bring about food shortages, flooding, and drought. But from the perspective of saving species, it’s a MacGuffin: a plot device that may impel the tired conservation narrative forward but is hardly a pragmatic strategy for preserving biodiversity.

Now them’s fightin’ words–not to me–but to many environmentalists who want the larger debate about ecological destruction to revolve around climate change.  I happen to think that Borrell is right, that greenhouse gases pose a less immediate and near-term threat to ecosystem services and biodiversity than that of habitat destruction.

But Carl Zimmer, who I have immense respect for, makes a good case that Borrell underplays the ecological fallout from climate change. In fact, Zimmer has written a cogent counter-argument that is a model of respectful criticism. I wish more bloggers who take issue with climate-related stories in the press were as classy as Zimmer, instead of resorting to name calling and ad hominem attacks.

I’ve also noticed a disturbing trend in comment threads that encourages a kind of politically correct policing. For example, this commenter at Zimmer’s blog, feels compelled to point out that the comments to Borrell’s article at Slate

are dominated by anti-global warming types and Al Gore bashing. We should keep our eye on Borrell; he may be an embryonic Lomborg.

What the hell is that? Could there be any more blatant and perverse example of guilt by association? Yeah, keep a stink eye on Borrell, because you have problems with some of the people who read his article and commented on it. What’s even more disturbing is that this sort of thinking  comes from a scientist and university professor. I’m hoping he was being inartfully sarcastic.

But this is not an isolated sentiment, though it is the only type of its kind to appear at this particular post by Carl Zimmer. I’ve seen many similar comments on other envirornment and climate-related blogs, including variations of that, which call on people to not read certain bloggers because of their supposed association with climate deniers or “delayers,” (this last term being a favorite of Joe Romm’s, which he uses to flog anyone he disagrees with).

That sort of close-mindedness–willfully disregarding other viewpoints–demeans the progressive spirit of environmental thinking.

Now, as to the merits of Borrell’s argument, I’m inclined to think, after reading Carl Zimmer’s critique, that Borell gets some of his details wrong. But I happen to think he gets the bigger picture right, which is that environmentalists, in their zeal to view everything through a climate change lens, are losing sight of a more tangible and truly urgent ecological crisis. As Borrell puts it,

while climate change remains a legitimate concern for wildlife—particularly on isolated mountaintops and in species-poor polar regions—it does not come close to the immediate, irreparable damage caused by the destruction of habitat. Our ecosystems are not just getting warmer or colder or wetter or drier. They’re disappearing.