The issue of human-manufactured biodiversity is controversial. After all, if humans are overrunning nature and degrading the vital ecosystem services that we depend on, isn't it rather beside the point if we also inadvertently boost biodiversity on some landscapes? 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.
