The mood among the team was happy, despite the fact that several of the climate sensors, which looked like oversize watch batteries, had gotten wet and were not recording properly, even though they were carefully duct-taped inside plastic pillboxes. Oaks that they had lugged up to the site were sitting in pots, so Hellmann could see how butterflies that feed on them would do if moved to the clearing. Of course, it would be more like a real migration if the oaks were planted in the ground rather than in pots; every gardener knows that potted plants are more affected by the cold. But Hellmann, despite having permission from the government to stick those oaks right into the ground, could not quite bring herself to personally move the Garry oak past its recorded range.
She's still ambivalent. "Philosophically we are entering an era of interventionism that I am not comfortable with," she says. But on the other hand, "I have not gotten comfortable with this idea of how many species are going to go extinct. There is less stuff than there used to be. That is one thing that we should care about. I am less concerned with how it is configured than that it exists."
While Hellmann and her ilk fret and study, a great uncoordinated, unofficial assisted migration is already underway. A group of citizen scientists has moved north many seedlings of Torreya taxifolia, or Florida torreya, one of the world's rarest evergreen trees, which is currently roasting to death in its tiny range in the US South. Many conservationists predict an explosion of similar efforts by fans of particular species. And an analysis of about 350 native European plants sold at nurseries in Europe has revealed that 73 percent of them are now sold farther north than their native ranges, with a mean shift of about 600 miles. Pretty pink-flowered rock soapwort doesn't occur north of Germany, according to official ranges published by botanists. But you can buy it in Sweden and grow it in your garden. The researchers suggest that these commercial movements might help these species adapt as the climate changes. "While the debate on assisted migration continues," they write, "it is clear that, across the planet, we have already given many species an unintentional head start on climate change."
Undoubtedly true. But there are likely few mosses, lichens or invertebrates in those seed catalogs. People tend to care more about certain kinds of species. And thus, Hellmann says she doesn't think the approach is "a panacea for saving biodiversity under threat from climate change." "There are some species that are very important, and for the species that are really important, people will do it ... but I have a hard time imagining how we would apply it to all the beetles and the microbes, the vast majority of biodiversity. No one is going to pick them up and move them."