Hellmann is gathering two species of butterflies, duskywing skippers and swallowtails, at all these sites, and breeding them, so she can look at the differences between the butterflies in different parts of the range. Essentially, she is trying to determine whether the northernmost butterflies are specially adapted to their edge-of-the-range existence, or whether they are in fact more or less miserable and dreaming of California. "I am trying to ask it, 'Where would you like to live?'" she says. If the butterflies would answer, "Ah, northern California, that is the homeland," then one might expect that as the climate warms, the Vancouver Island butterflies will become happier and more fit, reproduce more often, and push north on their own. If they would answer, "Vancouver Island! We are locally adapted," then a warming climate should make them less fit— and they might decline just when they would need a robust population to expand northward. If that is the case, they might need help to move north. Hellmann expects to see more local adaptation in the duskywing than in the swallowtails, as they are more isolated from their southern cousins. The duskywing doesn't fly as well, and it eats oak leaves only as a caterpillar, so many populations may live in particular Garry oak sites like little islands, never breeding with butterflies from the next savanna over.
As I drove up and down the island with Hellmann and her team, I learned that there's another wrinkle to the Garry oak study. Some of the sites they are looking at are probably at least partially anthropogenic. The pre-European residents of Vancouver Island also liked these systems and maintained them with fire. Apart from their aesthetic qualities, the oak meadows were easier to hunt in and provided additional calories in the form of camas bulbs. While the Garry oak meadows on rocky slopes may have looked after themselves, conservation managers have found it difficult to keep conifers from taking over Garry oak savannas on good soils. They've resorted to mowing and chopping down encroaching Douglas fir.
To learn more, I met up with Mark Vellend, a young conservation biologist from the University of British Columbia. Vellend walked me through a few Garry oak sites and told me a story as we strolled single file between slender but ancient and gnarled oak trunks, through buttercups, shooting stars, lomatium, and camas. "Eight thousand years ago the climate was warmer and dryer on Vancouver Island," said Vellend. "Oaks and flowers might have been more widespread back then, and then later were maintained only by people burning."
So, I asked him, if people didn't burn these areas after the climate cooled, would some of the flower species be extinct in Canada? He answered like a true scientist: "That's not an unreasonable hypothesis."
So Garry oak savannas in Canada are a human production, threatened by human activities. And people are worried that it is "unnatural" to save them by having humans move them north? Surely assisted migration of these ecosystems would just be a continuation of the care our species has put into them for thousands of years.
One of Hellmann's sites is a little bare rocky clearing in the woods up near Campbell River, north of the last Garry oak. This site was chosen as an example of the kind of place to which people might move the oak, the butterflies, the flowers, and all the other species that make up the little fairyland savannas. Right now, though, it is already occupied. Exposed rocks were covered with thick pads of acid-green moss interspiked with blades of grass and dotted with balls of elk dung. Small bushes grew from between the rocks; on this late April day their leaves were still tiny red buds, and they were more display stands for various species of lichens. Bears visit this clearing, too, to the mild worry of researchers downloading data. It was a very attractive forest room, with walls of Douglas fir, but it doesn't have a catchy name like Garry oak savanna or a fan club. I felt a bit sorry for it, almost as if the moving trucks were already on the way and the place was scheduled to be turned into a Garry oak savanna that very day. "What makes climate change different from reestablishing from a glaciation is that these northern areas are already full," said Hellmann.