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.
See what we're tweeting about
5 Comments
Add CommentNormally I would say that assisted migration is a dangerous thing but one has to consider that the rate of change is much faster than these systems are accustomed to and many ecosystems are now fragmented by human development so natural migration is difficult if not impossible. I would take a cue from the margin of the ecosystems as to how they transition from one biome to another but draw a new population from as wide a genetic base as possible. It is almost impossible to predict what traits will be off most benefit in a new system.
Reply | Report Abuse | Link to thisI think that is a bit of a stretch. The fact that we share dna with all other living things on this planet kinda rules that out. Besides, one first has to prove that multiple universes exist, then, that it is possible for one to move between universes before one could even consider that possibility.
Reply | Report Abuse | Link to thisBesides, humanity's effects on the planet are very similar to the effects of cancer on the body. We have metastasised, we have move outside our original niche, we are consuming resources at a rate that is much higher than the planet's ability to create them and we are shutting down important ecological processes that are required in order for the earth to sustain life, just as cancer kills by destroying organ function. So, there is nothing other-universy about us. Sadly our place on this planet is nothing to be proud of.
Actually you were being an idiot and a totally believable one at that. You also revealed yourself to be one of the typical low life scumbags that troll this site. Kind of pathetic that you try to compensate for your intellectual disabilities with idiotic comments. Or perhaps you were just demonstrating what I said about humanity being a cancer.
Reply | Report Abuse | Link to thisIt's not clear what Hellman's quote in the final paragraph refers to. Is she saying that the horticultural trade isn't going to pick up and move things like beetles and soil organisms or that even concerted efforts at ecosystem relocation will fail to move everything? Well, whichever she actually did mean, it does seem unlikely to me that we would be able to successfully recreate an entire ecosystem in a new location. First, our understanding of the complexity of real ecosystems is miniscule compared their actual functioning. Beyond a small handful of intensively researched species like garry oaks or swallowtail butterflies, we don't know which of the millions of other organisms in an ecosystem are critically important, what their critical proportions are relative to other organisms, what kind of spatial distributions they need, etc. Second, the idea of moving an ecosystem into a new range oversimplifies the actual patterns climate change is bringing. It's not true that suitable climates for an entire ecosystem will simply move further north or further upslope. Climate change can be expected to alter some, but not all of the climate patterns in a region, many will still be based on large and small scale topographic features and so will nto change. The organisms in an ecosystem have different ranges of tolerance, even if some will be able to thrive in a new habitat, say further north, it's not certain that all of them will.
Reply | Report Abuse | Link to thisThe article rightly refers to soil bacteria which would need to be displaced. Soil feeds us, yet we know next to nothing about the diversity and interactions of soil bacteria. Fungi too would have to be dispaced to ensure that vegetation can feed itself.
Reply | Report Abuse | Link to thisSo much remains to be learned and yet so much time needed study it all. Yet science will be our only salvation. Man has always studied nature but we are changing it recklessly.