Wednesday, June 25, 2008

Who are the creatures in your neighborhood?

Ok. The idea when I started blog this was to be informal, not so science-nerdy (since that's what I am in the rest of my life), so this post may just be a temporary departure, or may reflect a different idea of what this is for.

Lately I've been thinking a lot about science as a public service. If you pay taxes, you pay for me to do the work that I do (I'm funded by the NSF) and, as far as I'm concerned, that means that I not only have a responsibility to do good work, but I have a responsibility to communicate what I and my colleagues are learning.

One of the subjects that has come up quite a bit in my lab has been how plant and animal communities respond when their environment starts changing. Since I work in a paleontology lab most of my work focuses on how communities in the past have changed-but my greatest hope is that this work will provide us with some clues into how communities that exist today may change. One thing that seems clear from the fossil record is that not all members of a community will change in the same way at the same time.

Recently a paper came out in PLoS ONE examining what may happen to the plant communities in California as our climate changes.

Loarie, Scott R., Benjamin E. Carter, Katharine Hayhoe, Sean McMahon, Richard Moe, Charles A. Knight and David D. Ackerly (2008). Climate Change and the Future of California's Endemic Flora. PLoS ONE 3(6):e2502. doi:10.1371/journal.pone.0002502

The flora of California, a global biodiversity hotspot, includes 2387 endemic plant taxa. With anticipated climate change, we project that up to 66% will experience >80% reductions in range size within a century. These results are comparable with other studies of fewer species or just samples of a region's endemics. Projected reductions depend on the magnitude of future emissions and on the ability of species to disperse from their current locations. California's varied terrain could cause species to move in very different directions, breaking up present-day floras. However, our projections also identify regions where species undergoing severe range reductions may persist. Protecting these potential future refugia and facilitating species dispersal will be essential to maintain biodiversity in the face of climate change.

Endemic species are species that aren't found anywhere else. California has A LOT of endemic plant species, enough that it has been labeled a "biodiversity hotspot". The concern that biologists have about these endemic ecological communities that don't have a very big range is that, as our climate changes over the coming years these communities could disassemble, with some members moving faster, or in different directions than others. That's what these folks are talking about when they say "breaking up present-day floras". The result could be communities that look and behave very different than what we have today. The fancy phrase for these new groups of plants and animals is "non-analogous communities".

To which you might say, cool, we'll get the plants from Southern California and our plants will just move on up to Mendicino. We'll visit on weekends and holidays. Sounds good, except we've managed to put a lot of obstacles in the way of species. Roads, cities and farms are just a few of the things that may prevent species from following their optimal environment as the world around them changes. So, while at the end of the last ice age species could follow a retreating glacier, now it's not so easy, and may in fact put many more species at risk for extinction than there would be if they could move unimpeded.

This article made the front page of the website of our local newspaper and I was aghast at some of the comments that were left. Granted, there are always the same folks who pipe up and make some inane comment about Al Gore's weight or warming on Mars every time there's an article about climate change, but there were also people who seemed genuinely confused about the science of climate change and extinction. Part of the problem is that these are two really complicated issues that are interacting in complex ways. Even if our climate was not changing, we would still be losing species. We're losing species from overfishing, pollution, habitat destruction and on and on. Yes, species have always gone extinct, but we are disassembling ecological communities at an alarming rate-and the consequences of our actions could be severe. Regardless of how you feel about the inherent right of other species to exist on this planet (and I strongly believe that), the risks to humans alone are enormous. I'm not the first person to say this, but I think it's true, so I'll repeat it here. Human destruction of ecosystems is a huge, uncontrolled experiment, the consequences of which we are not yet able to predict, but which, by the time some of the effects become apparent, may to too late for us to change some of our choices. I'm not hopeless about the situation we are in, but I think we need to do some serious considering of what kind of world we want, and what kinds of choices we need to make right now in order to make that world a reality.

Read the entire article here.
(yay to the Public Library of Science!)

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