Vasseur talks temperature variation

David Vasseur, a professor in the Department of Ecology and Evolutionary Biology, recently led a team of international scientists exploring how climate change-associated temperature swings impact insect populations. Though previous research has suggested that rising temperatures will be an important factor for species’ survival, the team found that variation in temperature will also contribute to the impact of climate change. The News sat down with Vasseur to discuss his findings, as well as future directions for his research.

Q: What are the key points you hope readers will take away from this study?

A: [That] environmental variation matters. We often think about global change only in the context of things getting slowly warmer over the next century. But we need to consider what is happening with the variation in climate. I think the timing for that is right; if you look at what’s happening this winter all over North America, we’re seeing these monstrous swings in climate. For some regions of the earth, this is predicted to continue to get more variable. We’re going to see more and more of these swings and we can’t ignore the effects that these swings have on species. That’s the main result we want to send home.

 Q: Will the effects of temperature variation change how we think about and evaluate endangered species?

 A: One of the things that we might realize is that species that we didn’t believe would be at risk of climate change may certainly be at risk [of variation changes] in those environments. The real reasoning behind our findings is that if you start to include the change in climate variation along with the mean, you have a greater chance of seeing long extreme runs of conditions, and those have very detrimental effects on populations. A mean shift of one or two degrees might be inconsequential for a population, but if that is accompanied with an increase in the variation, what it will mean is that that organism might go from seeing very extreme conditions for 1 percent of its lifetime, to now seeing  those conditions for 10 percent of its lifetime. That will have a really big consequence.

 Q: In the study, why did your team decide to look at insects?

A:  We can make the assumption that the average air temperature correlates pretty well with the body temperature of [insects]. For vertebrates, for mammals and birds, even lizards and snakes, that actively regulate their temperature through behavioral mechanisms, the problem is much more challenging. It’s something that my group and others are working on.

Q: On this paper, you collaborated with eight other authors. Can you tell me about how the group of scientists came together?

A: This group came together actually because of [two] colleagues who put together a proposal to bring together a number of international researchers who were interested in understanding how temperature and temperature variation impacts the interactions among species. Although we didn’t talk about interactions among species in this paper, it was a first step towards where we’re headed with some of the research this group is doing.

Q: What are your next steps? What further research has this study prompted?

A: I am very interested in starting to understand how evolutionary changes may mediate this response. We use data and measurements that are based on species ecology, so it doesn’t leave room for species to actually adapt to those new conditions. I’m interested in using mathematical models and experiments to begin to predict how adaptation is also going to change what we know about the impact of climate change.

We can do that with E. Coli in the lab for example, [since] bacteria is a model system for thinking about temperature change. It gets a little harder when we start to think about multicellular organisms because of the evolutionary constraints. The evolutionary problem gets much more challenging to define.

Q: Is looking at the evolutionary factor in species response to climate variation something you hope to pursue with this group?

A: That will be something I will pursue on my own quite likely — our funding is basically dry. We are through our funding cycle, at the stage where we are publishing our results. It will be likely a different set of research which will move forward on some of these future questions.

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