Telling the Story of Science: Katie Boronow

During January 2014, the GSAS workshop ComSciCon Local helped young researchers learn how to communicate complex and technical ideas in a way that makes them vivid and comprehensible to a broad audience. Organized by Communicating Science, an organization founded and run by PhD students from Harvard and MIT, the workshop culminated with students preparing brief articles that answered the question, “What surprising role will your field take in explaining, shaping, or solving a problem faced by society this century?” Below is one student’s response. This is part three of a four part series.

A Tale of Two Lizards: How Behavior Can Buffer against Climate Change

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On a cold morning, 8,000 feet above sea level, the Caribbean island of Hispaniola looks and feels more like New England: Instead of palms, pine trees surround me, and I’m wearing a fleece and a rain jacket over my t-shirt to stay warm. I am here with fellow PhD student and head researcher Martha Muñoz and a team of undergraduates to study the lizards that live in this unusual environment. Unlike humans, these lizards can’t just put on a sweater to stay warm. Genetic evidence indicates that these high-elevation lizards (Anolis shrevei and A. armouri) are descended from the same ancestor as another species that lives in the island’s tropical lowlands (A. cybotes). By comparing the high-elevation species to their low-elevation relative, we hoped to identify differences between the species that could have resulted from adaptation to differing environments.

What we found surprised us: High- and low-elevation lizards are similar in fundamental ways. Crucially, Muñoz found no difference among the three species in either body temperatures recorded in the field or temperatures selected by lizards during a lab experiment that offered them a range of choices. How could high-elevation lizards living in a much colder environment still prefer the same temperatures as their tropical relatives?

We think the lizards have changed their behavior to compensate for the different temperatures in the two environments. At low elevation, lizards choose densely forested areas where they spend most of their day in the shade; at high elevation they spend almost all of their time in open areas in direct sunlight. But perhaps most important, the lizards switch from perching on tree trunks at low elevation to rocks at high elevation. Unlike tree trunks, rocks heat up rapidly, and it is only on rocks that high-elevation lizards can achieve body temperatures comparable to those of their tropical counterparts.

In this case, behavior appears to shield the high-elevation lizards from evolving a preference for cooler temperatures. This result challenges our assumptions of how animals will respond to global climate change. Scientists have often theorized that climate change will cause animals to migrate to areas matching their current environmental preferences, rather than stay put and adapt. This way of thinking forms the basis of models predicting how species’ habitat availability will change under hypothetical climate scenarios. For many species, suitable habitat is predicted to shrink, sometimes to levels that threaten their survival.

But these models ignore how individuals can use behavior to construct their own microclimates. By burrowing deeper into the ground, retreating into the shade, or perching on a rock, an animal can manipulate its local environment and maintain its climatic preferences even in seemingly unsuitable habitat. Incorporating this understanding into models of habitat shifts will lead to more accurate predictions of the impact of climate change on animal communities—and perhaps lower the number of species predicted to become endangered. While global climate change threatens our environment, animals acting to buffer themselves from climatic shifts will be able to stand their ground.

Katie Boronow is a third-year PhD candidate in organismic and evolutionary biology.
 

Photo by Ben Gebo