American Society of Naturalists

A membership society whose goal is to advance and to diffuse knowledge of organic evolution and other broad biological principles so as to enhance the conceptual unification of the biological sciences.

“65 million years of change in temperature and topography explain evolutionary history in eastern North American Plethodontid salamanders”

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Richard Barnes and Adam Thomas Clark

65 million years of temperature and topographic change explain phylogenetic and spatial patterns in salamanders

Study uses models to peer into salamanders’ pasts

<i>Plethodon shermani</i>, Macon County, NC, USA.<br />(Credit: Ben Lowe)
Plethodon shermani, Macon County, NC, USA.
(Credit: Ben Lowe)

What can salamanders tell us about how changes in climate and elevation might affect evolution? More than you might think, as it turns out. A new study suggests that models can be used to help disentangle how eroding mountains and changing temperatures act over millions of years to influence where and how salamanders live in the Appalachian Mountains.

Co-authored by Richard Barnes, a PhD student at the University of California, Berkeley, and Adam Clark, a PhD student at the University of Minnesota, the study asks whether it is possible to separate the effects of the many processes that may have influenced the present day distribution and evolutionary history of Plethodontid salamanders in eastern North America.

The salamanders have evolved and lived in the same region for up to 65 million years – a time period which includes several ice ages, the erosion of the Appalachians from a Himalayan-scale mountain range, and many chance events. For standard analytical tools, the complexity of these interactions makes the past too murky to reason about.

However, in systems where changes have been particularly large and well-documented, there is hope that at least some of these relationships might be teased apart. To that end, Barnes and Clark developed a “general simulation model” based on historical records of temperature and elevation changes, and the impacts of these changes on species throughout their entire evolutionary histories.

Building on existing examples of general simulation models, their findings present a possible path forward for researchers interested in combining models of ecology, evolution, and earth history to better explain the abundance and distribution of species over time. “Future studies may be able to adapt methods such as these to better understand species’ pasts, as well as their futures, as our planet’s climate and environment change,” says Clark. Read the Article