New framework sheds light on how, not if, climate change affects cold-blooded animals

Date: January 19, 2016

Source: University of Missouri-Columbia

Cold-blooded animals like lizards, insects and fish have a preferred body temperature range at which they hunt, eat, move quickly and reproduce. Fear that a warming climate will constrict this temperature range underlies recent studies that warn of the detrimental effects of climate change on the activity and survival of cold-blooded animals. While not contradicting these warnings, a new paper published in the latest issue of Ecology Letters offers a revised framework that may better answer how activity is affected by temperature.

"We've done very well at saying climate change will have an impact on ectotherms, but we've done less well at saying how they will be effected," said Manuel Leal, an associate professor of biological sciences at the University of Missouri and one of the paper's authors.

The researchers argue that most studies that look at the effects of climate change on cold-blooded animals, or ectotherms (animals whose body temperature depends on environmental temperature), treat optimal body temperature as the primary or only driver of activity. The approach, they say, fails to render the complexities of these animals' behaviors.

"While preferred body temperature is a good index of when most behaviors are affected by temperature, it is not a good representation of the biology of the animals because they are actually active cooler and warmer than their preferred temperature," said Leal.

To get a better idea of how temperature affects behaviors, the scientists propose a conceptual framework in which four components of temperature-dependent activity (thresholds, probabilities, modes and vigor) are integrated to predict activity windows at the scale at which organisms experience and respond to ambient temperature.

"The strength of this framework is its simplicity and organism-centered approach," said Leal. "Emphasis is placed on the importance of looking at the synergy that happens among ambient temperature, body temperature and activity."

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