A new study by the U.S. Geological Survey and its partners has identified the circumstances in which some animals change their behaviors in response to climate change. Behavioral flexibility allows animals to rapidly cope with changing environmental conditions. Behavior can also serve as an early indicator of environmental changes, as changes in behavior can be evident before detectable shifts in range or population.
Lead author Erik Beever and colleagues performed a systematic literature search and found 186 studies that detailed situations where animals displayed behavioral flexibility as a way of coping with climate variability. Most of the behavioral responses involved changing the timing of life events such as reproduction or migration, but changes in feeding, habitat choice, and temperature regulation were evident, as well. Beever and his colleagues found such behavioral flexibility in a number of different animal groups, including invertebrates, birds, mammals, reptiles, amphibians, and fishes.
Beever points out that species’ responses to climate variability are context-dependent. Even within a given species, some populations may exhibit behavioral flexibility while other populations do not. Many of the behaviorally flexible species discovered in the literature review are more generalist in their choice of diet and habitat, and so may be better equipped to accommodate new conditions than specialists.
Beever and his colleagues highlight the American pika as an example of an animal that uses many of these flexible behaviors to cope with climate variability. Pikas are typically found in high-elevation, cool and moist rocky habitats in the mountains of western North America. However, populations in parts of their range employ a suite of behaviors to avoid and accommodate climate change. These include changes in foraging strategy, habitat use, and heat-regulating postures. Beever says some pikas are moving off their rocky habitats and into the shade of nearby forests, while others bundle up into a more spherical shape in the winter to reduce heat loss. Although pikas have experienced declines in some parts of their range due to climate change, behavioral flexibility may allow other populations of pikas to acclimate to a changing climate.
Beever and his colleagues are careful to acknowledge that behavioral flexibility is not a panacea that allows all populations of all species to have an unlimited capacity to cope with contemporary climate change. There are limits to animals’ ability to change their behaviors; certain environmental conditions or physiological characteristics cannot be overcome. Behavioral responses to climate change may be constrained by trade-offs with other activities essential for survival and reproduction. For example, desert woodrats in Death Valley do not leave their dens until the nighttime temperature drops to a certain level. As a result, woodrats spend substantially less time outside their dens overall as evening temperatures rise, eating into the time available for necessary activities like mating and foraging.
Beever hopes this study spurs more research on characterizing those aspects of life history and ecology that can be modified by behavior and identifying constraints that limit the ability of animals to adjust to climate change.
“The climate is likely to become more variable with more extreme events like heat waves, cold snaps, pronounced droughts, and deluges of rain and snow,” says Beever. “These acute events might stretch the limits of behavioral flexibility.”
Beever also anticipates that a better understanding of different species’ capacity for behavioral flexibility will help inform conservation efforts and policy decisions. Considering how behavioral flexibility helps some animals, as well as the limits of that flexibility, will be critical to species conservation.
“Hopefully, this gives some inkling to conservationists and wildlife and land managers of where they might see vulnerabilities and where they might not need to dedicate as much conservation effort,” he says.
“I suspect that many species will hum along and not change too much, but the more species we investigate, the more we may find these occasional surprises where species are changing really quickly.
“More research on behavioral flexibility in response to climate variability might even suggest particular management actions that could facilitate conservation of some species in the face of an uncertain future.”
Beever, E. A., Hall, L. E., Varner, J., Loosen, A. E., Dunham, J. B., Gahl, M. K., Smith, F. A., and Lawler, J. L. (2017). Behavioral flexibility as a mechanism for coping with climate change. Frontiers in Ecology. doi: 10.1002/fee.1502.