UMaine Study Indicates Humans Accelerate Trait Change in Animals
Contact: Michael Kinnison (207) 581-2575; David Munson (207) 581-3777
ORONO, Maine — The influences humans have on the habitats of other species have long been recognized, raising concerns about loss of species. However, another widespread outcome of such disturbance has come to light. After examining over 3000 estimates of rates of evolution in wild animal populations, all occurring in modern times, UMaine researcher Michael Kinnison and colleagues from McGill University in Quebec have found that humans are accelerating changes in the animals themselves.
Working with Andrew Hendry and Thomas Farrugia of McGill, Kinnison established a database of studies that examine occurrences of trait change (observable physical or behavioral changes) in animals over 1-200 generations, using it to determine the rate at which these changes occur over time. The researchers then compared rates associated with human activities, such as harvesting (fishing, hunting), pollution and the introductions of invasive species, with rates associated with natural disturbances. When all of these rates were combined, considering everything from insects to bighorn sheep, the investigators found that change driven by humans is nearly twice as fast as the rate in more natural situations.
But what does this mean for the ability of species to keep pace with humans? The scientists suggest that the message may be mixed. On the one hand, these findings suggest that a wide range of animals can pick up the pace when exposed to human influences. When beneficial, these changes could help species persist. However, the authors caution that some of these changes may not be beneficial or sustainable over longer periods of human interference.
“What is clear”, says Kinnison, “is if we are concerned about these trait changes we probably don’t have the luxury of decades or centuries to deal with them. Our data suggest that changes seen in a few generations are often as large as those seen over hundreds. In some cases we may be changing the face of life nearly as quickly as we are impacting the environments on which life depends.”
While some scientists have suspected humans can speed changes in wild animals, this study is the first of its kind to pull together many studies to quantify the overall scale of this effect and its widespread nature.
“There’s a certain practicality and power in pulling together many studies in a combined analysis like this”, said Kinnison. “The argument that observed changes in species are just isolated cases that can be brushed aside loses ground significantly when confronted by a pattern that emerges from the work of many scientists combined. It helps us to see the big picture.”
The research was supported by the National Science Foundation, the Andrew Mellon Foundation and the Maine Agricultural and Forest Experiment Station.
Kinnison’s study can be found on-line early at the journal Molecular Ecology, along with other articles to soon appear in a special issue on evolutionary change in human altered environments.