In a study appearing in the November issue of The American Naturalist, biologists investigated the response of small animals to climate change on a remote sub-Antarctic Island. From an evolutionary standpoint, acclimatizing to a change in circumstances seems to make evolutionary sense. However, Steven Chown and Jacques Deere (both of Stellenbosch University) found that terrestrial animals don’t adapt. Why not?
“Acclimation only makes sense if tomorrow is likely to be similar to today,” noted Chown, “and at Marion Island the sea is always cool, but from one day to the next it’s never quite clear what the weather will bring on the land.”
Animals have adapted this flexibility. Terrestrial animals facing highly unpredictable environments show no acclimation response at all, whereas the marine species reacted to life in a cold, predictable environment. This research found that unpredictability is a key to status in the face of change.
Marion Island is a great place to see the effects of global warming. On this island the average annual temperature has increased by more than 1° Celsius for the past fifty years. According to Jacques Deere, “This island and its animals provide a great research platform for assessing the taste of things to come.”