A new report suggests that climatic variation can be as effective as geographic barriers are at isolating groups of animals. According to findings published online this week by the Proceedings of the National Academy of Sciences, weather differences could be responsible for the formation of distinct Canadian lynx populations.

In North America members of Lynx canadensis are divided into three geographical regions--the Pacific, Continental and Atlantic zones--each of which exhibits distinct genetic characteristics. Such genetic isolation within a species often occurs as a result of geographical hurdles, such as an island getting cut off from the mainland. Although the Rocky Mountains supply a barrier between the Pacific and Continental populations, no such obstacle exists between the Continental and Atlantic regions. Nils C. Stenseth of the University of Oslo and his colleagues analyzed genetic and census data on the Canadian lynx from as far back as 1897 and devised a computer model to integrate this information with climate records.

The new approach, dubbed climate forcing of ecological and evolutionary patterns (CEEP), demonstrated that weather patterns influence how the number of cats vary from year to year. These fluctuations are synchronized within each region, but all three demonstrate different patterns, which in turn boosts genetic isolation. The researchers plan to apply the model to study other species to determine if climate patterns have had a similar effect on other species as well.