"The data are not consistent with a conclusion that the Rocky Mountains are a barrier," he said. According to Mills, the data show very little genetic differentiation among lynx populations, "which implies considerable gene flow."
Stenseth, however, said the differences between the populations are distinct enough to suggest the populations do not fully mix. He said this is particularly clear when comparing eastern populations, which are separated by distance and not a topographic feature such as a mountain range.
"Distantly located populations are typically different because of them being distantly located from each other," said Stenseth. "In our case they are clearly more different, hence the observed differences are clearly real."
According to Stenseth and colleagues, the genetic differences among the lynx populations correspond to ecological divisions between the populations. For example, populations in the wetter regions west of the Rocky Mountains are different than those in drier regions to the east. In turn, these populations are distinct from those in cold, snowy Maine.
"Our study suggests that the Canadian lynx is genetically structured following ecological differentiation, which seems to be due to large scale climatic factors," said Stenseth, who was part of a team that published a paper in the August 13, 1999 issue of Science that found Canadian lynx populations were divided into three separate climatic regions.
Based on the analysis of the genetic data, Stenseth concludes that conservation efforts for the Canadian lynx ought to be focused on these three distinct regions, classified as Pacific-maritime, Continental, and Atlantic-maritime.
Mills, however, said that the data collected by Stenseth and colleagues "reflects high gene flow on a range-wide scale, underscoring the conservation recommendations that he and his colleagues made in 2002.
"This data set is similar to ours in showing that connectivity is an important process for lynx," he said. "Therefore, in the U.S., it may be at least as important to focus on maintaining connectivity with the northern populations as it is to manage areas where lynx are currently found."
Lori Nordstrom, a biologist with the U.S. Fish and Wildlife Service in Helena, Montana, said the agency is required to use the best scientific information available when making conservation management decisions under the Endangered Species Act. The new study, she said, is a welcome contribution.
"There is so little information on lynx genetics at this point that it is all new information," she said.
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