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University of Iowa News Release

July 9, 2004

UI Researcher Finds Link Between Weather And Canadian Lynx

A University of Iowa researcher and his colleagues have found a correlation between Canadian winter warm spells and the relative abundance of the Canadian lynx, according to an article published in the July 5-9 issue of the Proceedings of the National Academy of Sciences (PNAS).

K.S. Chan, professor in the UI College of Liberal Arts and Sciences Department of Statistics and Actuarial Science, helped develop a mathematical numerical analysis showing that lynx populations are affected by the frequency of winter warm spells, which cause zones of differential snow surface hardness. A harder snow surface, it seems, makes it easier for the lynx to travel along the surface and capture its prey.

In particular, the authors of the PNAS article write: "For instance, when there are few warm spells, the snow remains fluffy and the lynx sinks deep, whereas its main prey species, the snowshoe hare, does not sink in the snow and will easily escape under such conditions." Prior to using mathematical analysis, researchers had puzzled over the fact that genetic mixing between some lynx populations was relatively low, even though there are no obvious geographical barriers separating lynx populations in eastern Canada.

The researchers, whose fields include biology, climatology, statistics and informatics, say that their work reveals an ecological understanding of how an animal population is affected by climate.

STORY SOURCE: University of Iowa News Services, 300 Plaza Centre One, Suite 371, Iowa City, Iowa 52242-2500.

CONTACTS: Gary Galluzzo, 319-384-0009,