Snow quality may affect the Canadian lynx's ability to kill its prey, according to new research suggesting climate may be impacting one of the most fascinating ecological systems to intrigue biologists for decades. The University of Alberta's Dr. Stan Boutin is part of a research team to study the relationship between the lynx and the snowshoe hare--an interaction that has grave implications on the dynamics of the whole boreal forest.
Boutin teamed up with other researchers from Canada, the United States and Norway--including evolutionary ecologist Nils Stenseth--to study the lynx-hare cycle, and how it related to the overall boreal forest community. Stenseth has previously argued that the 10-year cycle, which means a rise and fall of the hare population followed by a similar pattern of the lynx, differed according to regions of the country and those differences were tied to large-scale climatic patterns.
"The genetics of the lynx are quite different among these Canadian regions and we questioned whether there was some sort of barrier that might stop gene flow," said Boutin, a biologist with the Faculty of Science. "We knew there was nothing physical between eastern and central regions, so we started to speculate that there may be something climate-related that would influence the lynx's ability to prey on snow hares and their propensity to move between regions."
In a paper published today in the Proceedings of the National Academy of Science, part of a series of papers already published, the team demonstrated that different snow conditions may, in fact, affect the dynamics of the Canadian lynx.
In particular, surface hardness, as determined by the frequency of warm winter spells control how deep the lynx sinks in the snow. For example, when there are few warm spells, the researchers write, the snow remains fluffy and the lynx sinks deep, whereas its main prey, the snowshoe hare does not sink in the snow and will easily escape under such conditions. But with increasing warm spells, the hares are not able to escape as well.
Boutin has collected rare data on the lynx's ability to kill under different snow conditions for more than 10 years. His team was able to track the type of snow and whether the animal was successful in the kill or not. "This lynx-hare cycle is an amazing phenomenon and it has proven to be a very robust relationship," said Boutin. "If we start to get climate warming and a crusting of the snow without long, deep cold spells, it could change the interaction and disrupt this robust system we're used to seeing."
This cycle forms one of the fundamental pulses in the boreal forest ecosystem. The hare is the prime herbivore in the system and if it were to disappear, it would have major implications to other species like predators and the structure of the plant community would be altered substantially, said Boutin.
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