The combination of a warming climate and human disruption of traditional habitats has been causing changes in the ranges of many animal species. Over the past century, white-tailed deer have greatly expanded their range in North America. Researchers from a group of Canadian institutions have been investigating the expansion of the deer in the boreal forest of Western Canada. A five-year study used 300 wildlife cameras throughout the region to track the activities of large mammals.
Climate change has created milder winters and habitat alteration from forestry and energy exploration have created new food sources for deer.
The expansion of deer in the forest has not been a good thing for the woodland caribou. The species was designated as threatened in 2002. As of 2011, only 34,000 remained in the region. Deer are ecosystem disruptors, in this case disrupting existing predator-prey dynamics. Areas with more deer typically have more wolves and wolves are predators of caribou. Deer can handle high predation rates, but the already threatened caribou cannot.
Understanding the relative roles of climate and human land use is essential in efforts to recover caribou populations. It is complicated because further north, the climate becomes harsher and human land use decreases. The debate over the relative effect of climate or habitat change is one of the most pressing issues facing ecologists globally as they pursue efforts for ecosystem restoration.
In any case, winter severity is expected to decline as climate change progresses. Therefore, deer are expected to keep expanding northward and increasing in abundance, which means increasing risk to caribou.
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Deer are expanding north, and that’s not good for caribou
Photo, posted January 12, 2016, courtesy of Gerry via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio
