John Organ holding a Canada lynx kitten. Credit: USFWS
John Organ holding a Canada lynx kitten. Credit: USFWS

Canada Lynx and Climate Change

Rising temperatures and declining snow fall spell trouble for Canada lynx

Canada lynx are uniquely suited for the rigors of snowy northern Maine. The furry feline’s thick coat, long, lean legs and massive paws allow it to hunt atop snowpack like a cat on snowshoes. But with temperatures predicted to rise in the coming years, the deep snow cover lynx depend on may be significantly reduced, eliminating their competitive advantage over other predators.

While their name suggests otherwise, the historic range of Canada lynx extended  across the border into northern parts of the contiguous United States from Washington to Maine and down into the Rocky Mountains. Experts believe a variety of factors contributed to lynx reduced range, notably land use changes with human expansion and a warming climate as possible contributing factors. Today, their range in the United States is confined to just a handful of northern states. Though it was occasionally reported as far south as Pennsylvania, northern Maine currently supports the only viable lynx population east of the Mississippi River.

The U.S. Fish and Wildlife Service officially listed Canada lynx as a threatened species in 13 states in 2000. As a federally-threatened species whose range has already been greatly diminished, climate change poses a grave threat to this rare wildcat.

John Organ, Chief of Wildlife and Sportfish Restoration for the Service in Northeast Region, has co-led an ongoing study along with researchers from the Maine Department of Inland Fisheries and Wildlife to research, track and identify conservation strategies for  Canada lynx in Maine.

“It is hypothesized that as the climate warms, lynx range will recede and move north,” said Organ. “Without significant snow cover, Maine’s lynx population could be in jeopardy.”

Maine is bordered by the Canadian provinces of Québec and New Brunswick in its northwest and northeast limits, respectively. But the peninsula encompassing Maine, New Brunswick and parts of Québec is separated from the rest of Canada by the Saint Lawrence River and Gulf of Saint Lawrence – impassable for a land bound cat because the river is kept free of ice in the winter for ship-borne commerce. As warming temperatures and decreasing snow fall push Canada lynx north, they may eventually be restricted south of the river to the high elevations of the Gaspe Peninsula of Quebec.

Adult Canada lynx. Credit: USFWS
Adult Canada lynx. Credit: USFWS

Lynx are a specialty species, tied to snow depth and snowshoe hare. They have evolved physical attributes, like large saucer-like paws, that provide a competitive advantage in deep snow habitats. But without deep snow, bobcats, fishers and other predators may out-compete lynx in northern Maine.

Chris Hoving, Endangered Species Coordinator for the Michigan Department of Natural Resources and Environment, conducted a study of lynx habitat dynamics while completing his Master’s degree at the University of Maine. The study determined that snow fall was one of the primary factors in determining suitable lynx habitats.

“Lynx are uniquely sensitive to climate change based on their physical attributes,” said Hoving. “Their preferred habitat requires at least 2.7 meters of average annual snowfall. If snowfall decreases, there may be almost no suitable habitat in Maine where the only verifiable lynx population on the East Coast exists.”

A specialized hunter, Canada lynx preys almost exclusively on snowshoe hare. Some estimates suggest snowshoe hare comprise 75-80 percent of a lynx diet. Researchers have also determined that lynx are directly tied to population cycles of snowshoe hare.

“Lynx and snowshoe hare are a classic case of co-evolution,” said Organ, who noted that skeletons of snowshoe hare and lynx appear nearly identical other than their feet and heads. “Lynx populations in the boreal forest follow the rise and fall of snowshoe hare within their habitat on a two year delay.”

As such an effective deep snow hare hunter, Canada lynx has so far had little need to hunt anything but the widely available snowshoe hares. But a warming climate favors animals who readily adapt to warmer temperatures and variations in a region’s biodiversity. Bobcats and fishers prey on a more diverse range of animals and are better equipped to adapt to a changing climate than specialists like Canada lynx.

State and federal conservation agencies are currently developing strategies to maintain Maine’s lynx population. Multiple studies have shown that snowshoe hare thrive in early successional boreal forests, or as Organ calls them: rabbitats. In Maine, which is south of the boreal forest, this equates to mid-to-late regenerating stands of spruce and balsam fir. By providing ample snowshoe hare habitat, Canada lynx can be expected to remain viable in the same areas.

“As the hare goes, so goes the lynx,” said Organ. “Providing guidance to land managers – within the context of larger biodiversity concerns – is critical to the success of lynx and all species.”

Chris Hoving suggests a forest of diverse habitats, those in different stages of succession, and in blocks large enough for area-sensitive species, will provide the greatest benefit to all forms of wildlife. While many conservationists focus on protecting large blocks of mature forest, many species, including Canada lynx, need large blocks of young forest as well. 

“Managed forests respond less severely to climate change than unmanaged,” said Hoving. “Through management, we can reduce the forest’s rate of change and soften the blow of climate change to a variety of species.”

Story by: Bill Butcher, NewVo Media

Probability of Canada lynx occurrence based on average annual snowfall

Probability of Canada lynx occurrence based on average snowfall in 1970 Probability of Canada lynx occurrence based on average snowfall in 1980 Probability of Canada lynx occurrence based on average annual snowfall

(click image for full-size) Credit: Chris Hoving

Flickr.com icon Check out our Flickr photo album of a Canada lynx study conducted in Maine.

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