The New World Order

Technically neither flora nor fauna, lichen sprout to life through the symbiotic relationship between fungi, bacteria and algae. Researchers from Alaska to Europe have reported possible declines in cool- to cold-climate lichen populations. In large part, they are being crowded out by shrubby vegetation that thrives in the warmer weather. Satellite imagery of the Canadian tundra clearly shows a burgeoning shrubland spreading across what was once prime lichen territory.

This has negative implications for everything from small mammals, such as the northern flying squirrel, to 200- kilogram caribou that rely on lichen as a winter food source, as well as for dozens of bird species that use lichen as nesting material.

Ontario’s wetlands are particularly susceptible to rising temperatures – which lead to increased evaporation – and projected changes in precipitation patterns, with long periods of drought broken up by torrential downpours. Mark Gloutney of Ducks Unlimited Canada suspects that many small, isolated wetland basins will go dry in the summer. “That’s going to create conditions that will be favourable for the expansion of phragmites and cattails,” he says. The former (pronounced “frag-mighties”) are tall, aggressively invasive plants that expand to the point of creating a monoculture along Great Lakes shorelines or around large wetlands, while the most common cattails in the wild today are a hybridized species that resulted from generations of native and invasive European strains cross-breeding. The convergence of these two dominating species would virtually eliminate the open water on which innumerable birds, amphibians and reptiles rely. Although cattails provide some degree of favourable wildlife habitat, “almost nothing uses dense stands of phragmites, and you get a really precipitous crash in biodiversity,” explains Gloutney.

One well-documented example of a species already basking in the warm glow of an altered climate is the lesser snow goose. Higher temperatures around James Bay have opened up new breeding grounds and reduced the rate of chick mortality, helping the goose population triple in the past 20 years to more than 4.5 million breeding birds. However, the feeding geese strip coastal marshes bare of grasses, leading to erosion. Environment Canada estimates that along the west coast of Hudson Bay “nearly one-third of the coastal salt marsh habitat has been destroyed, while another third is seriously damaged.”

The life cycles of the Canadian lynx and the snowshoe hare are closely related; as the hare’s numbers grow, so, too, do the numbers of lynx that prey on them. Eventually, the hare population crashes, and a decline in the lynx population soon follows. University of Alberta biologist Stan Boutin has been studying the two species’ codependence for years, and he predicts that warmer winters will have dire consequences for them.

When hunting, lynx sink in deep snow, allowing lightfooted hares to hop away to safety. But projections for milder, rainier winters suggest that snowshoe hares will be easier prey for lynx year-round, which could lead to long-term population declines for both species.

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