Climate Shift Could Help Struggling N.E. Species - Metro
Warm winters like the one that just passed are likely to become more frequent as the planet heats up, scientists predict, and many of the consequences could be dire, from rising sea levels to droughts to the spread of pests and diseases. But in the lesser-noted ledger of global warming, there are also potential benefits for wildlife.
Among the potential beneficiaries is the New England cottontail, an endangered brown rabbit that, in a typical winter, stands out against the snow, making it an easy target for predators. Not so this nearly snowless year.
Warm winters can mean more vegetation, which in turn can provide a greater food supply for a range of herbivores in New England. That could benefit white-tailed deer, fishers, opossums, and bobcats, scientists say.
“Severe winters tend to limit many species of wildlife, because they suffer increased mortality due to cold temperatures and reduced availability of prey,” said John Organ, chief of the division of the wildlife and sport fish restoration for the US Fish and Wildlife Service in Hadley. “Increased warming trends, resulting in reduced snow, are likely to allow more species to have a higher survival rate. All things being equal, that might mean increased populations, unless compensated by an increase in mortality factors such as disease.”
Scientists say some species of butterflies may benefit from warmer winters, allowing them to spawn successive generations in a life cycle, rather than just one.
Reduced snowfall may mean deer no longer congregate in small areas and therefore will not be such easy prey. Young bobcats and fishers may be less susceptible to starvation because of the difficulty of navigating through deep snow.
Also likely to thrive as the season grows less harsh are red-bellied woodpeckers, geese, and turkeys, which are pushing farther north than ever before. Migratory birds such as red knots are already benefiting from the earlier spawning of horseshoe crabs, whose eggs they eat.
And there is already evidence of the Virginia opossum moving farther north in New England and Canada, even though they are occasionally found dead from frostbite because they are not accustomed to the deep cold.
Of course, climate change will present a trial for a number of species. Snowshoe hares, unlike the New England cottontail, are more vulnerable without snow, as their fur turns white in winter, rendering them more visible to predators.
Moose are more likely to suffer from ticks, which survive in far greater numbers when the weather remains mild. Black bears are less likely to hibernate, which affects their metabolism, potentially hampering their ability to reproduce.
This winter’s lack of snow - just 9.3 inches fell in Boston, nearly 80 percent below normal and the second lowest on record - has left many of the state’s rivers and streams at record low levels for the time of year.
It is also making it harder for freshwater fish such as shad, herring, smelt, and salmon to spawn and easier for algae to bloom, which depletes oxygen and makes it harder for river life to thrive.
For the New England cottontail, a bark-colored rabbit with perky ears and tails like puffs of cotton, it may be years before scientists see the benefits of warmer winters.