Geoscience Reference
In-Depth Information
IN THE FAR
north, changes to the forest composition and the animals living there are likely to come about prin-
cipally through climate change. But farther south, as we have seen in the New England/Acadian Forest, human
activities have reduced the types of trees and the overall age of the forest—and therefore the kinds of animals
living there. For the near future, mammals best adapted to older forests are likely to decline, while species us-
ing younger forests, such as white-tailed deer, might well continue to increase as they have done during the last
century. It has been shown that an increase in mean summer temperature of as little as one degree might
destabilize predator-prey relationships, and as a result lynx populations could switch from cyclic to noncyclic
behavior. Climate change may adversely affect mammals that need snow, such as the snowshoe hare and lynx,
but positively affect those that have difficulty surviving long, hard winters, such as white-tailed deer and hi-
bernating bats.
Whereas southern species might move north, as the white-footed mouse already has done, expanding its
New England range since the 1950s into northern coastal Maine, it is unlikely that boreal species, such as lynx
and northern bog lemming, will move southward. Birds are more mobile than mammals, and the composition
of bird life in the Maritime Provinces and northern New England has been in a state of constant flux since
European colonization, with fully 22 percent of known breeding bird species having arrived after European
settlement. Grassland species, such as bobolink, have significantly declined as farmland, which peaked in the
late 1800s to early 1900s, has reverted to forest. At the same time, the loss of big trees has caused the decline
of birds dependent upon them, such as the red crossbill and pine grosbeak. The only prediction possible is that
future changes to the landscape will be accompanied by the historical pattern of near-constant change in bird
life.
A snowshoe hare hightails it for cover. Its population is in lockstep with predators like the lynx.
