Ahalf-mile-long beaver dam in
Canada made international news
recently when satellite photos
clearly showed the impact of Castor
canadensis upon the earth. The beaver is
one of the few species, besides humans,
that builds structures, such as the huge
dam in Canada’s Wood Buffalo National
Park, that are large enough to be visible
from space. Today, only in highly remote
locations of North America is it possible
for nature’s engineers to create similarly
impressive alterations of the landscape.
Ecologist Jean Thie found the immense
Alberta dam while scanning satellite
images for signs of climate change.
This is fitting because restoring beaver
wetlands is one of the most effective
and economical ways to minimize some
potential impacts of climate change on
wildlife habitat and the land’s hydrology,
and thus human communities.
The path to the future requires
understanding the past and how current
and historic human activities have
defined our present situation. Before
European settlement of North America,
the continent’s beaver population was
between 60 to 400 million, according
to estimates from historic data of
trapping harvests (Naiman et al. 1988).
It was the quest for “brown gold” that
stimulated much of the early exploration
and colonization of the New World,
where beaver pelts were commonly
used as currency. The first waves of fur
traders and trappers emanated from the
Northeast coast and the mouth of the
Mississippi River. By the early 1900s,
beaver populations in the continental
U.S. and southern Canada were nearly
eradicated. Eventually beavers from
isolated, surviving colonies were used