The loss of habitat is the greatest risk facing
threatened wildlife. Human activities like harvesting forests for
wood and paper can affect forest species such as Woodland
Draining wetlands and marshes for agriculture can limit the availability
of nesting habitat for Piping
Similarly, changing water quality or altering lake and river levels can
degrade habitat for species like the American white pelican.
Other factors besides habitat loss can threaten
wildlife. The use of harmful chemicals can have damaging effects
on a species, as shown by the rapid decline of the Peregrine Falcon
after the pesticide DDT was introduced into North America in the 1940s.
Sometimes a threatened species loses a food source that
people consider to be an unwanted pest. Both the Burrowing
the Swift Fox rely on prey species like grasshoppers and mice for
food. Poisoning these prey species can harm their predators.
Likewise, the poisoning and shooting of the Richardson's Ground Squirrel
have led to a loss of burrows for burrowing owls and a loss of major
food source for Ferruginous
When a species is designated as threatened, wildlife
managers try to identify the factors causing the decline. Habitat
loss, decreased food and supply, increased predation or repeated human disturbance may
be examined to determine their effect on the species. Once the
cause of the decline is identified, managers can take appropriate actions
to restore the population to its former status.
Providing nesting platforms for Ferruginous Hawks and
protecting gravel shorelines for Piping Plovers are actions that have
helped to resolve problems for these species.
Some species in Alberta have declined so dramatically
that only a few individuals remain or the species has disappeared
completely from the province. For example, the swift fox was
extirpated from the province 70 years ago as a result of habitat change,
trapping and predator-control programs. Fortunately, healthy
populations of this species still existed in the Midwestern United
States. These populations provided individuals for the Canadian
reintroduction and after 15 years of releases, a small number of Swift
Fox are once again sharing the Canadian prairie. Their status has improved
from extirpated to endangered.
For more information check out Species
at Risk or visit the Alberta
Sustainable Resource Development, Fish and Wildlife website!
Reprinted from Focus On Wildlife Management (1999) with permission of