What Are the Impacts of Oil Exploration and Drilling on ANWR
Primary-Level Consumers?
What Are the Impacts
of Oil Exploration and Drilling on ANWR Primary-Level Consumers?
Primary-level consumers in ANWR include several species of mammals, as
well as many different insects. However, the insect population of
the area has not been studied very extensively, and it is doubtful that
oil exploration can be detrimental to their survival. Mosquitos
and Oestrid flies are abundant during the summer and are a major
nuisance to individuals in the porcupine
caribou herd. The result is that the animals' foraging time
is reduced as they spend more time avoiding the flies, which decreases
their chances of surviving the winter. Lactating females are
especially effected.
The author
believes that the insect population will actually increase if human
activities begin in the area, due to the generation of trash and the
decomposition of individuals of other species negatively affected by
this human presence. Since little is actually known about the
insects of the area, we shall concern ourselves mostly with
the herbivorous mammals of the area, the most prominent of which is the
muskoxen. Other mammals include various species of voles and
lemmings.
See: http://www.absc.usgs.gov/1002/section3part3.htm
Muskoxen
Muskoxen (Ovibos moschatus)
were driven to extinction before the 20th century. They were
reintroduced in 1969 and their numbers reached a peak at almost 400
individuals in 1986. Since then, the muskoxen population has
declined to around 200 individuals. Reasons for this population
decline include emigration, increased predation by grizzly bears, and
severe winters. Also, hunting by humans has increased since their
reintroduction.
Picture taken from http://www.absc.usgs.gov/1002/images/Fig07-01.gif.
Muskoxen conserve energy by limiting their movement; they tend to stick
to a core area about 50 km2 in the winter and 200 km2
during the calving and summer seasons. Calving occurs from March
to June, so it is especially important for mothers to build up enough
reserves during the summer to last the winter and to feed the
newborn. Thus, a prolonged winter would have significant negative
impacts on calf survival.
Muskoxen depend on riparian cover along river corridors, floodplains,
and foothills year-round. During the winter, it seeks out areas
of soft shallow snow. Its winter diet consists mainly of
low-quality forage such as sedges, grasses, mosses, and forbs. In
the spring, it feeds on high quality flowering sedges. Muskoxen
tend to be very loyal to a particular spot, returning there year after
year.
Muskoxen
herd
Any human activity should stay away from the muskoxen habitats,
including adjacent uplands. The areas that muskoxen frequent are
places often used for gravel and water extraction for roads and/or
platforms. Muskoxen congregate into larger groups in the winter,
and large groups of animals are more likely to be disturbed by human
activity because they tend to have more sensitive individuals.
Muskoxen groups that have moved west tolerate the Trans-Alaskan
pipeline and the Dalton highway, but it is due to the wider area of
habitable land available to the animals. Muskoxen remaining in
the 1002 coastal plain are in a more geographically constricted
habitat, with the Beaufort Sea to the north and the Brooks Range to the
south. Eastern muskoxen populations are likely to suffer if human
activities displace their territories and there are few alternative
habitats available.
Range expansion of
muskoxen in mixed-sex groups in and near the Arctic National
Wildlife Refuge, Alaska, 1969-1993. Total ranges were defined
by 95%
adaptive kernel contours. Core areas were defined by 70%
adaptive kernel
contours.
From http://www.absc.usgs.gov/1002/section7part1.htm
As muskoxen populations in the far west have coexisted peacefully with
the Trans-Alaskan pipeline, a similar pipeline through the 1002 region
should have little impact as well-- if it is built with the same
environmental precautions. For example, the Trans-Alaskan
pipeline has 579 animal crossings over its 800 mile span.
Helicopters and low-flying aircraft have been noted to cause some herds
to stampede and abandon their calves. Some herds have been
agitated by 3-D seismic exploration as far as three kilometers away;
other herds seem unperturbed as close as 300 m. Generally, noise
produced by traffic, etc will have a negative effect on the animals.
Little data are available on the interaction between muskoxen and human
settlement associated with oil development. This is because
drilling platforms have been built in regions rarely visited by
muskoxen. However, the nature of the muskoxen's normal food
source is such that its scavenging among human waste is unlikely.
The major concern is the gravel used for the platforms, which would
have to be extracted from muskoxen habitats.
Locations of mixed-sex groups of muskoxen seen during winter and summer
surveys in the Arctic National Wildlife Refuge, Alaska, USA, 1982-1999.
Pictures taken from http://www.absc.usgs.gov/1002/images/Fig07-06.gif,
http://www.saskschools.ca/~gregory/arctic/animals/mox.jpg.
See: Section 7, Arctic Refuge Coastal Plane Terrestrial Wildlife
Research Summaries
http://www.absc.usgs.gov/1002/section7part1.htm
http://www.absc.usgs.gov/1002/section7part2.htm
http://books.nap.edu/books/0309087376/html/117.html
http://www.jpo.doi.gov/pthom/Environmental%20Report.pdf
Oil or Animals report
Lemmings and Voles
Lemmings and Voles tend to be more abundant and have less survival
issues than muskoxen. In the winter they live in large
underground burrows that may be as close as two inches from the
permafrost. There are two species of lemmings in the area: the
brown lemming (Lemmus sibiricus)
and the collared lemming (Dicrostonyx
groenlandicus).
The brown lemming prefers wetter environments like damp meadows and
river or lake shores, while the collared lemming prefers rockier
places. Lemmings live on plants, roots, berries, and lichens, and
stored seeds in the winter.
A lemming; picture located here.
There are two species of voles in the 1002 area: the northern
red-backed vole (Clethrionomys
rutilus) and the singing
vole (Microtus
miurus) . The northern red-backed vole feeds
on leaves, buds, and twigs. They are active all winter, making
the most of their short lives: by the end of the summer, all those born
before the last year have died. The signing vole is known for its
alarm call, a high pitched trill. Singing voles are colonial,
behaving much like prarie dogs. They feed on stored
tubers during the long winter season. Burrows of singing voles
are often
raided by native peoples, who pilfer the stored tubers for their own
use.
Because of their numbers lemmings and voles are not likely to be wiped
out by human activity in the region. However, they are an
important source of food for higher lever consumers, including polar
bears, wolves, and foxes. Lemming cycles-- population booms and
busts every four to five years-- for example, are
closely tied to the population cycles of various predators. A
sharp drop in their numbers could potentially cause a population
decrease in many other, higher-level consumers.
Read: The National Audubon Society
Field Guide to North American Mammals by John Whitaker Jr.
www.arctic.uoguelph.ca/cpl/organisms/mammals/Terrestrial/brownlem.htm
www.saskschools.ca/~gregory/arctic/Awildlife.html
McGill
University on northern red-backed voles
animal.discovery.com/guides/mammals/habitat/northforest/northvole.html
www.arctic.uoguelph.ca/cpl/organisms/mammals/Terrestrial/singingvole.htm
By Ross Fu
Ross Fu's Mission 2007 personal page