Geography Reference
In-Depth Information
definition of an “ecoregion” by Omernik [OME 87]. An ecoregion is a region which
is homogenous in terms of plant and animal species, land type, and available water
resources. Omernik's classification is hierarchical, and in addition to vegetation
takes into account topography, geology, climate, land type, land use, wildlife,
hydrography, and water quality. In its most detailed and complete form the
combination of climate, natural plant formations, and topography are key.
Alaska is characterized by a subarctic environment that has been changed little
by the presence of man. More than 15% of the state is officially classified as
“wilderness” - an area where nature presides and which has not been altered by
man.
Northern Alaska and the shores of the Bering Sea are dominated by bushy land,
which, moving north, gradually turns into shrub and then tundra. The short and cool
summers do not allow for the development of any forest area. The soil is
permanently frozen (permafrost), and Indigenous Indian and Inuit populations once
traditionally lived off fishing and hunting. This ecoregion covers 34% of the
territory of Alaska. Today, as a result of the effects of global warming, thawing
permafrost and the melting of polar ice are leading to coastal erosion which is
threatening the livelihood of coastal communities.
The lowlands of central Alaska are dominated by boreal, coniferous forests
(taiga). Despite similarities with the previous region, here the subarctic climate
allows forest to develop.
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Permafrost is widespread and the area is uncultivated.
Traditionally, Indians here are hunters and fishermen. This ecoregion covers 28% of
the territory of Alaska. Once again, thawing permafrost caused by global warming
challenges the existing infrastructures. It also causes the appearance of “drunken
forests”, as a result of land subsidence.
The mountain ranges of central and southern Alaska are not unique and can be
found in other states. Altitudinal layering and the orientation of slopes determine
microclimates and vegetation. The climate is cold and humid. Taiga covers the
lower slopes. In the southernmost areas, trees are quite tall and summers long
enough to make possible the use of forest resources. The ground is deeply frozen
and agriculture is generally absent. This ecoregion covers 18% of the territory of
Alaska. Today, as a result of global warming, the glaciers are retreating rapidly.
The most fertile regions of Alaska are found along a thin, coastal, and
mountainous area to the south, on the shores of the Pacific Ocean. This region is
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. Forest develops when average monthly temperatures exceed 10.5°C for at least two
consecutive months.
