The
Magellanic subpolar forests are a terrestrial ecoregion of southernmost
South America, covering parts of southern Chile
and Argentina
, and is part of the Neotropic ecozone.
It is a
temperate
broadleaf and mixed forests ecoregion, and contains the world's
southernmost forests.
Setting
The
Magellanic subpolar forests ecoregion lies to the west of the
Andes Mountains, which run
north-south for most of their length but curve eastward near the
southern tip of South America, terminating as the archipelago of
Tierra del
Fuego
. The Magellanic ecoregion was covered by
glaciers during the last ice age, and the
landscape is deeply dissected by fjords, with
numerous islands, inlets, and channels, including the Strait of
Magellan
, which separates Tierra del Fuego from the South
American mainland and is the route taken by Portuguese explorer
Ferdinand Magellan from the South
Atlantic to the South Pacific.North of roughly 48º south
latitude lies the
Valdivian temperate rain
forests ecoregion, which shares many affinities with the
Magellanic ecoregion in plant and animal life. To the east lie the
drier
temperate
grasslands and shrublands ecoregions of
Patagonia, which are in the rain shadow of the
Andean and Fuegian mountains.
Climate
The Andean
and Fuegan mountains intercept moisture-laden westerly winds,
creating temperate rain forest
conditions, while the cold oceanic Humboldt Current, which runs up the west
coast of South America, and the cold Antarctic Circumpolar Current,
which runs from west to east through the Southern Ocean
, keep the Magellanic ecoregion cool and wet, and
the strong oceanic influence moderates seasonal temperature
extremes. Averages temperatures a year vary from 6°C (42°F)
in the north to 3°C (37°F) in the south and rainfalls a year from
4000 mm (160 in) in the west to 450 mm (18 in) in the east.
Snowfalls can occur even in summer. Fog is very frequent. Very
strong winds whip the region and these compel trees to grow in
twisted and bent shapes fighting against the wind; and people call
them "flag-trees" .
Flora
Like the
Valdivian ecoregion, the Magellanic subpolar forests are a refuge
for the Antarctic flora, and share
many plant families with the temperate forest ecoregions of
New
Zealand
, Tasmania
, and
Australia, especially the southern beech, (Nothofagus).
Species of , including , , and , are the characteristic trees of
the Magellanic ecoregion. The Magellanic ecoregion does not have
the same species richness as the milder Valdivian ecoregion, both
on account of its colder climate and its recent glaciation. The
advancing glaciers caused the forests to retreat far to the north,
and the region was gradually reforested starting about 10,000 years
ago when the climate warmed and the glaciers retreated.
The Magellanic ecoregion has three main plant communities: the
Magellanic moorland, the evergreen Magellanic rainforest, and the
deciduous Magellanic forest.
The Magellanic moorland occurs on the western edge of the region
where the oceanic influence is strongest. High rainfall of 5000
mm/year (200 in/year) is typical of the moorland, as are cool
temperatures, strong winds, bad drainage conditions and rocky
ground with generally thin soil. Most of the moorland consists of a
mosaic of low-growing plants, including dwarf shrubs and
wind-sheared trees, cushion plants, grasses and mosses. These
plants can form an underlayer of blanket peat and boggy areas. In
more sheltered areas, small stands of evergreen forest can be
found, which include
Nothofagus betuloides,
Drimys winteri,
Lepidothamnus fonkii, and
Pilgerodendron uviferum.
Further from the ocean, in more moderate areas less exposed to the
oceanic wind and rain, moorland yields to evergreen Magellanic
rainforest. The Magellanic rainforest is mostly made up
Nothofagus betuloides, together with other evergreen
trees, most often
Drimys winteri and
Pilgerodendron
uviferum, and occasionally
Embothrium coccineum and
Maytenus magellanica. In the
better established forest stands, a species-rich shrub layer may
develop. In exposed, rocky, and poorly drained areas, pockets of
deciduous and the typical moorland species can be found.
As one moves further east, where rainfall decreases to 800-850
mm/year (30-33 in/year), becomes less dominant and mixes with
deciduous in the transition to the deciduous forest community. The
Magellanic deciduous forest is made up mostly of and . When one
reaches the drier rain shadow east of the mountains, the forests
disappear, transitioning to the grassland ecoregions of
Patagonia.
In open spaces some delicious fruits can be found:
Chilean strawberry (
Fragaria
chiloensis) and
calafate (
Berberis
buxifolia), they help to complement nourishment of native
people.
These forests are peerless in their endurance of cold summers
(averaging 9 degrees Celsius at sea level) and violent subpolar
winds.
Due to these traits, Magellanic forests'
plant species are exported to other parts of the world with similar
conditions where the native vegetation cannot grow, such as the
Faroe
Islands
and neighboring archipelagos. The following species
from Tierra del
Fuego: Drimys winteri,
Nothofagus antarctica,
Nothofagus pumilio, and Nothofagus betuloides, were
successfully introduced to Faroe
.
As a
general rule, Fueguian trees show better signs of acclimation than
those from Northern Europe to conditions in Faroe.
Fauna
The Magellanic subpolar forests are home to the Southern
Pudu, the world's smallest
deer,
which stands only 35-45 cm (14-18 inches) high at the shoulder.
Other animal species include the
Cougar
(
Puma concolor) and the endangered
Southern River Otter (
Lontra
provocax). Endemic
rodents include the
Patagonian rat, the mole mouse, and the
viscacha, a small rodent that looks almost like a
rabbit with a long, bushy tail.
Native
bird species include the
Magellanic Woodpecker (
Campephilus
magellanicus),
Patagonian
Sierra-finch (
Phrygilus patagonicus),
Patagonian Mockingbird (
Mimus
patagonicus), and
Andean Condor
(
Vultur gryphus).
The rich Magellanic coastal waters and numerous rocky islets host
many seabirds, including
albatrosses,
auks,
gulls,
terns, and
penguins.
Protected areas
Argentina
Chile
References
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