| These hills and
accompanying lava fields are characterized by dark colours spotted with lighter-coloured
bunchgrass, which creates a leopard-skin effect that intensifies the desolate, windswept
appearance of the Patagonian landscape. A peculiar type of rounded gravel called grava
patagónica lies on level landforms, including isolated mesas. Glacial ice in the past
extended beyond the Andes only in the extreme south, where there are large moraines.
Those winds are very wet over the Pacific, but looses the water on the
"Cordillera de los Andes", specially over the west plains (Chile). The air
masses descend across the eastern slopes getting hotter and too dry. The consequence is a
quick decreasing of precipitation to the Atlantic Ocean (descending from 3000 mm of annual
precipitation in the Chilean Range to less than 100 mm. in the central zones of the
provinces of Chubut and Santa Cruz). Patagonia "extrandina", that exclude the andino- patagónico forest
and the sub- antarctic forest, has its limits at the west the Cordillera de los Andes, at
North the plateaus that extend to the plains in the humid Pampa and at the east the
Atlantic Ocean. All this extension shares a characteristic: its strong winds that blows
all the year long, they predominate in east and south directions.
Ecologically, the Patagonia
extrandina is classified as a cold semi-dessert area. The landscape is mostly shaped by
sedimentary or volcanic rocks from Mesozoic Era that set up a system of table-lands and
hills. It is not an uniform land, and the region shows a rich specter of vegetation,
including extreme desert zones till bushy and gramineous plateau. The fauna is represented
by steppe and "monte" (scrub) species, the birds' number of species is low,
nevertheless mammas, specially rodents, are numerous. There is a high diversity of
reptiles with strong, mainly lizards, and a low diversity of amphibians.
The coast deserves an especial attention because it
has different characteristics from the other part of the continent. The coastal zone
deserves a special attention because it has deferential characteristics from the reminded
part of the continent as well to the Atlantic or Pacific Oceans. The Malvinas Island
current, that flows over the argentinean continental shelf is a powerful source of
plankton and nutrients. This current carries large amount of fishes and invertebrates
which attracts mammals and birds groups.
The economy of the region is based
mainly in the use of Natural Resources, cattle raising (mostly sheep) by utilizing the
natural pasture grounds, mining, petroleum extraction, fisheries, shellfish removal, the
industry and tourism. The number of inhabitants is too low, less than one person per
squared kilometer, and the human establishments are settled nearby the coast, important
rivers' valleys and the mountains. The center of the provinces of Chubut, Río Negro and
Santa Cruz are practically unhabited, specially the last province because the land has
been abandoned as a result of the low price of the wool.
Biodiversity: Amphibia: 29
species , 11 endemics, 9 restricted to Patagonia. Anura (toads and frogs) Reptils: 65
species autoctons. Seabirds: 71 species. Antartica, Islas Malvinas and Southern Atlantic
Island. Continental birds: 250 species. 4 extotic species. Marine mammals: Pinnipeds and
cetacean: 33 species , 11 accidental species. Continental mammals: 76 species, 3 exotic
species.
Patagonian vegetation consists of deciduous Andean
forests and the steppe and desert zones east of the Andes. The largest area--the steppe
region--lies in northern Patagonia between the Colorado River and the port city of
Comodoro Rivadavia. This zone represents an extension southward of the monte, which gives
way gradually to a xerophytic shrub region without trees except along river banks. In the
extreme west on the Andean border, small stands of araucaria survive, and clumps of wiry
grasses are also present. South of Comodoro Rivadavia to the tip of the continent, low
scrub vegetation and green grass steppe alternate. Wildlife in the region includes the now
rare guanaco and rhea, as well as eagles and herons, burrowing rodents and the Patagonian
hare, mountain cats and pumas, and various poisonous reptiles.
In Tierra del Fuego, it appears that grasses first covered
glaciated zones, but after volcanic ash settled there, forests advanced. Antarctic beech
colonized rapidly in valleys and grows along with cypress on steep slopes. A phenomenon in
the southern tip of the continent is the existence of species of parrots and canaries,
both of which are more associated with the tropics than with Patagonia.
The Patagonian Andes have coniferous and broad-leaved forests
that spread into Chile. Antarctic beech and needle-leaf trees mixed with araucaria are
common. The Patagonian Andes do not have a flourishing animal life. The smallest known
deer, the pudu, dwells there, and wild pigs, introduced by Europeans, have multiplied. |
