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In zones where the
rainfall is insufficient for the development
of forests, the temperate grassland
arise, that are characterized by the
presence of herbaceous vegetation.
In North America this biome extends
from the Missisipi river to the east
and the Great Lakes to the northeast
to Rocky mountains in the west. The
region of grassland of South America
is well-known like pampa. It includes
the south of Brazil, Uruguay and center-east
of Argentina; all this region of natural
grass is operated for agriculture
and livestock farming and numerous
industries have settled down there.
The aggravating
factor of grasslands is water. The
annual average of precipitations is
about 20-35 inches, and the annual
average temperature is 100°F.
In the most humid
zones, where rains balance with the
evaporation from the naked ground
and the sweating of the plants, the
high grass abounds. As the precipitations
diminish, the grass is lower and the
prairie ends up becoming steppe and
semi-desert. The plants adapt to the
climate, so that some grow in the
warm station and others in autumn
and spring.
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The ground
of the prairie is characterized
to have abundant undercoat, horizon
0, constituted by organic matter
in decomposition. In the second
layer, also of great thickness,
this matter is mixed with ground
particles. In the great development
of these two layers is the fertility
of the prairies. |
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GEOGRAPHIC
DISTRIBUTION OF THE PRAIRIES
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A space
for agriculture
Throughout
the water course there are shrubs
and trees. The natural grass
has been replaced by the culture
of cereals and pastures apt
for the livestock farming. The
fertility of the ground of the
prairies is remarkable. The
grass that grow there has very
short periods of life, reason
why humus, that forms from organic
matter in decomposition and
minerals of the ground, is accumulated
in a heavy layer.
The fires
that happen in these regions
devastate the shrubs, but not
them underground stems of the
grass. These return to appear,
fertilized in addition by the
carbonization to the organic
matter thanks to the action
of the fire.
The grassland
is a biome where the influence
of the man can be observed with
clarity. In Argentina, the most
humid regions are operated for
farming of l wheat, maize, oats,
barley and rye, and driest it
has dedicated to the livestock
farming, ovine and first of
all bovine. But not always that
task took control of the necessary
care from the ecological point
of view. When not being respected
the technique of rotation of
farming, many regions have been
eroded and degraded.
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The animals of
the grassland
Of the prairies
of South America are original rodents
and other small animals: vizcachas,
maras and cuises, armadillos like
the mulitas ones, weasels, small lizards
and foxes. Between the birds are ñandúes,
owls, ducks, martinetas, chajáes,
teros, and chimangos . Of the species
of birds that populate the hoisted
sites distinguish horneros, cardinals,
calandrias, benteveos, tijeretas,
churrinches and hummingbird.
In South America
are in danger of extinction puma and
the deer of Pampas. In North America
the bisons, that until the last century
formed great flocks, now live in natural
reserves. On the other hand, also
are animals characteristic of those
prairies the American badger, the
lined firedamp and coyote. In the
Asian prairies is the antelope saiga,
that also frequents steppes.
The fauna of the
prairie plays a fundamental role in
the preservation of the natural balance
for the food web. Numerous excavating
animal species of the prairies, when
removing the ground, modify the mineral
content of this one and make possible
the growth of vegetal species. Under
earth the earthworms and other invertebrates,
oxygenate the ground, along with million
bacteria that disturb the organic
remainders.
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