GEO Brasil - UNEP

annex 3 - biodiversity
annex 3
The Swampland
The Pantanal is the largest flooded plain in the world, and
covers an extension of 365,000 square kilometres including
the belt plateau surrounding the plain. Eighty percent
of the area is in the Brazilian territory, and the remaining
stretches out into Bolivia and Paraguay. The “Pantaneiro”
ecosystem can be divided into ten sub-areas with characteristics
that result from a unique interaction of the soil,
water and bio-geographic factors (Lourival et al. 2000).
The fauna and floristic diversity of the Pantanal is very
rich, with at least 3,500 species of plants, 264 of fish, 652
of birds, 102 of mammals, 177 of reptiles and 40 of amphibians
(Lourival et al. 2000). The fauna is largely derived
from the Savannah, with Amazonian influences. One
of the most interesting aspects is the high density of various
species of the great Brazilian vertebrates, which are
not found in any other place of the continent.
The great biodiversity of the Pantanal is associated to the
floods that maintain great wet areas for periods that vary
from six to 12 months. Many vertebrates invade the plain
during the drought in order to explore the food abundance
deposited and/or created by floods. Migratory animals
arrive at the Pantanal during the time of floods searching
for reproduction and shelter. The flood cycle determines
the availability of dry and flooded areas that, on the other
hand, influence the seasonal distribution of several species.
With the rise and fall of water level dynamics, generalist
species are favoured to the detriment of those very
specialised ones. This may explain the low number of
endemic groups and indicate the possible existence of a
great endemic amount associated to the only stable habitat
in the plain: the water (Brown 1984 in Lourival et al.
2000).
The area takes approximately 1,500 millimetres of rain a
year. This provokes the high sedimentation of the Pantanal.
The average annual rain in the flood plain is usually
between 1.000 to 1.400 millimetres. More than in the plateau,
the rain in the plain varies during the year, causing
a regular cycle of droughts and floods, which makes the
Pantanal a unique ecosystem (Lourival et al. 2000).
The annual floods allow some habitats to be mixed regularly,
while certain microhabitats remain isolated for as
long as 50 or 100 years and they develop distinct characteristics
until a great flood links them to the remaining
system. In the last decades the deforestation in the headwaters
has been causing a significant increase in sedimentation,
which resulted in decrease of soil productivity
and pasture, and in the increase of the frequency and
level of floods (Lourival et al. 2000).
Until 1993, only 2% of the State of Mato Grosso do Sul
was devoted to agriculture. This production is concentrated
in the plateau area, however, some rice (5.841ha)
is planted in the Pantanal. The soybean production has
been growing at a constant rate (374.164ha), and coffee,
hearts of palm and “pequi”, among other products, are
also cultivated. By far, the most expressive economic activity
in the area is cattle raising, present in this area for
centuries. The low part of Mato Grosso do Sul holds approximately
9.8 million head of cattle (1993 data) (Lourival
et al. 2000).
The fragile balance of “Pantaneiro” ecosystems, defined
by periodic flood dynamics, is being threatened by the
new economic development tendencies. The traditional
models of fishing and livestock are being rapidly replaced
by the intensive exploration, accompanied of deforestation
and alteration of natural areas (Conservation International
do Brazil et al. 1999). At the same time, very little
is officially protected, mainly along the central humid
plains. More recently, the Pantanal has also been facing
serious problems, mainly due to great settling projects,
such as hydraulic installations, new highways (MMA
2000e), or large-scale projects for soybean production.
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