GEO Brasil - UNEP

freshwater species for aqui-culture
was the most extensive action of
this type of introduction, undertaken
mainly by government sectors, or
with their incentive (Vieira & Pompeu
2001; Agostinho & Gomes, at press)
At least twenty-seven exotic species
and two of its hybrids were
introduced in Brazil, of which thirteen
established wild populations in
natural water bodies (Welcomme
1988, Ibama 1998) Additionally, 28
native species and four of its hybrids
were transferred to basins where
they didn’t exist originally (IBAMA
1998) Despite escapes having
contributed for part of these
introductions, the majority of these
were caused by intentional and
massive liberation of individuals in
natural water bodies and its barriers,
by programs for repopulating
reservoirs and increasing fish stock,
also known as fisheries At least
twenty exotic fish species or species
from another basin were liberated in
reservoirs of south and southeast
basins (Agostinho & Gomes, at
press) Only in the Basin of the São
Francisco River, the federal
government liberated 387 million
fish, from 1995 and 1997 (Vieira &
Pompeu 2001)
The impact from commercialisation
of flora, as well as the consumers, is
very diversified
There is little data on the impact of
exotic species on Brazilian
biodiversity The scarce available
reports indicate the elimination or
reduction of native species by
competition, predatory measures,
introduction of parasites and
changes in the ecosystem process
However, some cases have already
been documented as, for example,
introduced fish that eliminated
native species in natural lagoons of
Minas Gerais (Vieira & Pompeu 2001)
and introduced parasites that
attacked native species (Agostinho
& Gomes, at press); packs of deadly
dogs that are hunting wild animas
in the Brasilia National Park
(unpublished data of the Project for
Control of Wild Dogs – UnB);
European rabbits that may be
competing with the Brazilian rabbit
(tapiti), but that has been the prey
for native carnivores (Auricchio &
Olmos 1999); African grass,
introduced as forage, that is invading
non-forest formations, such as
Cerrado, excluding various native
vegetable species, exhausting soil
nutrients, and changing the fire
regime, due to its flammability
(Williams & Baruch 2000)
Even economic impacts are now well
known The best estimates available
are of direct losses caused by
agricultural plagues, calculated by
the reduction of production
volumes These values, from
millions to billions of dollars per
introduced specie, are certainly
underestimated, as they do not take
into account environmental and
indirect losses As an example, the
nematodes of soybean cysts caused
the loss of 360,000 tons of
production, in the first five years of
its presence in Brazil alone (1991-
1995), equivalent to US$ 54 millions;
the losses caused by the white moth
in Brazil reached US$ 1 billion The
losses estimate for South America
regarding the introduction of the
carombola fruit fly is US$ 12 billion
in 12 years
the state of the environment in Brazil
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