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What are
Invasive Alien Species? |
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Invasive alien species are plants, animals, pathogens
and other organisms that are non-native to an ecosystem,
and which may cause economic or environmental harm or
adversely affect human health. In particular, they
impact adversely upon biodiversity, including decline or
elimination of native species - through competition,
predation, or transmission of pathogens - and the
disruption of local ecosystems and ecosystem functions.
Invasive alien species, introduced and/or spread outside
their natural habitats, have affected native
biodiversity in almost every ecosystem type on earth and
are one of the greatest threats to biodiversity. Since
the 17th century, invasive alien species have
contributed to nearly 40% of all animal extinctions for
which the cause is known (CBD, 2006).
The problem continues to grow at great socio-economic,
health and ecological cost around the world. Invasive
alien species exacerbate poverty and threaten
development through their impact on agriculture,
forestry, fisheries and natural systems, which are an
important basis of peoples’ livelihoods in developing
countries. This damage is aggravated by climate change,
pollution, habitat loss and human-induced disturbance.
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The
Challenge |
The spread of invasive
plant species is creating complex and far-reaching
challenges that threaten the natural biological riches
of the earth and the well being of its citizens. While
the problem is global, the nature and severity of the
impacts on society, economies, health and natural
heritage are distributed unevenly across nations and
regions. Some problems require solutions tailored to the
specific values, needs, and priorities of communities
while others call for consolidated action by the global
community.
The Facts
People are major dispersers of plants. Many plants are
moved around with the world market, these plants would
never have been naturally introduced to a place without
the support of people.
The magnitude of spread of alien species of plants is
the greatest it has ever been and has promoted dispersal
of species that tend to have aggressive tendencies in
new locations.
Invasive plants are one of the most serious drivers of
environmental change globally characteristics that
promote many troublesome plants as invaders include
adaptability, prolific fruiting and aggressive
vegetative growth.
Many introduced species of plants are harmless and pose
no threat, bringing richness to our everyday lives.
However, there are quite a few that can cause havoc for
many natural systems, human and animal health, commerce,
and agriculture.
Prevention and early detection are the most cost
effective techniques that can be used to avoid the
problems caused by invasive plants.
The impacts of invasive plant species can occur at times
and places far removed from the place they were first
introduced seeds and plants may be dispersed far and
wide by wind, water, vehicles, animals, birds and of
course, people. |
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