for Biological Diversity
2009: INVASIVE ALIEN SPECIES
What are Invasive Alien Species?
• 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
Causes and impacts of invasive alien
• Globalization has resulted in greater trade, transport, travel and
tourism, all of which can facilitate the introduction and spread of
species that are not native to an area. If a new habitat is similar
enough to a species’ native habitat, it may survive and reproduce.
For a species to become invasive, it must successfully out-compete
native organisms for food and habitat, spread through its new
environment, increase its population and harm ecosystems in its
• Most countries are grappling with complex and costly invasive
species problems. For example, the annual environmental losses
caused by introduced pests in the United States, United Kingdom,
Australia, South Africa, India and Brazil have been calculated at over
US$ 100 billion (CBD, 2006). Addressing the problem of invasive
alien species is urgent because the threat is growing daily, and the
economic and environmental impacts are severe.
Examples of Invasive Alien Species
• Native to the Caspian and Black Seas, Zebra mussels (Dreissena
polymorpha) affect fisheries, mollusc diversity, and electric power
generation in the Great Lakes in North America and Mississippi basin
• Native to the Amazon basin, water hyacinth (Eichhornia crassipes) has
invaded tropical habitats worldwide spreading to more than 50 countries
on five continents. Water hyacinth blocks waterways, decimates aquatic
wildlife and the livelihoods of local people and creates ideal conditions for
disease and its vectors
• Native to the Indian sub-continent, the ship rat (Rattus rattus) have caused
extinctions and catastrophic declines of native birds on islands and have
spread throughout the world
• Deadly new disease organisms, such as avian influenza A (H5N1), attack
humans and animals, in both temperate and tropical countries
• Aquatic invasive species have done serious damage. A unique approach
using music as a medium to help prevent the spread of aquatic invasive
species in lakes and rivers is being used in Wisconsin (USA).
The CBD and Invasive Alien Species
• The Convention on Biological Diversity and its members (there are
191 Parties, as of October 2008) recognize that there is an urgent
need to address the impact of invasive alien species. Article 8(h) of
the CBD states that, “Each contracting Party shall, as far as possible
and as appropriate, prevent the introduction of, control or eradicate
those alien species which threaten ecosystems, habitats or species”.
The CBD sets global priorities, guidelines, collects information and
helps to coordinate international action on invasive alien species.
• The CBD has adopted guidance on prevention, introduction and
mitigation of impacts of alien species that threaten ecosystems,
habitats or species, which can be accessed on the CBD website
(Decision VI 23). The website also provides further information on
invasive species and relevant decisions of the Conference of the
Parties to the CBD.
Tackling the Problem
• Prevention is the most cost-efficient and effective method against
invasive alien species. Halting the establishment of potentially
invasive species in the first place is the first line of defense.
Governments conduct customs checks, inspect shipments, conduct
risk assessments and set quarantine regulations to try to limit the
entry of invasive species. However, global inspection and risk
analysis capacity is usually not sufficient.
• It is also important to develop economic tools and incentives for the
prevention of introductions, and to educate the general public and
raise awareness so that informed decisions can be made about how
to limit introductions and their spread. Invasive alien species are a
global issue that requires collaboration among governments,
economic sectors and non-governmental and international
organizations. Individuals also have a large part to play, including
policymakers, consumers, horticulturalists, landowners, educators,
youth and recreationists.
Celebrating the International Day for
• The CBD Secretariat encourages all parties to the Convention and all
organizations that deal in some way with the issue to organize activities
and events to celebrate the IBD and to take advantage of it to raise public
awareness and showcase their work to prevent and manage invasive alien
• From January 2009, this website will carry case studies and examples of
invasive species and action against them and will carry information on
actions that we can all take to help combat the problem. Information
materials posted on the site will include a booklet on IAS, a poster, a
logotype for use by partners and organizations celebrating the IBD, a
photo gallery as well as information and education materials targeted at
children and youth.
• The site will carry links to key international organizations working on
invasive alien species, key regional networks and initiatives, networks and
initiatives at national level as well as to key initiatives promoting
information-sharing. It will also provide links and information on
regulations and international agreements.