Invasive species: impacts on forests and forestry home

An integral part of sustainable forest management is measures to protect forests from natural threats such as fire, insects and diseases. Increasingly, an additional and more severe threat has been affecting the forest sector worldwide - invasive species. Invasive species are any species that are non-native to a particular ecosystem and whose introduction and spread causes, or are likely to cause, socio-cultural, economic or environmental harm or harm to human health.

The increasing global movement of people and products is also facilitating the movement of alien species around the world. These species may be unintentionally introduced to new environments in shipments of food, household goods, wood and wood products, new and used tires, animal and plant products, containers, pallets, internal packaging materials and humans. In the absence of their natural predators, competitors and pathogens, they can prosper in new environments and spread at the expense of native species, affecting entire ecosystems.

Not all invasive species have been inadvertently introduced, however. Particularly challenging to natural resource management are non-native species that have been intentionally introduced into an ecosystem to provide economic, environmental or social benefits. Many species of plants, trees and animals have been introduced outside their native ranges as ornamentals for gardening or for the pet industry. These species have escaped to become serious problems in forests and other ecosystems. This is a considerable concern in the forest sector since many of the tree species used for agroforestry, commercial forestry and desertification control are alien or non-native to the area. It is vital to ensure that such species serve the purposes for which they were introduced and do not escape to cause negative effects on native ecosystems.

See also

Contact us

For more information on FAO and issues related to invasive species and the forest sector please contact:

Gillian Allard
Forestry Officer (Forest protection and health)
Forest Resources Development Service
Forestry Department, FAO
Viale delle Terme di Caracalla
00153 Rome
Italy

Tel: (39) 06 5705 3373
Fax: (39) 06 5705 5137

While the definitions and impacts of invasive species on the forest sector are still debated and need reviewing in the context of forest management, a number of initiatives, programmes and activities have been initiated. Most programmes focus on damage caused to local forest ecosystems, or to a particular species or group of species, by a given pest* over a period of time. There is an overall lack of information on invasive species and the forest sector at the global scale. Information sharing is necessary in the planning and implementation of any strategy for the management of invasive alien species.

The FAO Forestry Department is addressing the pressing global issue of invasive species in the following ways.

  • A review of forest insect pests and diseases (including invasive species) in both naturally regenerating forests and planted forests was carried out in 25 countries representing Africa, Asia and the Pacific, Europe, Latin America and the Caribbean and the Near East.
  • Profiles on a number of important pest species impacting forests and the forest sector worldwide were prepared.
  • A publication on global forest health, including insect pests, diseases and invasives species will be available soon.
  • With the financial support of the FAO-Netherlands Partnership Programme, the FAO Forestry Department has launched a number of fact-finding studies to assess the extent and intensity of invasiveness by forest trees.
  • The data gathered in the global review of the status of invasiveness of forest tree species outside their native habitat is available in database format.
  • FAO is documenting the benefits and drawbacks of Prosopis spp. which have been introduced in many countries, especially in dry and semi-arid zones, because of its capacity to survive in harsh environments and its potential in the restoration of degraded lands.
  • FAO offers assistance to countries not only in response to pest outbreaks and emergencies but also in establishing long-term prevention and forest protection strategies.
  • FAO serves as a neutral forum, bringing countries together to discuss technical and policy issues related to invasive species and the forest sector.
  • FAO has also helped establish regional networks dedicated to the issue of invasive species and the forest sector such as the Forest Invasive Species Network for Africa and the Asia-Pacific Forest Invasive Species Network.

* Any species, strain or biotype of plant, animal, or pathogenic agent injurious to plants or plant products.

last updated: Wednesday, November 12, 2008