October 29th 2011
Biodiversity Corner - Invasive Alien Species (IAS)

(Photo) alien iguana - Soufriere

According to the Convention on Biological Diversity (CDB) 2009, “Invasive Alien Species (IAS) 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”. Invasive alien species are introduced accidentally or intentionally by humans or their activities.

Invasive species negatively impact on a country’s unique biodiversity by reducing species abundance and diversity and are capable of causing the extinction of native plants and animals by competing with native organisms for limited resources, forcing native species to decline in population or disappear from their natural environment. IAS tend to be highly adaptive and can live in a wide range of environments and they are also highly competitive and very successful at reproducing. IAS negatively impact on the resources that humans need for survival such as food, clean water and shelter; these species carry diseases and can directly harm humans and also impact the species humans depend on for livelihood such as farm animals and crops.

The spread of IAS is already creating a complex challenge that threatens the natural biological riches of the earth and the wellbeing of our people. In the Caribbean for example, many of the unique plants and animals are amongst the most endangered in the world mainly because of the size of most of the islands which means that the total population size of these species is naturally small and makes them especially vulnerable to any disturbance. While this problem is global, the nature and severity of the impact on the society, economic life and health is unequally distributed across nations and regions and for this reason decision makers must give awareness-raising and education regarding IAS high priority in their action plans.

(Photo) (Biodiversity)Coccinia grandis fruit (V. Sealys)

(Photo) Coccinia grandis. (V.Sealys)

There are a number of steps that can be taken depending on the invasive situation such as:

Prevention: such as keeping species out or exclusion by quarantine.

Eradication: once the species have reached the island, the next best option is to eradicate; this reduces the pest impact and the cost of managing the pest.

Containment or exclusion: means preventing the pest from spreading out of or into a defined area. This can be used to keep important (but invasive) crop species from escaping from farmland, or to keep invasive species from spreading into nature reserves or other natural areas.

Site-specific control: means keeping the pest population below a certain level in defined areas, such as reserves or other natural areas.

Biological control: means introducing a natural enemy of the pest, such as a predator or disease of it, to control pest population. Properly researched bio-control using carefully selected agents that attack only the target species and nothing else can sometimes bring serious pests under control without causing additional problems.
For further information, please contact the Forestry Department at 468-5648/5645 or visit our blog at forestryeeunit.blogspot.com

Forestry Department
Photo © Matthew Morton and Virginie Sealys

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