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 human or their activities.
Invasive species negatively impact on a country’s unique biodiversity by reducing species abundance and diversity and are capable of causing extinctions 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 tends 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 well being 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 are naturally small and make them especially vulnerable to any disturbance. While this problem is global, the nature and severity of the impacts on the society, economic life and health are 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.
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 has 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 from spreading into nature reserves or other natural areas.
Site-specific control means keeping the pest’s 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 its 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.