“INVASIVE Alien Species (IAS): one of the greatest threats to biodiversity, and to the ecological and economic well-being of the society and planet” is the theme for this year’s International Biodiversity Day on May 22.

The focus of this year’s celebration is to increase public awareness about the threats of invasive alien species, as well as to encourage action to address the problems they have caused.

Jamaica is among 191 countries that are Parties to the Convention on Biological Diversity which will be hosting activities this year in observance of the International Biodiversity Day.

Jamaica has rich biodiversity and high endemism. Biodiversity is the variety of plants, animals, organisms, and types of environment that exist in the area. Endemism refers to the number of species found only in a particular area or country.

Jamaica is ranked fifth among the islands for endemic plants, and first in the Caribbean for endemic birds. Approximately 98 per cent of Jamaica’s 514 land snails are endemic, as well 76 per cent of her reptiles, and all 22 species of her frogs.

As an island, Jamaica is vulnerable to invasive alien species because of its small size and its geographic isolation. Islands have high endemism, small habitat range and unique types of environments which were developed over millions of years in the absence of these invasive species. The arrival of these species often have a negative impact on native species. Invasive alien species are non-native animals, plants and other organisms that threaten native species through predation, competition for food and habitat, and the transmission of diseases. They may also affect the economy in cases where these native species are harvested commercially.

It is important to note that the labelling of a species as an alien or invasive is specific to that particular country as a species that is alien in one country may be native to another, and a species that is invasive in one country may pose no threat in another. Some examples of invasive alien species in Jamaica are the Small Indian Mongoose (Herpestes javanicus), Cane Toad (Bufo marinus) or Bullfrog as it is locally called, Australian Red-claw Lobster (Cherax quadricarinatus), and Mock Orange (Pittosporum undulatum), which is a plant.

How invasives operate

Invasive alien species can successfully take over an area by outcompeting other native species as they usually:

. have a high reproductive rate;

. have no known natural predators;

. grow rapidly;

. have high survival rates;

. are aggressive; and

. are very adaptable.

Introduction of invasives

Humans are primarily responsible for the introduction of invasive alien species. These introductions may be intentional – through smuggling, trade (such as agriculture, horticulture and the pet industry) or biological control or bio-control. They may also be unintentional – through the transportation of species within a country during flood events, between countries via airplanes, trains, packaging material and ships (ballast water), or as a result of natural migration such as the Shiny Cowbird (Molothrus bonariensis).

The introduction of the Small Indian Mongoose is an example of an intentional introduction of an invasive alien species. The Small Indian Mongoose was introduced to Jamaica in 1872 to kill the rats. It is believed that the mongoose has contributed to the possible extinction of two of Jamaica’s endemic ground nesting birds – the Jamaica Petrel (Pterodroma caribbaea) and Jamaican Paruraque (Siphonorhis americana) – as well as the Giant Galliwasp (Celestrus occiduus), and a snake, the Black Racer (Alsophis ater). It is also a threat to the endemic Jamaican Iguana (Cyclura collei).

The Green Mussel (Perna viridis) is an example of an unintentional human introduction of an invasive alien species. It was introduced through ballast water, and has reduced the biodiversity of the organisms on the mangrove roots in the Kingston Harbour by outcompeting them for the space. The Green Mussel sometimes clogs the pipelines within the harbour, and costs millions per annum to clean.