INVASIVE alien species are a significant threat to Jamaica’s biodiversity.

Their ability to reproduce quickly and spread rapidly has enabled them to out-compete native species for food and habitat. They may also threaten native species through predation, which in some instances has resulted in the extinction of such species.

An invasive alien species is a species that has been introduced into an environment, where it did not previously exist, and has become a threat to other species. It may have been introduced intentionally or unintentionally.

The Small Indian Mongoose (Herpestes javanicus) is an example of an invasive alien species which was introduced intentionally to control the rats in the canefield, and the Green mussel (Perna viridis), a marine bivalve mollusk, is an example of an unintentional introduction. The Green Mussel was introduced through ballast waster from ships. Some invasive species which were introduced intentionally for agricultural or domestic purposes have spread to the wild and have now become a threat to native species. One example of such introduction is the Silver Perch, (Tilapia sp) a native of Africa which was imported for aquaculture.

The Perch escaped to the wild where it breeds quickly and displaces native freshwater fish from their environment. It is suspected that tropical storms and the resulting flooding of fish ponds is a likely way that this fish enters natural freshwaters.

Protected areas and invasives

The biodiversity of protected areas are at particular risk from invasive species as these areas often have species which are rare and/or at the risk of extinction, or are endemic, that is only found in a particular area.

A protected area as defined by the World Conservation Union is “an area of land and/or sea especially dedicated to the protection and maintenance of biological diversity, and of natural and associated cultural resources, and managed through legal or other effective means”. Using this definition, examples of protected areas in Jamaica include the Blue and John Crow Mountains National Park, Portland Bight Protected Area, Mason River Protected Area, the Cockpit Country which is a forest reserve and the Lower Black River Morass in St Elizabeth, which is a Ramsar site, a wetland of international importance.

Threatened species

The Small Indian Mongoose is a major threat to the endemic Jamaican Iguana (Cyclura collei) in the Hellshire Hills of the Portland Bight Protected Area. It is the primary prey of young iguanas. The Jamaican Iguana Recovery Group has been operating a trap-and-removal programme for mongoose in the interior Hellshire Hills forest, in the vicinity of two known main nesting areas for the iguana. In addition to predating young iguanas, the mongoose is believed to have contributed to the possible extinction of two of Jamaica’s endemic ground nesting birds – the Jamaica Petrel (Pterodroma caribbaea) and Jamaican Paruraque (Siphonorhis Americana).

In the Blue and John Crow Mountains National Park, native plants are threatened by the Mock Orange (Pittosporum undulatum), a plant native to Australia which was introduced to Cinchona Gardens in 1883. The round orange fruits are eaten and dispersed by birds. The Mock Orange is now one of the most common plants in the Cinchona area and has out-competed native trees in both disturbed and mature forests of the Grand Ridge in the Blue and John Crow Mountains National Park.

Agricultural crops are also affected by invasive alien species. For example, the coffee berry borer is a pest of the coffee plant in Jamaica, targeting the coffee berry. It is an important economic pest as it reduces the number of harvestable berries and consequently the amount of coffee available on the market.

To prevent further threats from invasive alien species on native species, considerable research must be done on the lifestyle and habits of non-native species to determine if they will be impacted negatively by such introduction. Being informed, will allow us to protect both Jamaica’s natural heritage, as well as the island’s agriculture. Also, residents and visitors to our island should be made aware that illegally bringing in plants or pets can result in the introduction of an invasive species which could cause deleterious effects.

– National Environment and Planning Agency, the Institute of Jamaica, and the Office of the Prime Minister contributed to this article.