Alien Species Invading our Daily Lives in Saint Lucia

Dr.Ulrike Krauss, Invasive Species Coordinator, Forestry Department, Union.

Invasive alien species (IAS) are plants, animals or micro-organisms that are not native to a specific ecosystem and whose introduction threatens biodiversity, food security, health or economic development. 

Exotic (alien) species are more likely to be harmful (invasive) than local species, because the exotic ones often do not have any natural enemies locally and therefore proliferate in an uncontrolled manner.  IAS are the second most important threat to global biodiversity (second to habitat destruction).  The global cost of IAS was estimated at US$1.4 trillion per year (nearly 5% GDP) – and rising in times of globalization and climate change.  Extrapolated to Saint Lucia, the annual cost of IAS would be EC$244 million, or nearly EC$1,500 per capita per year!

A total of 130 IAS are reported in Saint Lucia across terrestrial, marine and freshwater ecosystems.  Nearly half of the invasive plants, at least 28, were brought deliberately onto the island as ornamentals, some legally, others illegally.  Nowadays, import applications are subjected to a risk assessment before a permit is granted or withheld.  Unfortunately, some ill-advised individuals smuggle plants or creatures into the country without consulting an expert. 

Even if these are intended only for enjoyment on private property, such introductions can be the epicentre of devastating invasions, as well as a source of dangerous parasites and pathogens, which the layperson cannot detect.  Well-intended, but ill-advised attempts to beautify the Pitons Management Area are now giving rise to a smothering carpet of Tradescantia that threatens Saint Lucia’s rare and endemic flora.  The illegal importation of iguanas for a private mini-zoo resulted in the proliferation of these alien reptiles, which now threaten the integrity of our Iyanola heritage and cost hundreds of thousands to control.  Orange-winged parrots (Amazona amazonica) have escaped from homes and/or visiting yachts, where they had been kept as pets. 

They paired up and may soon be nesting, directly competing with our iconic Amazona versicolor for nest sites and food.  Imported construction lumber and sand are suspected to have harboured unwanted hitch-hikers: the Cuban anole and a new species of sandfly.  Whereas the local sandflies were a nuisance on beaches and riverbanks during evening and morning hours only, the alien invasive sandfly established deep inland, bites at any time of the day and with a far more painful bite that triggers strong skin reactions in some victims.  This could have repercussions for human health and our tourism sector.

Saint Lucia wants to continue to be a unique jewel in the Caribbean – a tourist destination, known and appreciated for its local flora, fauna and culture and not replaceable by any other island.  Cherishing the beauty of local plants and creatures, we have to protect them from IAS by (1) preventing new introduction and (2) controlling those we already have at an early stage, before they do irreversible damage.  Given our limited resources for IAS management, the public and private sector as well as civil society need to partner, not only in monitoring and reporting suspicious sightings, but most importantly by practicing responsible behaviour.

Read more: Alien Species Invading our Daily Lives in Saint Lucia (PDF)