Exotic Invasive Species of the US Virgin Islands; Forest Health

Each year invasive exotic species cause both billions of dollars in damage and the extinction of many native species. The threat of invasive organisms is considered the second greatest threat to global biodiversity, after only habitat loss.

A former agricultural site currently dominated by an overstory of tan-tan and understory of guinea grass. Disturbed sites like this one are readily colonized by exotic ‘pasture pests’ like these plants

Geographic Consulting has just completed a series of fact sheets on exotic invasive species in the US Virgin Islands.  The publication was created with our partners at the

Virgin Islands Department of Agriculture and the US Forest Service, International Institute of Tropical Forestry and contributions from local ecologist and other scientists. It features an overview of the ecology of biological invasions and features 10 species that effect forest health in the US Virgin Islands. The sheets also features a few local, native nuisance plants in order to contrast the difference between a simple ‘weed’ and an exotic invasive.

In the US alone, invasive species cost an estimated $138 billion annually in economic damage and control costs. Invasive species are considered a major factor in the decline of half of all threatened or endangered species. The Virgin Islands are not immune to the harm caused by invaders. But how do you know if a plant or animal is going to be harmful? The purpose of this publication is to review the problem of invasive species around the world and take a detailed look at how they effect the US Virgin Islands. The introduction defines important terms and concepts. The following pages provide information on the invasive species most effecting Virgin Islands’ forests. Species are grouped together based on common characteristics and their preferred habitats (vines, pasture pests, forest invaders and harmful animals). The booklet is available for free download at this link and printed versions will be available next month.

Acacia macracantha, flower heads and thorns