Risk Assessment Model for Brown Treesnake Introduction into the Continental United States

Abstract

The proposed military expansion on the island of Guam has increased the potential for the spread of brown treesnakes (Boiga irregularis; BTS) to other areas. Prevention, rather than post-introduction management and control, is the most preferred method for combating introductions of invasive species. Here, we use risk assessment modeling as a tool which can be used to identify potential locations where brown treesnakes may become naturalized, if introduced, and thus could be used to help allocate resources to minimize the risk of invasion in those locations, and possibly aid in preventing the invasion of brown treesnakes into the continental United States. We used program MaxEnt to model climatically suitable areas for brown treesnake introduction into the continental United States. We then used ArcGIS to identify suitable areas that also receive the most shipments from the island of Guam, thus bringing together both risk of dispersal and risk of establishment. We identified Texas, Georgia, Florida, and several East Coast states as high-risk areas with respect to invasion of brown treesnakes. Shipments from Guam to these states should be considered high priority for inspection.