Trapping strategies for deterring the spread of Brown Tree Snakes from Guam

Abstract

The accidental introduction of the Brown Tree Snake Boiga irregularis to Guam has resulted in the extirpation of most of the island's native terrestrial vertebrates, has presented a health hazard to infants and children, and also has produced an economic problem. Prevention of its dispersal through Guam's cargo traffic to other Pacific islands has become a high environmental priority. Trapping around ports and other cargo staging areas is central to an integrated pest management programme designed to deter dispersal of the species. In this study, perimeter trapping of forested plots characteristic of those found in port areas was found to be the most effective trap placement strategy, although trap lines cut through the plot interior or placed along a single plot boundary were also effective. Snake removal potentially can be modelled using an exponential decay over time, providing the manager with a planning tool. Population recovery of Brown Tree Snakes in trapped plots was found to be slow in the fragmented forested habitats found around ports.