Comparison of the Density and Distribution of Anolis richardii (Dactyloidae) in its Native Range on Grenada with its Invasive Range on Tobago

Invasive species pose a significant threat to island ecosystems, with reptilian species in the Lesser Antilles at particular risk. This study assessed the population density and distribution of the invasive species Anolis richardii in Tobago, comparing it to its native range in Grenada. Three forest types were surveyed on Tobago using visual encounter methods: Lower Montane Rainforest, Lowland Rainforest, and Seasonal Deciduous Forest. A total of 174 Anolis richardii were recorded. The highest density occurred in the Seasonal Deciduous Forest, which was the most disturbed habitat. No A. richardii were found in the Lower Montane Rainforest, the least disturbed habitat. This strong habitat specificity contrasts with the catholic distribution found on its native island of Grenada. These findings support theories that disturbed habitats are more easily invaded, whilst intact species diversity increases resistance to invasion.