Climate Change and Weed Impacts on Small Island Ecosystems: Lantana camara L. (Magnoliopsida: Verbenaceae) Distribution in Fiji1

Oceanic island ecosystems are particularly vulnerable to invasion by exotic species, and this vulnerability may be intensified by the effects of climate change, particularly if favorable climate conditions allow exotic invaders to spread to new areas. Effective management of such species requires knowledge of their potential distribution under current and future climate. This research examines the value of species distribution modeling in invasive species management in small island ecosystems using the specific case of Lantana camara L. invasion in Fiji. A niche model of L. camara was developed using CLIMEX species distribution modeling (SDM) software. Several sources of data were used to develop the model including phenological observations and geographic distribution records. The model was used to estimate its potential distribution under historical climate. The CSIRO Mk3.0 Global Climate Model (GCM) was used to explore impacts of climate change on its potential future distribution. The model was run with the A1B and A2 scenarios for 2030 and 2070. Large parts of both major islands of Fiji, Viti Levu and Vanua Levu, were shown to have high climatic suitability for L. camara. However, under future climate scenarios, climatic suitability for L. camara in Fiji was projected to contract. The results illustrate that SDMs can play a useful role in formulation of cost-effective invasive species management strategies and the resulting species distribution maps have broad applicability throughout the many islands of the South Pacific region.