The impact of climate change on the distribution of wetland-associated invasive alien plant species in Western province, Sri Lanka

Introduction: Climate change and invasive alien plant species (IAPS) severely threaten natural ecosystems globally. Objective: To identify and assess climate suitability for seven wetland-associated species and predict their future distribution using shared socio-economic pathways (SSPs) 2 4.5 and 5 8.5 for 2050 and 2070. Methods: The species selected were Alstonia macrophylla, Annona glabra, Dillenia suffruticosa, Lantana camara, Leucaena leucocephala, Panicun maximum, and Sphagneticola trilobata. Data on species occurrence were collected by field surveys in the Western province (Colombo, Gampaha and Kalutara districts), and this, together with climate data, were fed into the Maximum Entropy model (MaxEat model). Climate suitability area maps were developed for the seven IAPS for the current climate and four future scenarios. Results: A. glabra, L. camara, and L. leucocephala showed an increase in climate-suitable areas for the years 2050 and 2070 under both climatic scenarios compared to the current distribution. S. trilobata showed a decrease in its range in the future compared to the current distribution. The climate-suitable area for A. macrophylla will also not expand under either scenario except for a modest rise in SSP2 4.5 in 2050. The current distribution of D. suffruticosa and SSP2 4.5 in 2050’s distributions were almost identical, and the other two future scenarios showed comparatively low distribution. For P. maximum SSP2 4.5 indicated a slight increase in climate-suitable areas for 2070 compared to the current distribution. Conclusion: A. glabra, L. camara, and L. leucocephala can become highly invasive as their ranges expand in response to future climate changes. The distribution of S. trilobata will be significantly reduced under future climate scenarios. As suitable areas for IAPS increase in the Colombo district over time compared to other districts in the province, its wetland-associated native plant species may face a greater risk of invasion by IAPS in future climatic scenarios.