Potential risks of Invasive Alien Plant Species on native plant biodiversity in Sri Lanka due to climate change

There have been few studies investigating the implications of the potential distribution of plant invasions on native biodiversity due to climate change. In this study, we used combined climatic suitability maps of 14 priority Invasive Alien Plant Species (IAPS) in Sri Lanka under the current climate and under Representative Concentration Pathway (RCP) 4.5 and RCP 8.5 climate scenarios for 2050 to examine the potential risks of plant invasions on native plant biodiversity. We used three types of layers defining plant biodiversity patterns for Sri Lanka; (i) nine zones of plant endemism (zones of high floristic richness and endemicity), (ii) eleven threatened endemic taxa and (iii) eight forest-related ecosystems. Our results reveal that the biodiversity-rich zones of endemism are at potentially high-risk under climate change. The potential risks on threatened endemic plants are likely to reduce slightly under an RCP 4.5 low-emissions scenario and be intensified under an RCP 8.5 high-emissions scenario. Forest-related ecosystems are vulnerable to IAPS to varying degrees; dry zone ecosystems are predicted to increase the risks of IAPS, while those in the wet zone are envisioned to decrease. Overall, our findings suggest that the potential risks of plant invasions on native plant biodiversity differ significantly under projected climate change. Greater understanding of the potential risks of IAPS at an early stage is important in prioritising future conservation measures for effective protection of native biodiversity.