Looking beyond the political boundaries: an integrated inventory of invasive alien flora of South Asia

Worldwide, invasive alien species (IAS) cause significant ecological and economic impacts. To meet the Target-6 of the Kunming-Montreal Global Biodiversity Framework that deals with IAS, it is crucial to fill the geographical knowledge gaps in invasion research. Towards this end, making available inventories of IAS from data-deficient regions of the world merits urgent research attention. Here we present an integrated inventory of invasive alien flora of South Asia—the most populous region of the world. We assembled the inventory by reviewing 236 studies published from 1890 to 2022, supplemented with expert validation. The inventory comprises 241 invasive alien plant species (IAPS) with perennial lifespan (65%) and herbaceous life form (61%) as the dominant life history traits. The number of IAPS varies considerably across the seven countries in the region with the highest in India (185) followed by Bhutan (53), Sri Lanka (45), Bangladesh (39), Nepal (30), Pakistan (29) and the lowest in Maldives (15). We found the highest species’ similarity between India and Bhutan and the lowest between India and Maldives, thus highlighting the role of geographical proximity and connectivity in shaping a similar species pool. Southern America was the major contributor both at country level and across the region, thereby indicating that the tropical climate matching aids in the establishment and spread of alien species. Our study will fill existing data gaps in the global reports, foster further research on biological invasions in South Asia, and guide invasion policy formulation and management strategies within each country and much beyond the political boundaries across the region.