Alien flora of the Himalayan highlands: naturalised and invasive plants in the Trans-Himalayan region of Ladakh, India.

Zargar, Shabir A.; Malik, Rayees Ahmad; Khuroo, Anzar Ahmad; Ganie, Aijaz Hassan; Reshi, Zafar A.

Biological invasions pose a serious threat to biodiversity and ecosystem services, with their frequency expected to increase due to globalization and climate change. Regional inventories of alien species are crucial for monitoring and managing these invasions, especially in the world’s mountainous regions, which were once believed to be resistant to plant invasions but are now increasingly vulnerable to invasive species. This study presents the first comprehensive inventory and status assessment of the alien flora in Ladakh—a remote and unique biogeographic region in Indian Trans-Himalaya. Based on field data collected from 2019 to 2023 and supplemented by previous floristic studies and herbarium collections, here we present an inventory of alien flora in Ladakh. Our study includes information on invasion status (cultivated, naturalized, and invasive), biogeographic affiliation, habitat and life-form characteristics, and pathways of introduction. In total, we recorded 104 alien plant species, accounting for ~ 5.7% of the region’s flora. Of these, 24 alien species are under cultivation, while the remaining 80 are aliens growing in wild, with 55 naturalized and 25 invasive. The most species-rich families are Asteraceae (22 species), Amaranthaceae (11 species), Poaceae (7 species), Salicaceae and Fabaceae (5 species each). Most alien species in the region are native to temperate Asia (34 species), followed by Europe (30 species). The alien species primarily colonize human-dominated habitats, such as roadsides and agricultural fields. Additionally, we found that the elevational distribution of the alien species richness in the region exhibits a unimodal hump-shaped pattern, with the highest number of alien species (72 species) occurring between 2600 and 3000 m. The elevational width and maximum elevation of alien species was positively correlated with the maximum elevation in their native region. In an era of rising risks of climate change and rapid land-use transformation in the Himalayan highlands, this first assessment of the alien flora of Ladakh will foster further research, inform early eradication and guide pro-active plant invasion management in the region, with lessons for such environments elsewhere.

Biological Invasions, 2025, Vol 27, Issue 4, p1

1387-3547

Academic Journal

10.1007/s10530-025-03562-z