Mapping the biological invasions in the biodiversity hotspot of Himalaya: Insights and policy implications for management

Biological invasions are among the leading drivers of biodiversity loss worldwide, posing an increasing threat to the ecologically sensitive Himalayan biodiversity hotspot. Despite growing research interest, a comprehensive synthesis of the development, structure, and emerging directions of biological invasions research in the Himalaya has been lacking. This study presents a bibliometric analysis of publications on biological invasions in the Himalayan region from 1990 to 2024 to evaluate research trends, scientific impact, collaboration patterns, and thematic evolution. Publications retrieved from the Web of Science Scopus and Lens.org databases were analysed using bibliometric indicators, citation analysis, collaboration networks, and science mapping techniques. Our study revealed that research output increased substantially after 2010, reaching a peak of 44 publications in 2024, reflecting the increasing recognition of invasive species as a major conservation challenge. However, research efforts remain geographically skewed towards the Western and Central Himalaya, whereas the highly biodiverse Eastern Himalaya is comparatively underrepresented. The literature is dominated by studies on plant invasions and ecological impacts, with comparatively limited attention to faunal invasions and the integration of socio-economic dimensions. Author productivity conforms to Lotka's Law, with a small group of researchers serving as key knowledge hubs despite relatively limited international collaboration. India contributed the highest number of publications. Bradford’s law analysis revealed a highly concentrated publication landscape, with 269 articles distributed across 156 journals, of which only 14 core journals accounted for one-third of the total research output, including Tropical Ecology, Environmental Monitoring and Assessment and Biological Invasions as the principal publication outlets. Thematic analyses revealed a transition from descriptive ecological investigations to predictive modelling and management-oriented research. Overall, this study identifies important geographical, taxonomic, and collaborative knowledge gaps and provides a strategic foundation for strengthening future research, policy development, and integrated management of biological invasions across the Himalayan region.