Pteridophyte diversity and distribution patterns in Kaushambi District: A comprehensive inventory

The Indo-Gangetic Plain is a vital yet often overlooked region for the diversity of pteridophytes in northern India. This study provides a comprehensive catalogue of pteridophyte species in Kaushambi district, Uttar Pradesh, and analyses their distribution patterns, habitat preferences, and conservation status. During two years (July 2023-June 2025), systematic surveys were conducted at 45 sampling sites, leading to the documentation of 28 species from 18 genera and 12 families. The riparian zones along the Yamuna River exhibited the highest species richness, with a Shannon diversity index of H’=2.34, in contrast to agricultural landscapes, which had an index of H’=1.12. Cluster analysis identified three unique pteridophyte assemblages aligned with moisture gradients: hydrophytic, mesophytic, and xerophytic communities. We have documented Pteris vittata and Adiantum lunulatum as new range extensions for eastern Uttar Pradesh. Human-induced pressures, especially the intensification of agriculture and the expansion of urban areas, present considerable risks to pteridophyte populations, with 32% of the recorded species exhibiting declining trends. This comprehensive inventory provides essential data for conservation initiatives and highlights the urgent need to protect the residual natural habitats within the extensively cultivated Indo-Gangetic region.