Tropical Riverine Grasslands of the Brahmaputra Basin: A Critical Assessment of Biodiversity Threats, Conservation Challenges, and Management Imperatives

Abstract

The Brahmaputra grasslands, stretching across the floodplains of Assam and adjoining regions of Bhutan, represent one of South Asia’s most ecologically vital and biodiverse tropical riverine ecosystems. This review presents a comprehensive synthesis of existing literature alongside insights from our recent field investigations, which corroborate many of the findings reported in earlier studies. By analysing peer-reviewed publications, government reports, and field data, we outline the distinctive ecological features of these grasslands, their exceptional biodiversity, including critically endangered bird species like Yellow-breasted Bunting (Emberiza aureola), White-bellied Heron (Ardea insignis), and Manipur Bush-Quail (Perdicula manipurensis), also flagship species such as the greater one-horned rhinoceros (Rhinoceros unicornis) and Bengal tiger (Panthera tigris) and the pressing conservation threats they face. These include altered fire regimes, biological invasions, overgrazing, encroachment by woody vegetation, and changes in soil conditions. Although conservation efforts in protected areas like Kaziranga and Manas have shown encouraging results, large portions of the grasslands remain vulnerable due to habitat fragmentation, climate change, ongoing human-wildlife conflict and anthropogenic activities. Our fieldwork confirms these patterns and has been compiled in alignment with existing scientific evidence Furthermore, this synthesis highlights several critical gaps, including the lack of long-term ecological monitoring, an inadequate understanding of grassland-specific management needs, and limited incorporation of community-based conservation approaches. The review offers a foundational framework for developing evidence-based strategies aimed at conserving tropical riverine grasslands. It underscores the pressing need for targeted management protocols tailored to the unique ecological dynamics of the Brahmaputra grasslands. To effectively address these challenges, we advocate for enhanced transboundary cooperation, the adoption of participatory, community-led management models, and the integration of advanced tools such as environmental DNA (eDNA) analysis and remote sensing technologies within adaptive conservation frameworks. These measures are essential to promoting the long-term resilience and ecological sustainability of these critical habitats.