Wetland on Ventilator: Ecological collapse of Satpura reservoir caused by invasive weeds, with a comprehensive checklist of aquatic plants

Aquatic macrophytes are integral to the structure, productivity, and ecological functioning of freshwater ecosystems; however, comprehensive floristic assessments remain scarce for Indian reservoirs. This study presents the first systematic evaluation of aquatic macrophyte diversity and community structure in the Satpura Reservoir - formerly the most productive reservoir of the state. The survey in 21 sites of four zones resulted in 24 aquatic plants, representing five growth forms; dominated by two families (Hydrocharitaceae and Polygonaceae) - indicative of meso-eutrophic conditions and pronounced mesohabitat variability. Multivariate analyses revealed significant spatial variation in community composition. The F1 zone supported a distinct flora (~ 25% similarity to other zones). Downstream zones exhibited greater species overlap, associated with topographical confinement. Diversity indices identified F2 and F3 as biodiversity-rich in contrary to L3 and T3, with invasives’ dominance. Salvinia molesta and Pontederia crassipes , two globally most invasive species, occurred in all zones except F1, indicating serious ecological and socio-economic risks. Ordination analyses showed clear zonal clustering, linking native species such as Najas kurziana, Hydrilla verticillata , and Ipomoea aquatica with more diverse sites. Co-occurrence patterns reflect niche complementarity and potential competitive exclusion. This study offers critical insights into ecological zonation, invasion dynamics, and conservation management in Indian reservoir.