Riparian flora of Kashmir valley-composition and diversity patterns

Riparian zones, interfaces between aquatic and terrestrial ecosystems, are known to support distinct floral elements which play vital ecological functions. For recording the diversity of floral elements in these habitats, a survey of riparian zones was undertaken in Kashmir Valley which revealed occurrence of 265 plant species belonging to 46 families and 170 genera. Riparian areas of this region are dominated by alien species as they represented 74.72% (198 species) while as native species represented only 25.28% (67 species). Of the 198 alien species, 84 were invasive, 100 were naturalized, 9 were casuals and 5 were casual or naturalized. Most of the species inhabiting these habitats were herbaceous perennial species. In comparison to riversides, number of species per site and mean values of diversity indices were higher in streamsides. In addition, riversides were characterised by highest level of invasion expressed both as proportion of aliens and invasives. High level of invasion in riversides is because of high level of disturbances in these habitats in comparison to streamsides which in turn has resulted in low levels of species diversity in these habitats. This high percentage of alien species in riparian habitats is alarming for the region as the connected nature of rivers and streams is likely to spread alien plant species to distant places in the region. This study provides baseline knowledge about the species composition and diversity patterns of these important vegetation zones which will help in their proper management in view of the spread invasive plants in the region.