High plant endemism in an Indian hotspot – eastern Himalaya

A preliminary investigation in the Subansiri area of the eastern Himalaya recorded high plant endemism. As a regular exercise of field sampling of various forest types to map the biorich areas, the number of species observed was evaluated to analyze their endemic status in one of the important hotspot regions of the world. The total number of individuals, species, genera and families observed were recorded in various natural and semi-natural forest types. A total of 122 plots sampled randomly in various forest types recorded 764 plant species, of which 59 were found to be endemic. The overall species endemism is observed to be 13 per ha. These 59 species belong to 27 families and 46 genera. Fifty percent of species were from just five families, Rubiaceae, Lauraceae, Acanthaceae, Magnoliaceae and Rosaceae. Stem size class distribution of the most abundantly found endemic tree species in three primary forest types indicated a quantitative status. This study envisages the status of plant endemism carried out following a proportional stratified random sampling method for various classified vegetation cover types using satellite remote sensing data. Many primitive genera and families were recorded which are indicative of long evolutionary age and affinities of the area with respect to species endemism.