habitat loss : new threat for rare endangered Rhinos

"Grassland is being invaded by weeds and other unwanted plants that are not suitable for rhinos," Bibhab Kumar Talukdar, co-chairman of the group said from the Chitwan National Park, home to 408 rhinos.

"We have to concentrate on how best to control the weeds and for this we have to intensify research."

The endangered animal, whose numbers have been rising in Nepal and India, is found mostly in the northeastern Indian state of Assam, and in southwestern Nepal.

"The weeds and wild plants are an exotic species and how it came we don't know. It is spreading fast in the habitat and we are looking into the reasons now," Shyam Bajimaya, an expert with Nepal's national parks said.