Nepal is blessed with abundant wetlands. Out of them 10 have been enlisted in the Ramsar sites. Despite of their worldwide recognition and publicity the lakes over here are facing many problems. Among them invasion by water hyacinth is severely intense. 

Water hyacinth is the free floating perennial plant native to tropical and subtropical South America. The plant rises above the surface of water as much as 1m in height. The leaves are 10-20 cm across and float above the water surface. This plant is known as Eichhorniacrassipes. This plant displays great diversity in its natural habitat, flower color and other characteristics. At present eight species of water hyacinth has been distinguished which occurs in every part of the world. 

Water hyacinth spreads with the lightening speed. This is the reason it has invaded over large parts of the world. The biomass doubles its surface area within 14 days sometimes even in 6 days. They propagate by sending out runners on which young plants develop. These divide away from the parent more easily. This plant has been found upto the 1600m and at the temperatures 1 to 40 C. When frozen the leaves die but not the plant.

Being the resident of Pokhara, I have noticed that this aggressive plant has become a terrible nuisance on every lake and associated wetlands over here. The plant has killed the beauty of the lakes. Some of the lakes like Khaste Lake, NeuraniLake, GundeLake are gigantically invaded by the plant. The large lakes like Phewa andBegnas are also greatly affected. The prolific growth of the plant has made the locals, environmentalists and the tourism entrepreneurs worried. It’s not only the local economy has been stagnated by the immense growth of the water plant, its dense coverage prevents sunlight from penetrating the water causing indigenous plants to die and rot. The weed removes oxygen from the water resulting in the death of aquatic creatures. In addition the luxurious mat of the vegetation provides an ideal breeding ground for many disease vectorsresulting health hazards and other considerable damage. Some fishes feed on their roots and during their meal are caught in their nets made from the same material. 

The species has wreaked havoc on the lakes and its ecosystem. So there is no other way left than controlling it. Methods like mechanical control, use of chemical herbicides and the introduction of natural predators and the integrated pest management can be practiced. 

Some of the NGOs and tourism entrepreneurs collaborating with the office of metropolitan city have initiated to control the species. It’s a matter of happiness that the water hyacinth has been used to extract fibers through which ropes can be plated, sacs and other ornamental goods can be made. The awareness on this issue has become important so that people may speed up with the preventive measures, eventually contributing to the livelihood and also controlling the lacustrine plague.

Pandey is a BSc student at the Institute of Forestry in Pokhara.