The freshwater sources in central Kerala have been facing a serious threat from the highly invasive cabomba weeds.
Varaalchal, the environmentally sensitive wetland in Koipram grama panchayat, near Aranmula, is the latest victim of this fast-spreading disastrous weed that has already started choking the waterbody.
The 2.5-km long, 150-metre wide wetland was known for its rich biodiversity, especially the inland fish species of Channa (‘Varaal’ as is locally known).
Rejuvenated
The district panchayat had rejuvenated the heavily weeded Varaalchal spending ₹50 lakh two years year ago. The rejuvenated Varaalchal had helped recharge the wells in the vicinity.
However, Varaalchal has once again become a vast pool of cabomba as the Water Resources Department failed to ensure its conservation and proper maintenance.
In Pampa
The growth of cabomba is fast in the Pampa too, especially along the Aranmula stretch. Pampa Parirakshana Samiti general secretary N.K. Sukumaran Nair has been demanding immediate intervention of the Water Resources Minister to save the Pampa from the weed.
In a recent study on the taxonomy and distribution of aquatic plants in Kuttanad, it was observed that cabomba is growing in all types of waterbodies. Dense growth of this aquatic weed was found in canals, rivers, Vembanad lake, and in paddy fields, says Mr. Nair.
According to him, cabomba is an alien species introduced in India many years ago. Nobody knows how and when it reached the State. This is a popular aquarium plant and the population in wetlands may be from aquarium escapes.
Thomas P. Thomas, botanist and environmentalist, said the propagation of the plant was through the broken stem and it was high time to launch a campaign to contain this weed.
The intense growth of this plant blocks the entry of light into water. It also affects the diversity of indigenous fish varieties and other fauna. The high-nutrient content of water promoted the growth of the weed. The source of nutrients was sewage, agrochemicals and land washouts. The weed had the capacity to change the entire ecology of the waterbodies. Unfortunately the scientific community and the government were not much aware of this serious issue, said Mr. Nair.
