The consequent effect of nutrient enrichment in water bodies fuels the rapid growth and expansion of introduced, exotic plant species which subsequently turn into invasives. That, as the Pune experience showed, is the same sequence seen in Nambul River, Waishel Maril and other numerous water bodies within the Imphal floodplains.
By Salam Rajesh
The sights of greens, and browns, are intermittently mixed with a host of native and non-native vegetation, looking green and fresh to the eye yet hiding a more sinister aspect of the environmental erosion in a State that is largely devoid of policies to tackle invasive species effectively in the very first place, and thereafter.
Monsoon showers more often than not flush out the rot within the system – the environmental erosion in the urban, peri-urban and the rural landscapes within a rudder-less State that is more focused on ‘developmental projects’ but less attentive to the issues within.
The rush of water in most water bodies during the monsoons is the time to watch out for the more notorious of those species that had practically overrun most landscapes, whether it be terrestrial or aquatic.
The problems within Loktak Ramsar site begins with the lack of scientific management of those water bodies that are directly linked to the freshwater lake. For instance, the lack of proper and scientific management of Nambul River causes the maximum problems for the lake, so much so as this single river deposits huge quantity of muck – wastes, invasive species of plants – directly into the lake.
The issue is not only with Nambul, whereas almost every water channel – Waishel Maril, Merakhong, Khongman Khong, Nambol Turel, Naga Turel, Arong Turel, you name it – contributes to the environmental rot within the Manipur River Basin.
Last week, Kajal Bhukan writing for the Times, observed that once a vital lifeline for Pune, the Mula-Mutha River is now gasping under thick layers of water hyacinth, an invasive aquatic plant that has engulfed large stretches especially around Keshav Nagar, Mundhwa and Kharadi where residents were up in arms on the growing health risks, and inherently accusing the Pune Municipal Corporation (PMC) of due negligence.
The story, as an observer would say, is a repeat of the sad old tale of Naga Turel and Nambul Turel in uptown Imphal, where obviously the neglect of the Town Planning and Municipal offices is evident, literally turning a blind eye to the pervasive issue of clogging drains, direct sewerage discharge into the two urban rivers, and accentuating nutrient enrichment in these water bodies.
The consequent effect of nutrient enrichment in water bodies fuels the rapid growth and expansion of introduced, exotic plant species which subsequently turn into invasives. That, as the Pune experience showed, is the same sequence seen in Nambul River, Waishel Maril and other numerous water bodies within the Imphal floodplains.
Water hyacinth (Pontederia crassipes), water lettuce (Pistia stratiotes), Alligator weed (Alternanthera philoxeroides) and paragrass (Brachiaria mutica) have all dominated most water bodies in the State, while Parthenium (Congress grass), climbing hemp vine (Mikania micrantha) and Lantana camara have dominated the terrestrial landscape, pushing aside the native species.
The Lantana camara, known as an aggressive invasive species, was recently reported as number one invasive species in Haryana’s reserved forest areas. The plant was reported to have infested approximately 89sqkm of the State’s forested regions, dominating over the native flora and leading to decline in local biodiversity. This plant grows wide spread in Manipur’s terrestrial landscape, too.
The East African Journal of Environment and Natural Resources in a 2023 study estimated that the invasion of water hyacinth in Kenyan lakes, including in Africa’s largest lake, Lake Victoria, had led to annual losses between 150 million and 350 million USD in Kenya’s fishing, transport and tourism sectors. The fishermen at Lake Naivasha know that very well, according to a news report of the Associated Press in January earlier this year.
The water hyacinth is native to South America and was reportedly introduced to Kenya in the 1980s ‘by tourists who brought it as an ornamental plant’, according to Gordon Ocholla, an environmental scientist at Mount Kenya University. Water hyacinth was first sighted on Lake Naivasha about 10 years ago. Now it has become a large, glossy mat that can cover swathes of the lake. To the local fishers, the invasive plant is a threat to their livelihoods.
That is the story for Manipur, too. The water hyacinth, Kabo-kang in the vernacular, is becoming a huge nuisance in most water bodies, choking the channels, canals, marshy swamps, ponds and importantly the Loktak Ramsar site. It is said this aquatic plant was brought here as an ornamental flower, similarly as in Kenya’s case.
The water hyacinth was the number one nuisance, next to paragrass, in most water bodies in the State in recent past, whereby it apparently looks like the water lettuce (Pistia stratiotes) has over-run the space once dominated by the kabo-kang.
Across the globe in Malaysia, Mohamad Haziq A Rahman, leader of Malaysia’s ‘foreign fish hunter squad’ and his team are out everyday hunting for the invasive African catfish, netting them along the Klang River in Puchong. Native to South America, varieties of the suckermouth fish have also been introduced into waterways in the United States, Bangladesh, India, and Sri Lanka, often when owners dump them into rivers, canals, dams or free them after they grow too large for their aquarium tanks. The story in this case is the same for Manipur, too.
Quite interestingly, Andrea Ravagnani, an ornithologist with the AsOER Ornithologists Association of Emilia-Romagna, says that the bird African Sacred Ibis is an invasive species that is thought to have invaded the Italian landscape after it escaped or was released from captivity, with some zoo populations historically allowed to fly freely. The wading birds are native to Africa and Iraq, but are now proliferating like wildfire across northern Italy, causing ornithologists to sound the alarm over risks to local fauna.
In the absence of effective quarantine measures to monitor and control the inroad and random introduction of invasive species in the State, both the terrestrial and aquatic landscapes of the State are chocked with all sorts of the invasives – whether it be fish or plant – and where the origin and method of introduction of many of the (introduced) species are still shrouded in mystery, while some are known to have been brought in by government agencies, ignorant of their uncontrolled spread in future times.
As some people do say, it is high time the Government of Manipur review the status of invasive species in the State in order to check the depletion and erosion of the State’s biological diversity.