Water hyacinth, ‘Kabo kang’ in the vernacular as the locals know the plant in the floodplains of central Manipur (in North East India adjoining Myanmar), is no longer an isolated problem for the State so much as information sourced from across the globe indicates that this pervasive plant is a problem for most countries across the seven continents
By Salam Rajesh
Water hyacinths just seem to appear repeatedly in all platforms of discussion on invasive alien species at all levels, whether local, subnational, national, regional or global. This aquatic plant with colourful, attractive violet flowers indeed persists as a major factor of concern in most water bodies spread across the globe!
Water hyacinth, ‘Kabo kang’ in the vernacular as the locals know the plant in the floodplains of central Manipur (in North East India adjoining Myanmar), is no longer an isolated problem for the State so much as information sourced from across the globe indicates that this pervasive plant is a problem for most countries across the seven continents.
From being termed as the “Terror of Bengal” to being seen as a huge nuisance in freshwater ecosystems, hyacinths come and go with the winds, literally. Physical removal is fraught with unsuccessful attempts a, s the plants return almost immediately as soon as most parts of the water body is cleared of the species. This is a first-hand encounter experienced in Manipur’s lone Ramsar site – the Loktak Lake, one of the many water bodies across the globe plagued by this single species.
On Monday (11 March) the IPBES (Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services) dwelt on the issue as part of a webinar discussion on the knowledge gaps identified in the Thematic Assessment Report on Invasive Alien Species and Their Control (Invasive Alien Species Assessment) and the needs of new assessments.
This writer did notice that one very prominent image that sprang out in the midst of the webinar was that of the water hyacinth, intentionally or unintentionally! It did appear that most people engaged in the study and documentation on invasive alien species is definitely obsessed with this singular plant, as much colourful as it is when it flowers widely.
The Invasive Alien Species Assessment builds on the landmark ‘IPBES Global Assessment Report on Biodiversity and Ecosystem Services’ which was launched in 2019. The Global Assessment identified invasive alien species as one of the five main direct drivers of biodiversity loss, with one million species of plants and animals at risk of extinction.
The assessment explores how invasive alien species affect nature and people globally. It analyzes the status and trends of invasive alien species in all regions worldwide, and identifies major pathways and drivers of the introduction and spread of such species between and within countries.
Of all the persisting invasive alien species globally, the water hyacinth stands out in the forefront as the ‘champion’! It is regarded as nuisance plant across Asia, Africa, the Americas, Europe and the Island nations. It dominates the landscapes, suffocates the water bodies and all organisms that thrive upon the water bodies including those human populations who largely depend on wetlands for their living.
In a recent roundtable discussion on invasive alien species at the Manipur State’s Directorate of Environment and Climate Change, this writer put up a reference comparison of hyacinths chocking water bodies in Asia and in Africa, vastly separated by the Indian Ocean yet sharing a similar issue on the impact of this seemingly unconquerable aquatic plant.
Two photographs in relative comparison, the one showing hyacinths chocking the Nambul River in urban Imphal (capital city of Manipur State in Asia) and the other chocking the Kisumu Docks within the Lake Victoria Basin in Kenya (in East Africa), amply demonstrated the assertion that hyacinths are plaguing everyone across continents, sparing none.
In India, there are numerous reports of hyacinths posing threat to wetland ecosystems and their functionality. For instance, The Hindu covered a recent story on how hyacinths were creating problems in Coimbatore’s Achankulam Lake leading to degradation of the lake ecosystem and biodiversity loss.
The UK-based international organization CABI (Centre for Agriculture and Bioscience International)’s Working Paper-I on “Climate change and invasive alien species” (2010) noted that, ‘Water hyacinth (Eichhornia crassipes) is a floating neo-tropical species which has become invasive both in the tropics and temperate areas. Outside its native range in South America it can quickly grow to very high densities (over 60 kg/m2) and clogs waterways, preventing movement of boats and fishing activities. Water hyacinth and other water weeds affecting water use currently cost countries in Africa and Asia over US$100 million annually’.
The CABI paper further noted that, ‘Precipitation patterns are changing or are projected to change in many parts of the world. Such changes disturb ecosystems and the dynamics of their species, which may not be able to adapt quickly. Changes in run-off alter wetland water regimes and the floristic composition will be prone to invasion by species such as water hyacinth (Eichhornia crassipes) under inundation and water spinach (Ipomoea aquatica) under semi-dry situations’.
This latter observation is seemingly true of for the Loktak Ramsar site where permanent inundation induced by the Loktak hydro project had created favourable conditions for water hyacinths and other invasive alien species like Alternanthera philoxeroides, Pistia stratiotes and Brachiaria mutica to over-run the water body. These species not only chocks the water body whereas they contribute to the decline of native plant species of food and fodder values that are harvested by the locals to supplement their livelihoods.
In some regions, hyacinths are seen as alternative source of livelihood as management strategy to control them. Hyacinth fiber is extracted to manufacture textile and handicraft items. In Bangladesh, floating vegetable farms utilizing layers of hyacinths is a localized adaptation strategy. In Manipur, there was some talk on utilizing hyacinth and other weed matter for compositing and value addition as organic manure but this is yet to take effect.
The IPBES’ Thematic Assessment Report on Invasive Alien Species and Their Control notes with some concern that, “More than 37,000 established alien species, including more than 3500 invasive alien species with documented impacts, have been recorded worldwide. Alien species (plants, animals, fungi and microorganisms, including pathogens) are being introduced globally at an unprecedented rate; currently, approximately 200 new alien species are recorded every year”.
At this reading, it is not only about hyacinths but the possible inroad of an increasing number of new species of invasive plants, fishes and insects that could add more issues to the already existing problem posed by the water hyacinth, water lettuce, alligator weed, congress grass and paragrass back home in Manipur, possibly impacting ecosystems and livelihoods, with a further reading on climate change implications