February 2 - World Wetlands Day: Help preserve ecosystem equilibrium | Sunday Observer

February 2 - World Wetlands Day: Help preserve ecosystem equilibrium

Waste water discharged to a canal
Waste water discharged to a canal

Colombo is one of the first 18 cities that has been accredited as a Ramsar Wetland City at the 13th meeting of the Conference of the Parties to the Convention (COP13) held in Dubai, United Arab Emirates.

The awarding of Wetland City Accreditation in accordance with the Resolution XII.10 on Wetland City Accreditation, approved by COP12 in 20151, is an honour and a reflection of hard work of the urban planners, agencies and scientists of the country.

While conservationists and the government are excited about the landmark achievement, it should also be reminded that this award brings an obligation to all the parties to sustain the vital green wetlands and the ecosystem services that these wetlands provide by abiding to the UN’s Sustainable Development Goals (SDGs). Authorities in Colombo should monitor and track progress in conserving and sustainable use of the green infrastructure and will have to justify retention of the accreditation for the next six years - the Independent Advisory Committee will review the status of the accredited Wetland City in every six years.

The Asian Wetland Directory describes that the country has 41 wetland sites of international importance covering an area of 274,000 ha of which the Colombo Wetland Complex covers 1,900 ha – which is almost eight percent of the city’s total area.

Wetlands are the habitats with permanent or temporary accumulation of water with associated floral and faunal communities. The Ramsar convention explains the term as “areas of marsh, fen, peat land or water, whether natural or artificial, permanent or temporary with water that is static or flowing, fresh, brackish or salt, including areas of marine water, the depth of which at low tide does not exceed six metres.”

Wetlands of Sri Lanka can be divided into three broad categories as inland natural fresh water wetlands (rivers, stream, marshes, swamp forests and villus), marine and salt-water wetlands (lagoons, estuaries, mangroves, sea grass beds and coral reefs) and man-made wetlands (tanks, reservoirs, rice fields and salterns).

Rich bio-diversity

Wetlands comprise a combination of water, soils, flora and fauna. The interaction of the elements helps the green infrastructure to perform several functions that are beneficial to humankind and the environment. The combination of these functions, together with the rich bio-diversity and cultural heritage of wetlands makes these ecosystems invaluable to people all over the world.

The services, that a wetland provides, can be classified into four groups: provisioning services, regulating services, cultural services and supporting services.

Wetlands are dynamic ecosystems that change over time as a consequence of natural phenomena, such as soil erosion, sedimentation and flooding. However, human activities, both within the wetland or in the catchment area can influence these natural processes and accelerate the rate of change, threatening the wetland’s sustainability.

Professor of Ornithology S.W. Kotagama summarised the threats to wetlands in Sri Lanka under four major categories; habitat deterioration and degradation, direct loss and exploitation of species, spread of invasive alien species and natural phenomena.

Farming in river basins and upstream combined with heavy usage of agrochemicals are major threats to fresh water and man-made wetlands. Seeped and percolated chemicals are often responsible for the degradation of water quality in the downstream and deterioration of wetland habitats.

Soil erosion due to unprotected upstream agricultural practices aggravates sedimentation which is seen as a potential threat that will increase with the intensification of agriculture.

Coastal erosion on the other hand is another problem, which is brought about by altered currents and sediment loads, and can also be caused by coastal land uses, such as unauthorised constructions. Reclamation for urban development, solid waste and garbage disposal and sand mining contribute to alter the structure of the wetland.

Wetland habitat can deteriorate due to clearing vegetation, especially, in the coastal belt and unauthorised and untreated sewage dumping in urban wetlands. Unplanned irrigation structures, regulation of water flow through large water infrastructure i.e. dams and mini-hydro power projects result in degradation of the quality of wetlands.

Wetland dependent communities rely on them for their income generation and living. Overexploitation of associated fauna and flora by these communities result in risking the extinction of endangered species. The most visible example is fisheries, and water birds that are being poached for consumption, while less visible, but important changes may also take place in the micro faunal communities that support the ecology of the system and the food chain. Tourism and freshwater recreation and trade of ornamental plants and species pollute the ecosystem, which leads to the loss of native species in the wetlands.

Introduced exotic aquatic animal and plant species can eventually escape into wild habitats, and can create serious threats to native aquatic biodiversity. The ornamental fish trade mostly established around water bodies has become the sole contributor to introducing invasive alien aquatic species in Sri Lanka. The most prominent examples that can be seen in local wetlands are these four species of fauna (Tilapia - Oreochromis mossambicus, Walking catfish - Clarias batrachus, Rainbow Trout - Oncorhynchus mykiss and Mosquito fish - Gambusia affinis) and two species of flora (Water Hyacinth - Eichhornia crassipes and Giant Mimosa - Mimosa pigra) that are also included in the list of the world’s 100 worst invasive alien species.

The spreading of alien invasive species can lead to the exploitation of native species as it creates a competition for limited resources. Agricultural pests and weeds can also be threatened by this while deteriorating the quality of the wetlands.

Colombo University Zoology and Environment Sciences Department Head Prof. Deepthi Wickramasinghe said, “Despite all the services, wetlands worldwide are threatened by human activities, and Sri Lanka is no exception. Reclamation and clearing for urban expansion, unsustainable solid waste disposal from domestic and industrial sources and the release of industrial, domestic and commercial waste have deteriorated the health of the wetland ecosystem. Increase in floods and declining aquatic biodiversity are, in part, the results of wetlands degradation and destruction. The conservation of our natural heritage is the duty of any responsible citizen.”

Wetlands are also threatened by natural phenomena common in Sri Lanka. For instance, the prolonged dry conditions in the dry zone results drying off of tanks, streams, salt marshes and lagoons, causing death to species of flora and fauna. The rise of sea water temperature due to climate change bleaches the coral reefs, especially, in the southwestern part of Sri Lanka.

Prohibitory order

The vigilance for wetland conservation reached high in Sri Lanka with high intensity and frequent flash floods in the past few years. The Cabinet on August 21, 2018 on a proposal by President Maithripala Sirisena, in his capacity as the Mahaweli Development and Environment Minister, decided to; to impose a prohibitory order preventing all types of land reclamation and constructions in the Colombo Metropolitan Region for any other purpose other than the constructions necessary to be done which are of national importance and the constructions identified under the Transit Railway Line Network, and to direct the Director General of Wildlife to declare the wetlands, other than the areas recognised adjacent to Kimbulaela and Diyawanna oya in which the development activities have been initiated, as protected areas.

Sri Lanka ratified the Ramsar Convention on Wetlands in 1990 and established a National Wetland Steering Committee (NWSC) while the Committee was reconstituted in 2003 to integrate plans for wetland areas and to coordinate development and conservation activities.

This resulted in the formal adoption of a National Wetland Policy under the auspices of the Ministry of Environment and Natural Resources in 2004.

Giant step

Since 1897 with the broadcasting of “protect the coastal belt systems”, Sri Lanka has taken steps towards conserving its wetlands. The Fauna and Flora Protection Ordinance of 1937 can be considered as another giant step. Using this legislation, wetlands of importance to birds have been declared as sanctuaries and other protected areas by the Department of Wildlife Conservation. The setting up of a Wetland Steering Committee, hosting international workshops on wetlands and declaring six Ramsar wetland sites (Bundala, Anaiwilundawa, Maduganga, Venkali Santuary , Kumana Wetland Cluster and Wilpattu Wetland showed the country’s willingness to protect these valuable water bodies.

The Government, non-government organisations, research organisations, academia and the cooperate sector are involved in wetland conservation and management related activities in the country.

Wetland management

Every one has a role to play in sustainable wetlands management – to ensure the wetland dependent communities continue to obtain the benefits that wetlands provide for reducing poverty and to ensure balanced ecosystems.

Wetland policies need to better reflect the realities of wetland agriculture – the dilemma remains how to maximise the benefits of agriculture while simultaneously minimising the adverse impacts on other valuable ecosystem services. Research is required to better understand trade-offs and determine best management practices.

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