|Wetland ecosystems in Sri Lanka
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|Author:||Rohan2 [ Sun Jun 25, 2006 3:10 pm ]|
|Post subject:||Wetland ecosystems in Sri Lanka|
Wetland ecosystems in Sri Lanka
Water, Life and Culture
Lanka's extensive network of rivers and streams cover more than 4500 km. The river Mahaweli is the largest basin covering 16% of the island and has a high socio-economic and ecological value. There are around 45 estuaries in Sri Lanka with around 10,000 ha. of mangroves along the coastline. The Maduganga Estuary and Bentota Estuary are estuaries with mangroves. There are 42 lagoons found around the coastline. Sri Lanka has around 10,000 man-made wetlands (Tanks and Reservoirs) which depict the cultural heritage of Sri Lanka. Major irrigation reservoirs cover an area of 7820 ha. Although there are no large natural lakes in Sri Lanka, there are several flood plain lakes known as "Villus".
@ CDN / February 2, 2002)
by Florence Wickramage
The Cultural heritage of Sri Lanka was based on the concept "Wewa, Dagoba and Pansala (temple). Rich in biodiversity, with bountiful natural resources, our country has earned a name as the "Hot Spot" in Asia.
For over 2500 years the country's environment and culture - had interspersed with each other and was protected and preserved by the Sinhala Kings and the nation's ancestors. Life giving Water was considered `holy' and was part and parcel of man's life and wetlands whether man-made or natural were guarded as sacred areas.
As this year's World Wetland Day emerges, the country is richer by another Ramsar site, Anaivilundawa which has earned international recognition, in addition to her first, the Bundala National Park. As one conservator observed the country as a whole is one vast wetland.
On February 2 1971, a significant milestone on the conservation of wetland ecosystems was achieved in the city of Ramsar in Iran. Here a global consensus was adopted to identify and protect wetlands of intentional importance especially as waterfowl habitat.
Today the Convention on Wetlands (popularly known as the Ramsar Convention) serves as an intergovernmental treaty which provides the framework for national action and international cooperation for the conservation and wise use of wetlands and their resources. (Ref: IUCN)
The Ramsar convention defines wetlands as " areas of marsh, fen, peatland 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 6 metres".
There are presently 130 Contracting Parties to the Convention with 1112 wetland sites, totalling 89.37 million hectares. Sri Lanka became a signatory to the Convention in 1991 declaring the Bundala Lagoon system as its first Ramsar Wetland site.
The principal wetland type in the Bundala National Park is a system of lagoons which has a high species richness of waterfowl, including migratory bird species.
The Anaivilundawa Sanctuary was declared a Ramsar site on August 2, 2001. The sanctuary is famous for its rich biological diversity and historic/cultural significance.
The principal wetland type in Anaivilundawa is a system of ancient cascading tanks established in the 12th Century. IUCN Research defines Sri Lanka's wetlands into three categories. Inland Fresh water wetlands, Salt water wetlands and Man-made wetlands.
The country's extensive network of rivers and streams cover more than 4500 km. The river Mahaweli is the largest basin covering 16% of the island and has a high socio-economic and ecological value.
Although there are no large natural lakes in Sri Lanka, there are several flood plain lakes known as "Villus". Many of the larger villus are located in the Mahaveli flood-plain in the East and among them are the Handapan and Pendiya Villus. The Wilpattu National Park also contains several villus.
Threats to wetland ecosystems: Spread of invasive alien flora. Bellanwila Attidiya marsh, Sri Lanka. Photograph: Channa Bambaradeniya
Among fresh water marshes, the Muthurajawela Marsh is the largest peat bog in the country. Fresh water Swamp Forests are a very rare wetland and one example of such is the Walauwa Watta Wathurana Swamp forest (12 ha) in the Kaluganga basin.
Saltwater wetlands include estuaries and mangroves, lagoons, coral reefs and sea grass beds. There are around 45 estuaries in Sri Lanka with around 10,000 ha. of mangroves along the coastline. The Maduganga Estuary and Bentota Estuary are estuaries with mangroves.
There are 42 lagoons found around the coastline and among them are the Bundala Lagoon, the Mundel Lake and the Kalametiya Lagoon.
Coral Reefs are famous for their spectacular beauty and rich biodiversity and are considered as the marine version of tropical rainforests. Some of Sri Lanka's famous coral reef habitats are found in the Gulf of Mannar, Trincomalee to Kalmunai in the East Coast and Rumassala and Hikkaduwa in the Southern coast.
Sri Lanka has around 10,000 man-made wetlands (Tanks and Reservoirs) which depict the cultural heritage of Sri Lanka. Major irrigation reservoirs cover an area of 7820 ha.
while the seasonal/minor irrigation tanks account for 52250 ha. Typical irrigation tanks include the Parakrama Samudraya and the Minneriya Tank. Rice fields are categorised as temporary and seasonal water bodies with a total area of 780,000 ha. under rice cultivation. The salt-pans of Hambantota are known as saltwater wetlands.
Values and functions
The Ramsar bureau has documented that wetland ecosystems are part of our natural wealth. " A recent assessment of the dollar value of our natural ecosystems estimated them at US$ 33 trillion. The study has estimated that the global value of wetland ecosystems at an amazing US$ 14.9 trillion, 45 percent of the total.
This reflects the many functions of wetlands which include Flood Control, Groundwater Replenishment, Shoreline Stabilisation and Storm Protection, Sediment and Nutrient Retention, Climate Change Mitigation, Reservoirs of Biodiversity, Wetland Products, Recreation/Tourism and Cultural value".
Much emphasis is now placed on the cultural significance of wetlands as there are many instances where wetlands have significant religious, historical, archaeological or other cultural values which form part of a nation's heritage. Ramsar Bureau states that although cultural values are largely unexplored and poorly documented subject, a preliminary survey of Ramsar sites, over 30 percent of a sample of 603 Ramsar sites recorded some archaeological, historical, religious mythological or cultural significance at either local or national level.
In Sri Lanka , wetlands such as rivers and floodplains have been the cradle of historic civilization. The man-made wetlands in Sri Lanka, especially the ancient irrigation tanks and rice fields, clearly highlight the rich cultural heritage associated with wetlands. It is generally believed that Indo-Aryan immigrants started rice cultivation in Sri Lanka more than 2500 years ago.
This was a period at which a settled civilization developed in the dry zone and an elaborate irrigation system was established for rice cultivation.
The earliest references to the establishment of tanks to conserve water for irrigation of rice in Sri Lanka was about 420 BC. Considering the size of these tanks and the network of neatly built sluices/canals, the technology of our ancient irrigation engineers is truly astonishing"(IUCN).
Documented is the fact that for over 6000 years river valleys and floodplains have been the focus of human civilisations. The survival of human communities have been based on water and wetland systems and the correctness of this social philosophy has been demonstrated in the royal proclamation ascribed to King Parakramabahu the Great "Let not one drop of rain water be allowed to flow into the sea without being harnessed to the maximum use of the human kind".
This was the policy our rulers and forefathers followed from the dawn of the Sinhala traditional culture in Sri Lanka which the present generation should adhere to, for posterity.
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