Bellanwila-Attidiya Sanctuary

Location: 60 52’ 0 N and 790 52’ 0 E to 60 48’ 0 N and 790 56’ 0 E; 759157 N and 374779 E to 751770 N and 382129 E; in the southeastern outskirts of Colombo city, in the Colombo District of the Western Province.

Area: c. 372 ha.

Altitude: 0-6m.

Overview: This is primarily a freshwater marsh ecosystem, surrounded by a rapidly developing urban landscape. The marshes serve as an important flood retention area, which provides protection to the surrounding inhabited areas. Additionally, the wetland is an important stopover for a number of migratory birds and an important roosting site for herons and egrets. As a result it has been identified as an IBA by BirdLife International. At present, much of the wetland is in a highly degraded state due to several adverse anthropogenic factors.

Physical features: The wetland is interconnected to the flood plains of the Bolgoda system through the Bolgoda Canal. Several other man made canals connect the Attidiya marshes to the Colombo marshes. A small man made lake is also located within the wetland system. Attidiya is located within the wet zone and receives an annual rainfall of 2500-5000mm. The average annual temperature is around 270 C with average humidity of around 80%.

Ecological features: The wetland consists of shallow freshwater ponds, marshes and seasonally flooded grasslands, with scattered shrubs and small trees. There is significant biodiversity including 77 species of butterflies and 37 species of dragonflies. Of this, 5 species of butterflies are considered nationally threatened. Additionally, 15 species of nationally threatened and endemic vertebrates have been recorded from the wetland. Bird life is profuse, and to date, over 168 species have been recorded. More than 30 species of freshwater fish have been recorded, including several exotic species.

Noteworthy fauna: The marsh harbours several species of endemic fish, including Esomus thermoicos, Clarias brachysoma, Aplocheilus dayi, and Channa orientalis. Among the amphibians, endemics include Bufo atukoralei, Polypedates cruciger, Rana gracilis, while the site also harbours Rana aurentiaca. Aquatic reptiles include freshwater turtles (Melanochelis trijuga, Lissemys punctata) serpents (i.e. Xenocrophis asperrimus, Acrochordus granulatus) and the crocodile (Crocodylus palustris). Water birds include uncommon species such as Pelecanus philippensis, Rallus striatus, Porzana fusca, Gallicrex cinerea, Phalacrocorax carbo and Rostratula benghalensis. Rare mammals such as Prionailurus viverrinus and Lutra lutra also inhabit this marsh, while troops of the endemic Trachypithecus vetulus occur in bordering trees. The endemic mammal Paradoxurus zeylonensis has also been recorded.

Noteworthy flora: The dominant floral species in this site are invasive aliens. Bellanwila-Attidiya also harbours the endemic sedge Eleocharis lankana.

Land use: The wetland is used for collecting reeds for making mats and collection of fuel wood. Some small-scale agriculture is carried out in the periphery, along with grazing of livestock such as water buffalo, cattle, goats and pigs. Fishing for finfish and shrimps is carried out in the water bodies. Much of the areas bordering the sanctuary have been reclaimed and used for urban development.

Possible changes in land use: Both legal and illegal reclamation of wetland area for housing and urban development and reduction in activities such as fishing and livestock grazing.

Hydrological and biophysical values: The marshes and canals are essential for flood detention and drainage.

Social and cultural values: Being an urban wildlife sanctuary within close proximity to Colombo city, the marsh provides valuable opportunities for bird watching, conservation education and scientific research. Additionally, it provides an important biodiversity refuge and breathing space in an urban landscape. The wetland is also culturally significant as a historically important temple is located adjacent to it. Traditionally, lotus flowers used in religious ceremonies have been collected from the wetland.

Scientific research and monitoring: A comprehensive study of the amphibian fauna of the marsh was conducted from 1995-1997. Periodic surveys of other wildlife have also been conducted.

Conservation education: The Environmental Education Unit of the CEA is currently building a visitor center at the Sanctuary.

Recreation and tourism: Several private companies conduct bird watching excursions to the marsh.

Conservation measures taken: The wetland was declared as a Sanctuary under the FFPO in 1990. In 1993, the CEA produced a wetland site report and management plan. The Sanctuary has been zoned for conservation with public nature park functions in the Dehiwala-Mt. Lavinia Municipal Council Urban Development Plan.

Conservation measures proposed: Detailed conservation measures have been proposed in the conservation management plan prepared by the CEA.

Disturbance and threats: Factories in the vicinity release effluent in the waterways passing through the marsh, which then enter the Bolgoda Lake. The Dehiwela-Mt Lavinia muncipal council uses the northern and eastern parts of the marsh for garbage dumping. Such factors have an impact on water bird habitat quality and cause large-scale fish kills. These fish kills have decimated the local populations of several species of fish, including Aplocheilus dayi, which is endemic to Sri Lanka. The economically important freshwater shrimp Macrobrachium rosenbergii has almost been exterminated in the marsh. Habitats have been lost due to clearing of shrubs for construction purposes in the surrounding areas, as well as human encroachment into the marsh from its periphery. On-going landfill of marshland, largely with household rubbish, has been observed on the West bank of Bolgoda Canal (northern end) and at land fronting the marsh at the Bellanwila Temple site. Road kills on main roads and consumption of meat from terrapins and birds cause a decline in these species. In addition, egg collection is a threat to the bird populations inhabiting the marsh. The spread of floral (Annona glabra, Eichhornia crassipes, Pistia stratiotes, Salvinia molesta, Lantana camara) and faunal (Pomacea spp., Chitala ornata, and Trachemys scripta) invasive alien species is also a major threat to native biodiversity in the wetland. The disturbances and threats are so large that some amphibian species underwent a rapid decline between 1997 and 2000. Need urgent actions to mitigate existing threats.

Land tenure: The marsh is state owned, while surrounding areas are mostly privately owned or owned by the Bellanwila Temple.

Management authority and jurisdication: The DWC has jurisdiction over the Sanctuary. The UDA, LLDC, CEA and the Department of Irrigation have responsibilities over the wetlands and low-lying areas adjacent to the Sanctuary.

References: Bambaradeniya (2002); BirdLife International (2005); CEA/ARCADIS Euroconsult (1994c); de A Goonatillake et al. (2001); Kotagama et al. (1989)