2nd February: World Wetland Day
NEW lungs to breath fresh air - WNPS Steps in to restore an important wetland bird
sanctuary in Suburban Colombo.
Wetlands play an important role in our natural environment. They reduce the impacts of floods, absorb
pollutants and improve water quality. They provide habitat for animals and plants and many contain a
wide diversity of life, supporting plants and animals that are found nowhere else.
Colombo is a city built on and around wetlands. Despite progressive loss and degradation, wetlands still
cover some 200 km 2 of the Colombo metropolitan area and suburbs. The wetlands are fundamental to the well‐being of the people of Colombo and its suburbs. All the wetlands, even the most degraded ones, still provide a range of indirect benefits to everyone such as their ability to mitigate floods, cooling of the
climate and regulation of pests.
The wetlands significantly benefit the urban poor from livelihood derived from products from wetland thus
contributing towards food security of the city. Fishermen are also active in the wetlands across the city.
The city folks have long‐benefitted from their knowledge of the curative powers of local plants and the
wetlands provide the traditional medicines.
The wetlands can reduce extreme air temperatures and make the city more liveable due to evaporative
cooling. Estimates suggest that the wetland soils contain approximately 1.43 million metric tons of carbon
that is equivalent to almost 90% of the annual carbon emissions from the Colombo Metropolitan Area.
The wetlands protect the health of citizens. Through the trapping and removal of particulate matter from
air, the wetlands reduce the incidence of cardiopulmonary and respiratory diseases, coughing, bronchitis
and lung cancer, as well as premature deaths from these diseases resulting from elevated concentrations
of ambient particulate matter.
The wetlands provide a critical land mass which helps to maintain the richness of Colombo’s biodiversity.
Over 250 plant species, including nine endemic, nine nationally threatened and eleven nationally near
threatened species of plant are present in the wetlands. Almost 280 species of animals, including 32
endemic species, are present in these urban wetlands.
The wetlands provide growth conditions to critically endangered plant species. An example is Aganope
heptaphylla, where the plant is recorded only at three sites in Sri Lanka, two of which are Beddagana
Biodiversity Park and the Kolonnawa Marsh.
The wetlands support endangered animals. Although 20 critical species inhabit the wetlands of Colombo,
these include four species of dragonfly, two species of butterfly, four species of land snails, two species of
freshwater fish, two species of amphibian, two species of reptile and four species of mammal. Two of the
endangered mammal species include the Fishing cat Prionailurus viverrinus and the Otter Lutra lutra.
Bellanwila-Attidiya wetland bird sanctuary
Bellanwila-Attidiya wetland bird sanctuary was gazetted in year 1990. According to references it extends
372 ha and is situated on the south-eastern outskirts of Colombo, directly east of Attidiya and south of
Bellanwila temple. Bellanwia-Attidiya sanctuary falls within the upper catchment of the Bolgoda river
The Department of Wildlife Conservation who manage the Bellanwila-Attidiya Sanctuary confine their
activities mostly to retain their land extent from encroachment while the sanctuary itself was getting
Despite all the benefits that the wetlands provide, wetlands continue to be completely lost or
Background to the Green Isle Project:
Bellanwila-Attidiya wetland bird sanctuary provided suitable habitat for many bird species including some
rare migrants like the Glossy Ibis and the Combed Duck. However, in the past 20-30 years, due to the
uncontrolled spreading of the aggressive invasive alien species, Annona Glabra the sanctuary lost almost
all of its indigenous flora. This uncontrolled growth of the invasive alien species downgraded the precious
bird sanctuary in Bellanwila-Attidiiya to a swamp of Annona Glabra. The authorities who manage the
sanctuaries failed to control this invasion of the aggressive alien species.
When WNPS heard the cry for help, they immediately responded by finding a sponsor to provide the funds
for the necessary restoration work. In 2019, WNPS embarked on this project. The work commenced with
help from Sri Lanka Land Development Corporation (SLLDC) first to clear the walking trail of 1.6 km of
Annona Glabra replacing with carefully selected indigenous species recommended by a team of eminent
Scientists who are experts in the field.
Green Isle consists of a 40 acre island where the restoration is taking place. Last year two inland lakes were created and a fair amount of Annona Glabra was thinned out with the assistance of the Sri Lanka Land Development Corporation. To date over 1500 saplings of recommended tree species have been planted. Each sapling is tagged and numbered and their growth is carefully monitored. In 2021, a further 1000 selected tree saplings will be planted while Annona Glabra is gradually thinned out further. Project
maintains a tree nursery and those who are interested in supporting the project with plant saplings are
most welcome to donate plants. WNPS can provide further information on the species of trees required.
One of the objectives of the project is to provide a refuge for the critically endangered endemic primate,
Nestor – Purple-faced Leaf monkey which has lost most of its natural habitat. The primate expert on the
technical advisory panel has assisted us in recommending suitable Nestor friendly tree species to be
planted particularly along the nature trail.
WNPS is also studying and monitoring the water quality of the two inland lakes and the surrounding
canals. This research is carried out by a team from the University of Kelaniya.
The Green Isle site provides ample research opportunities for Scientists interested in Flora and Fauna in
Wetland systems. WNPS is ready to provide all the necessary assistance for scientists and researchers who wish to carry out such studies.
The 4 year project currently in its second year managed by the WNPS is mainly funded by Abans plc as the principal sponsor and further supported with funds from a few well-wishers of WNPS. Continued support by the Sri Lanka Land Development Corporation is also gratefully acknowledged.