IN175
Carambolim Wetlands


Year of compilation: 2004

Site description
Carambolim lake lies in Ilhas taluka, about 12 km from Panjim, the capital of Goa. It is spread over an area of 70 ha, of which 40 ha is under water for most of the year. In order to grow paddy, a number of minor irrigation tanks have been developed in Goa. These tanks are made by the impoundment of run-off during the monsoon. They are also a natural source of fish, because every year, before the monsoon, the remaining water is drained out to empty the tanks and the fish are harvested. The sluice gates of Carambolim lake at the southeastern side are kept closed from late July to early May next year. The impounded water is used for irrigation of paddy fields in the lower reaches on the southern side of the lake (Shanbhag et al. 2001). The western embankment of the lake serves as the base for the recently laid Konkan railway track, while the eastern side has been partially cleared of its scrub forests, mango and cashew groves, to pave the way for the construction of residential buildings. Coconut and mango trees fringe the remaining sides of the lake. The water depth is between 1.5 m to 3 m, depending upon the season. The lake lies between the estuarine zone of the Mandovi and Zuari rivers. The main vegetation consists of Nymphea stellata, a rooted plant with floating leaves, Oryza rufipogon, an emergent wild paddy, and submerged Hydrilla verticillata.

Key biodiversity

AVIFAUNA: Carambolim lake attracts thousands of birds, especially waterfowl. Shanbhag et al. (2001) identified 92 species of birds including 17 winter visitors. In 1997, they reported the presence of 25,590 waterfowl, of which Northern Pintail Anas acuta numbered 15,187, Lesser Whistling Duck Dendrocygna javanica numbered 4,957 and Coot Fulica atra numbered 347. In the winter of 1987-88, when large parts of India were affected by drought, and Goa had an adequate monsoon, over 75,000 waterfowl were seen in Carambolim (Lainer 1999). According to Lainer (1999), in a normal year, over 35,000 waterbirds could be found in this wetland. Besides A4iii criteria, Carambolim lake also fits A4i criteria (the site is known or thought to hold, on a regular basis, >1% of a biogeographical population of a congregatory waterbird species). Over 4,000 Garganey Anas querquedula regularly winter at this IBA (Lainer 1999). The 1% threshold is 2,500 (Wetlands International 2002). Close to Carambolim lake, at Corlim (Tiswadi), is located the Swiss-owned Hindustan Ciba Geigy Ltd (HCGL) Factory which produces highly toxic pesticides for agricultural use. The large factory compound contains two shallow ponds that give undisturbed shelter to Goa’s only known heronry, and a safe haven to quite a number of migrant and vagrant Ciconiidae and Threskiornithidae (Lainer 1999). The following species are breeding regularly in the heronry (population numbers for 2002 in brackets): Little Cormorant Phalacrocorax niger (200 pairs), Indian Shage P. fuscicollis (100 pairs), Oriental Darter Anhinga melanogaster (21 pairs), Purple Heron Ardea purpurea (45 pairs), Large Egret Ardea alba (94 pairs). Regular visitors include Grey Heron Ardea cinerea (up to 37), Black crowned Night-Heron Nycticorax nycticorax (up to 14) Painted Stork Mycteria leucocephala (up to 5), Asian Openbill Stork Anastomus oscitans (up to 37), White-necked or Wooly-necked Stork Ciconia episcopus (up to 40), Lesser Adjutant Leptoptilos javanicus (up to 22) and Lesser Whistling Duck (up to 4000). Among the occasional and rare visitors count Black Stork Ciconia nigra (2), European White Stork C. ciconia (1), Oriental White Ibis Threskiornis melanocephalus (up to 89) and Eurasian Spoonbill Platalea leucorodia (up to 19). The dry fields near Carambolim are well known for raptors, and a very small chat, which was discovered in 1996. It is still not known for sure if it was a Stoliczka’s Bushchat Saxicola macrorhyncha or a species new to science! Although this site has one Restricted Range species of Western Ghats (Malabar Parakeet Psittacula columboides) and one Biome-10 species of Indian Peninsula Tropical Moist Forest (Blue-faced Malkoha Phaenicophaeus viridirostris), it is selected as an IBA based on A4i and A4iii criteria.

OTHER KEY FAUNA: Presently none of conservation significance.

Pressure/threats to key biodiversity
MAIN THREATS: Increasing disturbance due to urbanization.

One of the biggest threats faced by Carambolim lake was the construction of the railway track of the Konkan Railway Project, very close to the lake. Facing stiff resistance from environmentalists, the Konkan Railway Ltd agreed to shift the line, so as to minimize damage to the wetland. The railway project commenced in 1990 and took eight years to complete. During the construction period in 1995 - 1996, there was a lot of disturbance near Carambolim lake as nearly 200 labourers, and 20-30 trucks moved per hour, but once the railway track was completed, birds started reappearing, and now they have become used to the movement of trains (Shanbhag et al. 2001). Under pressure from conservationists, the Konkan Railway Corporation Ltd., planted a large number of trees on the track embankments, to muffle the sound of the moving trains and declared the area as ‘no hooting zone’. These steps have helped in restoring the bird life of this important IBA of Goa. The long-term and irreversible disturbance is from private encroachment, night soil generated from the migrant human population, and the silt deposition, leading to the development of marshy conditions. To protect the area from further encroachment and development threats, Carambolim lake needs to be protected under the new category of Community Reserve in the modified Indian Wildlife (Protection) Act.

Acknowledgements
Key contributors: A. B. Shanbhag and Heinz Lainer.


Recommended citation
BirdLife International (2022) Important Bird Areas factsheet: Carambolim Wetlands. Downloaded from http://www.birdlife.org on 18/05/2022.