Despite bad ecology, Sambhar got more birds this year than before
Despite the worst ecology among Indian wetlands, the Sambhar Lake got more birds this year than before, according to data of the Asian Waterbird Census (AWC) 2020.
The census carried out at India’s largest inland saline lake on January 6 and 7 found that 43,510 birds of 31 species, including four species categorized as threatened birds in the red list of International Union for Conservation of Nature (IUCN), were present at the lake. In 2018 census, the number was 1,161 of 25 species and 1,389 birds of 20 species was counted in 2019.
The wetland was in the news in November last year after more than 20,000 birds died due to botulism, a neuromuscular illness caused by bacteria, to the concern of environmentalists and ornithologists.
“Due to good monsoon, the lake revived after decades and attracted thousands of long distant winter migratory water birds,” said ecologist TK Roy, who is AWC Delhi state coordinator for Wetlands International.
The waterbird census is coordinated by Wetlands International South Asia and is carried out in January every year in Asia and Australasia across 27countries in participation of thousands of volunteers to record the status of important wetlands habitat and water birds diversity with population estimates. The AWC this year was done from January 4 to January 19.
The AWC is part of the global waterbird monitoring programme, the International Waterbird Census (IWC). In Indian sub-continent, AWC is carried out at few hundred wetlands (state, regional and national wetlands, Ramsar sites, protected areas, important bird and biodiversity areas and conservation reserves). In Rajasthan, the census was done at Sambhar, which is one of the two Ramsar sites in the state.
The census noticed a partial increase of species diversity but a major increase in number of water birds. Roy said. “Out of present 31 species diversity, seven species are resident water birds, including the local migratory, and 24 species are winter migratory water birds,” he said.
The census was done in collaboration with the Rajasthan forest department, Nagaur district administration and in active participation of the volunteers from Central University of Rajasthan, Kishangarh, Maharshi Dayanand Saraswati University, Ajmer, local NGO and territorial forest division. The AWC Delhi state coordinator supervised the census.
Roy said water birds are one of the key indicators of wetlands health. “Wetlands provide feeding, resting, roosting and foraging habitats for these charismatic species and birdlife provides ecosystem services to us,” he said.
The rise in number is a good sign at a time when a report by the environment ministry rated the Sambhar Lake among the eight worst-rated wetlands in the country for ecosystem management.
Earlier, the Bareilly-based Indian Veterinary Research Institute (IVRI) blamed heavy rains in July and August as a reason for mass mortality. Good monsoon resulted in filing of lake and there was formation of new marshy areas reported after 20 years. The report said salinity of lake water was less due to the heavy downpour, which became conductive environment for the proliferation of planktons, a bunch of mirco or small organisms which harbor the bacterium, which causes botulism, in their body. When water levels receded, there was mild increase in the salinity levels, leading to the death of planktons and accumulation of toxins, the IVRI report said.
Roy said due to global climate change impact, the arrival of winter migratory water birds from far Central Asia, North Asia was delayed in all of north India. “Winter migratory water birds were recorded in October at Sambhar after decades due to revived the wetland habitat,” he said.