Uttara Kannada district has lost 3,383 sq. km of dense forest cover in the last 37 years. This is more than one third of the total area of the district (10,280 sq. km). The loss of forest cover has adversely impacted mangroves and estuarine fisheries.Carrying capacity
A study by the Energy and Wetlands Research Group, Centre for Ecological Sciences, Indian Institute of Sciences, on the ‘Ecological carrying capacity of Uttara Kannada district’ has revealed that mega development projects such as hydel power plants, Project Seabird, Kaiga nuclear power plant and Konkan railway accounted for the loss of 26,186 hectares (ha) of forest, and 5,508 ha of forest was cleared for rehabilitating families displaced by the projects. Apart from these, setting up a colony for rehabilitating Tibetan refugees and encroachment of forestland for agriculture and mining activities resulted in the decline in the forest cover in the district.
The study was funded by the Karnataka Biodiversity Board and the Western Ghats Task Force.
Encroachments of 2,824.8 ha of forestland prior to April 27, 1978 were regularised by the Department of Forests during 2000–01.
The continuous release of freshwater used for power generation in the hydroelectric project has reduced salinity in the Sharavati and Kali estuaries, the study said.Growth declined
While most high salinity tolerant mangroves vanished, the growth of medium salinity tolerant mangroves declined. Only 43 species of fish were found in the Sharavati estuary, while estuary of the Aghanashini, which does not have any power projects, had nearly 90 species of fish. The Kali estuary had 58 fish species.
Seven kinds of edible bivalves which used to available in the Sharavati, Gangavali and Kali estuaries until about three decades ago, have disappeared due to the release of fresh water from the upstream dams. But, in the Aghanashini estuary, 22,000 tonnes of edible bivalves worth Rs. 66 crore were collected in 2008.