Brain Booster for UPSC & State PCS Examination (Topic: Biodiversity in Ganga)

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Biodiversity in Ganga

With celebrations of the Ganga Utsav—to mark the 12th anniversary of declaring the Ganga as a national river — having come to an end, the Wildlife Institute of India (WII) conducted the second phase of its survey of the entire main stem of the Ganga river (the main river without its tributaries).

The survey has found that 49 per cent of the river has high biodiversity and that biodiversity sightings including of the Gangetic Dolphin and otters, have increased in the river.
The study was initiated by WII on behalf of the National Mission for Clean Ganga, one of the flagship projects undertaken by the Ministry of Jalshakti, and the first phase of the survey was carried out between 2017-2019.
This is the first study ever done in the country on the entire river, and the first also of all its biodiversity.

The Ganga and its tributaries flow through 11 states and cover 26.3 per cent of the country’s total geographical area. But its main stem flows through five states — Uttarakhand, UP, Bihar, Jharkhand and West Bengal.
The high biodiversity stretches of the river have been divided into six zones – Devprayag to Rishikesh (61 km), Makdumpur to Narora (147 km), Bhitaura to Ghazipur (454 km), Chhapra to Kahalgaon (296 km), Sahibganj to Rajmahal (34 km) and Baharampur to Barackpore (246 km).
Ten per cent of the high biodiversity areas fall alongside national parks and sanctuaries such as Rajaji national park in Uttarakhand, Hastinapur wildlife sanctuary in UP and Vikramshilagangetic Dolphin sanctuary in Bihar.

Freshwater ecosystems account for 0.01% of the earth’s surface water but 10% of species.
According to the UN Environment Programme World Conservation Monitoring Centre (UNEP-WCMC), decline in diversity of freshwater species is the highest, and surpasses losses in marine and terrestrial species.
Globally 20% of all known freshwater fish, 44% waterbirds and 42% amphibian species are under threat of extinction. The highest loss of freshwater biodiversity has been reported from the Indian subcontinent, specifically the Gangetic plains.

Through some key aquatic and semi-aquatic species such as the Gangetic dolphins, gharials, otters, turtles and various species of water birds.
Many species that used to be found in the main stem and had disappeared, are now coming back.
Nesting colonies of the Indian Skimmer.
Seibold’s, a species of water snake, disappeared 80 years ago and has now resurfaced.
Found new distributions of the puffer fish.

Rapid biodiversity of the Ganga had revealed that the distribution and density of key aquatic species such as the Gangetic Dolphin, the gharial and the mugger had in earlier years, significantly reduced due to loss of
suitable habitat conditions,
Change in the river’s morphology due to the construction of dams and barrages, bank alteration, agriculture and sand mining led to the decline in river Ganga biodiversity.
In the early 19th century, 10,000 Gangetic dolphins were estimated which reduced to 3,526 by early 2000, disappearing entirely in Haridwar and most of the Yamuna and becoming extinct in smaller tributaries.