Indian dolphin, elephant among top 100 mammals facing extinction: Zoological society of London
Kounteya Sinha, TNN | May 20, 2013, 04.10 PM IST
LONDON: India's Gangetic river dolphin and wild elephants figure in the latest 100 top mammals on the verge of extinction.
The Zoological Society of London have for the first time scored the world's mammals according to how Evolutionarily Distinct and Globally Endangered (EDGE) they are.
The list that includes the world's most extraordinary threatened species - frogs that give birth through their skin and mammals that are immune to cyanide - yet most are unfamiliar and not currently receiving conservation attention includes the two entries from India.
The list has raised a serious alarm for the largest land mammal in Asia - the elephant.
Ranked 17th on the list of 100 most endangered mammals, ZSL says only 35,000-50,000 Asian elephants were thought to remain in the wild in 1995. Since then, several populations have dwindled further, and scientists fear that current populations may have fallen well below this estimate.
The majority of elephants occur in India (20,000-25,000) and Myanmar (5,000-6,000). There are thought to be fewer than 200 elephants surviving in Vietnam.
Habitat loss has been a primary factor in the decline of the Asian elephant.
ZSL said, "The elephants have become increasingly isolated in habitat patches as human settlements cut off ancient migratory routes. There is concern that many of these subpopulations are too small to be viable. Even protected populations are at risk from inbreeding and disease."
Elephants are increasingly coming into contact with farmers and local people as their feeding grounds are destroyed. They raid crops, destroy properties, and sometimes even kill people.
The villagers often retaliate by killing the elephants, and experts believe this is now the main cause of elephant deaths in Asia.
Poaching for ivory, and occasionally meat, continues to threaten wild populations, although reliable estimates of the number of elephants killed and the quantities of ivory and other body parts collected and traded are scarce.
Since only males have tusks, poaching has resulted in populations becoming skewed towards females. This has affected breeding rates and may lead to increased instances of inbreeding and decreased breeding success.
The River Dolphin has been ranked 60th most endangered mammal in the world.
In the river basins in India the dolphin is present mostly in plains with slow-flowing rivers. Today it is found in the Ganges-Brahmaputra-Meghna and Karnaphuli-Sangu river systems of Bangladesh and India.
Surveys of portions of the range of the Ganges subspecies have collectively accounted for 1,200-1,800 animals.
The main problem according to ZSL is that the dolphin lives in one of the most densely populated areas of the world. It is threatened primarily by the damming of rivers for irrigation and electricity generation, which degrades habitat, isolates populations and prevents seasonal migration. More than 20 barrages and 18 high dams have been constructed in the Ganges-Brahmaputra-Megna river systems alone since 1956, and in the northern Ganges tributaries at least three of six subpopulations that were isolated by barrages have recently disappeared.
ZSL says, "Further declines are expected as more barrages are planned and under construction throughout the species' range. The proposed Ganges-Brahmaptura inter-link canal and dam project, expected to be completed in India in 2016, will involve additional dam construction and diversion of water from rivers inhabited by dolphins. This will undoubtedly result in further habitat loss and degradation, population fragmentation, and an increase in dolphin strandings."
Since the mid 1990s, there have been increasing reports of dolphins trapped in irrigation canals near Sukkur Barrage, many of which die when the canals are drained for annual de-silting and maintenance.
Professor Jonathan Baillie, ZSL's director of conservation says, "The results of the mapping exercise are alarming. Currently only five per cent of the areas we've identified as priorities for EDGE mammals and 15% of the EDGE amphibian areas are protected."