Thursday, December 10, 2015

National Animal of Bangladesh.



Distribution and Habitat:
In 1982, a sub-fossil right middle phalanx was found in a prehistoric midden near Kuruwita in Sri Lanka, which is dated to about 16,500 ybp and tentatively considered to be of a tiger. Tigers appear to have arrived in Sri Lanka during a pluvial period during which sea levels were depressed, evidently prior to the last glacial maximum about 20,000 years ago.In 1929, the British taxonomist Pocock assumed that tigers arrived in southern India too late to colonize Sri Lanka, which earlier had been connected to India by a land bridge.
In the Indian subcontinent, tigers inhabit tropical moist evergreen forests, tropical dry forests, tropical and subtropical moist deciduous forests, mangroves, subtropical and temperate upland forests, and alluvial grasslands. Latter tiger habitat once covered a huge swath of grassland and riverine and moist semi-deciduous forests along the major river system of the Gangetic and Brahmaputra plains, but has now been largely converted to agricultural land or severely degraded. Today, the best examples of this habitat type are limited to a few blocks at the base of the outer foothills of the Himalayas including the Tiger Conservation Units (TCUs) Rajaji-Corbett, Bardia-Banke, and the transboundary TCUs Chitwan-Parsa-Valmiki, Dudhwa-Kailali and Sukla Phanta-Kishanpur.
Bangladesh:
Tigers in Bangladesh are now relegated to the forests of the Sundarbans and the Chittagong Hill Tracts. The Chittagong forest is contiguous with tiger habitat in India and Myanmar, but the tiger population is of unknown status.
As of 2004, population estimates in Bangladesh ranged from 200 to 419, mostly in the Sunderbans.This region is the only mangrove habitat in this bioregion, where tigers survive, swimming between islands in the delta to hunt prey .Bangladesh's Forest Department is raising mangrove plantations supplying forage for spotted deer. Since 2001, afforestation has continued on a small scale in newly accreted lands and islands of the Sundarbans From October 2005 to January 2007, the first camera-trap survey was conducted across six sites in the Bangladesh Sundarbans to estimate tiger population density. The average of these six sites provided an estimate of 3.7 tigers per 100 km2 (39 sq mi). Since the Bangladesh Sundarbans is an area of 5,770 km2 (2,230 sq mi) it was inferred that the total tiger population comprised approximately 200 individuals In another study, home ranges of adult female tigers were recorded comprising between 12 and 14 km2 (4.6 and 5.4 sq mi).which would indicate an approximate carrying capacity of 150 adult females. The small home range of adult female tigers (and consequent high density of tigers) in this habitat type relative to other areas may be related to both the high density of prey and the small size of the Sundarbans tigers.
Since 2007 tiger monitoring surveys have been carried out every year by WildTeam in the Bangladesh Sundarbans to monitor changes in the Bangladesh tiger population and assess the effectiveness of conservation actions. This survey measures changes in the frequency of tiger track sets along the sides of tidal waterways as an index of relative tiger abundance across the Sundarbans landscape.
The population size for the Bangladesh Sundarbans was estimated as 100–150 adult females or 335–500 tigers overall. Female home ranges, recorded using Global Positioning System collars, were some of the smallest recorded for tigers, indicating that the Bangladesh Sundarbans could have one of the highest densities and largest populations of tigers anywhere in the world. They are isolated from the next tiger population by a distance of up to 300 km (190 mi). Information is lacking on many aspects of Sundarbans tiger ecology, including relative abundance, population status, spatial dynamics, habitat selection, life history characteristics, taxonomy, genetics, and disease. There is also no monitoring program in place to track changes in the tiger population over time, and therefore no way of measuring the response of the population to conservation activities or threats. Most studies have focused on the tiger-human conflict in the area, but two studies in the Sundarbans East Wildlife sanctuary documented habitat-use patterns of tigers, and abundances of tiger prey, and another study investigated tiger parasite load. Some major threats to tigers have been identified. The tigers living in the Sundarbans are threatened by habitat destruction, prey depletion, highly aggressive and rampant intraspecific competition, tiger-human conflict, and direct tiger loss.

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