Bhitarkanika Conservation Area

Description

N 20 17 32 to N 20 48 00 and E 86 38 51 to 86 17 36

The Brahmani, Baitarni and Mahanadi deltaic region of Kendrapara district in northeastern part of the coastal state of Orissa make up the Bhitarkanika Conservation Area (BCA). A mangrove wetland ecosystem having high genetic and ecological diversity, Bhitarkanika covers a total area of 2154.26 km2 of which Bhitarkanika Wildlife Sanctuary and National Park covers 672 km2, the Gahirmatha (Marine) Wildlife Sanctuary covers 1435 km2 while the buffer zone in the Mahanadi delta covers 47.26 km2. The natural boundaries of the Sanctuary are defined by Dhamara river to the north, Maipura river to the south, Brahmani river to the west and the Bay of Bengal in the east. The coastline from Maipura to Barunei forming the eastern boundary of the Sanctuary is an ecologically crucial habitat.

The climate of the area is tropical characterized by three distinct seasons: summer(March to June), winter (November to February) and monsoons (July to October).The annual temperature variation is from 15º C to 30º C and the average rainfall is 1670 mm. The relative humidity remains at 75% to 80% throughout the year and tropical cyclones are prevalent.

The delataic slopes of Bhitarkanika Wildlife Sanctuary are extremely low lying and subject to regular tide inundation. The average elevation above mean tide level is between 1.5 and 2m and extends up to 3.4m (Dani and Kar 1999). The mangrove soils are fine grain silt or clay formed by the sedimentation of the Mahanadi and Brahmani rivers. Surface soils close to the rivers vary from 2 to 4m in depth and decreases gradually from shore to the mainland. The alluvial, silty soil is not very productive unless humus formed from the exuviae of organism such as molluscs and crustaceans are added to it (Chadha and Kar 1999).

The site epitomizes the merging of four different ecosystems namely terrestrial, freshwater, estuarine and marine ecosystems and shows all variations in genetic, specific and ecological diversity of both plant and animal communities. The peripheral areas in the buffer zone are dotted with numerous ornithologically important wetlands. The estuarine region of BCA can be classified into the outer funnel shaped estuarine zone and the inner narrow estuary. Tidal inundation causes heavy silt deposition and detrital content of the mangrove vegetation.

Bhitarkanika is a wetland of International importance and 2672 km2 area of wetland habitat has been declared as a Ramsar site in the year 2002.

The site contains 300 plant species belonging to 80 families of both mangroves and non-mangroves (Banerjee 1984). Bhitarkanika supports one of the largest mangrove plant diversity in India and has more than 82 species of mangroves and its associates. Fifty-five of the 58 Indian mangrove species (Bannerjee and Rao) and three varieties of Sundari trees (Heritiera spp.) including H.kanikensis which is an endemic species are found here. The characteristic mangrove species are Avicennia alba, A.officianalis,and Rhizophora mucronata, Excoecaria agallocha, Acanthus illicifolius, Sonneratia apetalaHeritiera minor.

About 62 species of invertebrates, 19 species of fish, and 5 amphibian species are recorded from this area. Twenty-nine reptilian species of which there are four species of turtles including Olive Ridley seaturtle (Lepidochelys olivacea), one species of crocodile (saltwater crocodile, Corcodilus), 9 species of lizards and 16 species of snakes including the King cobra (Ophiophagus hannah) are found here. BCA offers two types of bird habitats - one, riverine islands or heronry and second, the coastal wetlands along the eastern boundaries. Species diversity of birds at this site is 263 belonging to 63 families including 147 resident, 99 winter migrants, 15 vagrants and 16 local migrants (Gopi and Pandav 2007). Included in this list are more than 79 species of migratory waterfowl. In the site community nesting of aquatic birds (heronry) occurs and 12 wetland bird species nest and roost together annually (June to October). This habitat also supports eight varieties of Kingfishers including a sizeable population of endangered Brownwinged Kingfisher. Thirty-one species of mammals are reported from this area that includes five species of marine dolphins the humpbacked dolphin (Sousa), Irrawady dolphin (Orcaella brevirostris), chinensis Pantropical spotted dolphin, Common dolphin (Delphinus delphis) and Finless black porpoise (Neophocaena phocaenoides).

Apart from being rich in biodiversity, BCA has immense social and cultural values. A large proportion of the local economy is dependent on the thriving fishing industry of Hilsa illisha,and Mullet spp. The area is also an important source of Lates calcarifer, Mystus gulio prawn such as Penaeus indicus and Penaeus monodon. Nearly 3000 to 5000 kg of honey is collected every year from February to May (Chadha and Kar 1990) especially by the honey collecting tribe, 'Daleis'. Nalia grass Myriostachia wightiana, found in the tidal banks and Bahumurga climber Flagellaria indica, found in the mangrove forest, are used for basket and rope making. Phoenix pendulosa is exploited for thatching purpose. Wild strains of salt-resistant paddy occur in these habitats and have immense potential for cultivation along the east coast of India.

Justification de la Valeur Universelle Exceptionelle

Floristically in terms of mangrove vegetation, BCA is the largest in India and second largest after Papua New Guinea. The mangrove forests perform important ecosystem function by breaking tidal surges and devasting cyclones. By doing this they restrict and slow down erosion of tidal banks, stabilize silt deposits near the river mouth and also protect the lives of millions of coastal inhabitants by decelerating strong wave and tidal action.

BCA is an important repository of fauna. It is the nursery and spawning ground for innumerable fish, prawn, crabs and other invertebrates including the endangered King Crab. It is one of the best reptile refuges in India as well as in the entire Southeast Asian region. Bhitarkanika also has a high density of the world's largest water monitor lizard (Varanus salvator). It is home to the largest population of the endangered estuarine crocodile in the Indian sub-continent. BCA contains one of the world's largest nesting and breeding grounds of the endangered Olive Ridley Turtle. The Gahirmatha beach, on the eastern boundary of Bhitarkanika Wildlife Sanctuary, supports the largest known nesting beach of the endangered Olive Ridley Sea Turtle in the world. Mating pairs congregate in large numbers in the coastal waters off the shore of Gahirmatha and nearly half million turtles nest on the beaches.

Of the 263 bird species recorded from the Bhitarkanika heronry, 17 belong to various categories of globally threatened bird species based on the IUCN Red Data List and Birdlife International. More than 25,000 birds consisting of eleven species nest in the heronry in less than 5 ha area. BCA one of the oldest and largest mixed species heronry in the country.

BCA provides employment to the local people through fishing, honey resource collection and tourism.

Déclarations d’authenticité et/ou d’intégrité

Prior to 1952, the ownership over the forest land and non-forest land was with the Zamindars of erstwhile Kanika Raj. Consequent upon the enactment of Orissa Estate Abolition Act (OEA Act) in the year 1951, the ownership over the land was vested with the Govt. of Orissa and the Govt. in Revenue Department exercised control over the land till 1957.Thereafter, the forest lands were transferred to AthagarhForest Division for management purposes. Thus, the BCA has had a strong protection since 1951. As per provisions of the Wildlife (Protection) Act, 1972, a part of the Bhitarkanika extending over 672 km2 in Chandbali Wildlife Division has been declared as a Sanctuary in 1975 for the protection of the saltwater crocodile population and later an area of 145 km2 of pristine mangrove forests was upgraded as a National Park in 1998. The Gahirmatha Marine (Wildlife) Sanctuary, an area of1435 km2 has been designated as a marine sanctuary in the year 1997.

BCA is surrounded by thickly populated and agriculturally prosperous alluvial flat land. Within the Sanctuary, there are 307 villages and hamlets replacing mangrove habitats to paddy fields and aquaculture farms. However, over two and half decades of successful conservation measures has resulted in a dramatic increase in the crocodile population and decreased mortality of nesting Olive Ridley Turtles.

Comparaison avec d’autres biens similaires

Mangroves are distributed in the tropical and sub-tropical zones between the Tropic of Cancer and Tropic of Capricorn with the Malaysian and Indonesian region supporting the most diverse of mangrove communities. Mangroves derive their physical, chemical and biological characteristics from the sea as well as from inflowing freshwater from the upland forests. Once occupying 75% of tropical coastsand inlets, mangroves today, are restricted to very few pockets. Among the two mangrove distribution zones recognized, the eastern zone (East African coast,Pakistan, India, Myanmar, Malaysia, Thailand Philippines, southern Japan, Australia, New Zealand, south eastern Archipelago) harbours a greater percentage of genera and species as compared to the western zone (Atlantic coast of Africa and America and Galapagos islands).

Around 70% of mangroves occur along the east coast of India and they include i) Ganga delta (Sunderbans), ii) Mahanadi delta (Bhitarkanika), iii) Krishna delta, iv) Godavari delta and v) Cauvery delta (Badola and Hussain 2003).

The Bhitarkanika mangrove ecosystem, the second largest mangrove forest of mainland India, harbours the highest diversity of Indian mangrove flora, the larges trookery of the olive ridley sea- turtles in the world, the last of the three remaining population of salt-water crocodiles in India, the largest known population of king cobra, water monitor lizard, one of the largest heronry along the Indian east coast, one of the highest concentration of migratory water fowl (Badola and Hussain 2003). The largest diversity of estuarine and mangrove obligate fisheries resource andprawns is found in BCA. The mangrove and the associated forests provide the subsistence requirement of timber, fuel wood, tannin, honey, thatch roof and fodder for local communities (Chadah and Kar 1999). Thus, in comparison to other similar mangrove habitats, BCA supports a wider range of flora and fauna and plays a greater ecological and economic role and is therefore of greater conservation value compared to other similar properties.