In addition to this, the flora and fauna in Tripura also has a close affinity with Ethiopian and Palaearctic Zoogeographical Regions. A total of 34 (thirty four) Conservation Hot Spots (CHS) have been identified across the state representing Biodiversity Values, Taxa-based Values, Socio-economic Values, and Conservation Feasibility Values (Gupta 2000). Studies have revealed presence of 90 land-mammal species from 65 Genera and 10 Orders, 7 species (46.7% of total Indian primate species), 342 species of Ornithofauna, 14 (fourteen) species of fish,21 species of aquatic terrapines and soft-shelled turtles, 379 species of trees, 320 shrubs, 581 herbs, 165 climbers, 16 climbing shrubs, 35 ferns, 45 epiphytes and 4 parasites, 24 species of orchids, 266 species of medicinal plants (68 trees, 39 shrubs, 71 herbs and 88 climbers)& 19 species of bamboo. The state has a unique distinction of having more biodiversity outside notified six protected areas (4 sanctuaries and 2 national parks). The social, cultural, economic and traditional uniqueness in the State, being intimately entwined with biodiversity, present an uncompromising mandate of its conservation for saving our own culture and life.
The physiography of the entire state can be divided into three distinct physiographic zones, namely, Hill Ranges, Highland & Plateau, and Alluvial Valleys. The Hill Ranges Zone includes five major hill ranges with North-South orientation, each separated by narrow valleys (20 kms). The Highland and Plateau zone forms the western limit of the hilly region. The plateau gradually rises from West to East with an elevation ranging from 3m to 37 meters and finally merges with the eastern hilly tract. This zone is dissected by valleys, streams and gullies and is severely eroded. The Alluvial Valleys are below 7 meters in height above mean sea level. Low lands interspersed by hillocks and swamps are locally called `loongas’.
The state has typical warm and humid tropical climate with four distinct seasons, i.e. winter (December to February), summers (March to May), South West monsoon (June to September) and post monsoon (October to November). The average rainfall is 2100 mm. (82.7”). Mean maximum temperature is 10.4oC. Humidity is generally high throughout the year ranging from 70% to 80%. Tripura has diverse ecosystems ranging from forests and grasslands to freshwater wetlands. There are six types of 408 wetlands, of which, water logged (seasonal) are most numerous followed by oxbow lakes and lakes/ponds. The State has 10 major rivers running over a total length of 903 km across the State. All these rivers have watershed/catchments areas of over 9400 ha covering 6 major hill range.
A total of 30 (thirty) Conservation Hot Spots (CHS) were identified and assessed based on their performance against four major Values, namely, Biodiversity Values, Taxa-based Values, Socio-economic Values, and Conservation Feasibility Values (Gupta 2000). All CHS were further assessed for their ranking based on their score-types for each of the Sub-values under above mentioned 4 major Values, of these 30 CHS, 11 are from South District, 5 from West District, 6 from Dhalai District, and remaining 8 from North District.The area of hot spots ranged between 2 to 15 km2, majority of these CHS (22) were above 10 km2 in size.
BIODIVERSITY
Faunal Biodiversity
Sterndale provides the first scientific report about the wildlife species in Tripura, and in his book entitled Mammalia of India’, has described the presence of Javan rhinoceros, capped langurs, brush tailed porcupines, Tipperah langurs, etc. Stray records are, however, available on mammalian fauna in Tipperah (the old name of Tripura) from the reports of various travellers of British period. Rajamala, the famous literary work on Tripura Kingdom, mentions the abundance of different species of wild mammals all over the state such as rhinoceros, tigers, wild dogs, wild goats, slow loris, etc.
The updated list describes presence of 90 land-mammal species from 65 Genera and 10 Orders, which make up for about 19%, 48% and 100% of total land-mammal species, genera, and orders, respectively, in India. Main extant land-mammal species include Elephant (Elephas maximus), Bear (Melursus ursinus), Binturong (Arctitis binturong), Wild Dog (Cuon alphinus), Porcupine (Artherurus assamensis), Barking Deer (Muntiacus muntajak), Sambar (Cervus unicolor), Wild Boar (Sus scrofa), Gaur (Bos gaurus), Leopard (Panthera pardus), Clouded Leopard (Neofelis nebulosa), and many species of small Cats and Primates. Mustelids, viverids and herpestids also exist in rich diversity. Tripura has amazingly high density of primates all over the State, including some highly endangered species. Presence of 7 species (46.7% of total Indian primate species) in Tripura makes it highest recording in any one Indian State..
Ornithofauna comprises 342 reported species in the State, of which about 58 are migratory species one near threatened species – the darter. There is high diversity of birds of prey, frugivorous birds, marsh birds and flower peckers. In the aquatic ecosystem 14 (fourteen) species of fish have been recorded, of which 2 are endangered (Anguillabengalensis and Psuedeatroptusalterinoides) and 12 vulnerable. Due to silting of river-beds and filling up of wetlands, different species of marsh birds and fishes are on decline.
Definite information on various reptilian and amphibian species and their population status is also not known in Tripura. Based on the available habitat conditions, however, it can safely be concluded that Tripura must be rich in those. This is very well reflected in presence of 21 species of aquatic terrapines and soft-shelled turtles [including 7 endangered species according to Wildlife (Protection) Act, 1972], and other endangered poisonous (pit viper, viper, krait, cobra, etc.) and non-poisonous (python) snakes. Among the amphibian fauna noticeable are the skipping frog, Indian Bull frog, tree frog, toad, etc. Heteropneustes fossillis (singhis), Cirrhina mrigala (Mrigal), Pautius sophole (Ptui), Labeo rohita (rohu), Catla catla (Katal), Kal, Maka, carps, Durkina, etc. are the major fish fauna in the State.
Of the total 65 genera and 90 species of mammalian fauna in the State, about 14 genera and 18 species are included in Schedule I of Wildlife (Protection) Amendment Act, 2002 as highly `endangered’ species. Similarly, 10 genera and 14 species are included in the Appendix I of CITES (Convention in International Trade in Endangered Species of Flora and Fauna). Three land mammal species, namely, tiger (Panthera tigris), rhinoceros (Rhinoceros unicornis), and wild buffalo (Bubalus bubalis) have already become extinct from Tripura.
A total of 379 species of trees, 320 shrubs, 581 herbs, 165 climbers, 16 climbing shrubs, 35 ferns, 45 epiphytes and 4 parasites (Total 1,545 taxa) have been recorded from Tripura, of which 50 plants species are restricted to Tripura and its neighbouring States. Of these, 7 are endemic and 18 are rare plants. Angiopteris evecta, a fern and Gnetum montanum, a giant climber belonging to Gymnosperm are two rare species but occur profusely in Trishna Sanctuary. Tree ferns (Cyathia spp.), which are also primitive and endangered, are found in South Tripura. There are 24 species of orchids, of which, Dendrobium has the highest species diversity (14 species). Endangered orchids like Blue vanda (Vanda caerulea) and Red vanda (Renunthera imschootiana) are found in the state. There are 266 species of medicinal plants in the State (68 trees, 39 shrubs, 71 herbs and 88 climbers). Maximum value of Plant-Diversity Index (Shannon-Weiner) reported is 5.23, which generally ranges from 3-4, indicating presence of a variety of species uniformly. A total of 19 species of bamboo are reported in the state, which includes Barak (Bambusa balcooa), Bari (Bambusa polymorpha), Mritinga (Bambusa tulda), Muli (Melocanna baccifera), Kai (Bambusa nutans), Paora (Bambusa teres), Rupai (Dendrocalamus longispathus), Dolu (Neohuzeaua dullooa), Makal (Bambusa pallida), Pecha (Dendrocalamus hamiltonii), Kailyai (Oxytenanthera nigrociliata), Kanak kaich (Bambusa offinis), etc.
Following is the current status of the protected area network in the State:
