The biological diversity of any geographical region is estimated at the level of ecosystem diversity, species diversity and genetic diversity. Tripura being a part of North-East India, belongs to one of the two “Hot Spot” of India amongst 18 identified in the World. Hot Spots are designated on the basis of evidences of present day distribution, diversity and linkages of crop plants/ horticultural plants, with the past; Hot Spots are the original homeland for evolution and distribution of such plants.

At the ecosystem level, the State exhibits a part of Mountain ecosystem with moderate hill ranges and forest ecosystem. In between these two dominant ecosystems lies the freshwater ecosystem comprising 10 major rivers, numerous wetlands. Undulating high lands of narrow and broken plates cover extensive areas (Deb, 1975)

The diversity at the species level is largely determined by ecosystem diversity, which in turn is closely, linked with soil and climatic condition. The species diversity of Tripura is largely known from Floral and Faunal diversity studies.

 7.1 Floral Diversity

The range of floral diversity for a small state like Tripura appears significant from the fact the nearly 1463 of the 17,000 species or 8.6% Angiosperms (Flowering plants) known from India is recorded in Tripura (0.3% land of India). A total of 1546 species other than Bacteria, Fungi, Mosses, etc.) belonging to 862 genera and 192 families of Flora have been recorded (Deb, 1981, 1983) of which 86% are widely distributed in India and adjoining countries (Table-36).

Table-36: Flora of Tripura

 

Sl. No.	Plant Group		Families	Genera	Species
1.	Angiosperms		168	816	1463
	A.	Dicot	139	637	1160
	B.	Monocot	29	179	303
2.	Gymnosperm		6	8	13
3.	Pterodophytes		18	38	70
	Total		192	862	1546

[Source : Deb, 1981 & 1985]

It is also interesting to note that the ratio of Monocot : Dicot species for Tripura is much higher than for India (1:2.3 vis-à-vis 1:3.82).

Phytogeagraphically, Tripura belongs to the sub-zone Northern Burma (Hooker, 1909) which includes Mizoram, Chittagounj Hills in Bangladesh and Arakan in Myanmar, besides Andaman Islands. While a strong affinity with flora of Eastern Himalaya can be noted, absence of Alpine flora of Abies, Jumperus, Larix, Picia and Tsuga is conspicuous; this can be attributed to climatic and altitudinal differences which are conducive for such floral growth. On the other hand, a palm species in Nepal and Sikkim is also recorded in Hilly terrain of Tripura.

Within the State, flora of northern region shows close affinity with adjacent Barak valley flora of Assam and Sylhet area of Bangladesh. Of the other areas, Sabrum region specially shows close affinity with flora of Chittagong district of Bangladesh (Deb….).

7.1.1 Endemism

The Eastern Himalaya region is well known for high percentage of endemism in flora and fauna. The State of Tripura, however, does not exhibit any distinctive trait. Deb (…) opined that due to absence of scientific exploration in the State in earlier period, many new taxa, which have wider distribution into Tripura, were described from the adjoining regions. As such, no significant endemicity in flora of Tripura could be noted.

 

7.1.2 Rare and Endangered Flora

The Indian Wildlife (Protection) Act, 1972 amended till date include only six plant species while the Red Data Book on Indian Plants published by Botanical Survey of India contains data of more than 650 species considered rare and endangered. At least 15 of such species recorded from Tripura are known to be Rare or Threatened (Deb….). (Table-37).

 Table 37 : Rare and Threatened Taxa of Tripura

 

Sl. No.	Name of the Species	Family	Distribution
1.	Begonia surculigera	Beginiaceae	Unokoti
2.	Colona flagrocarpa	Tiliaceae	Sakhan, Tlangsang
3.	Ophiorrhiza viillosa	Rubiaceae	Kumarghat, sipaijala
4.	Torenia mucronulata	Scrophulariaceae	Ghorakappa
5.	Tournefortia roxburghii	Scrophulariaceae	Sabroom
6.	Jasminum listeri	Oleaceae	Jampui ranges
7.	Wallichia caryotoides	Arecaceae	Baramura and Atharamura ranges
8.	Cycas pectinata	Cycadaceae	Baramura range
9.	Podocarpus neriifolius	Podocarpaceae	Lalijuri
10.	Gnetum montanum	Gnetaceae	Teliamura
11.	Gnetum oblongum	Gnetaceae	Silachari
12.	Mangifera sylvatica	Anacardiaceae	Telimura and Ambasha
13.	Dischidia benghalensis	Asclepiadaceae	Tripura
14.	Dischidia nummularia	Asclepiadaceae	Tripura
15.	Dischidia major	Asclepiadaceae	Tripura

  7.1.3 Economic Botany

 

Deb (1975-1981) provided a detailed account of plants of economic uses. Such use pattern include manufacture of packing box (29 species), tea chest (14 species), plywood (30 species), musical instrument (13 species), match box (30 species), etc. A large number of species are used as timbers of both high and low value. A list of timber producing species of Tripura is given in Table-38.

Table-38 : Timber producing Flora in Tripura

 

Sl. No.	Scientific Name	Common Name
1.	Albizzia lucida	Silkoroi
2.	Albizzia procera	Safed Siris
3.	Artocarpus chaplasa	Sam
4.	Carrya arborea	Kumbhi
5.	Chukmsia velutina	Bogapoma
6.	Cinnamomum bejolghta	Tejpata
7.	Dillenia indica	Chalita
8.	Dillenia pentagyna	Akshi
9.	Dipterocarpus turbinatus	Kherjong
10.	Duanbanga gradiflora	Kokam
11.	Gmelina arborea	Gomari
12.	Lagerstroemia parsiflora	Sida
13.	Lagerstroemia speciosa	Ajur
14.	Magnolia pterocarpa	Thouthua
15.	Mesua ferrea	Nahor
16.	Michelia champaca	Titasopa
17.	Palaquium polyantha	-
18.	Shorea robusta	Sal
19.	Sterospermum personatum	Parolli
20.	Syzygium cuminis	Zamun
21.	Terminalia alata var. tomentosa	Asan
22.	Terminalia bellirica	Bairah
23.	Terminalia myriocarpa	Hollock
24.	Toona ciliata	-

Besides timber, the floral diversity of Tripura contributes significantly to the Bamboo and Cane furniture and craft industry. At least 13 different bamboo species and 6 cane species are known from the State (Table-39).

Table-39 : Bamboo and Cane Species from Tripura

 

Sl. No.	Scientific Name	Local Name
A.	Bamboo Species
1.	Bambusa affinis	Kanak-Kai
2.	Bambusa nutans	Kali bans
3.	Bambusa palida	Makal
4.	Bambusa polymorpha	Bari
5.	Bambusa teris	Purua
6.	Bambusa spp.	Jai/ Purua/ Bombans
7.	Dendrocalamus hamiltoni	Ponch bans
8.	Oxylanthum albouliata	Kalai
9.	Nedhoozca dulloa	Dolu
10.	Melocana bambusoides	Mul
B.	Cane Species
1.	Calamus ereetus	NA
2.	Calamus floribundus	NA
3.	Calamus garbna	Sundibet
4.	Calamus teotopathoides	NA
5.	Calamus viminalis	Pannabet
6.	Calamus tenuis	Chachibet

[Source: Nalini K. Chakrabarti, 2001 : Deb, op.cit]

An estimate shows that at least 27 plant species contribute towards Non-Timber Forest Produces (NTFP) including Tannin, Gum, Coloring material and others. The estimate mentions about 107 species of plants used for fodder, 60 species of plants for human food and at least 65 species providing fruits (Nalini Chakrabarti, Media article, Dainik Sambad, Agartala, 31^st January, 2001) While 628 species of plants from Tripura are reported to contribute towards herbal medicines. 129 species are recognized in Indian Pharmacopoeia; 61 of these species are recorded in Tripura, 26 as wild plants and 35 under cultivated ones in the garden. Of the total of 628 plants, following Chopra’s Glossary of Medicinal plants. 403 species grow in the wild while 225 species can be grown in the garden; of the wild ones 143 are rare. A list of 158 medicinal plants of Tripura with local names, parts used, occurrence, flowering and fruiting time is available in Deb (1968, 1975). Latter Forest Department of Tripura reported documentation and identification of around 266 species of medicinal plants (68 species trees, 38 species shrubs, 71 species of herbs and 81 species of climbers). A list of more important medicinal plants is given in Table-40.

 

Table-40 : List of Selected Medicinal Plants from Tripura

Sl. No.	Scientific Name	Family
1.	Andrographis paniculata	Acanthaceae
2.	Aquillaria malaceensis	Thymelaeaceae
3.	Asparagus reticulatus	Liliaceae
4.	Baeopa moniari	Scorphalariaceae
5.	Centella asiatica	Umbelliferae
6.	Hemidesmus indicus	Apocynaceae
7.	Holorrhea pubescens	Apocynaceae
8.	Hydrocarpus kurzi	Labiatae
9.	Justica adhatida	Acanthaceae
10.	Marsilea minuta	Acanthaceae
11.	Ocimum tenuifloram	Labiatae
12.	Phlogacanthus thyrsiflorus	Acanthaceae
13.	Rawlfia serpentina	Apocynaceae
14.	Saraca asoca	Fabaceae
15.	Terminalia belerica	Combretaceae
16.	Terminalia chebula	Combretaceae
17.	Vitex negabdo	Verbenaceae
18.	Vitex peduncularis	Verbenaceae

7.1.4 Agri-horticultural Diversity

North Eastern region occupies an important place with respect to agri-horticultural biodiversity. This region has a large varities of agricultural crops, viz., rice, maize, millets, beans and pulses, horticultural crops including fruits viz. guava, ber, jackfruit, mango, papaya, vegetable crops viz. brinjal, cucurbits, chillies, leafy vegetables, beans, colocasia and alocasia possessing a significant genetic resource base. The most common families of agri-horticultural species in Tripura and adjoining areas are given in Table-41.

 Table – 41 : Most common Families of Agri-horticultural Species

Sl. No.	Name of the Family	No. of Genera	No. of Species
1.	Papilionaceae	44	96 + var.
2.	Gramineae	49	79 + 1 var.
3.	Compositae	39	54
4.	Solanaceae	11	26 + 1 var.
5.	Cucurbitaceae	16	26 + 1 var.
6.	Malvaceae	10	25 + 1 var.
7.	Aracear	15	25 + 1 var.

North Eastern Region of India is well known as one of the 18 hotspot areas of the world for agricultural biodiversity. Tripura being a part of north-east India exhibit a rich varieties of rice germplasm which has been estimated to be 118 (Sadana, S., Dutta M. and Dhiman Kr. ICAR Research Complex for North East India, Tripura, personal communication). A total 119 cultivers of local rice varieties collected from different parts of Tripura were evaluated by the scientist of ICAR with reference to vigour, total number of grains, hundred gain weight and single plant yield, etc. In grain yield wide variation ranging from 0.18 to 22.68 gram was observed (single plant yield). These germplasm have been conserved in the gene bank of National Bureau of Plant Genetic Resources, New Delhi. No systematic programme for on-farm conservation is existent.

Plant Breeding Division of the Agriculture Department has collected and maintained a germplasm of 29 wild varieties of rice, 5 of small millet (Kaon), 5 of maize, 1 of cotton, 1 of sesame, 1 of arhar, 2 of moong, and 2 of black gram.

Among the beans and pulses, the region is quite rich and 10 species of beans have been recorded and huge bio-type variation have been collected within the species.

North Eastern Region is regarded as a secondary centre for maize (Zea maize) but 5 bio-types have been recorded in the Jhum areas of the state. Local biotypes of brinjal and chilies are rich in Tripura. The ICAR Centre has collected and catalouged 20 biotypes of brinjal and 16 biotypes of chilies.

Tripura and adjoining area of Bangladesh has 95-96 prominent vegetable species. Cucurbits have as many as 17 species with a large number of varieties. Sweet potato has two major types and within these types, 3-4 biotypes have been recorded.

Amaranth has six types in the state. Rhizotomatous crops belonging to family Araceae have 6 species and 20 biotypes. Dioscorcaceae has 5 species with 23 biotypes, which are generally found in upland and forest areas.

There are 5 types of seasamums, 3 types of cotton and 5-6 types jute and mesta lines native to Tripura.

The State is quite rich in fruits and spice crops also. There are 60 fruit crops cultivated in Tripura. The indigenous fruit crops have huge genetic variety, viz. banana with good number of biotypes, jackfruit with 28 variables. Other indigenous fruits included Amra, Guava, Ber, Gulapzam, Zamrul, Bael, Satkara, Taal, Totka, Gaab, Kamranga, Sharifa, Chafta, Jalpai, Karamcha, Dalim, Paniphal etc.

In the State there are 27 species of spices available but most of them are introduced other than chilies, zinger, cinnamon and turmeric; variability available is restricted within these species only.

7.2 Faunal Diversity

The faunal diversity of the State can be viewed from Aquatic and Terrestrial ecosystems. In the aquatic system, at least 129 species of fishes are recorded belonging to 32 families, and 11 order, the largest number of species being from the family Cyprinidae (49 species, including Rohu, Katla, Kalbasu, Puthi, Mahasheer, Chela, etc.). it has been recorded that the majority of the fishes are common to both Indo-Gangetic drainages and South East Asian fish fauna. The occurrence of some marine and estuarine fishes Pisodonophis boro, Tenualosa ilisha (Hilsa) (Hamilton), Nematolosa nasus (Bloch) and Johnius coitor (Hamilton) may be attributed with the riverine migration to Meghna and Gumti  system from Bay of Bengal. The fishes of the State include 11 vulnerable species three endangered species and three rare species (Table- 42). At 9 species endemic to India are recorded from Tripura (Barman, R.P, Pisces, Fauna of Tripura, Vol.–1,  Zoological Survey of India, In Press). The amphibian are represented by only two species while Reptiles are represented by 32 species including three species of freshwater turtles and tortoises and three species of water snakes. Besides the turtle aquatic snakes at least 13 species of lizards including two species of monitor lizards, Varanus bengalensis (Daudin) and Varanus salvator (Laurenti) are known from Tripura; both the species of varanus are endangered; at least 13 species of snakes other than the aquatic snakes are known from the State of which Python molurus molurus (Linnaeus), common Indian Python is an endangered species. (Sanyal, D.P., Dutta Gupta, B., and Gayen, N.C. Reptilia, Fauna of Tripura, Vol.-1, Zoological Survey of India, In, Press). No aquatic mammal has been recorded from the State.

Table-42 : Vulnerable, Endangered and Rare Fish fauna in the State

Sl. No.	Scientific Name
A.	Vulnerable Species
1.	Notopterus notopterus (Pallas)
2.	Cyprinion semiplotus (McClelland)
3.	Schismatorhynchus nukta (Sykes)
4.	Labeo pangusia (Hamilton)
5.	Chagunius chagunio (Hamilton)
6.	Bitia almorae Gray
7.	Rita rita (Hamilton)
8.	Aorichthys aor (Hamilton)
9.	Aorichthys seenghala (Sykes)
10.	Pangasius pangasius (Hamilton)
11.	Bagarius bagarius (Hamilton)
B.	Endangered Species
12.	Raiamas bola (Hamilton)
13.	Tor putitora (Hamilton)
14.	Tor tor (Hamilton)
C.	Rare Species
15.	Barilius nelsoni
16.	Puntius clavatus clavatus (Hamilton)
17.	Puntius  gelius (Hamilton)

The invertebrate fauna include 27 species of Protzoans, 30 species of Crustaceans, 10 species of Rotifers, two species of annelids, 14 species of insects (water beetles, bugs, Odonates, mosquitoes, etc.) and six species of Mollusca.

As such the freshwater ecosystem of the State harbour a rich biodiversity at different hierchial level including important food-species of fin fish and shell fish. Recent investigation reveal a number of fish species have become endangered including common species viz. Chana striatus, C. marulius, labeo bata, L. pangasia, L. dero, Mystus seengala, M. aor, Ompak pabda, O. bimaculatus, O. paba, Wallago autto, Natopterus chitala, Macroganthus aculeatus, Mastacembelus armatus, enentodon concila, Rita rita, Bagarius bagarius pangusius pangusius and Danio debario due to changing water quality and heavy silt load. Of all the species, Mahaseer, comprising of Tor tor and Tor putitora fish appear to be most endangered in the State.

Details of aquatic system (provided by Prof. B.K. Agarwala, Tripura University) are appended (Table-43). The total water resource area is given in Table-44.

Table-43 : Areas under land and water cover

 

1.	Total land area	10.49.169.00 hectares
2.	Total water area	22.924.58 hectares
3.	Total water area of biotic resources	20.492.59 hectares

 

Table- 44 : Aqua-bioresource Pattern                               

Sl. No.	Resource Types	Area (in hectares)
A.	Culturable resource	Water area	Biotic resource
2.	Ponds/Tanks	8850.90	7970.31
3.	Mini Barrages	4068.68	3658.28
B.	Partly culturable
1.	Gomoti River	4500.00	4000.00
2.	Natural lake (Rudrasagar)	240.00	130.00
C.	Capturable resource
1.	Rivers & Rivulets	5260.00	4734.00

7.2.1 Terrestrial Fauna

The terrestrial fauna of Tripura appears equally rich in terms of species diversity.

7.2.1.1 Mammalian Fauna

Mammalian fauna was reported to be composed 54 species (Bhattacharya, 1998) representing 9 orders. Forest Department, Government of Tripura (2000) recorded 90 mammalian species under 65 genera and 10 orders (Table-45). These represent more than 33% of the total mammalian fauna known from India. Of the 15 primate species known from India 7 species have been recorded from Tripura of which Phayre’s Leaf Monkey (locally known as “Chashma Banar”) is the most dominant species. Endangered species of primates, besides Leaf Monkey include Slow Loris, Stumped-tail Macaque, Pigtail Macaque and the only tail less ape, Hollock Gibbon. Some of the mammalian species like common Tree Shrew, Indian Bison, Chinese Pangolin is reported to be very rare, while the population of Hoolock Gibbon, Indian Elephant and Jackal are reported to be declining.

Population status (1989) of three mammalian species namely Leopard, Bison and Indian Elephant show as total of 39 Leopards, 92 Bisons and 162 Elephants. While Leopards and Elephants are recorded from North, South, West and Dhalai district, Bisons are only recorded from South district.

Table- 45 : Land Mammal Genera & Species of Tripura compared with India

S. No.	Order	General		Species
		India	Tripura	India	Tripura
1.	Insectivora	11	4	28	4
2.	Chiroptera	36	8	110	9
3.	Primates	6	4	15	8
4.	Pholidota	1	1	2	1
5.	Carnivora	33	20	55	31
6.	Proboscidae	1	1	1	1
7.	Perissodactyla	2	1	3	1
8.	Artiodactyla	20	9	32	10
9.	Lagomorpha	3	1	10	1
10.	Rodentia	43	15	101	24
	Total	156	64	357	90

 7.2.1.2 Avian Fauna

The avian fauna is composed of 341 species belonging to 51 families of which 77 species are winter visitors. It may be noted that Tripura with only 0.4 percent of the total geographical area of India exhibits more than 25% of the avian species diversity of the country. Of the avian species 4 species belong to Schedule I and 271 species belong to Schedule IV of the Indian Wildlife (Protection) Act, 1972, Amended till date.

7.2.1.3 Reptilian Fauna

The reptilian fauna of Tripura is composed of 32 species under 28 genera and 11 families. These include 3 species of turtles and tortoise, 13 species of lizards, and 15 species of snakes. At least three species of reptiles are listed as endangered under Indian Wildlife (Protection) Act., 1972. (Sanyal, D.P. et.al. Reptilia, Fauna of Tripura, Vol.-1, Zoological Survey of India, In Press)

7.3 Rare and Threatened Fauna

Table- 46 : Rare and Threatened Fauna of Tripura

Sl. No.	Common Name	Scientific Name	Schedule-I WL(P) Act	Appendix-I CITES
A.	Mammal
1.	Slow Loris	Nycticebus coucang	+	-
2.	Phayre’s Leaf Monkey	Presbytis phayrei	+	-
3.	Capped Langur	Presbytis pileatus	+	+
4.	Hoolock Gibbon	Hylobates hoolock	+	+
5.	Leopard	Panthera pardus	+	+
6.	Marbled Cat	Felis marmorata	+	+
7.	Leopard Cat	Felis bengalensis	+	+
8.	Golden Cat	Felis temmincki	+	+
9.	Common Otter	Lutra lutra	-	+
10.	Indian Elephant	Elephas maximus	+	+
11.	Indian Bison	Bos gaurus	-	+
12.	Chinese Pangolin	Manis pentadactyla	+	-

7.4 Domesticated Animal Species Diversity

No detail information on the breeds of domesticated animal is available. According  Dept. of Animal Resources Development, Govt. of Tripura, the population of indigenous breed of cattle, buffalo (Raing and Manipuri) pig, goat (Black Bengal), duck have been estimated during 1992 and 1997. An analysis of the data shows more than 25% decline in indigenous cattle population nearly 50% decline of indigenous buffalo population and pig population, nearly 40 decline of indigenous goat population and 30% decline in indigenous duck population between 1992 and 1997. This trend should cause serious concern and calls for an appropriate management strategy for conservation of genetic resources of domesticated animal species. A field based survey of breeds of domesticated animal should be of prime necessity to obtain the benchmark data before any management plan is conceived.

7.5 Biodiversity Conservation

The State Government has set up a total of 4 Sanctuaries covering 604 sq. km for in situ conservation. One more Sanctuary in Athramura hill range is proposed to be notified. It is to be noted that notification under 26(A) of Wildlife (Protection) Act, 1972 are yet to be issued for all the four sanctuaries, while there are already tremendous stress and man and animal conflict are reported to be rise. Details of the four sanctuaries are given in following Table-47.

 

Table – 47 : Sanctuaries in Tripura

Sl. No.	Name of the sanctuary	Area in Km2	Important flora and fauna found
1 .	Sepahijala Wildlife Sanctuary	18.540	Birds and primates. migratory birds in the winter
2.	Gumti Wildlife Sanctuary	389.540	Elephant, samber, barking deer, wild goats. serrow etc.
3.	Trishna Wildlife Sanctuary	194.710	Bison, leopard. barking deer, wild dog, capped languor, king cobra, spectacled monkey, slow lorries, etc.
4.	Roa Wildlife Sanctuary	0.860	Many species of birds and primates
	Total	603.650

 [Source: Forest Department, Govt. of Tripura, 2000]

With regard to ex situ conservation only one Zoological garden has been established in Sephalijila. The Zoo contains 408 animals belonging 46 different species of fauna. Captive breeding programmes of some selected species including Leopard cat, Spotted Dear and Primates have been initiated.

Under a centrally sponsored scheme on “non-timber forest produce including medicinal plants” more than 500 ha of plantation is being raised with trees having medicinal values, in degraded forest land. The species grown include Arjun, Bahera¸ Palas, Haritaki, Amla, Neem, etc.

7.6 Problems relating to Biodiversity Conservation

7.6.1 Habitat Destruction :

Change of land use due to conversion of forest for non forestry purposes specially to meet the demand of plantation crops and development activities cause serious concern for and degradation of wildlife habitat. No quantified data is available on annual or decadal basis for such conversion activities.

7.6.2 Grazing :

There is no pasture land in the state for livestock grazing. It is estimated that 60% of the livestock graze in the forest land. This far exceeds the carrying capacity of the forests and causes destruction of young growth of the forest and destruction of habitat for the wild animals.

7.6.3 Forest Fires

Forest fires are common and frequent in the state. It is now estimated that forest fire is common in 20 percent of the total forest area of Tripura. The major causes may be intentional burning of ground cover for grazing or for jhum cultivation. This led to complete wiping out the forest regeneration in some areas, (natural as well as artificial) and wildlife is severely damaged.

7.6.4 Shifting Cultivation

The slash and burn cultivation in the hill tribal areas has direct impact on biodiversity viz. destruction of wildlife and natural habitat, loss of natural forest and loss of ecological balance including destruction of feeding, breeding and roosting grounds.

7.6.5 Introduction of Exotic Species

Due to change in agricultural practices and emphasis in food security a number of plant species have been introduced in Tripura. It is estimated that 280 species of plant have been introduced in the state during the past period. The impact of such introduction has never been assessed but it may be assumed that in number of local indigenous varieties have become rare or have disappeared due to introduction of exotics.

7.6.6 IIIegal Hunting

The conservation of biodiversity depend on strict protective measures in the field condition besides, appropriate legal instrument. Due to disturbed geopolitical condition, it is apprehended that illegal hunting pressure has increased in many remote and isolated dense forest areas. In absence of lack of appropriate monitoring and surveillance mechanism, the human pressure on wildlife may continue to increase.