The Vegetation and Floristic Composition Along the Brahmaputra River and the Brahmaputra Valley, Assam, India

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THE VEGETATION AND FLORISTIC COMPOSITION ALONG THE BRAHMAPUTRA RIVER AND THE BRAHMAPUTRA VALLEY, ASSAM, INDIA

REPORT

Submitted by

Pranab Bujarbarua Department of Botany Handique Girls’ College, Guwahati

CONTENTS

Chapter 1: Introduction ………. 5

Chapter 2: Vegetation and Forest Type ………. 9

Chapter 3: Conspectus of the Flora of Brahmaputra Valley ………. 16 Chapter 4: Significance of the Flora ………. 21 Chapter 5: Utility of the Floristic Diversity ………. 22 Chapter 6: High Priority Taxa ………. 24 Chapter 7: Threats ………. 26 Chapter 8: Problems of Forest Management in the Brahmaputra Valley………. 29 Chapter 9: Discussion ………. 32 Bibliography ………. 37

List of Appendix:

Appendix I - Floristic diversity of the national parks of Assam 43

Appendix II - Floristic diversity of the Islands of Brahmaputra river 44

Appendix III - Floristic diversity of Assam worked out by different workers 45

Appendix IV - Comparisons of Evergreen species distributed in Brahmaputra and Barak valley 46

Appendix V - Endemic plant taxa of Assam 49

Appendix VI - List of primitive families and genera and representative 53 species in the Brahmaputra valley.

Appendix VII - Economically important plants of Brahmaputra valley 55

Appendix VIII - Wild relatives of cultivated plants found in the Brahmaputra 57 valley

Appendix IX - Rare, Threatened and Endangered Plant Taxa of Assam 59

Annexure

Annexure I - List of Orchids of the Brahmaputra valley 61

Photo Plates 1. Tree and Timber yielding plants 2. Economically important plants 3. Medicinal plants 4. Parasitic angiosperms 5. Orchids 6. Potential floricultural plants 7. Wild edible fruits 8. Other common plants 9. Invasive species 10. Gymnosperms and ferns

Acknowledgement

The report ‘The vegetation and floristic composition along the Brahmaputra river and the Brahmaputra valley, Assam, India’ has been submitted under the contract agreement between the undersigned and the Tetratech. I am deeply indebted to Dr. K.K. Dwivedi, CEO, AIFRERMIP and Mr. S. K. Choudhury, Officer in Charge, Tetratech, Guwahati and who have given me the opportunity to work under assignment. It gives me great pleasure to express my deep sense of gratitude to Dr. Dwivedi for his useful suggestions. I am also thankful to Dr. Udayan Borthakur, Co-ordinator of the project for his fruitful discussions and encouragement throughout the study.

I acknowledge the help and suggestions of the villagers of Mulai Kathoni, Jorhat, forest officials of Panidihing bird sanctuary, Garampani WLS and Mr. Joynal Abedin (Benu da) for his suggestions during my visit to Dibru-Saikhowa BR.

Last but not least my heartiest thanks to Dr. Jayanta Das for their fruitful suggestions. Some of the photographs used in the report are taken from Dr. A.K. Baishya, Dr. P.J. Bora, Dr. Bandana Nabis Das and Mrs. Prabhali Doley. I acknowledge their help in this regard.

Pranab Bujarbarua Assistant Professor Department of Botany Handique Girls’ College, Guwahati

Chapter 1

INTRODUCTION

Northeast India consisting of eight states of Assam, Arunachal Pradesh, Manipur, Meghalaya, Mizoram, Nagaland, Tripura and Sikkim comprising an area of about 2, 62, 179 Km2 is known for its rich biological and cultural diversity. Based on its physiography and biological composition, the region can broadly be categorized into the Eastern Himalaya, Northeast hills and Brahmaputra plains. Its unique location at the confluence of the Indo- Malayan, Indo-Chinese and Indian biogeographical regions coupled with its physiography has generated a profusion of habitats, which harbors diverse biota with high level of endemism. The region is part of Himalaya and Indo-Burma biodiversity hotspots, two of 34 such hotspots in the world (Mittermier, 2004). It is also home of over hundred ethnic communities and a large percentage of the population is dependent on traditional natural resource-based livelihoods. Northeast region is characterized by high rainfall and humidity. This along with varied altitudinal gradients influence the climate that ranges from tropical plains to temperate and alpine hills. These diverse climates supports almost all types of vegetation from cultivated plants to grasslands, meadows, marshes, swamps, scrubs, mixed deciduous and humid evergreen forest, temperate and even alpine vegetation.

Assam, one of the sister states of Northeast India is regarded as biogeographical gateway for much of India’s biological resources. Nestling between the eastern Himalayan foot hills and the Patkai and Barail ranges of hills, the state is one of the largest north eastern states of India. It is characterized by distinct habitats, landscape, broad valleys and hills. Though largely plain, the Barail range is mountainous. Both sides of this range are the Brahmaputra and Barak valleys. Situated between 24o2’- 27 o6’N latitude and 89o8’-96o E longitude, the political boundary of Assam extends to an area of 78,523 sq km of which total forest area is about 27,673 sq km that is about 35.28% of the total geographical area of the state (Forest Survey of India, 2011). This area excludes the unclassed state forest which is approximately 5865 sq. km. The occurrence of heterogenic physiography coupled with varied climatic conditions on and around the state has made the vegetation luxuriant and diverse that support unique flora and fauna. The variations in forest types and their vegetation composition in Assam occur mainly due to the range of climatic conditions and to certain extent due to local edaphic factors (Baishya, 1999). 5

The mighty river Brahmaputra traverse the state from east to west covering a distance of about 1300 km thereby separating the sub-himalayan region of Assam from the southern parts and forms the gorgeous Brahmaputra valley with an elevation of about 122m at Sadiya the eastern most and 30m at Dhubri the western most part of the valley. The uniqueness of Brahmaputra river system lies in its glacial origin, location in a highly seismic zone, heavy and intense rainfall resulting in flash flood, high sedimentation rate and an intricate link with the ecology of the beels (wetlands) in the plains.

Map 1: Map of Assam showing topographic feature & River Network (Source: Assam: National Disaster Risk Reduction Portal)

Brahmaputra valley being the largest plain in the northeast region and has a great significance not only for agriculture and industry of the region but also for its rich vegetation preserved in the various protected areas i.e. biosphere reserves, national parks and wildlife sanctuaries etc. There are 5 national parks, 20 wildlife sanctuaries and a number of reserve forests are present in this valley, of which two national parks viz. Manas and Dibrusaikhowa have also been categorised as biosphere reserves. The forest types are mostly tropical which harbours a rich pool of biodiversity.

The rich flora of the area has been the centre of attraction for various botanists since early 19th century which began with the famous Assam tea delegation comprising N. Wallich 6

(1820-1832), W. Griffith (1848), Robinson (1841) provided some floristic account of the region. Some of the earlier contributors to the flora of Assam are Carter (1921), Hooker et al (1872-1892), Kanjilal (1934-40), Bor (1940), etc. Baishya (1999) gave a detailed account of the florstics of Assam. Chowdhury (2005) compiled a detail account on the flora of Assam. More recently, Barooah and Ahmed (2014) made a comprehensive checklist of the angiosperms and gymnosperms of the state.

Flora of Assam by Kanjilal et al was the beginning of botanical studies by Indian Botanists. Subsequently, a number of Botanists contributed to the understanding the flora of the state (Rao & Verma 1969, Kar & Panigrahi 1963, Jain & Hajra 1975, Rao 1974, Islam 1990, Sarmah 1989 and Sas Biswas et al 1990). Many workers have attempted the floristic studies of different districts as well as the protected areas of the state (Gogoi 1976, Barua 1978, Hajra 1978, Sarmah 1989, Barua 1992, Sarkar 1993, Singh 1993, Nath & Choudhury 1994, Bora 1999, 2001, Barooah & Borthakur, 2003, Bujarbarua 2004, Begum, 2010, Begum et al., 2010, Nath, 2012, 2015 etc.). Bhagawati et al (2006) made an effort to prepare the biodiversity status of the state of Assam along with the strategy action plane for conservation.

Although the state has been well explored floristically, yet there are areas with ample scope of floristic study particularly protected areas of the state. Moreover, a detailed account of the flora of the present state of Assam is yet to be brought out. Considering the vastness and ecologically diverse area, there is plenty of scope to increase these numbers as many areas are still unexplored or underexplored. One such most important area of the state is the river bank vegetation. The river bank vegetation, ecologically termed as riparian is highly dynamic vegetation. River’s riparian zone acts as a bridge between terrestrial and aquatic habitat. These areas are represented by a particular type of vegetation that grows along the sides of rivers under the influence of a waterway, such as rivulet banks or riverbanks. Riparian i.e. river bank vegetation at a particular location and time results from interactions between the physical conditions created by geomorphic and hydrologic processes in the stream channel and responses by the plants (La Fayette & DeBano, 1990). The present report is being prepared with an aim to work out the

- vegetation types and flora along the course of the river Brahmaputra river. - documentation agro biodiversity, invasive species, grassland habitats, plants of economic and other uses in the areas along the Brahmaputra river, and - screening of the rare, threatened, endangered as well as the endemic taxa.

Work plan: The study was primarily based on the literature survey. Moreover, field visits to the various locations in the protected areas along the river Brahmaputra and other riparian locations along the river was also conducted to validate the secondary data.

1st Month 2nd Month 3rd Month Sl no. Component 1 2 3 4 1 2 3 4 1 2 3 4 Literature 1 Survey Field Visit 2

Data 3 compilation Report 4 Preparation

Chapter 2

VEGETATION AND FOREST TYPE

The geographical areas of the state lies in the transitional zone of Indo-Malayan and Indo-Chinese and India, along with two migratory route of birds - the Central Asian flyway and East Asian-Australian flyway which enriches floristic and faunal composition of the region (Islam & Rahmani, 2004). The major types of plant communities found in the state can be grouped under Moist Evergreen Forest, Moist Semi-Evergreen, Moist and Dry Deciduous forest, Hydrophytes in vast stretches of wetlands (riparian belts, swamps and marshes), Bamboo brakes, Scrubland and Grass land (both wet and dry). The forest types of northeast India including the state of Assam have already been described by Champion and Seth (2005). The state of Assam falls in the tropical climate belt in the northeastern region of India (Srivastava et al. 2002) and maximum forest area of the state included under tropical moist deciduous type (Agarwala 1990). In general the vegetation of Assam is primarily tropical type that covers large areas and embraces evergreen, semi evergreen, deciduous forests and grass lands. Stretches of riparian forest along the bank of rivers are also very prominent. The variations in forest types and their vegetation composition in Assam occur mainly due to the varied physiographic, edaphic conditions and range of climate. As there are not much altitudinal variations in the plains particularly in the Brahmaputra valley, it has little significance in determining the forest types of Brahmaputra valley.

It may be mentioned here that majority of the protected areas of the state are situated at the Brahmaputra valley and most of these are either well explored or under explored floristically. It is thus obvious that the vegetation and forest types of these protected areas have already been worked out. From all such available sources and personal observation, the vegetation and forest type along the Brahmaputra river in Assam may be considered as tropical moist evergreen, tropical semi evergreen, moist deciduous forest, Grass land and savannah, wetlands and swamps, riparian forest and degraded lands. A brief account of these forests given as follows -

2.1. Tropical Moist Evergreen Forests: The moist evergreen forests is characterised by the stratification of the plants into different storeys. These type of forests are prevalent in specific areas of upper Assam in the districts of Tinsukia, Dibrugarh, Sibsagar, Jorhat and in few places of Dhemaji and Lakhimpur. Luxuriant and gregarious growth of broad leaved lofty tree species of angiosperms along with a number of tree ferns, epiphytes including orchids are the characteristic features of these forests. Although it is difficult to demarcate easily various storeys in these forests, but a few tall trees along with some medium sized form the canopy and merge with large shrubs intermingle with climbers and dense undergrowth of low shrubs and herbs (Chowdhury, 2005). Rowntree (1954) termed these forests as Dipterocarpus – Mesua formation.

The giant Dipterocarpus retusus attaining a height of over 40m is the most prominent species in the top storey. The associated species are Alianthus grandis, Altingia excels, Artocarpus chama, Artocarpus lakoocha, Cinnamomum bejolghota, Mesua ferrea, Michelia champaca, Phoebe cooperiana, Shorea assamica, Tetremeles nudiflora etc.

The common species composed of middle storey are Actonodaphne angustifolia, A. obovata, Aglaia hiernii, Antidesma bunius, Aquilaria malaccensis, Baccaurea ramiflora, Beilschmiedia brandisii, Callicarpa arborea, Canarium strictum, Castanopsis indica, Chukrasia tabularis, Cinnamomum glanduliferum, Cryptocarya floribunda, Dillenia indica, Diospyros variegate, Dysoxylum procerum, Elaeocarpus sp, Engelhardtia spicata, Evodia meliaefolia, Ficus benjamina, Flacourtia jangomas, Garcinia acuminate, Garcinia kydia, G. xanthochymus, Gynocardia odorata, Litsea monopetala, L. glutinosa, Macaranga denticulate, Magnolia griffithii, Magnolia hodgsonii, Mesua ferrea, Mesua assamica (Kayea assamica), Michelia baillonii, Olax acuminate, Persea bombycina, Phoebe goalparensis, Quercus milroyii, Sapium baccatum, Sterculia guttata Symplocos ferruginea, Syzygium cumini, Terminalia myriocarpa, Vatica lancaefolia. etc.

The lower storey is often found in association of sparsely distributed species viz. Alangium chinensis, Aphanomixis polystachya, Camellia caudata, Croton roxburghii, Dillenia indica, Dysoxylum binectariferum, Litsea assamica, Litsea salicifolia, Mallotus philippinensis, Saurauia panduana, Symplocos ferruginea, Syzygium oblatum, Turpinia nepalensis, Zanthoxylum rhetsa, etc. 10

The common shrubs in these forests are Actephila excels, Antidesma acidum, Antidesma acuminatum, Ardisia paniculatum, Boehmaria malabarica, Brassiopsis glomerulata, Callicarpa longifolia, Chloranthus officinalis, Dendrocnide, sinuata, Euonymus attenuates, Glochidion assamicum, Morinda angustifolia, Wendlandia tinctoria, etc.

The lianas, vines and stragglers often show gregarious growth mingled with the species of plants in the storeys associated with a number of shrubs. The common species found are – Clematis acuminata, Celastrus monosperma, Cryptolepis sinensis, Desmos cochinchinensis, Dioscorea esculenta, Erythropalum scandens, Fissistigma bicolour, Gnetum montanum, Hoya acuminata, Jasminum nervosum, Naravelia zeylanica, Tetrastigma dubium, Tetracera indica, etc. Apart from these a number of climbers developed terrestrial but become epiphytic on trees and shrubs or creeping in nature. The common species are Piper peepuloides, P. sylvaticum, Pothos cathcartii, Raphidophora sp. etc.

2.2. Tropical Semi-evergreen forests:

Semi-evergreen forests are mainly confined to along the north and south banks of river Brahmaputra; Bura-pahar and the projection of Karbi-Anglong towards Brahmaputra (Chowdhury, 2005). This forest is mainly dominated by medium or short trees where large numbers of shrubs are entangled by lianas and stragglers. Ground vehetation is occupied by bulbous, rhizomatus plants scattered in association with herbaceous angiosperms; ferns and fern allies. Moreover, these forests are adorned with luxuriant growth of several epiphytic plants primarily orchids and ferns. Besides, large bamboo and cane thickets are found along the edges of forests and in degraded forest as secondary growth. The common species found in the forests are Actinodaphne obovata, Aesculs assamica, Albizia procera, Anthocephalus chinensis, Antidesma bunius, Aphanomixis polystachya, Artocarpus chama, Baccaurea ramiflora, Beilschmiedia fagifolia, Bauhinia purpurea, Bischofia javanica, Bridelia retusa, Castanopsis armata, Cinnamomum bejolghota, Duabanga grandiflora, Dysoxylum binectariferum, Elaeocarpus floribunda, E. sphaericus, Engelhardtia spicata, Gmelina arborea, Lagerstroemia parviflora, Litsea glutinosa, L. monopetala, L. salicifolia, Macaranga denticulate, Talauma hodgsonii, Mallotus ferrugineus, Mangifera sylvatica, Michelia champaca, Persea villosa, Stereospermum personatum, Syzygium cumini, S. oblatum, Tamarindus indica, Terminalia chebula, Terminalia myriocarpa, Trewia nudiflora, Toona ciliate, Vatical lancaefolia, Wendlandia grandis, etc. 11

Shrubby species in these forests composed of mainly Antidesma roxburghii, Chloranthus elatior, Euonymus attenuates, Ficus subulata, Glochidion assamicum, Grewia denticulata, Mussaenda roxburghii, Mycetia longifolia, Psychotria Montana, Randia spinosa, Rhamnus nepalensis, Saprosma ternatum, Solanum torvum, Vitex trifolia, Zizyphus mauritiana, etc.

The common species among the lianas, stragglers and vines are Ampelocissus barbata, Argyreia roxburghii, Bauhinia vahlii, Cissus rependa, Derris ferrginea, Dioscorea bulbifera, Entada pursaetha, Erythropalum scandens, Merremia umbellata, Naravelia zeylanica, Paederia foetida, Pothos scandens, Rhaphidophora decursiva, Rubia cordifolia, Smilax ochreata, Vitis planicaulis andexotic climber Mikania micrantha.

The under growth composed of several annual and perennial herbs viz. Ageratum conyzoides, Alocasia odora, Biophytum sensitivum, Begonia palmata, Coffea benghalensis, Crotalaria pallid, Curculigo orchioides, Elatostema integrifolia, Flemingia lineata, Globba clarkei, Impatiens tripetala, Justicia adhatoda, Justicia japonica, Leea aequata, Mollugo pentaphylla, Ophiorrhiza mungos, Panicum auritum, Phlogacanthus curviflorus, Polygonum auriculatum, Saccharum ravennae, Sida rhombifolia, Solanum nigrum, Spilanthes paniculata, Stachytarpheta jamaicensis, Synedrella nodiflora, Thysanolaena maxima, Urena lobata, Vernonia cinerea, etc. along with ground orchids Arundina graminifolia, Calanthe angusta, Geodorum densiflorum, Goodyera procera, Tainia latifolia, etc.

2.3. Moist Deciduous forest:

The moist deciduous forest may be categorised into Shorea (Sal) forest and mixed moist deciduous forest. The large parts of the lower Brahmaputra valley particularly in districts of Nagaon, Morigaon; in alluvial plains of south and north Kamrup, Darrang, Sonitpur, parts of Nalbari, Barpeta, Dhubri, heavy alluvial plains of Kokrajhar, Bhabor and Terai regions of Kokrajhar and Goalpara districts and parts of Karbi Anglong and Dima Hasao are covered with Sal forest. Rowntree (1954) described these Sal forest under Shorea- Schima-Lagerstroemis association while Bor (1938) named Shorea-Schima-Stereospermum formation. The most conspicuous naturally growing Shorea robusta in moist Sal forest is found near Chandubi in Kamrup district and also in the district of Dhubri, Kokrajhar, Goalpara and some parts of Kamrup district.

The mixed moist deciduous type of forest occupies a large area in both Brahmaputra and Barak valleys at the foot hills of Lakhimpur, Dhemaji, Karbi-Anglong and Dima Hasao districts. Tree species particularly Adina cordifolia, Albizia procera, Artocarpus chama, Beilschmiedia fagifolia, Bridelia retusa, Butea monosperma, Callicarpa arborea, Careya arborea, Caryota urens, Dalbergia ssissoo, Duabanga grandiflora, Dysoxylum binectariferum, Engelhardtia spicata, Ficus benjamina, Hydnocarpus kurzii, Garcinia paniculata, Garuga pinnata, Gmelina arborea, etc. occupy the upper storey.

The predominant species in the lower storey of these forests are Actephila excels, Antidesma acidum, A. bunius, Bauhinia acuminata, Bischofia javanica, Buddleia asiatica, Caesalpinia bonduc, Cinnamomum bejolghota, Litsea salicifolia, Premna benghalensis, Rhus semialata, Wrightia tomentosa etc. Dendrocalamus hamiltonii, D. strictus, Melocanna baccifera are common species of bamboo found in these forests.

2.4. Riverine forest:

River bank vegetation, ecologically termed as riparian is highly dynamic vegetation. River’s riparian zone acts as a bridge between terrestrial and aquatic habitat. These areas are represented by a particular type of vegetation that grows all over the evergreen and semi evergreen zones of the state along the sides of rivers under the influence of a waterway, such as rivulet banks or riverbanks. Generally in this type of forests commonly found tree species are Dillenia indica, Anthocephalus indicus, Semecarpus anacardium, Albizia lebbek, Dalbergia stipulacea, Bischofia javanica, Duabanga grandiflora, Lagerstroemia speciosus and Bombax ceiba. The middle storey of these forests are generally occupied by Altingia excels, Albizia lucida, Artocarpus lakoocha, Alstonia scholaris, Cedrela toona, Dalbergia assamica, Pterospermum acerifolium. Species viz. Alpinia nigra, Ammomum aromaticum, Lasia spinosa, Typha elephantina, Carex breviculmis, Zingiber zerumbet, etc. are commonly found to cover the ground vegetation of this type of forest.

The annual flood submerges these forests by several centimetres every year leaving the new alluvium and successive deposits of silts. These are first covered by the seedlings of Tamarix, Salicornea which soon establish themselves in a dense form either in pure formation or mixed with different grassy species. Moreover, in several places particularly in Majuli and adjoining areas riverine areas composed of some hydrophilous herbs and sedges

13 viz. Ranunculus scleratus, Anagallis arvensis, Cotula hemispherica, Ammannia baccifera, Grangea maderaspatana, Gnaphalium luteoalbum, Polygonum chinense, Cyperus rotundus, Fimbristylis dichotoma, Fimbristylis ovata, Scirpus articulates, etc.

2.5. Grassland and Savannahs:

This type of forest is one of the important components of the alluvial flood plains of Brahmaputra valley as extensive areas of the state are dominated by grassland and savannahs. This biome is primarily conspicuous in Kaziranga and Oranag national park, Manas and Dibrusaikhowa biosphere reserves and wildlife sanctuaries viz. Sonai-Rupai, Laokhoa, Pabitora, Barnadi, Bura Chapori etc. Generally the grassland vegetation of the state can be differentiated into grasslands in recent alluvial deposits in low lying and char areas annually inundated and flood water retained for a considerable period of time and grasslands in old alluvium deposits of high land. Flood water scarcely reaches but the soil remains moist only during rains where both pure grassland and savannah ecosystem occur (Chowdhury, 2005).

Here tree species viz. Careya arborea, Bombax ceiba, Sterculia villosa, Lagerstroemia parviflora, Dalbergia sissoo, Gmelina arbore, Premna bengalensis, etc. are scattered along with grasses. The dominant grasses in wet alluvial grasslands are Apluda mutica, Phragmatis karka, Sclerostachya fusca, Saccharum arundinaceum, S. procerum, S. ravennae, S. spontataneum, etc. These species show luxuriant growth at the advent of rainy season, often attain a height of over 5m and can withstand flood water. Other species of grasses occur in these areas include Arundo donax, Arundinella pumila, Carex breviculmis, Eleusine indica, Imperata cylindrica, Paspelidium flavidum, Paspalum conjugatum, etc.

2.6. Wetlands and swamps:

The mighty river Brahmaputra with its tributaries flows along the entire length of Assam through a distance of 760 km. Extensive flood plains of Brahmaputra annually inundated large patches of marshy depressions and swamps, perennial water reservoirs locally called beels and community ponds. Almost all the national parks, biosphere reserves, wildlife sanctuaries of the valley encompass vast patches of wetlands. The plants growing in wetlands are usually termed as hydrophytes. Members of the families like Araceae, Cyperaceae, Eriocaulaceae, Lemnaceae, Nymphaeaceae are common in these ecosystems. 14

The growth and development of hydrophytes vary according to their habitats. Therefore the hydrophytic vegetation of the valley is unique in terms of its floristic elements and will e dealt separately elsewhere.

2.7. Degraded forest:

The impact and interference of both biotic and abiotic factors on the forest has resulted in the formation of degraded forest in the state and the Brahmaputra valley is not an exception to this. About 45% of the reserve forests are gradually depleted. The commonly found plant species in these forests are Oroxylum indicum, Duabanga grandiflora, Bombax ceiba, Saurauia nepaulensis, S. roxburghii, Croton roxburghii, Macaranga denticulata, Eurya acuminata, Maesa indica, Clerodendrom viscosum, Callicarpa arborea, Rubus rugosus, Eriobotrya benghalensis, Mikania micrantha, Ageratum conyzoides, Saccharum spontaneum, Urena lobata, Solanum torvum, Leucas plukenetii, Zizyphus mauritiana, Schizostachyum polymorphum, Lantana camara, Imperata cylindrica, etc.

Chapter 3

CONSPECTUS OF THE FLORA OF BRAHMAPUTRA VALLEY

The flora of the state of Assam is rich both in terms of diversity and luxuriance. As stated earlier that lot of floristic studies have been made in the state right from 18th century till date leading to the addition of the data on the floristics of the state. Moreover, the protected areas situated along the riverine areas of the state particularly Dibrusaikhowa BR, Kaziranga NP, Oranag NP, Pabitora WLS, Laokhowa WLS along with other protected areas of the Brahmaputra valley have already been explored floristically. A list of flora of the 5 national parks of the valley is given in the Appendix I. The floristic composition of Majuli, the greatest river island of the Brahmaputra and that of Umananda has also been studied (Appendix II).

1000 882 900 800 700 580 591 600 560 471 500 450 Family 372 377 400 322 300 233 Genera Number of the taxon the of Number 200 159 95 111 108 115 100 Species 0 Nameri NP Rajib Gandhi Manas NP & BR Dibru-Saikhowa NP Kaziranga NP (Orang) NP & BR

National Parks

Fig. 1: Comparative account of the flora of the national parks of the Brahmaputra valley

As per conventional estimates the state flora comprise of 3017 species (Baishya 1999). Chowdhury (2005) gave an account of the 4273 species of comprising infra-specific taxa comprising of 1448 genera distributed in 272 families of vascular plants of Assam. These include fern allies, ferns gymnosperms and angiosperms. More recently Barooah and Ahmed (2014) compiled a detailed checklist of Angiosperms and Gymnosperms of the state by listing 3854 taxa (including infra-specific taxa) under 1394 genera and 236 families. Out of which, 2752 taxa are dicotyledons, 1080 taxa are monocotyledons and 22 taxa are

16 gymnosperms (Appendix III). The flora of Assam represents 18% of the Indian flora. However, the figures are provisional as still many areas are underexplored and constant changes are taking place in the flora due to human interference, biotic pressure and other ecological factors. As far as the habit is concerned, the percentage of tree in the flora is only 20% while the herbs occupy the highest 47% of the flora of the state.

Fig. 2: Percentage of Angiosperms of Assam in the Indian flora

India Assam 82% 18%

Fig. 3: Percentage of Angiosperms of Assam in the world India Assam 5% 1%

World 94%

Looking at the details of the floristic composition of the two valleys of the state it is observed that the floristic diversity of Brahmaputra valley is much rich than the Barak valley as over 90% of the total flora of the state have been reported from Brahmaputra valley. According to Das (1942), Brahmaputra valley harbours more of Giant and diverse tree species than in the Barak valley (Appendix IV).The difference in the floral compositions of the two valleys are readily apparent with the localised elements not found any were else in the state.

Chapter 4

SIGNIFICANCE OF THE FLORA

Vascular plants of the Brahmaputra valley show richness and luxuriance of the flora due to occrrrence of over ninety percent species of the the flora of Assam. The luxuriant vegetation and flora of the valley creates the treasure house multidimensional biotypes in the area with prevalence of a number of endemic plant species and some important primitive angiosperms. Apart from these, it is blessed with very high degree of taxonomically and ecologically valued floral species. The richness of the composition is reflected with more than 250 species of Orchids, 33 species of Bamboo, 12 species of Canes and number of plants with medicinal properties. The forest cover of the state represents 35.28% area of the state with 17.68% of geographical area in Reserve Forest and 5% of geographical area under protected area net work (Anonymous, 2011). It is noteworthy that there are a larger numbers of rare, threatened and endangered species found in the state outside the formal forest areas too.

Looking at the endemism in flowering plants, it is observed that the northeast region has the largest concentration of endemic plants, as out of total 5725 endemic species found in India, northeast region has a total of 1808 endemic species (Nayar, 1996). Although, the comprehensive account of the endemic taxa of the state Assam is yet to be worked out, the Botanical Survey of India listed 102 species of angiosperms belonging to 75 genera as endemic taxa for the political boundary of Assam, of which majority i.e. 91 species belonging to 68 genera are found in the Brahmapurta valley (Appendix V). The physio- climatic conditions of the state particularly of the Brahmaputra valley are the place of active speciation. Moreover, many endemic taxa are recorded from type locality and to pin point a particular taxa as endemic to the valley may cause confusion as several part of northeast region and also the country is under explored or unexplored.

The largest representation of endemic taxa from the state belongs to families Poaceae, Lauraceae, Magnoliaceae, Orchidaceae and Piperaceae. Genus Piper has the highest endemism in the valley with 6 species followed by other genera viz. Calamus, Dioscorea and Magnolia are with 3 species each.

Several groups of flowering plants viz. Orchids, Legumes, Cucurbits, etc. exhibit remarkable species diversity in the Brahmaputra valley. Apart from these, spectacular species diversity has been observed in the genera like Dendrobium, Elaeocarpus, Piper, Garcinia, Calamus and Dipterocarpus in the Brahmaputra valley. Families viz. Poaceae, Orchidaceae, Fabaceae, Asteraceae, Araceae, Cucurbitaceae, Lauraceae, Arecaceae, Zingiberaceae, etc. also contribute rich gene pool of the valley. The Brahmaputra valley has made one of the greatest contributions to world agriculture by discovering the cultivation of tea. The valley produces some of the finest and expensive teas in the world and has the indigenous species Camellia sinensis var. assamica.

The area is also known for several plants of botanical curiosities. Various interesting plants viz. species of Utricularia, Drosera, (all insectivorous plants), Sapria himalayana (parasitic angiosperm reported from Sadiya probably extinct in the state), Balanophora dioica, (parasitic angiosperm), etc. are available in the valley. Some of the phylogenetically primitive families such as Magnoliaceae, Anonaceae, Schizandraceae, Menispermaceae, Altingiaceae, Lardizabalaceae, etc. grow in the Brahmaputra valley and further eastwards but do not occur in other parts of India (Appendix VI). The distribution pattern of these primitive plants show that they are mostly localised and confined to the major forest types i.e. evergreen and semi evergreen forests and also on the riparian belts. This array of floristic richness has prompted many naturalists to describe Assam as the ‘Biological Gateway’ of northeastern India. Armen L. Takhtajan (1969), the eminent plant taxonomist and geographer observed ‘the cradle of flowering plants lies in between Assam and Fiji’.

The flora of the valley has distinct affinity with the nearby Nepal, Bhutan, Indo- Burma, Sino-Himalayan, Malaysian and to a lesser extent with peninsular India. Species viz. Albizzia procera, Antidesma acidum, Bischofia javanica, Bombax ceiba, Cassia fistula, Costus speciosus, Duabanga grandiflora, Hedychium coccineum, Hodgsonia macrocarpa, Oroxylum indicum, Tetremeles nudiflora are some examples of Indo-Burma and other southeast Asian floristic elements found in the flora of Brahmaputra valley. Besides, the taxa like Camellia, Eurya, Hoya, Maesa, Magnolia, Michelia, Hypericum, Viola, Sarauia etc. are some of the examples of Sino-Himalayan affinity found in the flora of the valley. Some plants of African and American flora are naturalized in the valley for eg. Pyrularia edulis of Santalaceae found

19 in western Assam and another solitary member in America are the best examples of transpacific distribution.

Gymnospermic diversity in India accounts for 48 species (Singh & Mudgal, 1997) and northeast region is represented by more than 28 species. Although the members of this group of plant is less, they are equally important for providing timber, wood, pulp, resins, tars, turpentine, etc. These gregarious plants mostly dominate the Himalayan landscape of the state Arunachal Pradesh and Sikkim in northeast region. However, in Assam they are poorly represented. In Brahmaputra valley they are restricted to Darrang, Dibrugarh, Goalpara, Golaghat, Lakhimpur, Sibsagar and Sonitpur districts. As many as 5 species of gymnosperm occur in the valley belonging to the families Cycadales, Coniferales and Gnetales. Species viz. Cycas pectinata, Podocarpus nerifolia, Gnetum gnemon and G. montanum are some of the common species of gymnosperm which grow naturally in the valley.

In India the pteridophytic flora i.e. fern and fern allies are represented by over 1200 taxa under 204 genera distributed almost all the climatic zones of the country. The northeastern region of India is regarded as the richest area of pteridophytic diversity that supports more than 800 taxa of which 97 species are endemic. In Assam, fern allies and ferns are the important component of biodiversity and Baishya (1999) and Chowdhury (2005) estimated separately on the diversity of the pteridophytic flora of the state. Borthakur et al. (2001) enumerated 87 genera and 221 species of fern and its allies from the state. All those estimates suggest that the members of the family Polypodiaceae has the highest representation followed by Thelypteridaceae, Pteridaceae and Athyriaceae in the Brahmaputra valley. Besides the species of the genera Lygodium, Stenochlaena is very widely distributed in the various forests of the valley. In the wetlands, generas viz. Azolla, Ceratopteris and Salvinia are commonly found. Another fern of amphibian nature viz. Marsilea is also commonly found in the valley. Other interesting species of ferns found in the valley are Psilotum nudum, Huperzia phlegmaria, Osmunda regalis, Angiopteris evecta etc. Likewise, the species representation of other cryptogamic group of plants such as Moss (Musci), Liverworts (Hepaticae), Lichens, etc. are also remarkable in the Brahmaputra valley.

The northeastern region is also very rich in wild relatives of cultivated plants. The region along with the rest part of the country is popularly known as Hindustani Centre of 20 origin of cultivated plants (Vavilov, 1926, 1951) and forms the richest reservoir of genetic variability of many groups of crop plants. The state of Assam serves as a centre of origin of economically important plants viz. Musa, Citrus, Mangifera, Zizyphus, Camellia sinensis var. assamica. Singh and Varaprasad (2008), identified Brahmaputra valley as ‘Probable Agricultural Heritage’ site due to unique and significant diversity in important crop plants. According to Rao (1994), wild relatives of 189 economically important species such as Citrus, Banana, Mango, Sugarcane, Pulses, cereals and other fruit plants are located in northeast region including Assam. Hore (2001) estimated tentative number of crop diversities in some major crops includes - Rice (9650+ races), Maize (15 races and 3 sub races), Banana (14 spp.), Citrus (17 spp., 52 varieties), Sugarcane and their wild relatives (15 spp.) and Bamboo (60 spp.) in the northeast region.

Chapter 5

UTILITY OF THE FLORISTIC DIVERSITY

The rich floristic diversity of Brahmaputra valley has tremendous utilitarian value. Plant resources available in the area starting from their timber yielding value can also be used as medicines, as food, as source of essential oils, gums, for making paper and pulp, dyes, resins, tannins, essential oils, fibres, etc. The valley harbours about 40 high prized timber yielding plant species. There are over 1000 species of plant reported to have medicinal properties available in the valley with commercial importance and are also used by different communities for treating various ailments. Some of the highly valued medicinal plants of Brahmaputra valley are Dioscorea bulbifera, Acorus calamus, Hydnocarpus kurzii, Oroxylum indicum, Piper peepuloides, Rauvolfia serpentina, etc. Proper exploration of these resources will lead to the discovery of novel drugs.

The state of Assam particularly Brahmaputra valley is famous for orchid diversity and the orchid cut flowers are prized all over the world for their long lasting ornamental value and are good source of revene generation. Many epiphytic and terrestrial orchids of surpassing horticultural potential as well as the progenitors of the present day commercial hybrids are available in the area. A list of the orchids of the State of Assam particularly of Barhmaputra valley is presented in the Annexure I. Besides, several ornamental plants with prospect for floriculture are found in the valley. Plant species viz. Agapetes, Arisaema, Aster, Bauhinia, Begonia, Camellia, Cassia, Hedychium, Holmskioldia, Impatiens, Jasminum, Mussaenda, Primula, Raphidophora, Tacca, etc. are potential floricultural plants.

The state is one of the important areas of northeast region as far as the production of canes and bamboos are concerned. As many as 12 species of canes and 33 species of bamboos are found in the Brahmaputra valley, which are of great importance in developing forest based cottage industries in different parts of the valley. Apart from bamboos and canes Thysanolaena maxima (broom stick), Imperata cylindrica (Thatch grass) are other economically important grasses of the valley. A list of economically important plant species are presented in Appendix VII.

Moreover, the cross cultural ethnobotany of the valley is also very rich as the area is resided by diverse ethnic communities with wide range of uses of plants of different groups. 22

Saklani & Jain (1994) reported 332 plant species of Assam used as food, drinks, medicine and also in cultural aspect. The statistics will go up if the information on ethnobotanical uses of plants from new areas and different ethnic communities of the valley is incorporated. Use of plants for a variety of purpose indicates the intimate relationships and dependence of people of the area with the plant resources of their viscinity.

It may be mentioned here that majority of the total population of the area live in the villages, interior areas nearby forests, and are enriched with plenty of traditional knowledge system of resource utilization. About 40 species of various wild plants are marketed as food and vegetables in local tribal and village markets of the valley. Patiri & Bora (2007) reported 350 species of wild edible plants of Assam used as green vegetables including root & root like vegetables; some are also used as fruits and condiments along with seeds, Bark and flowers. The valley has a rich diversity of wild relatives of cultivated plants (Appendix VIII). Wild crop diversity is considered as valuable biological assets as they are reservoir of various genes of agronomic and economic importance needed for genetic improvement of crop plants (Singh, 2010).

Like higher plants, the cryptogams are equally important as they are used in various aspects such as food, medicine, dye, antibiotic, ornamental purpose, etc. Fronds of pteridophytic plants viz. Diplazium esculentum, Drypetes elongata, etc. are eaten as vegetables. Some species of Selaginella, Lycopodium, Adiantum, etc. are also used as medicine. Similarly species of lichen such as Everniastrum cirrhatum is used as food, Heterodermia diademata as antibiotic, Parmotrema tinctorum as dye. Different species of edible mushroom such as Agaricus, Auricularia, Clavaria, Morchella, Pleurotus, etc. are commonly available in the forests of the valley and are often sold in the local markets.

Chapter 6

HIGH PRIORITY TAXA

The rich plant diversity of the region in the recent years is witnessing serious threats due to various abiotic and biotic factors. The gradual increase of human population, developmental, oil extraction and other anthropogenic activities coupled with natural calamities particularly seasonal flood and erosion of river banks, monocultural practice are contributing directly or indirectly towards the loss of habitat of several plant species. As a result several plant taxa become threatened and endangered in the flora of Assam and Brahmaputra valley as well. Some species become rare due to over exploitation for medicinal, ornamental and other industrial uses. According to an estimate of Botanical Survey of India, about 700 plant species of northeast region fall under various threat categories of which 43 species belong to Assam. Baishya (1999) compiled a list of 60 rare and threatened plant taxa from Assam. Barooah and Ahmed (2014) categorised 871 taxa of angiosperms and gymnosperms of the state under different conservational status. Among these, 167 taxa are recorded to be endemic, 318 taxa are kept under critically endangered, endangered and vulnerable and 386 taxa are identified as rare to the state.

The number will be much more if all the members of the family Orchidaceae are included in the threat list. It may be mentioned that the entire family Orchidaceae is kept under the Appendix II of the CITES. Orchid species viz. Vanda coerulea, Renanthera imschootiana and all the species of Paphiopedilum found in the region as well as outside the region are included under the Appendix I of CITES.

Sapria himalayana of family Rafflesiaceae which was reported from Sadiya long back is at present presumed to be extinct in the state. IUCN-CAMP, 2003 categorised 18 plants of the state in various threat categories. Some critically endangered species of the Brahmaputra valley are region are Livistona jenkinsiana, Swertia chirayita, Smilax glabra, etc. Plant viz. Aquilaria malaccensis, Brucea mollis, Cibotium barometz, Citrus macroptera var. assamensis, Dendrobium nobile, Flickingeria fugax, Garcinia pedunculata, Homalomena aromatica are endangered in the valley and vulnerable species include Elaeocarpus sphaericus, Gynocardia odorata, Hydnocarpus kurzii, Mahonia napaulensis, Oroxylum indicum, Piper peepuloides, Rauvolfia serpentina. A list of rare, threatened and endangered

24 plant taxa as prepared by Botanical Survey of India for the state of Assam in presented in the Appendix IX (Nayar et al. 1987, 1988 & 1990; Baishya, 1999). The IUCN categories of these taxa are also provided wherever available.

The present status in terms of exact location with GPS co-ordinates, population density, regeneration capacity are required to be work out to formulate the conservation strategy of these threatened and endangered plant taxa. Moreover, existence of certain taxa is also need to be verified in view of recent nomenclatural changes. There is a chance of wipe out many valuable plant species in a few decades if they are not given proper attention for conservation.

Chapter 7

THREATS

The geographical isolation from rest part of the country has helped to protect the biodiversity of northeast India from large-scale developmental activities. But the situation has changed gradually and the biodiversity of the region is now confined to only a few pockets. It was the British who first cleared the natural forest for tea plantation and propagation of commercial species like teak (Tectona grandis), sal (Shorea robusta), hollock (Terminalia myriocarpa), simul (Bombax ceiba), gamari (Gmelina arborea), etc. The forest of the state has attracted the attention of the world in the middle of the 19th century with the advent of railways in Bengal and is identified as the starting point of forest destruction in the region. Shifting agricultural practice is another cause of forest destruction in the state of Assam although it is prevalent only in the hill districts of Assam. However, in the extension areas of Kaziranga National Park i.e. in Karbi Anglong hills this kind of agricultural practice may lead to the destruction of the forest cover. To meet the increasing demand of the growing population, the period of jhum cycle has been reduced to considerable rate, affording no chance for natural regeneration and soil fertility. The rate of forest degradation is also supported by the invasion of weeds. It has been observed that various species of native and exotic weeds viz. species of Ageratum conyzoides, Argemone maxicana, Chromolaena odorata, Lantana camara, Mimosa rubicaulis, Mikania micrantha, Parthenium hysterophorus, etc. have completely dominated the forested land, degraded forests and the agricultural landscapes of the region posing serious threat to all sorts of healthy growth of plant species, forest regeneration and agricultural productivity as well. In Kaziranga national park, proliferation of various weeds like Mikania, Mimosa and Eichhornia, causes ecological degradation of the habitat and is a major problem confronting the Park authorities. Although some serious eradication efforts particularly for Mimosa, removal of water hyacinth etc. have been made in the recent past but still it is a threat to the wildlife habitat of the park.

Natural calamities like earthquake, seasonal flood, etc. as well as soil erosion also lead to the shrinkage of the forest cover in the region. Of late, the various developmental activities like construction of mega dams, hydroelectric plants, roads, etc. also act as the key

26 factors of forest destruction in the state. The impacts (upstream and down stream) of large river dams on ecosystem and environment as a whole are well established. Building of mega dam on the mainstream of the Brahmaputra as well as on some of its major tributaries may adversely affect the natural importance of some protected areas of the valley, for instance Kaziranga and Manas national park. The survival of charismatic species like rhino, flagship species like elephant and other herbivores in these critical ecosystems are determined by natural connectivity of the forests with waters of the rivers that makes these ecosystems capable to sustain certain types of grasses and other vegetation. Construction of large dams may change the flood cycle and hydrological relationship of some critical ecosystem of the state for example Kaziranga national park. The existence of different habitat types in the park viz. grassland, wetland and also woodland is dependent on the annual sluicing of the landscape by flood water. Moreover, the livelihood of the people living in the catchment areas of the river would also be at stake.

Injudicious collection of various plant resources for medicinal, dye making and ornamental purpose are very common that lead to the depletion of the rich bio-resources of the state. Political and social unrest prevailed in the state for the last couple of decades are also influencing adversely to the rich floristics of the state in general and the Brahmaputra valley in particular.

As far as the diversity of cultivated crops is concerned, the replacement of local land races by High Yielding Varieties (HYV) in cultivated fields has caused considerable loss in diversities of crop and economically important plant in the region.

Along with the deforestation, degradation, encroachment and associated concerns of logging, habitat fragmentation another important issue that need to be addressed for Assam is the climate change. Because of its sensitive geo-ecological set-up, strategic location with international boundary, presence of the Eastern Himalayan ranges, transboundary river systems, inhabitation of ecosystem by people of different ethnic groups and inherent socio-economic differences, the state is expected to be highly prone to consequences to climate change.

Forest ecosystems in particular are among the natural systems that will globally be severely affected by climate change (Pérez-García et al., 2002; Walther et al., 2002). This is also true for the forests of Assam and its adjoining northeastern states. At the ecosystem level, due to increase in atmospheric carbon dioxide and resultant temperature increases and there will be changes in rainfall regimes. This may result in increase in biomass production, alteration in forest structure and species composition and competitiveness, (Meer et al. 2001). At the community level, changes in floral phenology will likely to impact adversely the critical process of pollination and seed dispersal.

Climate change thus expected to impose a variety of stress on sustainable livelihood of the poor inhabitants of the state through stresses on ecosystem function. The major concerns are erratic & irregular rainfall patterns, longer dry spells, and implications on agriculture calendar, productivity, new pests; food security; health and disasters like flash floods. It is presumed that there would be a change in distribution, abundance of species, more particularly wild, endemic species, crop plants, pests and vectors. Due to change in habitat condition, displacement both human and other wilderness would take place. Apart from these, the food security, mitigation of hazards and addressing the epidemics like malaria, encephalitis etc. are other issues of major concerns for the state (Bujarbarua & Baruah, 2009). The marginalised people of the state who are dependent on the forests for basic livelihood needs such as fuelwood, bamboo, fodder, timber and Non Timber Forest Products including medicinal plants may face adverse consequences due to climate change. It worth to mention that, besides, traditional resource use, forests also provide germplasm (Anonymous, 2011).

Thus the impacts of climate change on forest may lead to decrease in water regulation and forest ecosystem services that may lead to increase social vulnerability. The growing human population and livestock pressure may gradually widen the gap between demand and supply of natural resources. These impacts will cut across multiple dimensions of day to day life affecting not just the environment but the communities as well. Under such circumstances, there is possibility of conflicts over reduced natural resources and may cause strained social relations taking toll on to the cultural and spiritual services provided by ecosystems (Bujarbarua & Barua, 2009).

Chapter 8

PROBLEMS OF FOREST MANAGEMENT IN THE BRAHMAPUTRA VALLEY

Environmental problems in the state of Assam have been influenced partly by the increasing population, survival needs of the poor and the economic greed of the commercial interests. They are also aggravated by prevalent economic disparities and unemployment, which are deeply embedded in unsustainable patterns of production and consumption; ill informed policies and programs; and inappropriate developing strategies. As far as the forest resources of the Brahmaputra valley is concerned, gap in scientific knowledge, increasing demands, lack of value addition are the main causes for which the vast potential is yet to be tapped properly and in some cases over exploited.

Gap in scientific knowledge on various forest resources and products is a major problem for management of resources in the state. Although considerable amounts of revenue have been collected from forest products where local people are also directly or indirectly involved in gathering and in some cases marketing as well, but they have hardly any knowledge on the silvicultural management of various minor forest products. Except for some well known commercial species, the information on distribution of various forest products, their density, regeneration status, yield estimate and harvesting levels are lacking. There is need to formulate sound management plan that addresses the knowledge about the life cycle pattern of the species, productivity and yield estimation techniques.

As a result of the increasing demands of various forest resources, there is a danger of fall in harvest in considerable rate. For example, Aquilaria malaccensis (Agar) is harvested only after fungal attack. But due to its high commercial value, plants without fungal infection are also harvested leading to the tremendous loss of natural population. Same with the case of Oroxylum indicum- a high valued anticancer medicinal plant. Indiscriminate collection of other medicinal plant species has caused wide spread loss to the natural population of these species. IUCN-CAMP (2003) has already categorised 12 species of medicinal plants of the state under various threat categories.

Valuation of biological resources is the most important aspect of its conservation, sustainable use and management. Proper valuation of rich and vast bio-resources of the state is yet to be done in terms of consumptive, non consumptive and productive use value. Moreover, middle men are much benefited rather than the actual collectors as far as the trade of forest products are concerned because of their inability to cope with exploitation from the middle men. Poor knowledge about processing, market fluctuations cause post harvest loss leading to insufficient returns of the products and ultimately causing over exploitation.

Monitoring and maintaining of the complex ecosystem is important aspect of bio- resource management. Technical aspects include choice between different methods and techniques and development of appropriate harvesting and processing technologies. There is also social aspect of resource management that deal with people, cultures, belief systems, attitudes and behaviour, ethics, aspirations and social values. As far as the state of Assam is concerned, all these aspects should be taken into consideration prior to the formulation of management strategies. Finally, exercise of administrative power in another important aspect to hold control over users of resources and decision-making.

In the perspective of the state of Assam, proper assessment of various forest ecosystems and resources, their potential in supporting life and livelihood are the foremost requirement. Moreover, there is little knowledge about the status of the forest resources, products that are extracted commercially from the valley, their distribution, rate of growth, threats. The sustainable management of these resources requires the collection of accurate information and a programme of regular monitoring. Information on density and distribution of the economically important species within the forest, population structure, productivity, regeneration capacity and ecological impact of harvest are prerequisite for the planning, design of management strategies and running enterprise based on raw materials collected from the forest.

The concept of sustainable forest management can also be tested in the state as it encompasses the wider issues and values. IIFM 2000 defined Sustainable Forest Management (SFM) as ‘a management approach to obtain full range of forest values

30 ensuring that the ecological, economic and social needs of the present and future generations can be met from the forest on a continuous basis’. Forest manage in this aspect would not only provide timber on a sustainable basis but would also provide various forest products and other services to the community living in and around it. It will also help to preserve genetic resources and biodiversity and at the same time environmental balance will also be maintained.

As far as the management of the wildlife habitats are concerned, lesson may be learnt from the Kaziranga National Park. The Habitat management in Kaziranga is aimed basically at restoration of grasslands - the main habitat of Rhino and most of the habivores and is achieved through controlled burning. De-siltation of water-bodies and channels, construction of temporary dam for water retention and control & eradication of weeds are other measures adopted for habitat management of the park.

Maintanance of seral stage of grassland is the important aspect of the habitat management in Kaziranga national park thereby preventing invasion of tree species. Thus annual burning of grassland is practiced to discourage the growth of tree sapling. This not only helps in enhancing the nutritional value of coarse grasses by facilitating growth of new shoots but also attracts the herbivores. Moreover, siltation of water bodies due to flood inside the park is a perennial problem leading to the shrinkage of water bodies. To address this issue desiltation drives are carried out inside the park annually and are submitted useful to maintain the water bodies which are integral part of the national park. Migratory birds are important components of the biodiversity of Kaziranga. Therefore to retain the water in the water bodies for attracting various migratory avifauna bunds are constructed. All these habitat management practices are integral part of the conservation success of Kaziranga national park. It is thus important that this success story be replicated in the other protected areas of the state too to conserve the pristine biodiversity.

Chapter 9

DISCUSSION

The Brahmaputra valley is blessed with very high degree of endemic, taxonomically and ecologically high valued plant species. The richness of the composition is reflected with over 3000 species of flowering plants, over 250 species of Orchids, 33 species of Bamboo, 12 species of Canes and plants of other economic uses. The forest cover of the state represents 35.30% area of the state with 17.68% of geographical area in Reserve Forest and 5% of geographical area under protected area net work. It is noteworthy that there are a larger numbers of rare, threatened and endangered species found in the state outside the formal forest areas too.

Recent years are witnessing considerable developments and the overwhelming demand for forest based raw materials, especially bamboo, cane and natural health products, which are renewable natural resources. Moreover, there is growing market demand globally for these products. However, majority of these species in wild are under severe threat, many are on the verge of extinction due to imprudent resource use and management practices. Therefore it is imperative that multi-dimensional action (social, ecological, economical, institutional) needs to be urgently taken for the conservation of these vital resources. Management plan should be in such a way that livelihood improvement and biodiversity conservation are in balanced state in order to reduce the poverty and underdevelopment of the state. There is a need of sustainable management of the important forest resources of the valley that would also contribute to the food security, poverty alleviation, economical development, and sustainable land use, in the wider context of sustainable development. Good forest management secures the survival of forest ecosystems and enhances their environmental, socio cultural and economic functions. It can both maximize forests’ contribution to climate change mitigation and help forests and forest-dependent people adapt to new conditions caused by climate change (ASTEC, 2011).

As far as the state of Assam is concerned there is a need of policy based initiatives to protect and conserve the pristine biodiversity of the state. It may be mentioned that the state has lost several hectares of forest cover in recent years. There is large scale unabated

32 encroachment in the reserved forests even in the protected areas by the new settlers, people displaced by floods and ethnic clashes in the state particularly the Brahmaputra valley, immigrants and excessive dependence of the people in the rural areas on the forests leading to deforestation. According to a report of forest department, 3,555 sq. km. of the forest land is under encroachment (Anonymous, 2012). The encroachment in reserved forests is a major concern in the management and conservation of forests of the state. The forest survey data reveal that loss of forest cover in the State has been increasing over the years. One of the general factors underlying these trends is land use land cover change, the dynamics of which vary greatly across the state. The state has experienced rapid urbanization, infrastructure development and the agricultural intensification with resulting large scale habitat loss and degradation. Special strategy may be formulated for recovering encroached areas.

Incorporation of some incentive mechanisms or benefit sharing mechanisms in the community conserved areas for instance Mulai Kathoni (Jorhat) and protection of valuable species outside the forest would be an encouraging steps towards conservation and management of biodiversity. Important carbon stocks in many forests around the world have been maintained and enhanced with the help of the local communities’ ranges from conservation to reforestation.

Payments for ecosystem services may be useful in this regard for preserving, acknowledging and rewarding good community forest management practices. Active participation of communities in all aspects of forest management, taking into account people’s needs, aspirations, rights, skills and knowledge, will contribute to the efficiency, sustainability and equity of forest-based measures to tackle the degradation and threats of climate change as well.

For reclamation of degraded forest lands and riparian sites, plantation and ecorestoration programme may be initiated with prioritize species in relation to ecoregion/ agro-climatic zones. In riparian sites plantation of bamboo and various species of grass can be initiated to check erosion. Eco-sensitive zones in the valley should be demarcated and regulations may be imposed on developmental projects like mega dams, industrial activities,

33 quarrying and mining in such areas are other important measures of conservation may be initiated.

More areas should be incorporated under protected area network. Strengthening of the ongoing programme/project of forestry sectors, viz. Joint Forest Management, Project Tiger, Project Elephant, Project Rhino, Eco-development programme, National aforestation programme, etc. is important and these should be integrated with watersheds, wetlands and also grass lands for formulating effective management planes. Special initiatives need to be taken for protection of the areas outside the protected areas or reserve forests with rich flora and fauna. The natural corridors of the wildlife in the valley disrupted due to change in the land use and land cover, industrialization and other developmental activities should be protected and restored.

Updation of the database on floristic diversity in terms of species, ecosystems & genetic traits with reference to status, pressures and also in regard to changing climate are other issues of resource management. Besides, pest-resistant or drought-tolerant varieties; genotypes of species expected to be adapted to new climate conditions are also to be screened out. Documentation ethno-cultural interlink is also important to safe guard IPR of the communities.

The state of Assam should try for lobbying at regional, national and international level against the large dams coming up on the Siang, Dibang, Lohit, Subansiri and even in the Brahmaputra river. Exchange of surface, sub-surface and ground water flow is important for maintaining the annual flood cycle and hydrological relationship of some important wildlife areas of the valley. Probable changes in water flow due to construction of large dams may significantly affect the supply of water, nutrient and silt which are vital for sustenance of the forest and various ecosystem types.

The threat to biodiversity due to invasive species alien species is considered second only to the habitat destruction. Invasive species cause loss of biodiversity including species extinction. The humid climate of the state is congenial for spread various invasive and alien species like Lantana camara, Mikania micrantha, Chromolaena odorata, etc. Special

34 measures to be taken for control of the alien /invasive plant species as several interacting factors contribute to successful invasion of these species. There is a need to increase public awareness of the threat of invasive plants to natural and man made ecosystems. Increased awareness wil help prevent the translocation of invasive species in new areas.

As far as the conservation efforts are concerned, research inputs are important. Therefore comprehensive studies on the floristics, phenological responses of wild flora in different ecosystems/habitat, identification of plant species with high carbon sequestration potentials need to be initiated. Identification of keystone species for different eco-zones with perspective of developing strategies for eco-restoration, research on the sensitivity of the endemic taxa to probable change including the possible impact on restricted range are other areas of research. Apart from these some long term study on the changes on the life cycle, physiology, reproductive biology some economically important plant species, also with reference to climate change may be initiated. Similarly, problems of invasive species, natural adaptation mechanism of species and the degree of resilience of their habitats are also required to be addressed. Intensity of diseases of wild flora due to changing climatic conditions is another issue need to be addressed as an adaptation measures to climate change in the state of Assam. Besides, the vulnerability of major forest types and associated fauna found in the state to climate change in PAs, grassland, riparian forests (prone to erosion & flooding) and patches of the rain forests in upper Assam and also areas outside the PAs need to be initiated to assess the impacts of climate change and possible adaptation interventions.

All these initiatives are fruitless without involvement of the local communities. Therefore, community training and capacity building are necessary prerequisites to local biodiversity conservation programme and also for income generation. It is imperative that the local communities should be made aware of the benefits of nature conservation. They should also be imparted with technical, financial, managerial, marketing and training support so that they will have a new economic incentive to conserve the resource base of their raw material.

Various government institutions like North East Development Finance Corporation Ltd. (NEDFI), North East Council (NEC) and Department of development of North East Region (DONER) have already started encouraging to tap the vast bio-resource of the northeast region in general and Assam in particular involving both local citizen as well as state governments in a sustainable way to boast the economy and to provide livelihood to the entire population of northeast India. Citizens are provided with technical, financial, managerial, marketing and training support, so that they have a new economic incentive to conserve the resource base. There must be co-ordination between government developmental policies and biodiversity conservation strategies so that the critical balance between the ideology of conservation and the necessity of development are maintained involving local communities as the principal stakeholders of bio-resources.

There is a need to reassess the challenges and opportunities of sustainably managing the bio-resource of the state. The strategies should be formulated in the context of all the imperatives of biodiversity conservation, livelihood improvements and unsustainable commercial utilization. The rich floristic diversity with a large number of endemic plants of state of Assam in general and Brahmaputra valley in particular not only constitutes the ‘green gold’ of the present century but also of the future. These rich genetic resources of the region also hold promises to yield organisms. A rational, scientific and judicious utilization of the bio-resources of the region will help us in the long run in improving the welfare of the humanity; at the same time will also facilitate to conserve this pristine glory for the posterity.

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Appendix I: Floristic diversity of the national parks of Assam Nameri Rajib Gandhi Manas NP & Dibru-Saikhowa Kaziranga NP NP (Orang) NP BR NP & BR Nath & Begum, Choudhury, Hajra & Baishya & Bora, Hajra & Jain, 2010 1994 Baishya, 2002 2002 1996 District Sonitpur Darrang & Kokrajhar, Tinsukia & Golaghat, Sonitpur Chirang, Baska Dibrugarh Nagaon & & Udalguri Sonitpur Area 200 sq. 78.81 sq. km. 500 sq. km. 340 sq. km. 430 sq. km km. Family 159 95 111 108 115 Genera 580 322 372 233 377 Species 882 450 591 471 560

Appendix II: Floristic diversity of the Islands of Brahmaputra river. Plant Group Flora of Majuli Island Flora of Umananda Island (M. Islam, 1990) (P. Bujarbarua, 2015) Families 139 54 Genera 505 117 Species (Angiosperms) 692 123

Appendix III: Floristic diversity of Assam worked out by different workers.

Baishya (1999) Chowdhury (2005) Barooah & Ahmed (2014) Plant Group Family Genera Species Family Genera Species Family Genera Species Fern & Fern allies - - 297 32 97 355 - - - Gymnosperm 4 4 7 8 13 23 7 14 22 Angiosperm 170 824 2251 190 1006 2823 189 1011 2752 (Dicotyledons) Angiosperm 37 287 759 42 332 1072 40 368 1080 (Monocotyledons)

Appendix IV: Comparisons of Evergreen species distributed in Brahmaputra and Barak Valley (after Das 1942)

Brahmaputra valley Barak valley Magnoliaceae Magnolia griffithii Absent M. hookeri Absent M. cavena Absent M. pealina Absent M. pterocarpa Absent M. insignis Absent M. hodgsoni M. rabaniana Pachylarnax pleiocarpa Absent Kadsura roxburghiana Absent Annonaceae Polyalthia simiarum Absent Absent Cyathocalyx malabaricus Flcourtiaceae Hydnocarpus kurzii Absent Clusiaceae Garcinia affinis Absent Absent Mammea suriga Maesa assamica Maesa floribunda Theaceae Adiandra griffithii Absent Camellia caudate Absent Dipteroarpaceae Dipterocarpus retusus Dipterocarpus turbinatus D. mannii Absent Shorea assamica Absent Hopea shingkeng Absent Fabaceae

Dalbergia assamica D. reniformis Derris ferruginea Absent Absent Maniltoa polyandra Hamamelidaceae Altingia excels Absent Combretaceae Absent Anogeissus acumata Myrtaceae Eugenia Formosa Absent Lythraceae Crypteronia paniculata Absent Sapotaceae Palaquium obovatum P. polyanthum Ebenaceae Absent Maba cacharensis Apocynaceae Chonemorpha griffithii Absent Asclepiadaceae Cryptolepis buchanani Absent Lauraceae Beilschmiedia roxburghiana Absent B. assamica Absent B. pseudomicrocarpa Absent Absent Endiandra firma Absent Cinnamomum cacharensis Alseodaphne petiolaris Alseodaphne owdenii Absent Alseodaphne andersonii Persea bombycina Absent P. globularia Absent Phoebe goalparensis Absent P. cooperiana Absent Euphorbiaceae

Aporusa wallichii Absent Absent Drypetes eglandulosa Fagaceae Lithocarpus elegans Absent Podocarpaceae Podocarpus nerifolius Absent Absent P. wallichianus Gnetaceae Gnetum gnemon Absent

Appendix V: Endemic plant taxa of Assam

Sl. No. Species Family 1 Acacia diadenia Mimosoideae 2 Acacia pennata ssp. Herrii Mimosoideae 3 Adhatoda cymosa Acanthacecae 4 Agapetes kanjilali Vacciniaceae 5 Agapetes variegata var. bhareliana Vacciniaceae 6 Allophyllus chartaceous Sapindaceae 7 Ardisia pardalina Myrsinaceae 8 Artabotrys cubitti Annonaceae 9 Bambusa cacharensis Poaceae 10 Bambusa mastersii Poaceae 11 Begonia tessaricarpa Begoniaceae 12 Beilschmiedia gammieana Lauraceae 13 Beilschmiedia pseudomicropora Lauraceae 14 Bousigonia angustifolia Lauraceae 15 Camellia sinensis var. assamica Theaceae 16 Calamus floribundus var. drepauperatus (Cachar & N.C. Hills) Arecaceae 17 Calamus kingianus (Cachar & N.C. Hills) Arecaceae 18 Calamus nambariensis (Cachar & N.C. Hills) Arecaceae 19 Celastrus paniculata var. venulosoides Celastraceae 20 Chonemorpha assamensis Apocynaceae 21 Chrysoglossum assamicus Orchidaceae 22 Cinnamomum cacharensis (Cachar & N.C. Hills) Lauraceae 23 Citrus assamensis Rutaceae 24 Cymbopogon jwaracus var. asamensis Poaceae 25 Dalbergia rimosa var. griffithii Papilionoideae 26 Dendrocalamus patellaris Poaceae 27 Dendrobium assamicum Orchidaceae 28 Dendrobium aurantiacum Orchidaceae 29 Derris cuneifolia var. cuneifolia forma assamica Papilionoideae

30 Dinochloa indica Poaceae 31 Dioscorea cumingii var. inacquefolia Dioscoreaceae 32 Dioscorea pentaphylla var. communis Dioscoreaceae 33 Dioscorea pentaphylla var. kussok Dioscoreaceae 34 Diospyros cacharensis (Cachar & N.C. Hills) Ebenaceae 35 Diospyros kika Ebenaceae 36 Dipterocapus manii Dipterocarpaceae 37 Dischidia albiflora Asclepiadaceae 38 Drypetes assamica Euphorbiaceae 39 Ecdysanthera lakhimpurensis Apocynaceae 40 Eria calmifolia Orchidaceae 41 Eulophia santapaui Orchidaceae 42 Euonymous assamicus Celestraceae 43 Euonymous vagans ssp. Macrophyllus Celestraceae 44 Fimbristylis circumciliata Cyperaceae 45 Fissistigma santapaui Annonaceae 46 Flacourtia helferi Flacoutiaceae 47 Garcinia keeniana (Cachar & N.C. Hills) Clusiaceae 48 Garcinia lanceafolia var. oxyphylla Clusiaceae 49 Gigantochloa macrostachya Poaceae 50 Glochidion assamicum Euphorbiaceae 51 Glycosmis singuliflora Rutaceae 52 Heritiera dubia Sterculiaceae 53 Homalium ceylanicum var. debbermani Flacoutiaceae 54 Hymenachne assamica Poaceae 55 Hypericum assamicum Hypericaceae 56 Illigera gammiei Hernandiaceae 57 Ixora goalparensis Rubiaceae 58 Justicia craibii Acanthaceae 59 Litsaea assamica Lauraceae 60 Maba cacharensis (Cachar & N.C. Hills) Ebenaceae 61 Maesa kurzii Myrsinaceae

62 Maesa maxima Myrsinaceae 63 Magnolia baillonii Magnoliaceae 64 Magnolia caveana Magnoliaceae 65 Magnolia gustavi Magnoliaceae 66 Mesua assamica Clusiaceae 67 Michelia manii Magnoliaceae 68 Michelia montana Magnoliaceae 69 Mussaenda intuspilosa Rubiaceae 70 Myristica clarkeana Myristicaceae 71 Pachylarnax pleiocarpa Magnoliaceae 72 Pandanus assamensis Pandanaceae 73 Parakaempfera synantha Zinziberaceae 74 Paspalum longifolium var. lorirhachis Poaceae 75 Pavetta assamica Rubiaceae 76 Persea dubia Lauraceae 77 Persea globularia Lauraceae 78 Phoebe cooperiana Lauraceae 79 Phoebe goalparensis var. marliniana Lauraceae 80 Phoebe goalparensis var. boriana Lauraceae 81 Phyllostachys assamica (Cachar & N.C. Hills) Poaceae 82 Physurus hirsutus Orchidaceae 83 Piper clarkei Piperaceae 84 Piper crassistipes Piperaceae 85 Piper gullatlyi Piperaceae 86 Piper gammei Piperaceae 87 Piper jenkinsii Piperaceae 88 Piper listeri Piperaceae 89 Poa wardiana Poaceae 90 Polygonum sarbhanganicum Polygonaceae 91 Rotboellia goalparensis Poaceae 92 Salacia jenkinsii Celestraceae 93 Schizostachyum dulooa (Cachar & N.C. Hills) Poaceae

94 Schizostachyum griffithii (Cachar & N.C. Hills) Poaceae 95 Schizostachyum pergracile (Cachar & N.C. Hills) Poaceae 96 Sclerostachya milroyi Poaceae 97 Syzygium assamicum Myrtaceae 98 Stztguyn cyanophyllum Myrtaceae 99 Thamnocalamus prainii Poaceae 100 Trachelospermum assamense Apocynaceae 101 Typhonium listeri Araceae 102 Uvaria hamiltonii var. kurzii Anonaceae

Appendix VI: List of primitive families and genera and representative species in the Brahmaputra valley

Family Genera No. of Species in Assam Magnolia 9 Magnoliaceae Michelia 8 Pachylarnax 1 Alphonsea 1 Annona 3 Artabotrys 2 Desmos 4 Fissistigma 3 Friesodielsia 1 Annonaceae Goniothalamus 1 Miliusa 2 Mitrephora 1 Orophea 1 Poyalthia 4 Trivalvaria 1 Uvaria 4 Schizandraceae Kadsura 1 Aspidocarya 1 Menispermaceae Pycnarrhena 1 Lardizabalaceae Parvatia 3 Hamamelidaceae Altingia 1 Chloranthaceae Chloranthus 1 Horsfieldia 2 Myristicaceae Knema 2 Myristica 1 Actinodaphne 5 Lauraceae Beilschmiedia 5 Cinnamomum 5

Cryptocaria 2 Dehaasia 1 Endiandra 1 Lindera 5 Litsea 19 Machilus 2 Neocinnamomum 1 Persea 5 Phoebe 5 Saururaceae Houttuynia 1 Myricaceae Myrica 1 Betulaceae Betula 1 Gnetaceae Gnetum 3 Podocarpaceae Podocarpus 1 Cycadaceae Cycas 1

Appendix VII: Economically important plants of Brahmaputra valley

Category Name of the plant species Timber yielding plants Albizia lebbek, A. odoratissima, Altingia excelsa, Artocarpus chama, Chukrassia tabularis, Duabanga grandiflora, Dipterocarpus retusus, Mesua ferrea, Michelia champaca, Species of Magnolia, Talauma hodgsonii, Palaquium polyanthum, Schima wallichii, Phoebe goalparensis, Shorea assamica, S. robusta, Terminalia myriocarpa, Lagrestroemia reginae. Paper and pulp: Besides Bamboo, plants viz. Garuga pinnata, Bombax ceiba, Helicteres spp., Kydia calycina, etc. forms the raw material for paper industries. Gums and resins Canarium strictum is the important resin yielding plant of Assam. Essential oils Brahmaputra valley is rich habitat for Cymbopogon flexuosus, yielding Citronella oil. Other oil yielding species are Hydnocarpus kurzii, Gynocardia odorata, Mesua ferrea, Homalomena aromatica, Pogostemon cablin, etc. Aquillaria malaccensis is the high valued oil yielding plant found in the state of Assam particularly in the Brahmaputra valley. Fibre yielding plant The important fibre yielding plant found in the area are Sterculia villosa, Bombax ceiba, Corchorus spp., Boehmeria nivea, Butea monosperma, Bauhinia spp., Grewia spp., Firmiana colorata, and the species of Hibiscus. Bamboos and canes: Some important bamboo species are - Bambusa balcooa, B. pallida, B. cacharensis, B. tulda, Dendrocalamus hamiltonii, D. strictus, D. giganteus, Melocanna bambusoides, M. baccifera, etc. Cane species include Calamus flagellum, C. floribundus, C. latifolius, C. tenuis, etc. Medicinal plants: Adhatoda vasica, Centella asiatica, Clerodendron colebrookianum, Costus speciosus, Zingiber gerumbet, Hollarhoena antidysenterica, Paederia foetida, Phyllanthus emblica, Eclipta alba, Asparagus racemosus, Terminalia bellirica, T. chebula, etc.

Plants with horticultural Orchids viz. Arundina bambusifolia, Rhynchostylis retusa, importance Papilionanthe teres, Cymbidium aloifolium, Dendrobium spp., etc. along with Allamanda cathartica, Bauhinia purpurea, B. variegate, Canna indica, Cassia fistula, Celosis argentia, Cestrum nocturnum, Clerodendrum spp., Hedychium spp., Holmskioldia sanguine, Ixora acuminata, Saraca indica, Mussaenda spp. are some of the important plant species with horticultural and floricultural importance. Dye Bixa orenella, Rubia cordifolia, Talauma hogdsonii, etc. Cereals, pseudo-cereals Eleusine coracana, Setaria italic, Zea mays, Oryza sativa, etc. and millets Grain legumes and Vigna mungo, V. vexillata, V. umbellate, Cicer arietinum, Lens oilseeds culinaris, Linum usitatissimum, Brassica juncea, B. rapa, Cajanas cajan, Sessamum indicum, etc. Tubers Beta vulgaris, Amorphophallus bulbifer, Ipomoea batatus, Colocasia esculenta, Dioscorea alata, D. bulbifera, D. hispida, etc. Spices Pimpinella anisum, Ammomum aromaticum, Nigella sativa, Piper nigrum, Piper peepuloides, Elettaria cardamomum, Cinnamomum tamala, Syzygium aromaticum, Cinnamomum zeylanicum, Alpinia malaccensis, Zingiber officinale, Z. zerumbet, Cymbopogon jawarancusa var. assamensis, Curcuma amada, Curcuma longa, etc. Minor fruits Musa spp., Dillenia indica, Flacourtia jangomas, Baccaurea ramiflora, Garcinia pedunculata, G. sopsopia, G. stipulata, G. xanthochymus, Artocarpus lakoocha, Terminalia chebula, Holboellia latifolia, etc.

Appendix VIII: Wild relatives of cultivated plants found in the Brahmaputra valley Sl. No Name of the Plant Family 1 Artocarpus chama Moraceae 2 Brassica trilocularis Brassicaceae 3 Camellia kissi Theaceae 4 Cinamomum bejolghota Lauraceae 5 Cinnamonum glanduliferum Lauraceae 6 Cinnamomum pauciflorum Lauraceae 7 Citrus assamensis Rutaceae 8 Citrus indica Rutaceae 9 Coffea bengalensis Rubiaceae 10 Coffea fragrans Rubiaceae 11 Colocasia fallax Araceae 12 Colocasia mannii Araceae 13 Cucumis hystrix Cucurbitaceae 14 Cucumis trigonus Cucurbitaceae 15 Curcuma amada Zingiberaceae 16 Curcuma aromatic Zingiberaceae 17 Dioscorea hamiltonii Dioscoreaceae 18 Dioscorea sinensis var. assamica Dioscoreaceae 19 Echinochloa crusgalli Poaceae 20 Elaeocarpus floribundus Elaeocarpaceae 21 Eleusine indica Poaceae 22 Erianthus filifolius Poaceae 23 Erianthus ravennae Poaceae 24 Euonymus assamicus Celastraceae 25 Euonymus vagans Celastraceae 26 Garcinia keeniana Clussiaceae 27 Garcinia lanceaefolia Clussiaceae 28 Luffa graveolens Cucurbitaceae 29 Mangifera sylvatica Anacardaceae 30 Miscanthus nudipes Poaceae

31 Miscanthus wardii Poaceae 32 Momordica macrophylla Cucurbitaceae 33 Musa assamica Musaceae 34 Musa acuminate Musaceae 35 Musa velutina Musaceae 36 Narenga fallax Poaceae 37 Oryza rufipogn Poaceae 38 Piper peepuloides Piperaceae 39 Polytoca wallichiana Poaceae 40 Prunus cerasioides Rosaceae 41 Prunus nepalense Rosaceae 42 Rubus moluccanus Rosaceae 43 Saccrahum longisetosum Poaceae 44 Saccharum wardii Poaceae 45 Solanum kurzii Solanaceae 46 Syzygium assamicum Myrtaceae 47 Trichosanthes bracteata Cucurbitaceae 48 Vigna clarkei Fabaceae 49 Zingiber spectabilis Zingiberaceae

Appendix IX: Rare, Threatened and Endangered Plant Taxa of Assam (Both Brahmaputra and Barak valley, Source: Baishya, 2009) Sl. No. Species Family Status 1 Acalypha australis Euphorbiaceae Rare 2 Acanthephippium silhetense Orchidaceae VulnerableIUCN

3 Acranthera tomentosa Rubiaceae Vulnerable, Endemic, Not EvaluatedIUCN 4 Adinandra griffithii Theaeceae EndangeredIUCN 5 Albertisia mesistophylla Menispermaceae Extinct, Not EvaluatedIUCN 6 Anoectochilus sikkimensis Orchidaceae Critically EndangeredIUCN 7 Apostasia nuda Orchidaceae EndangeredIUCN 8 Begonia tessaricarpa Begoniaceae Extinct, Not EvaluatedIUCN 9 Beilschmiedia pseudomicropora Lauraceae Endemic, Not EvaluatedIUCN 10 Brassiopsis polycantha Araliaceae Rare 11 Bulbophyllum mishmeense Orchidaceae Rare, Endemic Sunipia cirrhata 12 Bulbophyllum virens Orchidaceae Rare, Endemic Sunipia virens 13 Calanthe herbacea Orchidaceae EndangeredIUCN 14 Calanthe odora Orchidaceae EndangeredIUCN 15 Cassia wallichiana Leguminosae Not EvaluatedIUCN 16 Ceropegia lucida Asclepediaceae Rare, Extinct, Not EvaluatedIUCN 17 Chrysoglossum assamicum Orchidaceae EndangeredIUCN 18 Clematis fulvicoma Rannunculaceae Rare, Not EvaluatedIUCN 19 Coelogyne trinervis Orchidaceae VulnerableIUCN 20 Dendrobium aruanticum Orchidaceae Endangered 21 Dioscorea deltoidea Dioscoreaceae Vulnerable 22 Diospyros cacharensis Ebenaceae Rare Not EvaluatedIUCN 23 Dysoxylum gotadhora Meliaceae Rare, Not EvaluatedIUCN

24 Erythrorchis altissima Orchidaceae EndangeredIUCN, Probably Extinct 25 Eulophia manii Orchidaceae Rare, Endemic, EndangeredIUCN 26 Fissistigma santapaui Annonaceae Endemic, Not EvaluatedIUCN 27 Flacourtii helferi Flacourtiaceae Rare, Not EvaluatedIUCN 28 Goniothalamus simsonii Anonaceae Rare, Not EvaluatedIUCN 29 Goodyera recurva Orchidaceae Endemic, EndangeredIUCN 30 Habenaria trifurcata Orchidaceae Rare, Not EvaluatedIUCN 31 Illigera appendiculata Hernandiaceae Rare, Not EvaluatedIUCN

32 Indofevillea khasiana Cucurbitaceae Rare, Not EvaluatedIUCN 33 Lagerstroemia minuticarpa Lythraceae Extinct, EndangeredIUCN 34 Leptomischus wallichii Rubiaceae Rare Not EvaluatedIUCN 35 Liparis cespitosa Orchidaceae Endemic, EndangeredIUCN 36 Liparis delicatula Orchidaceae Rare, Endemic, EndangeredIUCN 37 Liparis vestita Orchidaceae Endemic 38 Livistona jenkinsiana Arecaceae Endangered, Not EvaluatedIUCN 39 Lophopetalum chinense Hamamelidaceae Rare 40 Magnolia baillonii Magnoliaceae Rare, Not EvaluatedIUCN 41 Magnolia caveana Magnoliaceae Rare, Not EvaluatedIUCN 42 Magnolia mannii Magnoliaceae Rare, Endemic, Not EvaluatedIUCN 43 Miliusa dolicantha Annonaceae Rare, Not EvaluatedIUCN 44 Miliusa gustavi Annonaceae Endemic 45 Miliusa insignis Annonaceae Rare 46 Miliusa rabaniana Annonaceae Rare 47 Oldenlandia monocephala Rubiaceae Rare, Not EvaluatedIUCN 48 Oldenlandia scabra Rubiaceae Rare, Not EvaluatedIUCN 49 Ophiorrhiza hispida Rubiaceae Endangered, Not EvaluatedIUCN 50 Ophiorrhiza tingens Rubiaceae Vulnerable, Not EvaluatedIUCN 51 Orophea polycarpa Annonaceae Rare 52 Paphiopedilum spicerianum Orchidaceae Rare, Critically endangeredIUCN 53 Phlogocanthus asperulus Acanthaceae Rare, Not EvaluatedIUCN 54 Smithia grandis Leguminosae Rare, Not EvaluatedIUCN 55 Sterculia khasiana Sterculiaceae Rare 56 Stylidium kunthii Stylidiaceae Rare Not EvaluatedIUCN 57 Symplocos glauca Symplocaceae Rare, Not EvaluatedIUCN 58 Syzygium assamicum Myrtaceae Rare 59 Vanilla pilifera Orchidaceae Rare, EndangeredIUCN

Annexure – I List of Orchids of Brahmaputra valley, Assam (Source: Singh, Phukan & Bujarbarua, 2001 and Barooah & Ahmed, 2014) Genus Species Habitat A. ochracea E A. papilosa E Acampe A. praemorsa E A. rigida E A. striatum T Acanthephippium A. sylhetense T A. falcate E A. multiflora E Aerides A. odorata E A.rosea E A. brevipes E Agrostophyllum A. callosum E A. planicaule E A. elwesii T A. grandiflorus T A. luteus T Anoectochilus A. roxburghii T A. setaceus T A. sikkimensis T A. tortus T Anthogonium A. gracile T Aphyllorchis A. montana T A. nuda T Apostasia A. odorata T A. wallichii T Appendicula A. cornuta E A. flos-aeris E Arachnis A. labrosa E

Arundina A. graminifolia T A. ampullaceum E Ascocentrum A. curvifolium E Biermannia B. bimaculata E B. helferi T Brachycorythis B. iantha T Bryobium B. pudicum E B. affine E B. capillipes E B. careyanum E B. cariniflorum E B. crassipes E B. cylindraceum E B. delictescens E B. ellasonotum E B. forrestii E B. guttulatum E B. helenae E B. hookeri E Bulbophyllum B. iners E B. muscicola E B. obrienianum E B.odoratissimum E B. pectinatum E B. polyrrhizum E B. psychoon E B. pumilo E B. reptans E B. retusiusculum E B. sarcophyllum E B. secundum E

B. tricorne E B. triste E B. wallichii E C. angusia T C. biloba T C. clavata T C. densiflora T C.herbacea T C. lyroglossa T Calanthe C. mannii T C. masuca T C. odora T C. sylvatica T C. triplicate T C. vaginata T Cephalanthera C. longifolia T C. gracilis T Cephalantheropsis C. longipes T C. himalaica E Ceratostylis C. subulata E C. teres E Cheirstylis C. griffithii E Cleisocentron C. trichomum E Chiloschista C. lunifera E Chrysoglossum C. assamicum T Cleisocentron C. pallens E C. appendiculatum E C. arietinum E Cleisostoma C. filiforme E C. loratum E C. paniculatum E

C. racemiferum E C. striatum E C. subulatum E C. assamica E C. barbata E C. fimbriata E C. griffithii E C. nitida E C. ovalis E C. prolifera E Coelogyne C. punctulata E C. rossiana E C. schultesii E C. stricta E C. suaveolens E C.tomentosa E C. trinervis E C. viscose E Collabium C. assamicum E Conchidium C. muscicola E Corymborkis C. veratrifolia T Cremastra C. appendiculata T C. biauritum T Crepidium C. mackinnonii T Cryptostylis C. arachnites T C. aloifolium E C. assamicum E C. bicolour E Cymbidium C. cochleare E C. dayanum E C. eburneum E

C. elegans E C. hookerianum E C. iridioides E C. lancifolium E C. macrorhizon E C. mastersii E C. javanica T Cyrtosia C. lindleyana T D. acinaciforme E D. aduncum E D. anceps E D. angulatum E D. aphyllum E D. assamicum E D. bensoniae E D. bicameratum E D. chrysanthum E D. chryseum E D. chrysotoxum E Dendrobium D. crepidatum E D. cretaceum E D. cumulatum E D. densiflorum E D. devonianum E D. eriiflorum E D. falconeri E D. farmer E D. fimbriatum E D. formosum E D. gibsonii E D. griffithianum E

D. heterocarpum E D. hookerianum E D. infundibulum E D. jenkinsii E D. keithii E D. kentrophyllum E D. lindleyi E D. lituiflorum E D. mannii E D. miserum E D. moschatum E D. nathanielis E D. nobile E D. praciflorum E D. polyanthum E D. perula E D. podagraria E D. pulchellum E D. salaccense E D. spatella E D. stuposum E D. sulcatum E D. terminale E D. transperans E D. wardianum E D. willamsonii E D. himalaica T Didymoplexis D. pallens T Dienia D. ophrydis T Doritis D. pulcherrima E Epigenium E. ampulum E

E. indicum E Epipogium E. roseum E E. alba E E. amica E E. apertiflora E E. biflora E E. bractescens E E. carinata E E. clavicaulis E E. javanica E E. excavate E Eria E. lasiopetala E E. muscicola E E. paniculata E E. pannea E E. pudica E E. pumila E E. sharmae E E. spicata E E. stricta E E. tomentosa E Erythrodes E. hirsute T Erythrorchis E. altissima T E. bicallosa T E. bracteosa T E. candida T E. dabia T Eulophia E. graminea T E. herbacea T E. kamarupa T E. mannii T

E. nuda T E. spectabilis T E. zollingeri T F. fugax E Flickingeria F. macraei E Galeola G. altissima E Gastrochilus G. dasypogon E G. inconspicuus E G. obliquus E G. densiflorum E Geodorum G. laxiflorum E G. recurvum E G. cordata T G. foliosa T G. hispida T Goodyera G. procera T G.recurva T G. repens T G. viridiflora T Gymnadenia G. orchidis E H. commelinifolia T H. digitata T H. furcifera T H. longifolia T H. mandersii T Habenaria H. marginata T H. plantaginea T H. reniformis T H. stenopetala T H. trifurcata T Herminium H. lanceum E

Herpysma H. longicaulis E H. affinis T Hetaeria H. anomala T H. rubens E/T K. deliciosum E Kingidium K. taenialis T L. assamica E L. bootanensis E L. caespitosa E L. delicatula E L. distans E L. elliptica E L. luteola E Liparis L. mannii E L. odorata E L. paradoxa T L. petiolata T L. plantaginea E L. vestita E L. viridiflora E L. bracystachys E L. macrotis E L. microptera E L. platyglossa E Luisia L. psyche E L. trichorhiza E L. tristis E L. zeylanica T/E M. acuminata T Malaxis M. latifolia T Micropera M. obtuse E

M. pallida E M. rostrata E Neogyna N. gardneriana E Nephelaphyllum N. cordifolium T N. aragoana E Nervalia N. Juliana T N. plicata T O. acaulis E O. anthropophora E O. bicornis E O. emarginata E O. ensiformis E O. falconeri E Oberonia O. jenkinsiana E O. mannii E O. mucronata E O. myriantha E O. obcordata E O. pachyrachis E O. pyrulifera E O. lanceolatus E Odontochilus O. tortus E Ornithochilus O. difformis E O. albus E O. fuscus E Otochilus O. lancilabius E O. porrectus E Pachystoma P. pubescens T P. demissa E Panisea P. tricallosa E Paphiopedilum P. venustum T

P. villosum T

P. teres E Papilionanthe P. uniflora E P. vandarum E P. susannae T Pecteilis P. triflora T Pelatantheria P. insectifera E Pennilabium P. proboscideum E P. constrictus T P. goodyeroides T Peristylus P. hamiltonianus T P. parishii T P. prainii T P. flavus T Phaius P. mishmensis T P. tankervilliae T P. cornucervi E P. mannii E Phalaenopsis P. parishii E P. pulcherrima T P. articulate E P. bracteata E P. chinensis E Pholidota P. convallariae E P. imbricate E P. pallida E P. wattii E Phreatia P. elegans E P. acervata E Pinalia P. amica E P. excavate E

P. stricta E Platanthera P. clavigera T Podochilus P. cultratus E P. mannii E Pomatocalpa P. spicatum E Pteroceras P. teres E Renanthera R. imschootiana E R. divitiflora E Rhinerrhiza R. freemanii E Rhynchostylis R. retusa E Robiquetia R. succisa E Saccolabiopsis S. pusilla E Smitinandia S. micrantha E Satyrium S. nepalense T Schoenorchis S. gemmata E Spathoglotis S. plicata T Spiranthes S. sinensis T Stereochilus S. ringens E S. distans E S. elliptica E Stichorkis S. mannii E S. vestita E S. viridiflora E S. cirrhata E Sunipia S. virens E Taeniophyllum T. glandulosum E T. latifolia T Tainia T. viridifusca T Thelasis T. pygmaea E T. centipede E Thrixspermum T. trichoglottis E

Thunia T. alba T/E Trichotosia T. pulvinata E T. angulosa T Tropidia T. curculigoides T Tylostylis T. discolour E U. acuminata E Uncifera U. obtusifolia E V. bicolour E V. coerulea E V. coerulescens E Vanda V. cristata E V. stangeana E V. tessellate E V. testacea E Vandopsis V. undulate E V. borneensis T Vanilla V. pilifera T V. walkeriae T Z. assamica T Z. cordata T Z. flava T Z. goodyeroides T Zeuxine Z. gracilis T Z. longilabris T Z. membranacea T Z. nervosa T Z. strateumatica T E – Epiphyte, T - Terrestrial

Note: The names of the plant taxa mentioned in the appendix and annexure are subjected to recent nomenclatural changes.