PARTICIPATING INSTITUTIONS

Centre for Inter-disciplinary Studies of Mountain & Hill Environment, University of Delhi, Delhi

Centre for Atmospheric Sciences, Indian Institute of

Technology, Delhi

Centre for Himalayan Studies, University of North Bengal, Distt. Darjeeling

Department of Geography and Applied Geography, University

of North Bengal, Distt. Darjeeling

Salim Ali Centre for Ornithology and Natural History, Anaikatti, Coimbatore

Water and Power Consultancy Services (India) Ltd., Gurgaon,

Haryana

Food Microbiology Laboratory, Department of Botany, Sikkim Government College, Gangtok

VOLUMES INDEX* Volume I INTRODUCTORY VOLUME

Volume II LAND ENVIRONMENT - GEOPHYSICAL ENVIRONMENT

Volume III LAND ENVIRONMENT - SOIL

Volume IV WATER ENVIRONMENT

Volume V AIR ENVIRONMENT

Volume VI BIOLOGICAL ENVIRONMENT TERRESTRIAL AND AQUATIC RESOURCES

Volume VII BIOLOGICAL ENVIRONMENT - FAUNAL ELEMENTS

Volume VIII BIOLOGICAL ENVIRONMENT - FOOD RESOURCES

Volume IX SOCIO-ECONOMIC ENVIRONMENT

Volume X SOCIO-CULTURAL ENVIRONMENT

EXECUTIVE SUMMARY AND RECOMMENDATIONS

*For Volume-wise Detailed Index Refer to the end of the report

CONTENTS

Page No. CHAPTER 1 FOREST TYPES AND VEGETATION 1.1 TROPICAL MOIST DECIDUOUS FORESTS 2 1.2 SUB-TROPICAL FORESTS 3 1.2.1 Sub-tropical Broad Leaved Forests 3 1.2.2 Sub-tropical Chir Pine Forests 5 1.3 MONTANE WET TEMPERATE FORESTS 5 1.3.1 Wet Temperate Forests 5 1.3.2 Mixed Coniferous Forests 7 1.4 SUB-ALPINE FOREST 9 1.5 ALPINE SCRUBS AND PASTURES 9 1.5.1 Alpine Scrub Forest 10 1.5.2 Dwarf Rhododendron Scrub 10 1.5.3 Alpine Pastures 10 1.5.4 Dry Alpine Scrub 11 1.5.5 Dwarf Juniper Scrub 11 1.6 VEGETATION PROFILE 11 1.6.1 Rangpo-Singtam, Gantok, Kyongnosla, Sherathang, 12 Menmoi Chho, Kupup in East Sikkim

1.6.2 Singtam-Tarko, Khemdong, Ravongla, Maenam 17 Wildlife Sanctuary in South Sikkim 1.6.3 Dikchu, Mangan, Tong, Chakung Chhu, Chungthang, 20 Chhaten, Lachen, Zemu, Yathang, Thangu, Gurudongmar in Sikkim 1.6.4 Chungthang, Lachung, Shingba, Yumthang, 26 Yumesamdong in North Sikkim 1.6.5 Sangklang, Selem, Sakkyong, Talung, Lingzah, Lingdem, 28 Lingmum in North Sikkim 1.6.6 Melli Bazar, Jorethang, Sombaria, Okhrey, Hilley and 32 Barsey Rhododendron Sanctuary in West Sikkim 1.6.7 Jorethang-Legship, Rangit Nagar, Tashiding, Yuksom, 35 Gyalzing, Pelling, Yuksom, Bakhim, Tshoka, Dzongri in West Sikkim

CHAPTER 2 FLORISTICS 2.1 INTRODUCTION 42 2.2 PLANT EXPLORATIONS IN TEESTA BASIN 44

2.2.1 Objectives 47 2.3 TAXONOMIC DIVERSTIY 48 2.3.1 Flowering Plants 49 2.4 PHYSIOGNOMIC DIVERSITY 56 2.5 PHYTOGEOGRAPHICAL AFFINITIES 57 2.6 ENDEMICS 62

2.6.1 Field survey of the endemic species 64 2.6.2 Districtwise distribution of endemic species 65

2.7 THREATENED FLORA 72 2.7.1 Present Status of some Endangered Taxa 72

2.7.2 District-wise distribution of threatened species 80 2.7.3 Threatened endemic plant species 81 2.7.4 Economic Importance of Threatened Species 84

2.8 RHODODENDRONS 87 2.8.1 Important uses of Rhododendrons in Sikkim 91 2.8.2 Conservations measures for Rhododendron species 92

2.9 PRIMULA spp. 95 2.10 ORCHID DIVERSITY 96 2.11 ECONOMICALLY IMPORTANT PLANT SPECIES 108 2.11.1 Medicinal Uses 108 2.11.2 Timber, Fuel wood and other Uses 110 2.11.3 Cultigens and Aliens 111 2.11.4 Cereals and Pseudocereals 112 2.11.5 Pulses 112 2.11.6 Vegetables 112 2.11.7 Spices and Condiments 113 2.11.8 Exotic Species 113 2.12 FLORAL HOT SPOTS OF SIKKIM 116 2.13 PERSPECTIVE PLANNING 117 CHAPTER 3 AQUATIC ENVIRONMENT AND WATER QUALITY 3.1 INTRODUCTION 119 3.2 METHODS 120 3.2.1 Physical and Chemical Characteristics 121 3.2.2 Biological Characteristics 124 3.3 TEESTA RIVER 128 3.3.1 Physical and Chemical Characteristics 128

3.3.2 Biological Characteristics 140 3.3.3 Community Structure 145 3.4 RANGPO CHHU 157 3.4.1 Physical and Chemical Characteristics 157 3.4.2 Biological Characteristics 158 3.4.3 Community Structure 160 3.5 RANI KHOLA 163 3.5.1 Physical and Chemical Characteristics 164 3.5.2 Biological Characteristics 166 3.5.3 Community Structure 166 3.6 RANGIT RIVER 169 3.6.1 Physical and Chemical Characteristics 169 3.6.2 Biological Characteristics 171 3.6.3 Community Structure 172 3.7 RANGYONG CHHU 175 3.7.1 Physical and Chemical Characteristics 175 3.7.2 Biological Characteristics 178 3.7.3 Community Structure 180 3.8 OTHER STREAMS OF TEESTA BASIN 184 3.8.1 Rishi Khola 184 3.8.2 Ramam Khola 186 3.8.3 Rangpo Khola 187 3.9 CONCLUSION 188

3.10 LAKES 190 3.10.1 Distribution of lakes in Sikkim 191 3.10.2 Significance of lakes in Sikkim 193 3.10.3 Lake avifauna 195 3.10.4 Mythological importance of lakes 195

3.10.5 Limnology of a few selected lakes 196 3.11 CONCLUSIONS 208 CHAPTER 4 FISH FAUNA 4.1 INTRODUCTION 209 4.2 FISH COMPOSITION AND DISTRIBUTION 210 4.2.1 Salmo trutta fario 214 4.2.2 Salmo gairdneri gaordneri 215 4.2.3 Schizothorax richardsonii 215 4.2.4 Schizothoraicthys curviforns 216

4.2.5 Schizothoraicthys progastus 216 4.2.6 Tor putitora 216 4.2.7 Acrossocheilus hexagonolepis 217 4.2.8 Acrossocheilus spinulosus 217 4.2.9 Puntius clavatus 217 4.2.10 Labeo species 218 4.2.11 Barilius spp. 218 4.2.12 Garra spp. 218 4.2.13 Crossocheilus latius latius 219 4.2.14 Anguilla bengalensis 219 4.2.15 Noemacheilus spp. 219 4.2.16 Glyptothorax spp. 220 4.2.17 Euchiloglanis hodgarti 220 4.2.18 Pseudecheneis sulcatus 220 4.2.19 Other fishes 220 4.3 FISH MIGRATION IN SIKKIM 221 4.4 ENDEMIC AND THREATENED SPECIES 222 4.5 FISH INTRODUCTION IN SIKKIM 223 4.6 FISHERIES DEVELOPMENT IN SIKKIM 224 4.6.1 Fish Farms in Sikkim 224 4.6.2 Fish Catch in Sikkim 225 4.6.3 Daily Fish Catch in Sikkim 226 4.6.4 Game Fishing 227 4.7 STRESSES ON FISH POPULATIONS IN SIKKIM 227 4.8 MITIGATION MEASURES 228 CHAPTER 5 PROTECTED AREAS 5.1 INTRODUCTION 230 5.2 KHANGCHENDZONGA BIOSPHERE RESERVE 231 5.2.1 Topography and Climate 233 5.2.2 Forests 234 5.2.3 Floristic Diversity 237 5.2.4 Fungi 240 5.2.5 Lichens 241 5.2.6 Pteridophytes 241 5.2.7 Endemic Taxa 242 5.2.8 Threatened Species 242 5.2.9 Fauna 243

5.3 KHANGCHENDZONGA NATIONAL PARK 243 5.4 MAENAM WILDLIFE SANCTUARY 244 5.5 SHINGBA RHODODENDRON SANCTUARY 245 5.6 KYONGNOSLA ALPINE SANCTUARY 246 5.7 BARSEY RHODODENDRON SANCTUARY 247 5.8 FAMBONG LHO WILDLIFE SANCTUARY 249 5.9 PANGOLAKHA WILDLIFE SANCTUARY 250 5.10 PROPOSED PROTECTED AREAS 251 BIBLIOGRAPHY 253 ANNEXURE I i-xviii

LIST OF TABLES

Table 1.1 Principal forest types found in Teesta basin Table 2.1 Floral richness of Teesta basin in Sikkim vis--vis other Himalayan

regions and north-east India Table 2.2 Some important plant explorers of Sikkim Table 2.3 Literature on floral wealth of Sikkim Table 2.4 Number of species in different plant groups from Sikkim Table 2.5 Monocot families in Sikkim Table 2.6 Dominant dicot families in Sikkim Table 2.7 Some dominant dicot genera in Sikkim Table 2.8 Gymnosperms of Sikkim Himalaya Table 2.9 Some common pteridophytes of Sikkim Himalaya Table 2.10 Floristic elements in Sikkim Himalaya from different regions of world Table 2.11 Endemic flowering plants of Sikkim Table 2.12 Endemic species recorded from different parts of Sikkim Table 2.13 Threatened flowering plant species in Sikkim Table 2.14 Threatened plant species recorded from Sikkim Himalaya during the

survey Table 2.15 Endemic as well as threatened plant species of Sikkim Himalaya Table 2.16 Economic importance of some of the endemic and threatened species

of Sikkim Himalaya Table 2.17 Census of Panax pseudoginseng individuals in Sikkim Himalaya (2004-

2005) Table 2.18 Rhododendron species of Sikkim Table 2.19 Threatened species of Rhododendron from Sikkim Himalaya Table 2.20 Species of Primula available in Sikkim Himalaya Table 2.21 Some ornamental species of orchids from Sikkim Table 2.22 Orchid species used for curing various ailments in Sikkim Table 2.23 Some naturalized exotic weeds in Sikkim Table 2.24 District-wise floristic richness of Sikkim Table 3.1 Physical and chemical characteristics of lower stretch of Teesta river in

Sikkim Table 3.2 Physical and chemical characteristics of upper stretch of Teesta

(Lachen Chhu) and Lachung Chhu in Sikkim

Table 3.3 Densities of different biotic communities in the lower stretch of river Teesta

Table 3.4 Densities of different biotic communities in upper stretch of Teesta and Lachung Chhu in Sikkim

Table 3.5 Species composition of phytoplankton in Teesta river and Lachung Chhu in Sikkim during post-monsoon season

Table 3.6 Species composition of phytobenthos in Teesta river and Lachung Chhu in Sikkim during post-monsoon season

Table 3.7 Micro-invertebrates composition in river Teesta and Lachung Chhu in Sikkim during post-monsoon season

Table 3.8 Physical and chemical characteristics of Rangpo Chhu in Sikkim Table 3.9 Density of different biotic communities of Rangpo Chhu in Sikkim Table 3.10 Species composition of planktonic and phytobenthic communities in

Rangpo Chhu in Sikkim Table 3.11 Density (individuals/m3) of macro-invertebrates in Rangpo Chhu in

Sikkim Table 3.12 Physical and chemical characteristics of Rani Khola in Sikkim Table 3.13 Densities of different biotic communities of Rani Khola in Sikkim Table 3.14 Species composition of planktonic and phytobenthic communities i