Studies on the diversity and ethnic uses of wetland vascular plants in Terai and Duars of West Bengal, India A THESIS SUBMITTED TO THE UNIVERSITY OF NORTH BENGAL FOR THE AWARD OF DOCTOR OF PHILOSOPHY IN BOTANY By Anurag Chowdhury Guide Dr. Abhaya Prasad Das Professor Department of studies in Botany University of North Bengal November, 2015 Acknowledgements I express my heartiest gratitude to my respected teacher, mentor and supervisor, Prof. Abhaya Prasad Das of Plant Taxonomy and Environmental Biology laboratory, Department of Botany, North Bengal University for his inspiration, motivation, suggestion and continuous encouragement, co-operation and invaluable guidance, which were tremendously helpful for me to take up and to complete the present work. I would like to convey my heartiest thanks to our teacher Dr. Monoranjan Chowdhury, Plant Taxonomy and Environmental Biology laboratory, Department of Botany for his valuable guidance, suggestion and continuous encouragement. I would like to convey my heartiest thanks to the Head of the Department of Botany who looked after the department during my tenure of work for extending all the required facilities. I am also thankful to all the teachers of Department of Botany for their continuous support, help and encouragement. My thanks also go for all the non-teaching staff of the Department of Botany for their various kinds of assistance. I express my heartiest thanks to our senior scholar (Didi) Dr. Chandra Ghosh, Head, Botany Department, Gour Mahavidayalaya, Malda for her kind advices and cooperation. I want to express my cordial thanks to my Teacher Dr. Shubhasis Panda, now posted at Darjeeling Govt. College, for his continuous encouragement and support. I also express my gratitude to Mrs. Rubi Das who always provided me the motherly environment, enough loves and continuous support which helped me to reach the goal. I would like to extend my heartiest thanks to my senior scholars in the Taxonomy and Environmental Biology Laboratory, namely, Mr. Animesh Sarkar, Dr. Sonam Rinchen Lepcha, Mr. Suman Nirola, Dr. Ajita Sarkar, Mr. Rajib Biswas, Mr. Saurav Moktan, Mr. Dibakar Choudhury, Mr. Amalesh Bijali, Mr. Kishor Biswas, and my juniors Mr. Biman Krishna Saha, Mrs. Baishakhi Sarkar and Miss Payel Paul for their continuous help and support. I also want to mention my thanks to Mr. Binod Singha & Mrs. Sangita Oraon, the laboratory attendants in the Plant taxonomy & Environmental biology laboratory for their assistance in field and laboratory works. I would like to extend my heartiest thanks to Mr, Dhaniram Toto, Mr. Uday Toto, Mr. Khagen Murmu, Mr. Tikka Oraon, Mr. Anil Rabha, Mr. Giribala Santal and Mr. Chandalal Karzi for their continuous help and assistance in ethnobotanical survey of wetland plants. I must extend my sincere thanks to different Forest Department (Govt. of West Bengal) officials and other staff-members for permitting and assisting me to work, especially in the Protected Areas, which helped me to record some novelties. Other Govt. offices like Land Reforms Department, Jalpaiguri; Fishery Department, Jalpaiguri; Meteorological Department, Jalpaiguri and Wetland Management office Kolkata for providing useful ancillary data required for the proper interpretation of my work. I want to express my heartiest thanks to Ms. Roshni Biswas, Mr. Janardan Biswas and Mrs. Krishna Biswas for their continuous help, encouragement and moral support. Abstract Wetlands are the transitional zones where aquatic and terrestrial habitats meet. Terai and Duars are generally situated on the western and Eastern bank of River Teesta of West Bengal. The Terai means dampness or marshiness and the Duars means the door or the gate way of Bhutan. These regions are under Himalayan Hotspot. Numerous wetlands are present in this region due to its geographical variations. The wetlands of these areas are generally Riverine, Lacustrine and Palustrine. The study area covers a total of 6227 sq km, out of which 484.27 sq km area is occupied by wetlands. Regular recurrence flood, almost every year gradually increases the wetlands in Terai & Duars. This area is the house of so many fresh water wetlands. Among the 23 larger wetlands of west Bengal 06 are present in the study areas. Several parameters have been studied during the last five years. 40 wetlands of Terai & Duars have studied for Taxonomical explorations. But, to examine the other parameters several small and larger wetlands, lakes, ponds, roadside ditches, river beds, ephemeral water bodies and streams have been studied and huge bulk of data was accumulated. 53 largest wetlands like Gajoldoba Beel, Mahananda Barrage, Shova Bari Beel, Kuchi Daineer Beel, Khatambari Beel, and several forest wetlands like Gossaihat Beel, Garati Beel and Chukchuki Beel have been chosen for detailed study. Beside these, several ancient dighi ponds, rivers and roadside ephemeral ditches have also been chosen. Floristic exploration in different wetlands has been conducted mainly in three important seasons in last few years and during the survey total 455 species are recorded from Terai & Duars. The collected plants are generally hydrophytes, fenland loving and few pseudo wetland plants that grown during summer within the boundary of wetlands areas. Among these 241 species are dicot, 192 species are monocot and 22 species are pteridophytes. The total collected specimen is almost 37.58 % of the Indian total wetland flora. Two novelties [Nymphaea abhayana A. chowdhury & M. Chowdhury of Nymphaeaceae and Lindernia palustris A. Chowdhury, M. Chowdhury & A.P Das ofLinderniaceae] recoded during the present work. In addition, the new records of as much as eight species of plants is also significant for the vegetation. Of these one [Adenostemma suffruticosum Gardner of Asteraceae] is new record for the entire northern hemisphere; three [Potamogeton gramineus Linnaeus of Potamogetonaceae, Murdania keisak (Hasskarl) Handel-Mazzetti of Commelinaceae and Polygonum hastatogagittatum Makino of Polygonaceae] are for the flora f the country; and, Four [Ludwigia peruviana (Linnaeus) H. Hara of Onagraceae), Hygrophila erecta (N.L. Burman) Hochreutiner of Acanthaceae, Soliva anthemifolia (A. Jussieu) R. Brown of Asteraceae and Carex phacota Sprengel of Cyperaceae] are forming the new records for the state of West Bengal. 244 species of aquatic and semi-aquatic species have been selected for the phonological study in their in situ condition. The information about the life cycle of the collected plant species have been studied in details. The flowering and fruiting calendar of the plant species of wetland have been prepared. Abstract ii The pollination patterns of these plants are very interesting that involves almost all types of pollination for fertilization. The wetlands are also natural habitat for several economically important plants. This segment studied in two ways firstly the Ethnobotany i.e., wetland plants those are used by different local and tribal peoples of the Terai & Duars. They use those plants in various purposes like as medicine, food, fodder, manure, building materials and some other purpose. Around 83 species are found to as medicinal importance, 31 leafy vegetables,7 building materials, 12 plants used in broom, utensil etc making. Except these several species used as fodder, fuel and ornamental purpose. Secondly, the wetlands plants of these areas are with various economical importances. 149 species of these wetlands are found to as useful. As much as 87 species have been recorded on sale in different village and urban markets. The wetlands of Terai & Duars are under various threats, which are mostly anthropological and few are natural. Among the anthropological causes excessive irrigation and agricultural activities are most dangerous. The urban sewage, garbage, vehicle washable materials reduces the depth of wetlands and badly affects the water quality and the wild ecosystem leading to the drastic reduction in biological diversity. After the study of different parameters of the wetlands areas of Terai & Duars it is found that these wetlands are very rich in their biodiversity. Regarding conservation of those wetlands few measures or management strategies have suggested in the dissertation. Too much of exploitation in the form of crop-cultivation, pisiculture, and ecotourism are need to be reduced drastically. Considering several aspects and understandings strategies for the management of the wetland ecosystems of Terai and Duars have been framed for the proper conservation of their natural biological diversity. Preface Since the wetlands are the highly biodiversity ecotonal zone caring wide range of ecological importance as global ecosystem concern. These water land interface are distributed in all altitudinal ranges of tropical, temperate and arctic regions of the earth. Terai-Duars of sub-himalayan foot hills of North Bengal are blessed with several ephemeral & perennial drainage systems originating from the glacial of Himalayas and through anastomating with each other during their long zigzag run ways forming several permanent and temporary wetlands or marshes. These wetlands are harboring various kinds of floras and faunas and the interrelationship of such biodiversity and inorganic entities forming a stable and healthy ecosystem in this region. Several wetlands of this region are also associated with different conservatories and providing continuous water supply to the existing vegetation and wildlife’s. The green and dense forest and associated water-bodies makes