Effect of Forest Fragmentation on Vascular Plant Diversity in Khangchendzonga Biosphere Reserve, Sikkim with Emphasis on Regeneration of Some Important Taxa
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EFFECT OF FOREST FRAGMENTATION ON VASCULAR PLANT DIVERSITY IN KHANGCHENDZONGA BIOSPHERE RESERVE, SIKKIM WITH EMPHASIS ON REGENERATION OF SOME IMPORTANT TAXA BY ARUN CHETTRI THESIS SUBMITTED IN FULFILMENT OF THE DEGREE OF DOCTOR OF PHILOSOPHY IN BOTANY DEPARTMENT OF BOTANY NORTH-EASTERN HILL UNIVERSITY SHILLONG, MEGHALAYA, INDIA 2010 ACKNOWLEDGEMENTS I express my deep sense of gratitude to my Supervisor Dr. S.K. Barik, Department of Botany, North-Eastern Hill University, Shillong for his valuable guidance, constant encouragement and constructive criticisms throughout the course of this study and for going through the manuscript. I am extremely obliged to my Joint Supervisor Prof. H. N. Pandey (retired), Department of Botany, North- Eastern Hill University, Shillong for his constant inspiration, valuable guidance, and keen interest throughout this study. I also offer my sincere thanks to Prof. M.S. Dkhar (Head of the Department of Botany, NEHU) for providing necessary facilities during the course of study. I am thankful to the Joint Director, Botanical Survey of India, Sikkim Himalayan Circle, Gangtok and Eastern Circle, Shillong for herbarium survey and library facilities. I am also thankful to Forest, Environment and Wildlife Management Department, Gangtok and Home Department, Government of Sikkim for allowing us to conduct research studies in KBR. I offer my earnest gratitude to Sunder daju, Pradhan daju, Dewan daju, Giri daju and Geeta didi (BSI, Sikkim) for their help, identification of specimens and encouragement. I am thankful to Dr. Kiranmay Sarma, and Dr. Dibyendu Adhikari for their ever ready active help in field of GIS, Remote Sensing and statistics. I am thankful to my research mate Mr. Mark Kordor Lyngdoh, for his cooperation during the field studies. My sincere thanks goes to all my labmates from forest Ecology and Biodiversity Research Lab. Dr. Jenpuireu, Dr. John, Assistant Prof. Ratul Baishya, Eva, Debashree, Lucy, Wishfully, Namita, Dona and to all other research colleagues of the Department of Botany, NEHU. I also extend my thanks to Dr. K. Upadhaya, Mr. Don and Dr, Takhel for their help and support during the finalization and submission of the thesis. I wish to offer my warmest thanks to Mrs Anjila Tamang (wife) who at every stage of the study rendered tremendous academic help as well as moral support. It would have been impossible to complete this study without the constant encouragement, inspiration and support of my Mother, Mama & Maiju, Sita didi & Vena, brother Amber, sister Sunita, Indu, Basu & Juay and so, I express my special gratitude to them. Financial support received from Ministry of Environment and Forests, Government of India under its Biosphere Reserve Programme is thankfully acknowledged. Financial support received from UGC as Research Fellowship for meritorious research fellow (on Science for Meritorious student) in the Department of Botany, NEHU, Shillong is also highly acknowledged. Last, but not the least, I thank Almighty God without whose blessings has helped me in facing all the critical problems faced during the course of the study. Date: Place: NEHU, Shillong (Arun Chettri) Contents Page No. Chapter 1 General Introduction 1-9 Chapter 2 Review of Literature 10-17 Chapter 3 Study sites 18-27 Chapter 4 Plant diversity-environment relationship in three forest types 28-85 Chapter 5 Pattern of forest fragmentation in Khangchendzonga Biosphere 86-103 Reserve Chapter 6 Tree diversity along the fragment size gradient 104-121 Chapter 7 Regeneration of selected trees and lianas 122-150 Chapter 8 General Discussion 151-169 Summary 170-179 References 180-191 List of Publications Table No. List of Tables Page No. Table 3.1. Area (km2) statistics of Khangchendzonga Biosphere Reserve 22 Table 3.2. Topographical features of six study sites in three forest types of KBR 26 Table 3.3. Mean of edaphic characteristics of three forest types in Khangchendzonga 27 Biosphere Reserves (after Chettri et al. 2010). Table 4.1. Terrestrial ecosystem types identified along the elevational gradient in KBR, 29 Sikkim Table 4.2. Species richness, density and basal area of trees, shrubs and herbs, in KBR 38 Table 4.3. General diversity patterns for different Lifeforms in three forest types 39 (values in parenthesis indicate Jackknife standard error) Table 4.4. Similarity test values of ANOSIM and SIMPER in the sampled sites for 39 Lower montane, Montane and Upper montane forests. The ANOSIM ‘R value’ is the statistical value of similarity within each forest stands with a probability of 0.001 Table 4.5. Results of two-way ANOVA of microenvironmental factors to assess the 42 variations due to forest types (Lower montane, Montane, Upper montane) and seasons (winter, summer, monsoon) in KBR. For each environmental variable n = 9 and d. f. = 2 for both forest type and season Table 4.6. Variance explained in the Canonical Correspondence Analysis (CCA) for 44 trees by the first two axes across the forest types in KBR Table 4.7. Results of forward stepwise multiple regression analysis of environmental 45 variables with tree density in three forest types in KBR Table 4.8. Similarity test values of ANOSIM and SIMPER on the sampled sites for 46 Lower montane, Montane and Upper montane forests areas. The ANOSIM ‘R value’ is the statistical value of similarity within each forest stands with a probability of 0.001 Table 4.9. Variance explained in the Canonical Correspondence Analysis (CCA) for 47 shrubs by the first two axes across the three forest types in KBR Table 4.10. Results of forward stepwise multiple regression analysis of environmental 49 variables with shrub density in three forest types in KBR Table 4.11. Similarity test values of ANOSIM and SIMPER on the sampled sites for 50 Lower montane, Montane and Upper montane forests areas. The ANOSIM ‘R value’ is the statistical value of similarity within each forest stands with a probability of 0.001 Table 4.12. Variance explained in the Canonical Correspondence Analysis (CCA) for 51 herbs by the first two axes across the forest types in KBR Table 4.13. Results of forward stepwise multiple regression analysis of environmental 54 variables with herb density in the three forest types in KBR Table 4.14. General epiphytic diversity patterns in three forest types (values in 54 parenthesis indicate Jackknife standard error) Table 4.15. Similarity test values of ANOSIM and SIMPER in the sampled sites for 56 Lower montane, Montane and Upper montane forests areas. The ANOSIM ‘R value’ is the statistical value of similarity within each forest stands with a probability of 0.001 Table 4.16. Epiphytic flora of KBR according to habit and extent of their dependency 59 and interaction with the host plants Table 4.17. Variance explained in the Canonical Correspondence Analysis (CCA) for 60 epiphyte by the first two axes across the forest types in KBR Table 4.18. Results of forward stepwise multiple regression analysis of environmental 62 variables with epiphyte density in the three forest types in KBR Table 4.19. Liana species diversity indices in Lower montane (LM), Montane (M) and 62 Upper montane (UM) forests of KBR. The figures in parentheses are Jackknife standard error Table 4.20. List of liana species with density and IVI in three forest types in KBR 64 Table 4.21. Variance explained in the Canonical Correspondence Analysis (CCA) by the 66 first two axes across the forest types in KBR Table 4.22. Results of forward stepwise multiple regression analysis of environmental 66 variables with liana density in the three forest types in KBR Table 4.23. List of Rare and Threatened plants in three forests 68 Table 5.1. Land cover classes of KBR 89 Table 5.2. Characteristics of the 25 forest fragments in Khangchendzonga Biosphere 91 Reserve, Sikkim Table 5.3. Spatial variables for the 25 fragments in KBR 93 Table 5.4. Land use changes in KBR during 1999 - 2008 94 Table 5.5 Fragment dynamics in KBR during 1999-2008 95 Table 6.1. Fragments size, tree diversity summary for 25 forest fragments and adjacent 109 continuous forests in KBR, Sikkim Table 6.2. Summary of the DECORANA ordination of tree species across the 25 116 fragments in KBR Table 7.1. Distribution of the four selected species in the KBR and their importance 124 Table 7.2. Ecological description of the selected four species 130 Table 7.3. ANOVA to test the variation in sprouting intensity due to stump diameter in 134 Holboellia latifolia and Toricellia tillifolia Table 7.4. Regression models showing the relationship between stump size and number 134 of sprouts Table 7.5. Mean (±SD) of flower production, fruit production and flower abortion in 136 different forests and years. F-ratios show their variances across DBH, stands and years Table 7.6. ANOVA for testing the variation in seed bank due to tree girth size, forest 137 type and year Table 7.7. Seed Viability (%) during storage at room temperature (values are based on a 138 sample of 100 seeds) Table 7.8. ANOVA for testing the effects of forest type and leaf litter treatment on seed 138 germination of selected species Table 7.9. Seedling recruitment and mortality of the selected species in three forests 140 Table 7.10. Life history trait of four species studied and used for classifying them into 142 two distinct guilds viz., pioneer and non-pioneer species Table 7.11. ANOVA to test for the effects of habitat and fragment type on mean seedling 142 density for the selected species in 25 forest fragments Table 7.12. Results of forward stepwise multiple regression analysis of environmental 143 variables with mean seedling density across the fragments Figure No. List of Figures Page No. Figure 3.1.