Saurashtra University Re – Accredited Grade ‘B’ by NAAC (CGPA 2.93) Upamanyu, Hore, 2009, “Diversity and Structure of Spider Assemblages in Terai Conservation Area”, thesis PhD, Saurashtra University http://etheses.saurashtrauniversity.edu/id/eprint/589 Copyright and moral rights for this thesis are retained by the author A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the Author. The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the Author When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given. Saurashtra University Theses Service http://etheses.saurashtrauniversity.edu [email protected] © The Author DIVERSITY AND STRUCTURE OF SPIDER ASSEMBLAGES IN TERAI CONSERVATION AREA (TCA) THESIS SUBMITTED TO THE SAURASHTRA UNIVERSITY, RAJKOT (GUJARAT) FOR THE AWARD OF THE DEGREE OF D O C T O R O F P H I L O S O P H Y IN W I L D L I F E S C I E N C E BY U P A M A N Y U H O R E Wildlife Institute of India Chandrabani, Dehradun Uttarakhand, India June 2009 Contents Page No. List of Appendices i List of Figures ii List of Tables v List of Plates vii Acknowledgements viii Summary x CHAPTER 1: INTRODUCTION 1-8 1.1 Challenges for Invertebrate Conservation 1 1.2 Spiders for Biodiversity Assessments 3 1.3 Forest Management Practices and Spiders 4 1.4 Spiders in Conservation Research and Future Direction 6 1.5 Aim and Objectives 7 1.6 Organization of the Thesis 7 CHAPTER 2: STUDY AREA 9-14 2.1 Terai Conservation Area - Global Priority Region for Conservation 9 2.1.1 Location and Extent 10 2.1.2 Physiography, Soil, Drainage and Climate 11 2.1.3 Floral and Faunal Diversity 12 2.1.4 History of Forest Management Practices 13 CHAPTER 3: FAUNISTIC INVENTORY OF SPIDERS IN TERAI 15-79 CONSERVATION AREA 3.1 Introduction 15 3.2 The Classification of Spiders 15 3.3 Spider Anatomy 17 3.4 Anatomy as it Relates to Classification 22 3.5 Research and Studies on Indian Spiders 23 3.6 Inventory of Spiders in Terai Conservation Area 25 CHAPTER 4: DIVERSITY AND COMPOSITION OF SPIDER 80-97 (ARANEAE) ASSEMBLAGES 4.1 Introduction 80 4.2 Methods 81 4.3 Sampling Design and Techniques 83 4.3.1 Pitfall Sampling 84 4.3.2 Semi-quantitative Sampling 84 4.4 Analysis 85 4.4.1 Species Richness and Local Diversity 85 4.4.2 Site Similarity and Cluster Analysis 86 4.5 Results 87 4.5.1 Species Richness and Local Diversity 87 4.5.2 Species Composition and Site Similarity 91 4.5.3 Family Composition and Site Similarity 92 4.6 Discussions 94 CHAPTER 5: HABITAT ASSOCIATION OF SPIDER ASSEMBLAGES 98-124 5.1 Introduction 98 5.1.1 Habitat Heterogeneity Hypothesis 98 5.1.2 Patterns and Process of Global Diversity 99 5.1.3 Habitat Factors and Spider Assemblage 100 5.2 Methods 102 5.2.1 Vegetation Variables 103 5.2.2 Microclimate Variables 104 5.2.3 Prey Biomass 105 5.2.4 Disturbance Variables 105 5.2.5 Analysis 106 5.2.5.1 Richness, Abundance, Diversity and Habitat 106 Variables 5.2.5.2 Community Composition and Habitat Variables 108 5.2.5.3 Indicator Species 108 5.3 Results 110 5.3.1 Richness, Abundance, Diversity and Habitat Variables 110 5.3.2 Community Composition and Habitat Variables 113 5.3.3 Indicator Species 118 5.4 Discussions 121 CHAPTER 6: EFFECT OF GRASSLAND BURNING ON SPIDER 125-157 (ARANEAE) ASSEMBLAGES 6.1 Introduction 125 6.1.1 Habitat Disturbance and Biodiversity 125 6.1.2 Prescribed Burning and Impact on Biodiversity 125 6.1.3 Tall Grasslands in India 126 6.1.4 Tall Grasslands and Fire in India 127 6.1.5 Tall Grasslands, Fire and Biodiversity Conservation in 127 India 6.2 Methods 129 6.2.1 Study Site 129 6.2.2 Spider Sampling 130 6.2.3 Vegetation and Microhabitat Variables 131 6.2.4 Analysis 132 6.3 Results 136 6.3.1 Species Richness, Abundance and Fire Effects 136 6.3.2 Community Composition 142 6.3.3 Fire Regime Effect on Individual Species 149 6.3.4 Microhabitat Composition 150 6.3.5 Habitat Variables and Fire Effects 154 6.4 Discussions 154 CHAPTER 7: HIGHER TAXA SURROGACY AND EFFICIENCY IN 158-175 SPIDER CONSERVATION 7.1 Introduction 158 7.2 Methods 160 7.2.1 Analysis 162 7.3 Results 164 7.3.1 Species Richness Prediction 165 7.3.1.1 Choosing the Best Surrogate 165 7.3.1.2 Influence of Factors 165 7.3.1.3 Cross-level Correlations in Complementarity 166 7.3.2 Conservation Priority 166 7.3.2.1 Scoring Approach 166 7.3.2.3 Iterative Approach 166 7.4 Discussions 167 CHAPTER 8: GENERAL DISCUSSION AND CONCLUSION 176-182 8.1 Introduction 176 8.2 Faunistic Inventory of Spiders in Terai Conservation Area 177 8.3 Diversity and Composition of Spider (Araneae) Assemblages 177 8.4 Habitat Association of Spider Assemblages 178 8.5 Effect of Grassland Burning on Spider (Araneae) Assemblages 180 8.6 Higher taxa Surrogacy and Efficiency in Conservation 181 References 183-213 Appendices 214-221 List of Appendices Title Page No. Appendix 4.1 Lists of spider species recorded in each habitat type 214 during sampling 100 sites in 5 habitat types in TCA. Appendix 5.1 List of sampling sites with their attributes representing 218 habitat gradient in the study area, TCA. i List of Figures Title Page No. Fig.2.1 Base map of Terai Conservation Area (TCA). 10 Fig. 3.1 External morphology of spiders showing the dorsal and 17 ventral views. Fig. 3.2 Eye morphology and eye patterns of showings various eye 18 parts. Fig. 3.3 Segments of typical spider leg. 20 Fig. 3.4 Ventral view of spider showing various parts of spinnerets. 21 Fig. 3.5 Ventral view of cribellum of typical cribellate spider. 21 Fig. 3.6 Ventro-lateral view of an expanded palpal organ of a male 22 spider. Fig. 4.1 Base map of Terai Conservation Area (TCA) showing 82 sampling sites in five different habitat types. Fig. 4.2 Species-Accumulation curve and estimation curves Chao1 88 and Jacknife 2, for the Regional (all samples pooled) dataset. Fig. 4.3 Comparison of species richness values (±95% confidence 90 interval) at lowest number of individuals (300) derived from individual-based species rarefaction curves of spider assemblages across the different habitat types. Fig 4.4 Mean spider diversity (fisher’s alpha) in five habitat types. 90 Fig. 4.5 MDS ordination plots of sampling sites in the TCA, 91 generated by species composition sorted according to habitat types. Fig. 4.6 MDS ordination plots of sampling sites in the TCA, 93 generated by family composition sorted according to habitat types. Fig. 5.1 Axis 1 and Axis 2 of a CCA based on species composition 116 and environmental variables with sites. Fig. 5.2 Axis 1 and Axis 2 of CCA based on family composition and 117 environmental variables with sites. Fig. 5.3 Axis 1 and Axis 2 of CCA based on species composition 117 showing species with sites. ii Fig. 5.4 Axis 1 and Axis 2 of CCA based on family composition 118 showing species with sites. Fig. 6.1 Mean species richness and mean abundance of spiders in 137 (a) two grassland types and (b) four sampling seasons. Fig. 6.2 Mean number of (a) species and (b) individuals of spiders in 138 burnt and unburnt sites of lowland and upland grassland habitat. Fig. 6.3 Mean number of species and individuals of spiders in 139 unburnt, single fire and repeated fire sites of grassland habitat. Fig. 6.4 Comparison of species richness values (±95% confidence 139 interval) at the lowest number of individuals (21) derived from individual-based species rarefaction curves of spider assemblages across the different fire regimes. Fig. 6.5 Species turn over between fire treatments using Bray-Curtis 140 Index. Fig. 6.6 K dominance curve (cumulative dominance vs species 141 rank) for spider assemblage of burnt and unburnt sites in lowland grassland. Fig. 6.7 K dominance curve (cumulative dominance vs species 141 rank) for spider assemblage of burnt and unburnt sites in upland grassland. Fig. 6.8 Non-metric multi-dimensional scaling ordination of 143 abundance of spider assemblages in two different grassland habitats in Terai grassland. Fig. 6.9 Non-metric multi-dimensional scaling ordination of 144 abundance of spider assemblages in upland grassland habitat in Terai grassland, based on frequency of burn. Fig 6.10 Non-metric multi-dimensional scaling ordination of 144 abundance of spider assemblages in lowland grassland habitat in Terai grassland, based on frequency of burn. Fig. 6.11 Non-metric multi-dimensional scaling ordination of 145 abundance of spider assemblages in lowland grassland habitat in Terai grassland, based on season of burn. Fig 6.12 Non-metric multi-dimensional scaling ordination of 145 abundance of spider assemblages in upland grassland habitat in Terai grassland, based on season of burn Fig. 6.13 Multi-dimensional scaling ordination for burnt and unburnt 147 sites for four sampling season: (a) lowland grassland, and (b) upland grassland.