Wagina Island (Choiseul Province) 1
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Ecosystem and Socio- WAGINA economic Resilience ISLAND Analysis and Mapping Solomon Islands ESRAM: Volume 2 Wagina Island (Choiseul Province) 1 SPREP Library Cataloguing-in-PubliĐĂƟon Data Solomon Islands Ecosystem and Socio-Economic Resilience Analysis and Mapping (ESRAM), Volume 2: Wagina Island (Choiseul Province). Apia, Samoa: SPREP, 2018. 162 p. 29 cm. ISBN: 978-982-04-0759-6 (print) 978-982-04-0760-2 (ecopy) 1. Ecosystem management – Wagina Island (Choiseul Province) - Solomon Islands. 2. Nature conƐĞƌǀĂƟon. ϯ͘ůŝŵĂƟc changes – AdĂƉƚĂƟon. 4. Biodiversity consĞƌǀĂƟon – Economic aspects. 5. Biodiversity conservĂƟon – Social aspects. 6. Environmental impact analysŝƐ͘/͘WĂĐŝĮĐ Regional Environment Programme (SPREP). II. Title 333.72’9593 Copyright © Secretariat of the PaciĮc Regional Environment Programme (SPREP), 2017. ReproduĐƟon for eduĐĂƟonal or other non-commercial purposes is authorised without prior wrŝƩen permission from the copyright holder provided that the source is fully acknowledged. ReproduĐƟon of this pubůŝĐĂƟon for resale or other commercial purposes is prohibited without prior wrŝƩen consent of the copyright owner. Cover photo: Stuart Chape PO Box 240, Apia, Samoa [email protected], www.sprep.org Our vision: The PaciĮĐĞnvironment, sustaining our livelihoods and natural heritage in harmony with our cultures. This report produced by BMT WBM for the Secretariat of the PaciĮc Regional Environment Programme (SPREP) presents Volume 2 (of three volumes) prepared as part of the Solomon Islands Ecosystems and Socio-economic Resilience Analysis and Mapping (ESRAM) to assess and priorŝƟse climate change-related ecosystem-basedĂĚĂƉƚĂƟon oƉƟons for selected lŽĐĂƟons in Solomon Islands. Volume 2 is the ESRAM report for Wagina Island in Choiseul Province. Authors: Beth Toki, Lyn Leger, Suanne Richards, Sophie Hipkin, Joseph Lorimer (Aither), Rod Coulton (Aither). Project coordinĂƟon: Fred PĂƟson. All photographs are credited to Beth Toki unless stated otherwise. Ke y project partners Solomon Islands ESRAM: Volume 2 Wagina Island (Choiseul Province) 2 Contents List of Abbreviations 9 Acknowledgements 10 Executive summary 11 1 Introduction 15 1.1 Background 15 1.2 Aims and objectives 15 1.3 Volume 2 report scope 16 2 Wagina specific methodology 18 2.1 Study approach 18 2.2 Review of existing information and validation 19 2.3 Workshop methodology 22 3 Provincial context 25 3.1 Choiseul Province setting 25 3.1.1 Geographic and socio-economic setting 25 3.1.2 Current climate 27 3.1.3 Climate change governance 28 3.2 Biodiversity values, ecosystem threats and conservation 28 3.2.1 Biodiversity values 28 3.2.2 Existing ecosystem threats 33 3.2.3 Conservation 33 4 Wagina Island context 36 4.1 Wagina Island setting 36 4.1.1 Geographic 36 4.1.2 Cultural context 36 4.1.3 Socio-economic profile 38 5 Wagina Island ± ecosystems and ecosystem services 41 5.1 Overview ± ecosystems and ecosystem services 41 5.1.1 Community-derived identification 41 5.1.2 Additional ecosystem services identification 50 5.2 Cultivated land ± gardens 52 5.2.1 Description of ecosystem and ecosystem services 52 5.2.2 Key threats 56 5.3 Cultivated land ± plantations 56 5.3.1 Description of ecosystem and ecosystem services 56 Solomon Islands ESRAM: Volume 2 Wagina Island (Choiseul Province) 3 5.3.2 Key threats 61 5.4 Mangroves 62 5.4.1 Description of ecosystem and ecosystem services 62 5.4.2 Key threats 67 5.5 Terrestrial forest 70 5.5.1 Description of Ecosystem and Ecosystem Services 70 5.5.2 Key threats 73 5.6 Lowland swamps 75 5.6.1 Description of ecosystem and ecosystem services 75 5.6.2 Key threats 76 5.7 Reefs 76 5.7.1 Description of ecosystem and ecosystem services 76 5.7.2 Key threats 80 5.8 Marine lagoons 80 5.8.1 Description of ecosystem and ecosystem services 80 5.8.2 Key threats 84 5.9 Rocky shores 86 5.9.1 Description of ecosystem and ecosystem services 86 5.9.2 Key threats 88 5.10 Sandy beaches and islands 90 5.10.1 Description of ecosystem and ecosystem services 90 5.10.2 Key threats 92 5.11 Marine (Other) 95 5.11.1 Description of ecosystem and ecosystem services 95 5.11.2 Key threats 95 5.12 Rivers and streams 96 5.12.1 Description of ecosystem and ecosystem services 96 5.12.2 Key threats 100 5.13 Groundwater 102 5.13.1 Description of ecosystem and ecosystem services 102 5.13.2 Key threats 103 5.13.2.1 Groundwater well testing 104 5.14 Summary of human-induced threats to ecosystem services 106 6 Valuation of ecosystem services 109 6.1 Grouping of ecosystem services 109 6.2 Tropical forests 110 Solomon Islands ESRAM: Volume 2 Wagina Island (Choiseul Province) 4 6.2.1 Overview 110 6.2.2 Input values 110 6.2.2.1 Localised values 110 6.2.2.2 Global median values 111 6.3 Mangroves 112 6.3.1 Overview 112 6.3.2 Input values 112 6.3.2.1 Localised values 112 6.3.2.2 Global median values 113 6.4 Marine 114 6.4.1 Overview 114 6.4.2 Input values 114 6.4.2.1 Local values 114 6.4.2.2 Global median values 116 6.5 Summary of economic valuations 117 7 Climate change vulnerability assessment 119 7.1 Ecosystem service vulnerability to climate threats 120 7.1.1 Sea-level rise 120 7.1.2 Air and sea temperature 121 7.1.3 Ocean acidification 122 7.1.4 Extreme rainfall events 123 7.2 Summary of ecosystem service vulnerability 123 8 ESRAM outcomes 126 8.1 Resilience of ecosystem services to human-induced and climate change effects 126 8.1.1 Freshwater ecosystems and services 126 8.1.2 Coastal and marine ecosystems and services 127 8.1.3 Terrestrial ecosystems and services 130 8.2 Ecosystem-based adaptation options for Wagina Island 131 Glossary 136 9 References and Bibliography 137 9.1 References 137 9.2 Bibliography 140 Appendix A Wagina Island Workshop Participants A-1 Appendix B Ecosystem service values by biome B-5 Appendix C Results of well-water quality testing C-1 Solomon Islands ESRAM: Volume 2 Wagina Island (Choiseul Province) 5 Appendix D Wagina Island vulnerability assessment results D-1 List of Figures Figure 1-1 Location of Choiseul Province and Wagina Island 17 Figure 2-1 Conceptual framework 18 Figure 2-2 Summary of key climate change vulnerabilities identified for Choiseul Province (source: Iacovino et al. 2013). Note: Wagina Island is not pictured on the map, due to its exclusion from the Iacovino et al. (2013) vulnerability study. Wagina Island is located further east of Arariki and Kukitin. 20 Figure 2-3 Young onlookers watch measuring of water quality at village wells in Tekaranga (a) and Arariki (b) 21 Figure 2-4 Examples of groups participating at community workshops: a) Nikumaroro, b) women at Arariki, c) youth at Tekaranga, d) Tengangea 23 Figure 3-1 Choiseul Province 26 Figure 3-2 Monthly average (top) and annual average (bottom) rainfall, Taro Island, 1075±2012. For annual rainfall, the blue line shows the average over all years. 27 Figure 3-3 Terrestrial vegetation and marine reef classifications for Choiseul Province 32 Figure 3-4 Choiseul managed areas 35 Figure 4-1 Wagina Island location map 37 Figure 5-1 Distribution of key ecosystems on Wagina Island 44 Figure 5-2 Key areas of direct community utilisation of land and sea resources 49 Figure 5-3 Staple garden vegetable crops: a) sweet potato, b) cassava, c) greens, d) taro 53 Figure 5-4 Example of mixed produce (pumpkin, swamp taro, betel nut) garden in vicinity of houses at Nikumaroro 53 Figure 5-5 Staple garden fruits: a) paw paw, b) bananas 54 Figure 5-6 Sup sup garden, Tengangea village 55 Figure 5-7 Toddy collection 55 Figure 5-8 Main plantation crops: a) pandanus Pandanus spp., b) betel nut Areca catechu, c) sago palm Metroxylon solomonense, d) coconut Cocos nucifera 58 Figure 5-9 House roofing maintenance 59 Figure 5-10 Weaving mats from: a) pandanus and b) coconut leaves 60 Figure 5-11 Mangrove communities in good condition along the Seleana River: a) downstream and b) midstream 63 Figure 5-12 Example of old growth mahogany (Xylocarpus sp.) mangroves in the upstream reaches of Seleana River 64 Figure 5-13 Example mangrove species dominating Wagina Island: a) Xylocarpus sp., b) Nypa fruticans, c) Rhizophora .sp., d) Bruguiera sp. 65 Figure 5-14 Preparation of mangrove timber for house construction or maintenance 66 Solomon Islands ESRAM: Volume 2 Wagina Island (Choiseul Province) 6 Figure 5-15 Common large estuarine bivalve molluscs at Fourth River: a/b) collecting te toa, Polymesoda sp., c) large oyster bed, and d) mixed oysters on mangrove roots 66 Figure 5-16 Mangrove area with a high level of clearing for timber (top), and sparse mangrove canopy at location affected by prolonged inundation 68 Figure 5-17 Loss and alteration of mangrove habitat for milkfish Chanos chanos farming through a) reclamation, and b) channelisation/bunding 69 Figure 5-18 Variation in terrestrial vegetation communities in village surrounds 70 Figure 5-19 Provision of timber for housing (top) and canoes (bottom) 71 Figure 5-20 Lowland rainforest in central interior of Wagina Island 72 Figure 5-21 Area cleared of terrestrial forest for replacement by garden crops (a), and canoe tree felled in interior of Wagina Island (b) 74 Figure 5-22 Swamp taro (Cyrtosperma chamissonis) in lowland swamp west of Tengangea 75 Figure 5-23 Coral rock used to construct a seawall 77 Figure 5-24 Typical shark (and turtle) catches 78 Figure 5-25 Preserved shark products: a) and b) smoked or salted and dried meat; c) and d) drying shark fins 79 Figure 5-26 Seagrass meadows in lagoon adjacent to eastern side of Wagina Island 81 Figure 5-27 Starfish common in marine lagoons around Wagina Island: a) Protoreaster nodosus, b) Astropecten sp.