BIODIVERSITY OF THE ZAMBEZI BASIN WETLANDS: REVIEW AND PRELIMINARY ASSESSMENT OF AVAILABLE INFORMATION PHASE 1 FINAL REPORT FEBRUARY 1998 CONSULTANCY REPORT FOR IUCN, THE WORLD CONSERVATION UNION ! REGIONAL OFFICE FOR SOUTHERN AFRICA (IUCN!ROSA), HARARE, ZIMBABWE FUNDED BY THE CANADIAN INTERNATIONAL DEVELOPMENT AGENCY (CIDA) by Jonathan Timberlake with contributions from BFA consultants The Zambezi Society Biodiversiversity Foundation for Africa P.O. Box HG 774 P.O. Box FM 730 Highlands Famona Harare Bulawayo tel: +263-4-747003/5 tel: +263-9-64424/7 fax: +263-4-747002 fax: +263-9-540709 E-mail: [email protected] Email: [email protected] Publishers’ note This evaluation was undertaken as a partnership between the Zambezi Society and the Biodiversity Foundation for Africa The Zambezi Society is a non governmental, membership agency devoted to the conservation of biodiversity and wilderness in the Zambezi basin. Its partnership role includes donor liaison; financial, logistics and project management; and information dissemination. The major objective of the Biodiversity Foundation for Africa is to undertake biological research into tropical African biodiversity, and to make the resulting information more accessible. It provides biological, ecological and taxonomic expertise and technical management for the partnership. The ZAMSOC/BFA partnership applies its combined skills to biodiversity research and conservation within the Zambezi basin. CONTENTS Page Contents .......................................................................i List of Tables and Figures ..........................................................iv Acknowledgements ..............................................................vi Executive Summary ............................................................. vii 1. INTRODUCTION ......................................................... 1 1.1 Background .......................................................... 1 1.2 Wetlands and definitions ................................................. 1 1.3 Biodiversity – the conceptual base .......................................... 2 1.3.1 Definitions and scope ............................................. 2 1.3.2 Sources and sinks ................................................ 4 1.3.3 Further developments in landscape ecology ............................. 5 1.3.4 A continental perspective .......................................... 6 1.3.5 Organismal biodiversity and ecological processes ......................... 7 1.4 Structure of report ...................................................... 7 1.5 References on biodiversity concepts ........................................ 8 2. DESCRIPTION OF THE ZAMBEZI BASIN ...................................... 9 2.1 Physical description ..................................................... 9 2.1.1 Introduction .................................................... 9 2.1.2 Upper Zambezi .................................................. 9 2.1.3 Middle Zambezi ................................................ 13 2.1.4 Lower Zambezi ................................................. 14 2.2 Palaeogeography of the Zambezi Basin ..................................... 15 2.2.1 Upper Zambezi ................................................. 15 2.2.2 Middle and Lower Zambezi ....................................... 16 3. BIBLIOGRAPHY & LITERATURE REVIEW .................................... 21 3.1 Bibliographic database ................................................. 21 3.1.1 Introduction ................................................... 21 3.1.2 Criteria ....................................................... 21 3.1.3 Format ....................................................... 22 3.2 Review of published information .......................................... 22 3.2.1 Introduction ................................................... 22 3.2.2 Plants and vegetation ............................................. 23 3.2.3 Mammals ..................................................... 27 3.2.4 Birds ........................................................ 28 3.2.5 Reptiles and amphibians .......................................... 36 3.2.6 Fish ......................................................... 43 3.2.7 Invertebrates ................................................... 49 3.2.8 Upper Zambezi ................................................. 51 3.2.9 Middle Zambezi ................................................ 59 3.2.10 Lower Zambezi, Lake Malawi and the Shire Valley ...................... 62 i 3.3 Gaps in knowledge .................................................... 67 3.3.1 Taxonomy .................................................... 67 3.3.2 Distribution .................................................... 68 3.3.3 Ecological roles ................................................. 69 3.3.4 Threats and concerns ............................................ 70 3.3.5 Barotse floodplain ............................................... 71 3.3.6 Chobe/Caprivi ................................................. 71 3.3.7 Lower Shire wetlands ............................................ 71 3.3.8 Zambezi Delta .................................................. 72 3.4 Summary ........................................................... 72 4. SITES & SPECIES OF CONCERN ............................................ 75 4.1 Introduction ......................................................... 75 4.2 Sites of interest or concern .............................................. 75 4.2.1 Barotse floodplains .............................................. 76 4.2.2 Chobe/Caprivi ................................................. 76 4.2.3 Lower Shire ................................................... 77 4.2.4 Zambezi Delta .................................................. 77 4.2.5 Other wetlands in the Zambezi Basin ................................. 77 4.3 Species of interest or concern ............................................ 78 4.3.1 Plants and vegetation ............................................. 78 4.3.2 Mammals ..................................................... 79 4.3.3 Birds ........................................................ 80 4.3.4 Reptiles and amphibians .......................................... 81 4.3.5 Fish ......................................................... 81 4.3.6 Invertebrates ................................................... 82 4.4 Summary ........................................................... 83 5. HISTORICAL CHANGE AND HUMAN IMPACTS ............................... 85 5.1 Introduction ......................................................... 85 5.2 Overview of impacts of water development .................................. 86 5.2.1 Impact of dams on selected wetlands ................................. 86 5.2.2 Impact of dams on humans ........................................ 88 5.2.3 Summary ..................................................... 89 5.3 Historical change at project sites .......................................... 89 5.3.1 Introduction ................................................... 89 5.3.2 Barotse floodplains .............................................. 90 5.3.3 Chobe/Caprivi ................................................. 91 5.3.4 Lower Shire ................................................... 93 5.3.5 Zambezi Delta .................................................. 94 6. WETLANDS EXPERTISE ................................................... 97 6.1 Expertise database .................................................... 97 6.2 Review of expertise .................................................... 97 6.3 Identification of gaps in expertise ......................................... 100 ii 7. ECOLOGICAL STRATIFICATION ........................................... 103 7.1 Introduction ........................................................ 103 7.2 Ecological mapping to date ............................................. 103 8. PRELIMINARY ASSESSMENT ............................................. 105 8.1 Introduction ........................................................ 105 8.2 Assessment of the importance of wetland biodiversity .......................... 105 8.2.1 Role and characterisation of wetlands ............................... 105 8.2.2 Biodiversity of wetlands ......................................... 106 8.2.3 Importance of wetlands by area .................................... 109 8.3 Summary .......................................................... 111 9. CONCLUSIONS & RECOMMENDATIONS ................................... 113 9.1 Biogeography ....................................................... 113 9.2 Knowledge of biodiversity .............................................. 114 9.3 Wetland areas and conservation sites ...................................... 116 9.4 Historical change and human impact ....................................... 117 9.5 Biodiversity expertise ................................................. 117 9.6 Limitations and evaluation .............................................. 118 9.6.1 Limitations of study ............................................. 118 9.6.2 Evaluation of outputs ............................................ 118 9.7 Recommendations .................................................... 119 10. PROPOSAL FOR PHASE 2 10.1 Introduction ........................................................ 123 10.2 Phase 1 ............................................................ 123 10.3 Phase 2 ...........................................................