The Effects of Climate Change on Migratory Waterbirds Within the African-Eurasian Flyway
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Secretariat provided by the Workshop 3 United Nations Environment Programme (UNEP) Doc TC8.24 22 February 2008 8th MEETING OF THE TECHNICAL COMMITTEE 03 - 05 March 2008, Bonn, Germany The Effects of Climate Change on Migratory Waterbirds within the African-Eurasian Flyway Authors Ilya M.D. Maclean1, Mark M. Rehfisch1, Simon Delany2 & Robert A. Robinson1 October 2007 1 British Trust for Ornithology, The Nunnery, Thetford, Norfolk IP24 2PU 2 Wetlands International, PO Box 471, 6700 AL Wageningen, The Netherlands Report of work carried out by The British Trust for Ornithology under contract to the AEWA Secretariat © British Trust for Ornithology Registered Charity No. 216652 1 CONTENTS CONTENTS............................................................................................................................................ 2 List of Tables........................................................................................................................................... 5 List of Figures ......................................................................................................................................... 5 List of Appendices .................................................................................................................................. 6 EXECUTIVE SUMMARY..................................................................................................................... 8 1. INTRODUCTION ........................................................................................................................ 12 2. CLIMATE CHANGE WITHIN THE AEWA AGREEMENT AREA ........................................ 14 2.1. Temperature change ................................................................................................. 14 2.1.1. Global............................................................................................................... 14 2.1.2. Africa................................................................................................................ 15 2.1.3. Europe and the eastern Nearctic....................................................................... 16 2.1.4. Middle East and Asia Minor ............................................................................ 16 2.2. Rainfall change and drought .................................................................................... 17 2.2.1 Global............................................................................................................... 17 2.2.2. Africa................................................................................................................ 17 2.2.3. Europe and the north-eastern Nearctic ............................................................. 18 2.2.4. Middle East and Asia Minor ............................................................................ 18 2.3. Global changes in wind patterns .............................................................................. 18 2.4. Global large-scale climate circulation patterns ........................................................ 19 2.5. Sea-level rise............................................................................................................ 19 3. CURRENT EFFECT OF CLIMATE CHANGE ON WATERBIRDS ........................................ 22 3.1. Changes in range and distribution............................................................................ 22 3.1.1. Changes in breeding range ............................................................................... 22 3.1.2. Changes in wintering range.............................................................................. 23 3.1.3. Changes in migratory routes ............................................................................ 25 3.2. Timing of biological events...................................................................................... 27 3.2.1. Timing of migration ......................................................................................... 27 3.2.2. Timing of breeding........................................................................................... 27 3.2.3. Mechanisms, evolutionary traps and constraints.............................................. 28 3.3. Changes in demography........................................................................................... 29 3.3.1. Survival ............................................................................................................ 29 3.3.2. Productivity ...................................................................................................... 31 3.3.3. Population impacts ........................................................................................... 32 3.4. Effects of changing rainfall patterns ........................................................................ 33 3.4.1. The Sahel region and crucial stop-over sites.................................................... 34 3.5. Effects of sea-level rise ............................................................................................ 34 3.6. Wind, Storms and Hurricanes .................................................................................. 36 3.7. Indirect impacts of climate change........................................................................... 36 3.7.1. Climate change and land-use change ............................................................... 36 3.7.2. Climate change and water-use change ............................................................. 36 3.7.3. Climate change and flood-defences ................................................................. 37 3.7.4. Climate change and tourism and recreation ..................................................... 37 4. FUTURE EFFECTS OF CLIMATE CHANGE ON WATERBIRDS......................................... 38 4.1. A framework for modelling future changes: approaches and limitations ................ 38 4.1.1. Extrapolation .................................................................................................... 38 4.1.2. Experiments...................................................................................................... 38 4.1.3. Phenomenological models................................................................................ 38 4.1.4. Behaviour-based models .................................................................................. 39 2 4.1.5. Expert opinion.................................................................................................. 39 4.1.6. Outcome-driven models ................................................................................... 39 4.1.7. Scenarios .......................................................................................................... 40 4.2. Future distribution and range changes ..................................................................... 40 4.3. Future changes in timing of biological events ......................................................... 42 4.4. Future changes in predation and parasitism ............................................................. 43 4.5. Future changes in demography ................................................................................ 43 4.6. Future effects of changing rainfall patterns.............................................................. 44 4.7. Future effects of sea-level rise ................................................................................. 44 4.8. Future indirect impacts of climate change ............................................................... 46 4.7.1. Future climate change and land-use change..................................................... 46 4.7.2. Future climate change and water-use change................................................... 46 4.7.3. Future climate change and flood-defences....................................................... 47 4.7.4. Future climate change and recreational disturbance ........................................ 47 5. POSSIBLE MEANS OF ADAPTING TO CLIMATE CHANGE............................................... 50 5.1. Site management ...................................................................................................... 50 5.2. Protected area networks ........................................................................................... 50 5.3. Management of the wider countryside..................................................................... 51 5.4. Minimising other impacts......................................................................................... 51 6. SPECIES ESPECIALLY VULNERABLE TO CLIMATE CHANGE........................................ 54 6.1. Criteria used to assess vulnerability......................................................................... 54 6.1.1. Population size................................................................................................. 54 6.1.2. Range score...................................................................................................... 55 6.1.3. Fragmentation score ......................................................................................... 55 6.1.4. Habitat score..................................................................................................... 56 6.1.5. Food score........................................................................................................ 56 6.2. List of vulnerable species......................................................................................... 57 6.2.1.