Distr. GENERAL UNEP/CBD/COP/11
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CBD Distr. GENERAL UNEP/CBD/COP/11/INF/2 10 September 2012 ORIGINAL: ENGLISH CONFERENCE OF THE PARTIES TO THE CONVENTION ON BIOLOGICAL DIVERSITY Eleventh meeting Hyderabad, India, 8-19 October 2012 Item 13.3 of the provisional agenda* REPORT OF THE WORK OF THE EXPERT GROUP ON MAINTAINING THE ABILITY OF BIODIVERSITY TO CONTINUE TO SUPPORT THE WATER CYCLE Note by the Executive Secretary 1. The tenth meeting of the Conference of the Parties to the Convention on Biological Diversity, in decision X/28 paragraph 39, recognized the good synergies between the Convention on Biological Diversity and the Ramsar Convention on Wetlands and requested the Executive Secretary, and invited the Secretariat and Scientific and Technical Review Panel (STRP) of the Ramsar Convention, and other relevant partners, subject to the availability of financial resources, to establish an expert working group, building upon the relevant core expertise of the STRP, to review available information, and provide key policy relevant messages, on maintaining the ability of biodiversity to continue to support the water cycle. Progress with the work of the expert group was reported to the fifteenth meeting of the Subsidiary Body on Scientific, Technical and Technological Advice (SBSTTA). SBSTTA recommendation XV/5, section II subparagraph (b), requested the Executive Secretary of the Convention on Biological Diversity to make the report of the expert group available for the information of the eleventh meeting of the Conference of the Parties. Consequently, the Executive Secretary is hereby making the report of the expert group available. 2. This document is circulated in the form and languages in which it was received by the Secretariat of the Convention on Biological Diversity. 3. The summary report of the expert group is provided for the consideration of the eleventh meeting of the Conference of the Parties to the Convention on Biological Diversity as document UNEP/CBD/COP/11/30. *UNEP/CBD/COP/11/1. /… In order to minimize the environmental impacts of the Secretariat’s processes, and to contribute to the Secretary-General’s initiative for a C-Neutral UN, this document is printed in limited numbers. Delegates are kindly requested to bring their copies to meetings and not to request additional copies. Report of the expert group on maintaining the ability of biodiversity to continue to support the water cycle September 2012 Acknowledgements This work was made possible through the generous support of the Governments of Australia, Canada, Finland, Norway and the Republic of Korea. Contributors to the work of the expert group are acknowledged in Table 1.1 of this report. TABLE OF CONTENTS EXECUTIVE SUMMARY .................................................................................... 1 CHAPTER 1 Introduction .................................................................................... 2 1.1 Background to the work .......................................................................................................... 2 1.2 Ongoing work of the expert group .............................................................................................. 2 1.3 Contributors to the work of the expert group ............................................................................... 2 CHAPTER 2 Forests .......................................................................................... 5 2.1 Scope of the assessment .......................................................................................................... 5 2.2 Global extent of forests ........................................................................................................... 5 2.3 Hydrological processes within forests .................................................................................... 6 2.4 Observed evidence for the hydrological functions of forests .................................................. 9 2.4.1 Guiding principles for reviewing the observed evidence of the hydrological functions of forests 9 2.4.2 Summary schematic of the hydrological functions of forests .............................................. 10 2.4.3 Water availability via evaporation function ......................................................................... 11 2.4.4 Precipitation capture function .............................................................................................. 14 2.4.5 Microclimate function .......................................................................................................... 15 2.4.6 Enhanced infiltration (& reduced overland flow on slopes) function .................................. 15 2.4.7 Reduced slope erosion function ........................................................................................... 17 2.4.8 Exclusion of pollutant inputs function ................................................................................. 18 2.4.9 Downslope utilisation of leached nutrients function ............................................................ 19 2.4.10 Downslope (and coastal) physical function ....................................................................... 20 2.4.11 Peak-flow damping and low-flow enhancement function ................................................. 21 2.4.12 Enhancement of river water quality function ..................................................................... 24 2.5 Related issues: carbon and water cycle interactions ............................................................. 25 2.5.1 Carbon dioxide capture function .......................................................................................... 25 2.5.2 Aquatic carbon source function ........................................................................................... 25 2.5.3 Hydrological co-benefits of enhancing the carbon function of forests ................................ 26 2.6 Economic values of water-related forest ecosystem services ............................................... 26 2.7 Global and regional policies ................................................................................................. 28 2.8 Management options ............................................................................................................. 30 2.9 Policy recommendations for future activities ....................................................................... 30 CHAPTER 3 Wetlands ...................................................................................... 31 3.1 Definition ................................................................................................................................... 31 3.2 Extent .................................................................................................................................... 31 3.3 Hydrological processes ........................................................................................................ 32 3.4 Evidence for hydrological functions .................................................................................... 32 3.4.1 Flood reduction by floodplains ........................................................................................... 34 3.4.2 Coastal wetlands and floods ................................................................................................ 34 3.4.3 Headwater wetlands and floods .......................................................................................... 34 3.4.4 Wetlands and groundwater .................................................................................................. 35 3.4.5 Evaporation ......................................................................................................................... 35 3.4.6 Water quality improvement ................................................................................................ 36 3.5 Economic values of water-related wetlands services ............................................................ 37 3.6 Related issues ........................................................................................................................ 37 3.6.1 Wetlands and carbon sequestration ..................................................................................... 37 3.6.2 Wetlands and climate change.............................................................................................. 38 3.7 Global and regional policies ....................................................................................................... 39 3.8 Management options .................................................................................................................. 40 3.9 Policy recommendations ............................................................................................................ 41 3.10 Gaps .......................................................................................................................................... 41 CHAPTER 4 Mountains .................................................................................... 43 4.1 Scope of the assessment ......................................................................................................... 43 4.2 Extent ..................................................................................................................................... 43 4.3 Hydrological processes in the mountains ............................................................................... 44 4.4 Hydrological functions of mountain ecosystem ....................................................................