Green2009-herbivore monitoring

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Executive Summary Browsers: unicornfish (Naso unicornis: left) and a rudderfish (Kyphosus vaigiensis: right). Images by A. Hoey and G. Allen respectively. MONITORING FUNCTIONAL GROUPS OF HERBIVOROUS REEF FISHES Coral reef monitoring has traditionally focused on monitoring the status of coral communities and populations of conspicuous species, particularly fisheries species (fish and invertebrates). While these measures provide useful information of the current status of coral reef communities and associated fisheries, they do not provide information on the status of key ecological processes that are essential for maintaining coral reef resilience. Developing new metrics for monitoring coral reef resilience that are process oriented is an urgent priority for the improved management of coral reefs. Monitoring coral reef resilience will require a combined approach to monitoring key ecological processes, and functional groups that contribute to these processes including: • Coral population dynamics (size structure and patterns of recruitment). • Factors that influence coral recruitment and survivorship, particularly water quality, substratum consolidation, and benthic communities (particularly macroalgae). • Factors that influence the establishment and growth of macroalgal communities, particularly functional groups of herbivorous reef fishes. Methods for assessing and monitoring coral reef resilience have been developed by the International Union for Conservation and Nature (IUCN) Working Group on Climate Change and Coral Reefs. The following is a protocol for monitoring functional groups of herbivorous reef fishes, which was developed as part of that process. These protocols were developed using standard monitoring methods for coral reef fishes to facilitate their integration into new or existing programs, where field practitioners are interested in monitoring for multiple objectives (e.g. status of key fisheries species, coral reef resilience). They are not intended to represent the only method that should be used to monitor coral reef fishes, and in most locations, they are expected to form part of broader monitoring programs based on multiple objectives. This document provides practical advice to field practitioners based on an example from the Asia Pacific Region. Key functional groups of herbivores are identified, species are assigned to each functional group, and methods are provided for monitoring their abundance, biomass and size structure. Key components include: • A hierarchical or stratified sampling design. • Site selection of representative areas with adequate space to conduct the monitoring program. • Standardising coral reef exposures and zones (reef slopes and crests on exposed linear reef fronts). • Survey timing (between 9am and 4pm) and frequency for long term monitoring and rapid assessments of coral reef resilience: Long term monitoring requires a baseline survey, repeated every three years or more frequently if required to monitor the success of management actions or impacts of large scale disturbances. Rapid assessments usually comprise a single survey on one occasion. • Underwater visual census methods for rapid assessments (20 minute timed swims) and long term monitoring (a combination of five 50m belt transects and 20 minute long swims). 9
Executive Summary Advice is also provided on data analysis, interpreting results, simplifying methods, and modifying the protocol for other biogeographic and geographic regions. This document represents the first attempt to develop a monitoring program that is specifically designed to monitor key functional groups of herbivorous reef fishes as indicators of coral reef resilience. Even though it is based on the best available information, it is important to remember that the science underpinning these methods is still new and developing. Further research is now required to address knowledge gaps and refine monitoring methods. 10
Page 1 and 2: Monitoring Functional Groups of Her
Page 7 and 8: TABLE OF CONTENTS EXECUTIVE SUMMARY
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Page 13 and 14: Background STATUS AND TRENDS The di
Page 15 and 16: Coral Reef Resilience Resilient ree
Page 17 and 18: Coral Reef Resilience In summary, h
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Page 21 and 22: Herbivorous Coral Reef Fishes HERBI
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Page 25 and 26: Herbivorous Coral Reef Fishes The r
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Page 57 and 58: References CBD 2009 Identifying and
Page 59 and 60: References Hamilton, R.J. 2004 The
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References McCook, L. J., Folke, C.
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References Wainwright, P.C., Bellwo
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Glossary Fish Families and Common N
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Appendix 1 Timed Swims (Large Indiv
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Appendix 1 50 m Transects (Large In
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Appendix 2 APPENDIX 2 Biomass Const
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Appendix 2 Family Species a b Sourc
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INTERNATIONAL UNION FOR CONSERVATIO
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Green2009-herbivore monitoring

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