Green2009-herbivore monitoring

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Background BACKGROUND CORAL REEFS AND THEIR ECOSYSTEM SERVICES Coral reefs are the most structurally complex and taxonomically diverse marine ecosystems on earth, providing habitat for tens of thousands of associated fishes and invertebrates (Knowlton 2001, Jackson et al 2001). Despite occupying less than 0.1% of the world’s marine environment (Spalding et al 2001), they support almost one third of the world’s marine fish species (Reaka-Kudla 1996). Coral reefs are critically important for the maintenance of biodiversity and the ecosystem goods and services they provide (Moberg and Folke 1999, Hughes et al 2003). Globally, more than 100 countries have coastlines with coral reefs (Moberg and Folke 1999), and almost 500 million people, or 8% of the total population, live within 100kms of a coral reef (Bryant et al 1998). In most of these countries, many people live subsistence lifestyles and millions of people depend on coral reefs for all or part of their protein intake (Salvat 1992, Moberg and Folke 1999). The average global value of annual ecosystem services of corals reefs has been estimated to be US$375 billion per year (Constanza et al 1997). THREATS Threats to coral reefs and the ecosystem goods and services they provide are both natural and anthropogenic (see Glossary) in origin. Natural Disturbances Coral reefs and associated ecosystems have a high degree of natural variability due to large scale episodic disturbances such as major storms (hurricanes, typhoons and cyclones: Brown 1997, Green et al 1999). While these disturbances can result in large scale fluctuations in coral communities (Brown 1997, Green et al 1999, Bruno and Selig 2007), they are part of the natural disturbance regime under which coral reefs have evolved (Moberg and Folke 1999). In the absence of anthropogenic threats, reefs are generally able to recover from these disturbances in a few years to decades (Brown 1997, Green et al 1999). Anthropogenic Threats Coral reefs are seriously threatened both locally and globally by a variety of direct and indirect anthropogenic threats (Brown 1997, Bryant et al 1998, Jackson et al 2001, Halpern et al 2008). Of primary concern are threats to ecosystem health from overexploitation of marine resources, destructive fishing practices, runoff of sediments and nutrients from poor land use practices, coastal development and uncontrolled tourism activities (Bryant et al 1998, Jackson et al 2001, Fabricius 2004, Wilkinson 2008, Halpern et al 2008). Another issue of concern is the degree to which human activities have influenced the proliferation of other threats, particularly outbreaks of corallivorous crown of thorns starfish. In the last few decades, starfish outbreaks have substantially reduced coral cover on many reefs in the Indo-Pacific Region (Jackson et al 2001, Bruno and Selig 2007). While the causes of these outbreaks remain controversial, their increasing incidence and severity is increasingly linked to human activities, particularly increased runoff of nutrients from land and overfishing of starfish predators (Jackson et al 2001, Fabricius 2004, DeVantier and Done 2007. Sweatman 2008). Climate change also represents a new and increasing threat to coral reefs and associated ecosystems worldwide (Hoegh-Guldberg 1999, McLeod and Salm 2006, Hoegh-Guldberg et al 2007, Veron 2008). Major threats include rising sea temperatures leading to mass coral bleaching, rising sea levels that threaten coastal ecosystems (e.g. mangrove forests), and changes in ocean chemistry that affect the ability of calcifying organisms (including corals) to deposit their calcium carbonate skeletons (Hoegh- Guldberg 1999, McLeod and Salm 2006, Hoegh-Guldberg et al 2007, IPCC 2007, Veron 2008). Another issue of concern is the degree to which global climate change may influence the frequency and intensity of tropical storms (IPCC 2007), leading to shorter recovery times between recurrences (Hughes et al 2003). Climate change has also been linked to the recent proliferation of other threats, particularly coral diseases (Bruno et al 2007, Harvell et al 1999, 2007). 11
Background STATUS AND TRENDS The diversity, frequency, and scale of these threats have now increased to the extent that many coral reefs have suffered severe, long-term declines in abundance, diversity and habitat structure, and are threatened globally (Pandolfi et al 2003, 2005, Hughes et al 2003, Wilkinson 2008). A recent assessment found that the world has effectively lost 19% of its coral reefs, with 35% under threat in the next 10 to 40 years (Wilkinson 2008). Fortunately, 46% of the world’s reefs are regarded as being relatively healthy, and not under immediate threat of destruction (except from climate change). Declines in coral reef status vary around the world (reviewed by Wilkinson 2008), with a higher proportion of reefs effectively lost in the western Atlantic and the Indian Ocean than in the Red Sea, Australia and the Pacific Islands. The most serious declines have been recorded in Asia and the Arabian Gulfs. Within the Asia Pacific Region, the reefs of Southeast Asia are most seriously threatened, with 40% of reefs effectively lost, 45% under threat, and 15% at low threat. In contrast more reefs in Australia and the Pacific Islands are in better condition, with 2 to 8% effectively lost, 2 to 35% under threat, and 44 to 90% at low threat. Nonetheless, Bruno and Selig (2007) showed that average coral cover on Indo- Pacific reefs has declined from approximately 50% to 22% in the last four decades, due to major storms and a variety of direct and indirect human impacts. These studies demonstrate that there are few, if any, reefs that have not been affected by human activities (Jackson et al 2001, Pandolfi et al 2003, Bruno and Selig 2007, Halpern et al 2008), and urgent action is required to halt or reverse these declines in coral reef health. One approach is to manage for coral reef resilience. 12
Page 1 and 2: Monitoring Functional Groups of Her
Page 7 and 8: TABLE OF CONTENTS EXECUTIVE SUMMARY
Page 9 and 10: Executive Summary exposing hard, re
Page 11: Executive Summary Advice is also pr
Page 15 and 16: Coral Reef Resilience Resilient ree
Page 17 and 18: Coral Reef Resilience In summary, h
Page 19 and 20: Coral Reef Resilience herbivores, b
Page 21 and 22: Herbivorous Coral Reef Fishes HERBI
Page 23 and 24: Herbivorous Coral Reef Fishes to wh
Page 25 and 26: Herbivorous Coral Reef Fishes The r
Page 27 and 28: Herbivorous Coral Reef Fishes reefs
Page 57 and 58: References CBD 2009 Identifying and
Page 59 and 60: References Hamilton, R.J. 2004 The
Page 61 and 62: 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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