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17 - Redesigning coral reef conservation
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- By Callum M. Roberts, University of York, John D. Reynolds, Simon Fraser University, Isabelle M. Côté, Simon Fraser University, Julie P. Hawkins, University of York
- Edited by Isabelle M. Côté, Simon Fraser University, British Columbia, John D. Reynolds, Simon Fraser University, British Columbia
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- Book:
- Coral Reef Conservation
- Published online:
- 05 June 2012
- Print publication:
- 17 August 2006, pp 515-537
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Summary
INTRODUCTION
Coral reefs are the most diverse shallow water marine ecosystem but in many parts of the world they are becoming degraded rapidly by a combination of human stresses and climate change (Birkeland, 1997 Wilkinson, this volume). Recent analyses suggest that at least 58% of corals reefs worldwide are directly threatened by human activities (Bryant et al., 1998). Major stressors impacting reef habitats include sediment and nutrient pollution from coastal development, land clearing and agriculture, over- fishing, pest and disease outbreaks, and global warming (Polunin and Roberts, 1996 Birkeland, 1997 Hoegh- Guldberg, 1999).
An estimated 20%of reefs have already been destroyed (Wilkinson, this volume), while less than a half of the 16% of reefs seriously damaged by global warming- induced increases in sea- surface temperatures in 1998 have recovered (Wilkinson, 2000). Where reefs are exposed to multiple stresses recovery could be slow or may not occur (Connell, 1997). In the Caribbean,; Gardner et al. (2003) have shown a region- wide decline in coral cover from 50% to 10% between 1977 and 2001. Spalding and Grenfell (1997) estimated that there are 20 000 km2 of reefs in the Caribbean, implying a loss of 8000 km2 of coral in 24 years, or 333 km2 of coral per year. Analyses of fossil records from the Caribbean suggest that recent reef degradation has been unprecedented over the last 100 000 years (Jackson et al., 2001 Wapnick et al., 2004 Precht and Aronson, this volume).
The threatened status of restricted-range coral reef fish species
- Julie P. Hawkins, Callum M. Roberts, Victoria Clark
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- Journal:
- Animal Conservation forum / Volume 3 / Issue 1 / February 2000
- Published online by Cambridge University Press:
- 01 February 2000, pp. 81-88
- Print publication:
- February 2000
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Coral reefs are the most diverse ecosystem in the sea. Throughout the world they are being over-fished, polluted and destroyed, placing biodiversity at risk. To date, much of the concern over biodiversity loss has centred on local losses and the possibility of global extinction has largely been discounted. However, recent research has shown that 24% of reef fish species have restricted ranges (< 800 000 km2), with 9% highly restricted (< 50 000 km2). Restricted-range species are thought to face a greater risk of extinction than more widespread species since local impacts could cause global loss. We searched for information on status in the wild and characteristics of 397 restricted-range reef fish species. Fish body size, habitat requirements and usefulness to people were compared with those of a taxonomically-matched sample of more widespread species. We found that on average species with restricted ranges were significantly smaller (mean total length 19.1 cm versus 24.4 cm), tended to have narrower habitat requirements and were less used by people. Greater habitat specificity will tend to increase extinction risk while, if real, more limited usefulness (equivalent to exploitation) may reduce risk. Fifty-eight percent of restricted-range species were considered common/abundant in the wild and 42% uncommon/rare. Population status and threats to 319 species for which data were available were assessed according to the categories and criteria of the IUCN red list of threatened animals. A number of species were found to be rare, were exploited and had highly restricted ranges overlapping areas where reef degradation is particularly severe, placing them at a high risk of extinction. Five species were listed as Critically Endangered, two of them possibly already extinct in the wild, one as Endangered and 172 as Vulnerable. A further 126 species fell into Lower Risk categories and 11 were considered Data Deficient. Given the intensity of impacts to reefs, the broad geographical areas affected and the large numbers of restricted-range species, global extinctions seem likely. Urgent management action is now crucial for the survival of several species of reef fishes.