E-Letter responses to:

reports: Kent E. Carpenter, Muhammad Abrar, Greta Aeby, Richard B. Aronson, Stuart Banks, Andrew Bruckner, Angel Chiriboga, Jorge Cortés, J. Charles Delbeek, Lyndon DeVantier, Graham J. Edgar, Alasdair J. Edwards, Douglas Fenner, Héctor M. Guzmán, Bert W. Hoeksema, Gregor Hodgson, Ofri Johan, Wilfredo Y. Licuanan, Suzanne R. Livingstone, Edward R. Lovell, Jennifer A. Moore, David O. Obura, Domingo Ochavillo, Beth A. Polidoro, William F. Precht, Miledel C. Quibilan, Clarissa Reboton, Zoe T. Richards, Alex D. Rogers, Jonnell Sanciangco, Anne Sheppard, Charles Sheppard, Jennifer Smith, Simon Stuart, Emre Turak, John E. N. Veron, Carden Wallace, Ernesto Weil, and Elizabeth Wood One-Third of Reef-Building Corals Face Elevated Extinction Risk from Climate Change and Local Impacts Science 2008; 321: 560-563 [Abstract] [Full text] [PDF]

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Response to N. Knowlton and F. Nunes' E-Letter

Kent E. Carpenter, Beth A. Polidoro, Suzanne R. Livingstone, Richard B. Aronson, William F. Precht   (10 November 2008)

Atlantic Corals—Least of our Concerns?

Nancy Knowlton, Flavia Nunes   (10 November 2008)

Response to N. Knowlton and F. Nunes' E-Letter 10 November 2008
Kent E. Carpenter Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529, USA, Beth A. Polidoro, Suzanne R. Livingstone, Richard B. Aronson, William F. Precht Respond to this E-Letter: Re: Response to N. Knowlton and F. Nunes' E-Letter	In our Report, we pointed out that Caribbean reefs have been devastated by declines of the ecologically and geologically dominant species Acropora palmata, A. cervicornis, and two species within the Montastraea annularis complex. Our Figure 2A (1) shows the Caribbean as the only region with a high concentration of reef-building corals in the IUCN Red List highest threat category of Critically Endangered. By this metric, Caribbean reefs are much worse off than Indo-Pacific reefs, particularly considering the disparity in diversity of the two regions: 72 species versus 759 species in the Indo-Pacific. Although coral cover has declined to a greater extent than previously assumed in the Indo-Pacific (2), Caribbean reefs could be less resilient to species loss than high diversity Indo-Pacific reefs. A challenge of Red List Assessments is to apply the criteria globally. A species that has declined locally may be doing well elsewhere in its range. For reef-building Caribbean corals, we used species-specific population data to support our listing wherever practicable. In the absence of broad scale species-specific population data, a proxy such as habitat loss can be applied. Our proxy was based on observed loss of coral reef area (3). Estimates of loss in the Caribbean range from 5 to 16%, compared to 1 to 65% for the Indo-West Pacific. With habitat losses >30% over large tracts of the Indo-Pacific, proportionally more species fell into "vulnerable" threat categories than in the Caribbean. Not always reflected in these assessments is the potential for future reef loss, with higher projections for the Caribbean (9 to 67%) than the Indo-Pacific (2 to 36%). Future loss was only taken into consideration when a species was considered highly susceptible to the threats in its region. Because in many cases we used a proxy rather than species-specific population declines, we were conservative in projecting future loss. Massive bleaching events continue to occur in the Caribbean (4), so our reef loss estimates may be understated; some species of Least Concern may now be reaching thresholds that will place them in higher Red List threat categories. Nevertheless, populations of many Caribbean coral species are still thriving and some short-lived, early successional brooding species may even be expanding in the wake of regional disturbances (5). In addition, not all the news is grim. Localized recovery has been observed at a number of sites throughout the Caribbean (6). It remains to be seen whether the recovery of these coral populations will outpace future mortality from the onslaught of regional and global stressors. As Knowlton and Nunes correctly note, the coral faunas of Brazil and the eastern Atlantic are highly endemic, having restricted ranges and low genetic diversity. Until recently, most of these corals showed low levels of mortality related to the major disturbances linked to global-scale coral declines, which include bleaching and disease (7). The IUCN Red List is a living document. Updates can and should be made regularly as new information becomes available, in addition to the mandated re-evaluation at least every 10 years. The Data Deficient category is clearly portrayed in the Red List guidelines (8) as being of serious potential conservation concern and underscores the urgency of collecting information to complete Red List assessments. When population trend information becomes available, assessments can be revised and species up-listed or down-listed as appropriate. It is important that coral specialists remain dedicated to the process of Red List assessments. A voluntary commitment from these specialists to form an IUCN Species Survival Commission Coral Red List Authority will ensure frequent re-assessments of coral species. Such an authority would be able to gauge the effectiveness of management actions to stem reef degradation. Kent E. Carpenter, Beth A. Polidoro, Suzanne R. Livingstone International Union for Conservation of Nature Species Programme, Species Survival Commission (SSC), and Conservation International Global Marine Species Assessment, Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529, USA. Richard B. Aronson Dauphin Island Sea Lab, Dauphin Island, AL 36528, USA. William F. Precht National Oceanic and Atmospheric Administration, Florida Keys National Marine Sanctuary, Damage Assessment and Restoration Program, Key Largo, FL 33040, USA. References 1. K. E. Carpenter et al., Science, 321, 560 (2008). 2. J. F. Bruno, E. R. Selig, PloS ONE, 2, e711, doi:10.1371/journal.pone.0000711, (2007). 3. C. Wilkinson, Status of Coral Reefs of the World [Australian Institute of Marine Studies (AIMS), Townsville, Australia, 2004]. 4. S. D. Donner, PNAS, 104, 5483 (2007). 5. D. H. Green et al., Mar. Ecol.-Prog. Ser. 359, 1 (2008). 6. R. B. Aronson, W. F. Precht, Coral Reefs 25, 441 (2006). 7. R. B. Francini-Filho et al., Mar. Poll. Bull. 56, 1008 (2008). 8. IUCN, Guidelines for Using the IUCN Red List Categories and Criteria (IUCN Species Survival Commission, Gland, Switzerland, 2005).
Atlantic Corals—Least of our Concerns? 10 November 2008
Nancy Knowlton Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093, USA, Flavia Nunes Respond to this E-Letter: Re: Atlantic Corals—Least of our Concerns?	K. E. Carpenter and colleagues (Reports, "One-third of reef-building corals face elevated extinction risk from climate change and local impacts," 25 July 2008, p. 560) showed high extinction risks for corals globally, but most Atlantic species fared surprisingly well in their analysis, despite the poorer health of Atlantic reefs (1-3). Although two once dominant Atlantic acroporids accounted for 40% of the critically endangered corals, overall, 56% of Atlantic corals with adequate data were ranked as "least concern," compared to 33% for Indo-Pacific corals. The situation for Atlantic corals, which include highly distinctive lineages (4), may be much worse than portrayed, however. First, 28% of Atlantic and Mediterranean corals were excluded as "data deficient" compared to 15% for the much larger and more diverse Indo-Pacific corals. Notably, all corals found exclusively around coastal Brazil or the eastern Atlantic (including two endemic genera) were so listed [these regions do not even appear on the maps listed in (5)]. Many of these corals are likely at risk because of their restricted ranges (6), low genetic variability (Nunes, in prep.) and increasing mortality (7). "No data" does not mean "not important" or "not at risk." Second, risk may have been underestimated for Atlantic corals with data. The primary difference between "least concern" and "some level of threat" stemmed from whether or not projected future losses in habitat were added to past losses (few assessments used abundance data). This distinction was based on aspects of distribution, life history, and vulnerability to disease and bleaching likely to increase or decrease risk. In corals found only in the Atlantic, including projected losses invariably resulted in a "vulnerable" or "endangered" designation, but only 7.5% of Atlantic corals were analyzed in this fashion, compared to 31% in the Pacific. Substantial declines of many Atlantic corals in the "least concern" category (8, 9) suggest that more of them should have been analyzed using projected losses, which would have resulted in their elevation to higher risk categories. It is also unclear why estimates of population reductions for most Atlantic corals fell from 21% before 1998 to 10% in 2004 (that is, their status improved) when coral cover in the region continued to decline (4). If we are indeed entering the "California condor" age of coral conservation, we need precise data on individual species, which usually go unreported in meta-analyses and many reef surveys. A global system of monitored sites like that which exists for tropical forests (10) could give us this urgently needed information. Nancy Knowlton National Museum of Natural History, Smithsonian Institution, Washington, DC 20013, USA, and Center for Marine Biodiversity and Conservation, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093-0202, USA. Flavia Nunes Center for Marine Biodiversity and Conservation, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093-0202, USA. References 1. T. A. Gardner et al., Science 301, 958 (2003). 2. R. B. Aronson, W. F. Precht, Coral Reefs 25, 441 (2006). 3. J. M. Pandolfi, Science 301, 955 (2003). 4. H. Fukami et al., Nature 427, 832 (2004). 5. K. E. Carpenter et al., Science 321, 560 (2008). 6. R. L. Moura, Proc. 9th Intl. Coral Reef Symp. 2, 917 (2002). 7. R. B. Francini-Filho et al., Mar. Poll. Bull. 56, 1008 (2008). 8. E. Pante, A. King, P. Dustan, Hydrobiologia 596, 121 (2008). 9. M. M. Nugues, R. P. M. Bak, Mar. Ecol. Prog. Ser. 315, 75 (2006). 10. N. Knowlton, J. Jackson, PLoS Biol., 6, e54.