13.07.2015 Views

Status of Caribbean coral reefs after bleaching and hurricanes in 2005

Status of Caribbean coral reefs after bleaching and hurricanes in 2005

Status of Caribbean coral reefs after bleaching and hurricanes in 2005

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

<strong>Status</strong> <strong>of</strong> <strong>Caribbean</strong> Coral Reefs <strong>after</strong> Bleach<strong>in</strong>g <strong>and</strong> Hurricanes <strong>in</strong> <strong>2005</strong>Arlene (TS)C<strong>in</strong>dy (TD)Emily (4)Stan (TS)Wilma(4)Beta (3)Gamma (TS)Weekly mean % Temperature (C)313029282726Dennis(3)2 DHW 3 DHW 1.5 DHW 2 DHWWeeksCold air mass‘northers’ beg<strong>in</strong>1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4June July August September October November DecemberTropical storm name (strength category) <strong>and</strong> time <strong>of</strong> occurence for <strong>2005</strong> storms <strong>in</strong> the Western <strong>Caribbean</strong>/MAR area.Water temperatures provided by Smithsonian Institution’s laboratory on Carrie Bow Caye, Belize (CCRE Program)Water temperatures <strong>in</strong> <strong>2005</strong> reached the <strong>bleach<strong>in</strong>g</strong> threshold (around 30°C) on several occasions,however the passage <strong>of</strong> tropical storms <strong>in</strong> the Gulf <strong>of</strong> Mexico <strong>and</strong> Western <strong>Caribbean</strong> between June<strong>and</strong> December may have contributed to the series <strong>of</strong> sharp temperature decl<strong>in</strong>es noted <strong>in</strong> the graphabove.The numerous tropical storms <strong>and</strong> <strong>hurricanes</strong> by-pass<strong>in</strong>g Belize <strong>in</strong> <strong>2005</strong> may have benefitedthe <strong>reefs</strong> <strong>of</strong> Belize by lower<strong>in</strong>g SSTs, truncat<strong>in</strong>g the cumulative thermal stress, <strong>and</strong> therebyreduc<strong>in</strong>g the eventual extent <strong>of</strong> <strong>coral</strong> mortality.<strong>Status</strong> <strong>of</strong> Reefs <strong>in</strong> 2006: A comprehensive reef assessment was conducted by WWF <strong>and</strong> partners<strong>in</strong> summer 2006 us<strong>in</strong>g the Atlantic <strong>and</strong> Gulf Rapid Reef Assessment (AGRRA) protocol. Thissurvey found negligible <strong>bleach<strong>in</strong>g</strong> <strong>and</strong> m<strong>in</strong>imal recent mortality on 141 <strong>reefs</strong> that were selectedbased on geomorphology <strong>and</strong> a r<strong>and</strong>omized design us<strong>in</strong>g the millennium <strong>coral</strong> reef maps forthe region. Only 207 <strong>of</strong> the 5614 colonies assessed (3.7%) showed any signs <strong>of</strong> <strong>coral</strong> <strong>bleach<strong>in</strong>g</strong>.Interest<strong>in</strong>gly, <strong>bleach<strong>in</strong>g</strong> <strong>in</strong>cidence was higher among fore-reef sites compared with other reefhabitats. Disease <strong>in</strong>festation was also low overall, with less than 2% <strong>of</strong> colonies affected by anydisease. Mean recent mortality for the 140 <strong>reefs</strong> (5614 <strong>coral</strong> colonies) was less than 1.5%, withno significant differences among habitats. Although the <strong>2005</strong> <strong>bleach<strong>in</strong>g</strong> event did not causesignificant damage to Belize’s <strong>reefs</strong>, overall live <strong>coral</strong> cover rema<strong>in</strong>s relatively low, averag<strong>in</strong>gabout 10% <strong>and</strong> the <strong>bleach<strong>in</strong>g</strong> may have slowed recovery by 1 to 2 years.Fore- <strong>and</strong> p<strong>in</strong>nacle <strong>reefs</strong> were dom<strong>in</strong>ated by colonies <strong>of</strong> Agaricia, while Porites dom<strong>in</strong>ated patch<strong>reefs</strong> <strong>and</strong> reef flats. Mean fleshy macroalgae cover was 16% on fore-<strong>reefs</strong>, 18% on patch <strong>reefs</strong>,15% on reef flats <strong>and</strong> 14% on p<strong>in</strong>nacle <strong>reefs</strong>. Coral recruitment was greatest on p<strong>in</strong>nacle <strong>reefs</strong>(7 per m 2 ) followed by reef flats (4/m 2 ), patch <strong>reefs</strong> (3/m 2 ) <strong>and</strong> fore-<strong>reefs</strong> (3/m 2 ). Herbivorous52

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!