scispace - formally typeset

Journal ArticleDOI

A study on the recovery of Tobago's coral reefs following the 2010 mass bleaching event.

15 Mar 2016-Marine Pollution Bulletin (University of British Columbia)-Vol. 104, Iss: 1, pp 198-206

TL;DR: The juvenile distribution and the response of individual species to the bleaching event support the notion that Caribbean reefs are becoming dominated by weedy non-framework building taxa which are more resilient to disturbances.

AbstractIn 2010, severe coral bleaching was observed across the southeastern Caribbean, including the island of Tobago, where coral reefs are subject to sedimentation and high nutrient levels from terrestrial runoff. Here we examine changes in corals' colony size distributions over time (2010-2013), juvenile abundances and sedimentation rates for sites across Tobago following the 2010 bleaching event. The results indicated that since pre-bleaching coral cover was already low due to local factors and past disturbance, the 2010 event affected only particular susceptible species' population size structure and increased the proportion of small sized colonies. The low density of juveniles (mean of 5.4±6.3 juveniles/m(-2)) suggests that Tobago's reefs already experienced limited recruitment, especially of large broadcasting species. The juvenile distribution and the response of individual species to the bleaching event support the notion that Caribbean reefs are becoming dominated by weedy non-framework building taxa which are more resilient to disturbances.

Topics: Resilience of coral reefs (64%), Environmental issues with coral reefs (64%), Coral bleaching (62%), Reef (59%), Coral reef (57%)

Summary (1 min read)

2.2.4 Statistical  analysis    

  • All   juvenile   and   sediment   data  were  tested  for  normality  using  the  Shapiro-‐Wilk  test  and  homogeneity  of  variance  using   graphical  methods.
  • Sedimentation   rate  data  were   found   to  be  normally  distributed,  although   juvenile  data  did  not  follow  a  normal  destruction.

2.3.1 Juvenile  density  and  composition  

  • Broadcasting  juvenile  taxa  represented   the  minority  (27.1  %)  such  as  Siderastrea,  Diploria,  Montastrea  and  Colpophyllia.
  • The  small-‐sized  brooding  Scolymia  spp.,  had  moderate  abundances  of  juveniles,   mainly   at   Culloden   sites.

3.4 Discussion  

  • Many  species  experienced  a  decline   in  colony   abundance;  percent  cover  and  mean  colony  size  by  2011,  symptomatic  of  corals  having  suffered   complete  mortality  and/or  partial  mortality.
  • This  study  indicates  that  across  Tobago’s  different  reef  sites,  the  bleaching  disturbance  can  lead   to  a  dominance  of   smaller   size   coral   colonies,  which   could  negatively  affect   the   reproductive   output.

Did you find this useful? Give us your feedback

...read more

Content maybe subject to copyright    Report

!"#$%&'"()"$*+",+-(.+,'"(/"0(123(4#"-(,25",++/#"/(55(67)3"$*+"
89:9";2##"15+2-*7)3"+.+)$"
!"#
$%&'()#*+,&%--#
#
*$./#0)',1%23"4#5678)1-79"#:'&&),)#;'6<'64#5679)<#=76,<'(4#>??@#
#
A#BCD$E$#$5*FEBBDG#EH#IAJBEA;#K5;KE;;FDHB#LK#
BCD#JDM5EJDFDHB$#KLJ#BCD#GD0JDD#LK#
#
F%-9)1#'N#$.7)6.)#
76#
BCD#KA:5;BO#LK#0JAG5ABD#AHG#IL$BGL:BLJA;#$B5GED$#
#P0)',1%23"Q#
#
B3)#5678)1-79"#'N#*1797-3#:'&+(!7%#
PR%6.'+8)1Q##
#
G).)(!)1#>?ST#
#
#
U#$%&'()#*+,&%--4#>?ST#

77#
#
!1#$,2-$"
B3)#17-)#'N#'.)%6#9)(2)1%9+1)-#,&'!%&&"#3%-#!).'()#%#,1%8)#931)%9#9'#.'1%&#1))N-4#%-#79#7-#
76.1)%-76,#93)#-)8)179"#%6<#N1)V+)6."#'N#(%--#.'1%&#!&)%.376,#)8)69-#%6<#2'-9W!&)%.376,#
.'1%&# ('19%&79"/# B3)# .'6976+)<# )X7-9)6.)# 'N# 21'<+.978)# .'1%&# 1))N-# Y7&&# 1)&"# '6# .'1%&-Z#
%!7&79"#9'#+6<)1,'#1).'8)1"/#E6#>?S?4#B'!%,'Z-#.'1%&#1))N-#Y)1)#)X2'-)<#9'#-)8)1)#3)%9#
-91)--# &)%<76,# 9'# (%--# !&)%.376,# 'N# +2# 9'# >@W[?\# 'N# .'&'67)-# %9# '!-)18)<# -79)-/# B37-#
-9+<"#)8%&+%9)<#93)#7(2%.9#'N#.'1%&#!&)%.376,#%6<#1).'8)1"#'N#.'1%&#.'((+6797)-#%.1'--#
931))# (%]'1# 1))N# -"-9)(-# 76# B'!%,'# 93%9# <7NN)1# 76# 93)71# )X2'-+1)# 9'# 9)11)-917%&# 1+6'NN/#
A--)--()69-# Y)1)# <'6)# '6# 93)# SQ# <)6-79"# %6<# .'(2'-797'6# 'N# .'1%&# ]+8)67&)-# 9'#
.3%1%.9)17-)# 93)# &)8)&-# 'N# 1).1+79()694# >Q# -)<7()69%97'6# 1%9)-# %6<# .'(2'-797'6# 9'#
+6<)1-9%6<# 79-#2'9)697%&#7(2%.9#'6#1).'8)1"4#%6<#^Q#-2).7)-Z# - 7_)#N1)V+)6."#<7-917!+97'6-#
76#>?S?4#>?SS#%6<#>?S^#9'#)X%(76)#9)(2'1%&#.3%6,)-#%('6,#2'2+&%97'6#-7_)#-91+.9+1)/##
E6#>?S^4# &'Y#]+8)67&)#<)6-797)-#Y)1)#'!-)18)<#P`/TS#a#[/^S#(
W>
Q#%9#('-9#1))N#-79)-4#Y37.3#
Y)1)# <'(76%9)<# !"# !1''<76,# ,)6)1%# Y37&)# !1'%<.%-976,# ,)6)1%# Y)1)# 1%1)/# $)<7()69#
(%9)17%&4# ()%-+1)<# 76# F%"# %6<# b+6)# P)6<# 'N# B'!%,'Z-# <1"# -)%-'6Q# Y%-# ('-9&"#
9)117,)6'+-#%6<#<)2'-79)<#%9#1%9)-#!)&'Y#.'1%&#-91)--#931)-3'&<#&)8)&-#%9#('-9#-79)-/#L+9#
'N# >c# -2).7)-# 2'2+&%97'6-# %--)--)<# !)9Y))6# %&&# -79)-4# T# 2'2+&%97 '6 -# ()%6# .'&'6"# -7_)#
3%<#-7,67N7.%69&"#.3%6,)<#!"#93)#!&)%.376,#)8)694#%6<#'6&"#.3%6,)<#`#2'2+&%97'6-#'8)1#
93)#9Y'#N'&&'Y76,#")%1-/#B3)#N)Y#2'2+&%97'6-#93%9#Y)1)#-7,67N7.%69&"#%&9)1)<#P(%76&"!"#!
$%&'(')!%6<! *#!+),'-.)/)Q#%N9)1#93)#!&)%.376,# -%Y#%#17-)#76#-(%&&# -7_)<#.'&'67)-4# ('-9&#
&7d)&"#%-#%#1)-+&9#'N#.'&'6"#N1%,()69%97'6/##
B37-# -9+<"#37,3&7,39-#93%9# 1).'8)1"# 87%#-)X+%&&"#21'<+.)<# 1).1+79-# %('6,# !1'%<.%-976,#
-2).7)-#Y%-#&7(79)</#e37&)#-)<7()69%97'6#1%9)-#Y)1)#&'Y4#79#7-#&7 d)&"# 93)"# %1)# - 7,67 N7.%6 9&"#
37,3)1# 931'+,3'+9# 93)# 1%76"# -)%-'64# 93+-# %# &'6,W9)1(# -)<7()69%97'6# -9+<"# 7-# 37,3&"#
1).'(()6<)</#F'-9#.'1%&#2'2+&%97'6-#1)-7-9)<#-7,67N7.%69#%&9)1%97'6#N1'(#3)%9#-91)--#76#
>?S?/#C'Y)8)14#,78)6#93%9#N+9+1)#93)1(%&#-91)--#7 -#21']).9)<#9'#!).'()#('1)#769)6-)4#
937-# -9+<"# -3'Y-# 93%9# (%--# !&)%.376,# <7-9+1!%6.)# .'+&<# &)%<# 9'# <).&76)# .'1%&#
2'2+&%97'6Z-#()%6#.'&'6"#-7_)4#Y37.3#.'+&<#%NN).9#.'1%&#1).'8)1"#%-#-(%&&)1#.'&'67)-#%1)#
&)--#N).+6</##
#

777#
#
<,+/2-+"
B37-#93)-7-#7-#!%-)<#'6#N7)&<#<%9%#.'&&).9)<#76#>?S^#76#.'&&%!'1%97'6#Y793#93)#E6-979+9)#'N#
F%176)#ANN%71-#PEFAQ#+6<)1#93)#,+7<%6.)#%6<#-+2)187-7'6#'N#G1/#$7('6#G'66)1/#A&&#<%9%#
N1'(# 93)# N7)&<# Y)1)# .'&&).9)<# !"# ("-)&N# Y793# 93)# %--7-9%6.)# 'N# 8'&+69))1-/# *)6937.#
2)1.)69# .'8)1# %6<# .'1%&# .'&'6"# -7_)# N1)V+)6."# <%9%# N'1# >?S?4# >?SS# %6<# >?S># Y)1)#
21)87'+-&"# .'&&).9)<# !"# 93)# EFA# %-# 2%19# 'N# 93)71# *7'<78)1-79"# %6<# D.'&',"# J)-)%1.3#
I1',1%(()/# ;%!'1%9'1"# -%(2&)# 21'.)--76,# Y%-# 2)1N'1()<# 2%19&"# 76# 93)# EFAZ-#
*7'<78)1-79"# %6<# D.'&',"# ;%!'1%9'1"# %6<# '6# 5*:# R%6.'+8)1# .%(2+-/# E# +6<)19''d# %&&#
&%!'1%9'1"#-%(2&)#21'.)--76,4#%6%&"-7-#'N#<%9%4#%6<#Y17976,#'N#93)#93)-7-#(%6+-.1729/#

78#
#
0215+"(/"=()$+)$#"
#
!1#$,2-$">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>"77#
<,+/2-+">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>"777#
0215+"(/"=()$+)$#">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>"7.#
?7#$"(/"0215+#">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>".7#
?7#$"(/"@73%,+#">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>".77#
!-A)(65+&3+;+)$#">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>".777#
=*2B$+,":>"C)$,(&%-$7()">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>":#
=*2B$+," 8>" !)" 2##+##;+)$" (/" -(,25" D%.+)75+" -(;;%)7$'" 2)&" #+&7;+)$" &+B(#7$7()"
2;()3"$*,++";2D(,",++/"#'#$+;#"7)"0(123(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>"E#
>/S# E691'<+.97'6#////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////#T#
>/># F)93'<-#/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////#[#
>/>/S# $9+<"#%1)%#///////////////////////////////////////////////////////////////////////////////////////////////////////////////////#[#
>/>/># $)<7()69%97'6#%--)--()69#/////////////////////////////////////////////////////////////////////////////////////////#f#
>/>/^# b+8)67&)#.'((+679"#-+18)"#//////////////////////////////////////////////////////////////////////////////////////#S?#
>/>/T# $9%97-97.%&#%6%&"-7-#/////////////////////////////////////////////////////////////////////////////////////////////////////#SS#
>/^# J)-+&9-#//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////#SS#
>/^/S# b+8)67&)#<)6-79"#%6<#.'(2'-797'6#////////////////////////////////////////////////////////////////////////////#SS#
>/^/># :3%1%.9)17_%97'6#'N#-)<7()69%97'6#//////////////////////////////// //////////////////////////////// ///////////#ST#
>/T# G7-.+--7'6#/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////#S[#
=*2B$+,"F>"G#7)3"-(,25"#7H+"&7#$,71%$7()"$("2##+##"$*+",+-(.+,'"/,(;";2##"15+2-*7)3"7)"
$*+"#(%$*+,)"=2,711+2)">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>"8:#
^/S# E691'<+.97'6#//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////#>S#
^/># F)93'<-#///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////#>^#
^/>/S# *)6937.#.'8)1#-+18)"#////////////////////////////////////////////////////////////////////////////////////////////////#>T#

8#
##
^/>/># :'&'6"#-7_)#N1)V+)6."#-+18)"#///////////////////////////////////////////////////////////////////////////////////#>`#
^/>/^# $9%97-97.%&#%6%&"-7-#/////////////////////////////////////////////////////////////////////////////////////////////////////#>`#
^/^# J)-+&9-#//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////#>[#
^/^/S# :3%6,)-#76#2)1.)69#.'1%&#.'8)1#////////////////////////////////////////////////////////////////////////////////#>[#
^/^/># :3%6,)-#76#.'1%&#2'2+&%97'6#-91+.9+1)#%6<#.'((+679"#.'(2'-797'6#//////////////////////#>c#
^/T# G7-.+--7'6#/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////#^>#
=*2B$+,"E>"=()-5%#7()">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>"FI#
J7157(3,2B*'">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>"FK#
!BB+)&7-+#">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>"EI#
#

Citations
More filters

Journal ArticleDOI
TL;DR: How coral communities have changed in the northern sector of the Mexican Caribbean between 1985 and 2016 is evaluated, and the implications for the maintenance of physical reef functions in the back- and fore-reef zones are evaluated.
Abstract: Functional integrity on coral reefs is strongly dependent upon coral cover and coral carbonate production rate being sufficient to maintain three-dimensional reef structures. Increasing environmental and anthropogenic pressures in recent decades have reduced the cover of key reef-building species, producing a shift towards the relative dominance of more stress-tolerant taxa and leading to a reduction in the physical functional integrity. Understanding how changes in coral community composition influence the potential of reefs to maintain their physical reef functioning is a priority for their conservation and management. Here, we evaluate how coral communities have changed in the northern sector of the Mexican Caribbean between 1985 and 2016, and the implications for the maintenance of physical reef functions in the back- and fore-reef zones. We used the cover of coral species to explore changes in four morpho-functional groups, coral community composition, coral community calcification, the reef functional index and the reef carbonate budget. Over a period of 31 years, ecological homogenization occurred between the two reef zones mostly due to a reduction in the cover of framework-building branching (Acropora spp.) and foliose-digitiform (Porites porites and Agaricia tenuifolia) coral species in the back-reef, and a relative increase in non-framework species in the fore-reef (Agaricia agaricites and Porites astreoides). This resulted in a significant decrease in the physical functionality of the back-reef zone. At present, both reef zones have negative carbonate budgets, and thus limited capacity to sustain reef accretion, compromising the existing reef structure and its future capacity to provide habitat and environmental services.

25 citations


Journal ArticleDOI
08 Sep 2016-PLOS ONE
TL;DR: Investigating coral community composition across three different temperature and productivity regimes along a nearshore-offshore gradient on lagoonal reefs of the Belize Mesoamerican Barrier Reef System suggests that corals utilizing these two life history strategies may be better suited to cope with warmer oceans and thus may warrant protective status under climate change.
Abstract: Coral reefs are increasingly threatened by global and local anthropogenic stressors such as rising seawater temperature, nutrient enrichment, sedimentation, and overfishing. Although many studies have investigated the impacts of local and global stressors on coral reefs, we still do not fully understand how these stressors influence coral community structure, particularly across environmental gradients on a reef system. Here, we investigate coral community composition across three different temperature and productivity regimes along a nearshore-offshore gradient on lagoonal reefs of the Belize Mesoamerican Barrier Reef System (MBRS). A novel metric was developed using ultra-high-resolution satellite-derived estimates of sea surface temperatures (SST) to classify reefs as exposed to low (lowTP), moderate (modTP), or high (highTP) temperature parameters over 10 years (2003 to 2012). Coral species richness, abundance, diversity, density, and percent cover were lower at highTP sites relative to lowTP and modTP sites, but these coral community traits did not differ significantly between lowTP and modTP sites. Analysis of coral life history strategies revealed that highTP sites were dominated by hardy stress-tolerant and fast-growing weedy coral species, while lowTP and modTP sites consisted of competitive, generalist, weedy, and stress-tolerant coral species. Satellite-derived estimates of Chlorophyll-a (chl-a) were obtained for 13-years (2003–2015) as a proxy for primary production. Chl-a concentrations were highest at highTP sites, medial at modTP sites, and lowest at lowTP sites. Notably, thermal parameters correlated better with coral community traits between site types than productivity, suggesting that temperature (specifically number of days above the thermal bleaching threshold) played a greater role in defining coral community structure than productivity on the MBRS. Dominance of weedy and stress-tolerant genera at highTP sites suggests that corals utilizing these two life history strategies may be better suited to cope with warmer oceans and thus may warrant protective status under climate change.

22 citations


Cites background from "A study on the recovery of Tobago's..."

  • ...in the Caribbean [25] and continued decline is expected as temperature stress increases [6, 26, 27], leading to a decline in reef complexity [28] Temperature Regimes Impact Coral Assemblages of Lagoonal Reefs...

    [...]

  • ...A shift from dominance of competitive and generalist species to weedy and stress tolerant species occurred on Okinawan reefs following the 1998 El Niño bleaching event [29, 30] and an overall decline in coral cover and abundance currently occurring in the Caribbean has been coupled with an increase in abundance of weedy species [27, 31]....

    [...]


Journal ArticleDOI
TL;DR: The results reinforce the notion that corals are sensitive to anthropogenic changes and reveal the scarcity of information on coral responses to pollution, tourism, overfishing and acidification, particularly in mesophotic ecosystems and in ecoregions outside the Indo-Pacific and Caribbean.
Abstract: Coral reefs have long inspired marine ecologists and conservationists around the world due to their ecological and socioeconomic importance. Much knowledge on the anthropogenic impacts on coral species has been accumulated, but relevant research gaps on coral ecology remain underappreciated in human-modified seascapes. In this review we assessed 110 studies on coral responses to five major human disturbances– acidification, climate change, overfishing, pollution and non-regulated tourism –to identify geographic and theoretical gaps in coral ecology and help to guide further researches on the topic. We searched for papers in Web of Science published from 2000 to 2016 and classified them according to the ocean, ecoregion, human threat, level of biological organization, study approach, method of data collection, depth of data collected, and type of coral response. Most studies were carried out in the Indo-Pacific and Caribbean (36.3 and 31.9%, respectively) and used observational approach (60%) with scuba diving (36.3%) to assess the impact of ocean warming (55.4%) on coral communities (58.2%). Only 37 of the 141 global ecoregions that contain coral reefs were studied. All studies were restricted to shallow waters (0.5–27 m depth) and reported negative responses of corals to human disturbance. Our results reinforce the notion that corals are sensitive to anthropogenic changes. They reveal the scarcity of information on coral responses to pollution, tourism, overfishing and acidification, particularly in mesophotic ecosystems (>30 m depth) and in ecoregions outside the Indo-Pacific and Caribbean. Experimental studies at the individual and population levels should be also encouraged.

16 citations


Journal ArticleDOI
TL;DR: It is postulate that the decline in skeletal extension rates for nearshore corals is driven primarily by the combined effects of long-term ocean warming and increasing exposure to higher levels of land-based anthropogenic stressors, with acute thermally induced bleaching events playing a lesser role.
Abstract: Anthropogenic global change and local stressors are impacting coral growth and survival worldwide, altering the structure and function of coral reef ecosystems. Here, we show that skeletal extension rates of nearshore colonies of two abundant and widespread Caribbean corals (Siderastrea siderea, Pseudodiploria strigosa) declined across the Belize Mesoamerican Barrier Reef System (MBRS) over the past century, while offshore coral conspecifics exhibited relatively stable extension rates over the same temporal interval. This decline has caused nearshore coral extension rates to converge with those of their historically slower growing offshore coral counterparts. For both species, individual mass coral bleaching events were correlated with low rates of skeletal extension within specific reef environments, but no single bleaching event was correlated with low skeletal extension rates across all reef environments. We postulate that the decline in skeletal extension rates for nearshore corals is driven primarily by the combined effects of long-term ocean warming and increasing exposure to higher levels of land-based anthropogenic stressors, with acute thermally induced bleaching events playing a lesser role. If these declining trends in skeletal growth of nearshore S. siderea and P. strigosa continue into the future, the structure and function of these critical nearshore MBRS coral reef systems is likely to be severely impaired.

11 citations


Journal ArticleDOI
Abstract: Climate change and human disturbance threatens coral reefs across the Pacific, yet there is little consensus on what characterizes a "healthy" reef. Benthic cover, particularly low coral cover and high macroalgae cover, are often used as an indicator of reef degradation, despite uncertainty about the typical algal community compositions associated with either near-pristine or damaged reefs. In this study, we examine differences in coral and algal community compositions and their response to human disturbance and past heat stress, by analysing 25 sites along a gradient of human disturbance in Majuro and Arno Atolls of the Republic of the Marshall Islands. Our results show that total macroalgae cover indicators of reef degradation may mask the influence of local human disturbance, with different taxa responding to disturbance differently. Identifying macroalgae to a lower taxonomic level (e.g. the genus level) is critical for a more accurate measure of Pacific coral reef health.

8 citations


References
More filters

Journal ArticleDOI
14 Dec 2007-Science
TL;DR: As the International Year of the Reef 2008 begins, scaled-up management intervention and decisive action on global emissions are required if the loss of coral-dominated ecosystems is to be avoided.
Abstract: Atmospheric carbon dioxide concentration is expected to exceed 500 parts per million and global temperatures to rise by at least 2 degrees C by 2050 to 2100, values that significantly exceed those of at least the past 420,000 years during which most extant marine organisms evolved. Under conditions expected in the 21st century, global warming and ocean acidification will compromise carbonate accretion, with corals becoming increasingly rare on reef systems. The result will be less diverse reef communities and carbonate reef structures that fail to be maintained. Climate change also exacerbates local stresses from declining water quality and overexploitation of key species, driving reefs increasingly toward the tipping point for functional collapse. This review presents future scenarios for coral reefs that predict increasingly serious consequences for reef-associated fisheries, tourism, coastal protection, and people. As the International Year of the Reef 2008 begins, scaled-up management intervention and decisive action on global emissions are required if the loss of coral-dominated ecosystems is to be avoided.

4,047 citations


Journal ArticleDOI
Abstract: Five test runs were performed to assess possible bias when performing the loss on ignition (LOI) method to estimate organic matter and carbonate content of lake sediments. An accurate and stable weight loss was achieved after 2 h of burning pure CaCO3 at 950 °C, whereas LOI of pure graphite at 530 °C showed a direct relation to sample size and exposure time, with only 40-70% of the possible weight loss reached after 2 h of exposure and smaller samples losing weight faster than larger ones. Experiments with a standardised lake sediment revealed a strong initial weight loss at 550 °C, but samples continued to lose weight at a slow rate at exposure of up to 64 h, which was likely the effect of loss of volatile salts, structural water of clay minerals or metal oxides, or of inorganic carbon after the initial burning of organic matter. A further test-run revealed that at 550 °C samples in the centre of the furnace lost more weight than marginal samples. At 950 °C this pattern was still apparent but the differences became negligible. Again, LOI was dependent on sample size. An analytical LOI quality control experiment including ten different laboratories was carried out using each laboratory's own LOI procedure as well as a standardised LOI procedure to analyse three different sediments. The range of LOI values between laboratories measured at 550 °C was generally larger when each laboratory used its own method than when using the standard method. This was similar for 950 °C, although the range of values tended to be smaller. The within-laboratory range of LOI measurements for a given sediment was generally small. Comparisons of the results of the individual and the standardised method suggest that there is a laboratory-specific pattern in the results, probably due to differences in laboratory equipment and/or handling that could not be eliminated by standardising the LOI procedure. Factors such as sample size, exposure time, position of samples in the furnace and the laboratory measuring affected LOI results, with LOI at 550 °C being more susceptible to these factors than LOI at 950 °C. We, therefore, recommend analysts to be consistent in the LOI method used in relation to the ignition temperatures, exposure times, and the sample size and to include information on these three parameters when referring to the method.

3,664 citations


"A study on the recovery of Tobago's..." refers methods in this paper

  • ...Sediment compositionwas analyzed using the loss on ignition (LOI) method (Heiri et al., 2001) to determine what fraction of the sediment was composed of organic and carbonate matter; the remaining non-carbonate material represented the terrigenous fraction of the sample....

    [...]


Journal ArticleDOI
24 Jun 2004-Nature
TL;DR: The ecological roles of critical functional groups (for both corals and reef fishes) that are fundamental to understanding resilience and avoiding phase shifts from coral dominance to less desirable, degraded ecosystems are reviewed.
Abstract: The worldwide decline of coral reefs calls for an urgent reassessment of current management practices. Confronting large-scale crises requires a major scaling-up of management efforts based on an improved understanding of the ecological processes that underlie reef resilience. Managing for improved resilience, incorporating the role of human activity in shaping ecosystems, provides a basis for coping with uncertainty, future changes and ecological surprises. Here we review the ecological roles of critical functional groups (for both corals and reef fishes) that are fundamental to understanding resilience and avoiding phase shifts from coral dominance to less desirable, degraded ecosystems. We identify striking biogeographic differences in the species richness and composition of functional groups, which highlight the vulnerability of Caribbean reef ecosystems. These findings have profound implications for restoration of degraded reefs, management of fisheries, and the focus on marine protected areas and biodiversity hotspots as priorities for conservation.

2,812 citations


Journal ArticleDOI
09 Sep 1994-Science
TL;DR: A dramatic phase shift has occurred in Jamaica, producing a system dominated by fleshy macroalgae (more than 90 percent cover), and immediate implementation of management procedures is necessary to avoid further catastrophic damage.
Abstract: Many coral reefs have been degraded over the past two to three decades through a combination of human and natural disturbances. In Jamaica, the effects of overfishing, hurricane damage, and disease have combined to destroy most corals, whose abundance has declined from more than 50 percent in the late 1970s to less than 5 percent today. A dramatic phase shift has occurred, producing a system dominated by fleshy macroalgae (more than 90 percent cover). Immediate implementation of management procedures is necessary to avoid further catastrophic damage.

2,688 citations


"A study on the recovery of Tobago's..." refers background in this paper

  • ...This ecological change has been attributed to the reduction of herbivory, due to overfishing and the regional die-off of grazing urchins in the 1980s, increased terrestrial runoff, marine pollution and possibly related disease outbreaks (Hughes, 1994; Jackson et al., 2014)....

    [...]


Book
07 Apr 2011
TL;DR: This book is aimed at professional researchers, practitioners, graduate students and teachers in ecology, environmental science and engineering, and in related fields such as oceanography, molecular ecology, agriculture and soil science, who already have a background in general and multivariate statistics and wish to apply this knowledge to their data using the R language.
Abstract: Numerical Ecology with R provides a long-awaited bridge between a textbook in Numerical Ecology and the implementation of this discipline in the R language. After short theoretical overviews, the authors accompany the users through the exploration of the methods by means of applied and extensively commented examples. Users are invited to use this book as a teaching companion at the computer. The travel starts with exploratory approaches, proceeds with the construction of association matrices, then addresses three families of methods: clustering, unconstrained and canonical ordination, and spatial analysis. All the necessary data files, the scripts used in the chapters, as well as the extra R functions and packages written by the authors, can be downloaded from a web page accessible through the Springer web site(http://adn.biol.umontreal.ca/ numericalecology/numecolR/). This book is aimed at professional researchers, practitioners, graduate students and teachers in ecology, environmental science and engineering, and in related fields such as oceanography, molecular ecology, agriculture and soil science, who already have a background in general and multivariate statistics and wish to apply this knowledge to their data using the R language, as well as people willing to accompany their disciplinary learning with practical applications. People from other fields (e.g. geology, geography, paleoecology, phylogenetics, anthropology, the social and education sciences, etc.) may also benefit from the materials presented in this book. The three authors teach numerical ecology, both theoretical and practical, to a wide array of audiences, in regular courses in their Universities and in short courses given around the world. Daniel Borcard is lecturer of Biostatistics and Ecology and researcher in Numerical Ecology at Universite de Montreal, Quebec, Canada. Francois Gillet is professor of Community Ecology and Ecological Modelling at Universite de Franche-Comte, Besancon, France. Pierre Legendre is professor of Quantitative Biology and Ecology at Universite de Montreal, Fellow of the Royal Society of Canada, and ISI Highly Cited Researcher in Ecology/Environment.

2,227 citations


"A study on the recovery of Tobago's..." refers methods in this paper

  • ...The impact of the bleaching event on the coral community of each site over the three years was also analyzed using a non-metric multidimensional scaling (NMDS) based on Bray–Curtis dissimilarities of each species abundance per site, using vegan package version 2.0- 10 (Borcard et al., 2011)....

    [...]