scholarly journals Coral (Anthozoa: Scleractinia) Recruitment at Bahías de Huatulco, Western México: Implications for Coral Community Structure and Dynamics1

2007 ◽  
Vol 61 (3) ◽  
pp. 355-369 ◽  
Author(s):  
R. A. López-Pérez ◽  
M. G. Mora-Pérez ◽  
G. E. Leyte-Morales
Keyword(s):  
Community Structure ◽  
Coral Community ◽  
Western Mexico

scholarly journals Transects, quadrats, or points? What is the best combination to get a precise estimation of a coral community?

2019 ◽  
Author(s):  
Luis M. Montilla ◽  
Emy Miyazawa ◽  
Alfredo Ascanio ◽  
María López-Hernández ◽  
Gloria Mariño-Briceño ◽  
...  
Keyword(s):  
Community Structure ◽  
Coral Reef ◽  
Effect Size ◽  
Standard Error ◽  
Scleractinian Coral ◽  
Statistical Power ◽  
Coral Community ◽  
Sampling Effort ◽  
Precise Estimation

ABSTRACTThe characteristics of coral reef sampling and monitoring are highly variable, with numbers of units and sampling effort varying from one study to another. Numerous works have been carried out to determine an appropriate effect size through statistical power, however, always from a univariate perspective. In this work, we used the pseudo multivariate dissimilarity-based standard error (MultSE) approach to assess the precision of sampling scleractinian coral assemblages in reefs of Venezuela between 2017 and 2018 when using different combinations of number of transects, quadrats and points. For this, the MultSE of 36 sites previously sampled was estimated, using four 30m-transects with 15 photo-quadrats each and 25 random points per quadrat. We obtained that the MultSE was highly variable between sites and is not correlated with the univariate standard error nor with the richness of species. Then, a subset of sites was re-annotated using 100 uniformly distributed points, which allowed the simulation of different numbers of transects per site, quadrats per transect and points per quadrat using resampling techniques. The magnitude of the MultSE stabilized by adding more transects, however, adding more quadrats or points does not improve the estimate. For this case study, the error was reduced by half when using 10 transects, 10 quadrats per transect and 25 points per quadrat. We recommend the use of MultSE in reef monitoring programs, in particular when conducting pilot surveys to optimize the estimation of the community structure.

scholarly journals Coral communities condition in varying wave exposure: the gulf of Cazones, Cuba

2016 ◽  
Vol 64 (1) ◽  
pp. 79 ◽  
Author(s):  
Hansel Caballero Aragon ◽  
Pedro M Alcolado ◽  
Néstor Rey-Villiers ◽  
Susana Perera Valderrama ◽  
Juliett González Méndez
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Marine Protected Area ◽  
Coral Cover ◽  
Coral Community ◽  
Wave Exposure ◽  
Maximum Diameter ◽  
Live Coral ◽  
Coral Mortality ◽  
Coral Communities

Wave exposure can influence community structure and distribution of shallow coral reefs, by affecting organisms both directly and indirectly. To assess the current stony coral community condition under different degrees of wave exposure at a marine protected area of the Gulf of Cazones (SW Cuba), two expeditions were carried out in May 2010 and June 2012. Four sampling sites were sampled at reef crests (1.5 m deep), and twelve at fore-reefs, at 10, 15 and 20 m deep in four geographic locations. Live coral cover, species richness and composition, colony density, and maximum diameter were assessed using the AGRRA 2001 methodology. Multivariate and non-parametric statistics were applied to compare sites. The coral community structure within reef crests was not homogenous. The observed variability of indicators apparently was determined by great coral mortality events resulting from natural disturbances that occurred in the past (hurricanes, bleaching and diseases). Fore-reef coral communities displayed better condition and lower coral mortality than reef crests. Species richness and coral composition varied, while multivariate and statistical methods did not reveal site grouping with regard to wave exposure. The remaining biological condition indicators were similar among sites, except in the most exposed one, where coral cover and coral size were slightly lower. Wave exposure in the gulf of Cazones seemed not to have a significant influence on differences in condition and structure of the assessed coral communities.

scholarly journals Temperature regimes impact coral assemblages along environmental gradients on lagoonal reefs in Belize

2016 ◽  
Author(s):  
Justin H. Baumann ◽  
Joseph E. Townsend ◽  
Travis A. Courtney ◽  
Hannah E. Aichelman ◽  
Sarah W. Davies ◽  
...  
Keyword(s):  
Life History ◽  
Community Structure ◽  
Coral Reefs ◽  
Coral Species ◽  
Environmental Gradients ◽  
Coral Community ◽  
Life History Strategies ◽  
Percent Cover ◽  
Chl A ◽  
Reef System

AbstractCoral 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.

scholarly journals Coral community bleaching response on a highly urbanised reef

2014 ◽  
Author(s):  
James R Guest ◽  
Jeffrey Low ◽  
Karenne Tun ◽  
Jani I Tanzil ◽  
Peter A Todd ◽  
...  
Keyword(s):  
Community Structure ◽  
Thermal Stress ◽  
Anthropogenic Impacts ◽  
Coral Cover ◽  
Regional Scale ◽  
Coral Community ◽  
Bleaching Response ◽  
Sea Surface Temperature Anomalies ◽  
Relative Cover ◽  
June July

Projected increases in the magnitude and frequency of sea surface temperature anomalies present a significant threat to the persistence of tropical coral reefs, however, detailed studies of community level responses to thermal stress are needed if its effect on reef resilience are to be understood. While many studies report on broad, regional scale responses to thermal stress (e.g., proportion of corals bleached), far fewer examine variation in susceptibility among taxa and change in coral community structure, before, during and after bleaching on individual reefs. Furthermore, relatively few studies of bleaching response come from highly urbanised reefs that experience chronic disturbances such as elevated sedimentation and turbidity. Here we report in detail on the bleaching response of corals at a highly urbanised reef site south of mainland Singapore during (June, July) and immediately after (October) a major thermal coral bleaching event in 2010. To estimate the capacity for resistance and resilience to thermal stress, we report on a) the overall bleaching severity during and after the event, b) differences in bleaching susceptibility among taxa during the event and c) the response of the reef in terms of taxonomic community structure before (2009) and after (2012) bleaching. Despite severe bleaching in 2010 (66% of colonies bleached), post-bleaching recovery appeared to be relatively rapid and coral taxa that are usually highly susceptible (e.g., Acropora and Pocillopora) were relatively unaffected, i.e., either they did not bleach or they bleached and recovered. Although there was no significant change in coral taxonomic community structure among years, taxa that bleached most severely tended to have the greatest reductions in relative cover. Several factors may have contributed to the overall high resistance of this site to bleaching including turbidity, symbiont affiliation and heterotrophy. A parsimonious explanation for the reversed pattern of bleaching susceptibility among taxa is that these coral populations have adapted and/or acclimatised to thermal stress. Despite ongoing chronic anthropogenic impacts, we suggest that this site has potential for rapid recovery of coral cover due to the dominant coral taxa and growth forms being capable of rapid regrowth from remnant colonies.

Fundamental change in coral community structure at Green Island

Coral Reefs ◽  
1990 ◽  
Vol 9 (3) ◽  
pp. 166-166 ◽  
Author(s):  
T. Done ◽  
L. De Vantier
Keyword(s):  
Community Structure ◽  
Coral Community ◽  
Fundamental Change ◽  
Green Island
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