scholarly journals EFECTOS DE UN INUSUAL PERÍODO DE ALTA FRECUENCIA DE HURACANES SOBRE EL BENTOS DE ARRECIFES CORALINOS

2009 ◽  
Vol 1 ◽  
pp. 73 ◽  
Author(s):  
Pedro M. Alcolado ◽  
Darlenys Hernández-Muñoz ◽  
Hansel Caballero ◽  
Linnet Busutil ◽  
Susana Perera ◽  
...  
Keyword(s):  
Coral Cover ◽  
Disease Incidence ◽  
Structural Complexity ◽  
Acropora Palmata ◽  
Diadema Antillarum ◽  
Porites Astreoides ◽  
Species Dominance ◽  
Montastraea Annularis ◽  
Hard Coral Cover ◽  
Diameter Reduction

En arrecifes coralinos del suroeste de Cuba, se evaluaron los impactos de la inusitada frecuencia e intensidad de huracanes entre el 2001 y el 2007, y de las enfermedades de corales, ambos factores asociados al cambio climático. En las crestas arrecifales, la reducción de la cobertura de coral duro vivo varió de nula a 21%, mientras que la reducción del diámetro máximo promedio de los corales varió de 16 a 40 cm. En los arrecifes frontales, la reducción de la cobertura de coral varió de nula a 14%, mientras que la reducción del diámetro máximo promedio varió de nula a 26 cm. Sin embargo, en todos los sitios se observaron grandes cambios en el predominio numérico de las especies. En las crestas, este se desplazó de  Acropora palmata y otros corales duros hacia Millepora complanata, Porites astreoides o Acropora prolifera. En los arrecifes frontales, el cambio ocurrió de la dominancia de Montastraea annularis (complejo de especies), Diploria strigosa y Agaricia agaricites a la de P. astreoides o Siderastrea siderea. Con esos cambios, las crestas están perdiendo efectividad como refugios y como disipadoras del oleaje, a causa de la reducción de complejidad estructural. La densidad del erizo Diadema antillarum se mantuvo insignificante y sin cambio en el sur del Golfo de Batabanó, mientras que se incrementó de manera importante en la cresta de Faro Cazones. Los porcentajes de mortalidad reciente y de incidencia de enfermedades de corales se mantuvieron bajos, lo que sugiere una influencia dominante de los huracanes en la condición de los arrecifes coralinos evaluados.In coral reefs of southwestern Cuba, we assessed the impacts from unprecedented frequent and intense hurricanes during the period 2001-2007, and from coral diseases, which are both factors considered to be associated with climate change.. At the reef crests, live hard coral cover reduction varied from null to 21%, while maximum average coral diameter reduction varied from 16 to 40 cm. In the fore-reefs, the reduction of coral cover varied from null to 14%, while diameter reduction varied from null to 26 cm. However, at all sites, great shifts in species dominance patterns were observed. In reef crests, numerical dominance of Acropora palmata and other hard corals shifted towards increases of Millepora complanata or, to a lesser extent, of Porites astreoides or Acropora prolifera. At the fore-reefs, the shifts occurred from the dominance of Montastraea annularis complex, Diploria strigosa and Agaricia agaricites, towards combined increases of P. astreoides or Siderastrea siderea. With those ongoing changes, reef crests are losing effectiveness as refuges and wave dissipators because of reduction of structural complexity. The population density of the sea-urchin Diadema antillarum remained negligible and unchanged in the southern Gulf of Batabanó, while it increased significantly at the Faro Cazones reef crest. Percentages of recent mortality and percentages of disease incidence in corals remained low, suggesting a dominant influence from hurricanes on assessed coral reef decline.

scholarly journals Spatial Variations in Density and Size of the Echinoid Diadema Antillarum Philippi on some Venezuelan Coral Reefs

1984 ◽  
Vol 54 (1) ◽  
pp. 73-82 ◽  
Author(s):  
Ernesto Weil ◽  
Freddy Losada ◽  
David Bone
Keyword(s):  
Coral Species ◽  
Size Structure ◽  
Structural Complexity ◽  
Acropora Palmata ◽  
Growth Morphology ◽  
Diadema Antillarum ◽  
Montastrea Annularis ◽  
Reef Zone ◽  
Reef Zones ◽  
Reef Platform

The distribution, population density and size structure of Diadema antillarum Philippi was found to vary with reef locality, food availability and the structural complexity of the reef. Structural complexity was classified according to the growth morphology and abundance of the coral species found in the different reef zones. Mean urchin density in the reef varied between 2.6 and 3.7 ind. m−2. High densities (4.0-7.0 ind. m−2) were found in the upper reef zone, which was characterized by high structural complexity, and by a dominance of the coral species Acropora palmata, A. cervicornis, Montastrea annularis and the hydrozoans Millepora alcicornis and M. complanata. Low densities (1.5-4.0 ind. m−2) were found in the deep fore reef and flat reef platform, which were characterized by low structural complexity.

scholarly journals Phenotypic variation in two widespread Caribbean corals — Porites astreoides and P. divaricata — between mangrove and lagoon habitats

2020 ◽  
Author(s):  
Karina Scavo Lord ◽  
Anna Barcala ◽  
Hannah E. Aichelman ◽  
Nicola G. Kriefall ◽  
Chloe Brown ◽  
...  
Keyword(s):  
Coral Species ◽  
Phenotypic Diversity ◽  
Coral Cover ◽  
Patch Reef ◽  
Reef Coral ◽  
Structural Complexity ◽  
Environmental Parameters ◽  
Porites Astreoides ◽  
The Difference ◽  
The Tropics

ABSTRACTAs coral reefs experience dramatic declines in coral cover throughout the tropics, there is an urgent need to understand the role that non-reef habitats such as mangroves play in the ecological niche of corals. Mangrove habitats present a challenge to reef-dwelling corals as they can differ dramatically from adjacent reef habitats with respect to key environmental parameters such as temperature and light. As variation in temperature and light within reef habitats is known to drive intraspecific differences in coral phenotype, we hypothesized that coral species which can exploit both reef and mangrove habitats will exhibit predictable differences in phenotype between habitats. To investigate how intraspecific variation, driven by either local adaptation or phenotypic plasticity, might enable particular coral species to exploit these two qualitatively different habitat types, we compared the phenotypes of two widespread Caribbean corals — Porites divaricata and P. astreoides— in mangrove versus lagoon habitats on Turneffe Atoll, Belize. We document significant differences in colony size, color, structural complexity, and corallite morphology between habitats. In every instance, the difference between mangrove and lagoon corals was consistent in P. divaricata and P. astreoides. This study is the first to document intraspecific phenotypic diversity in corals occupying mangrove versus patch-reef habitats, and it provides a foundation for understanding why some “reef coral” species can exploit mangroves, while others cannot.

scholarly journals Diversity and abundance of conspicuous macrocrustaceans on coral reefs differing in level of degradation

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4922 ◽  
Author(s):  
Roberto González-Gómez ◽  
Patricia Briones-Fourzán ◽  
Lorenzo Álvarez-Filip ◽  
Enrique Lozano-Álvarez
Keyword(s):  
Coral Reefs ◽  
Habitat Degradation ◽  
Coral Cover ◽  
Structural Complexity ◽  
Live Coral ◽  
Percent Cover ◽  
Acropora Palmata ◽  
Coral Rubble ◽  
Local Diversity ◽  
Census Techniques

Coral reefs sustain abundant and diverse macrocrustaceans that perform multiple ecological roles, but coral reefs are undergoing massive degradation that may be driving changes in the species composition and abundance of reef-associated macrocrustaceans. To provide insight into this issue, we used non-destructive visual census techniques to compare the diversity and abundance of conspicuous macrocrustaceans (i.e., those >1 cm and visible without disturbance) between two shallow Caribbean coral reefs similar in size (∼1.5 km in length) and close to each other, but one (“Limones”) characterized by extensive stands of the branching coral Acropora palmata, and the other (“Bonanza”) dominated by macroalgae and relic coral skeletons and rubble (i.e., degraded). We also assessed the structural complexity of each reef and the percent cover of various benthic community components. Given the type of growth of A. palmata, we expected to find a greater structural complexity, a higher cover of live coral, and a lower cover of macroalgae on Limones, and hence a more diverse and abundant macrocrustacean community on this reef compared with Bonanza. Overall, we identified 63 macrocrustacean species (61 Decapoda and two Stomatopoda). Contrary to our expectations, structural complexity did not differ significantly between the back-reef zones of these reefs but varied more broadly on Limones, and the diversity and abundance of macrocrustaceans were higher on Bonanza than on Limones despite live coral cover being higher on Limones and macroalgal cover higher on Bonanza. However, the use of various types of microhabitats by macrocrustaceans differed substantially between reefs. On both reefs, the dominant species were the clinging crab Mithraculus coryphe and the hermit crab Calcinus tibicen, but the former was more abundant on Bonanza and the latter on Limones. M. coryphe occupied a diverse array of microhabitats but mostly coral rubble and relic skeletons, whereas C. tibicen was often, but not always, found associated with colonies of Millepora spp. A small commensal crab of A. palmata, Domecia acanthophora, was far more abundant on Limones, emerging as the main discriminant species between reefs. Our results suggest that local diversity and abundance of reef-associated macrocrustaceans are partially modulated by habitat degradation, the diversity of microhabitat types, and the establishment of different commensal associations rather than by structural complexity alone.

scholarly journals Reef Rugosity and Butterflyfish Community Structure in Punta Dumalag Marine Protected Area, Davao City

2018 ◽  
Vol 1 ◽  
pp. 2
Author(s):  
Samuel Herbert T. Mamora
Keyword(s):  
Community Structure ◽  
Fish Species ◽  
Protected Area ◽  
Marine Protected Area ◽  
Coral Cover ◽  
Structural Complexity ◽  
Correlation Coefficients ◽  
Hard Coral ◽  
Confounding Effect ◽  
Hard Coral Cover

This study investigated the rugosity and butterflyfish community structure in Punta Dumalag, Davao City in twelve transects distributed in three stations. The transects were laid parallel to the shore at a depth of five to six meters in three stations. Rugosity indices, percent hard coral cover, butterflyfish species richness, abundance, diversity, biomass and density across all sampling stations registered low values, which may be attributed to a combination of fishing pressure and a strong prolonged southeast monsoon. Correlation analysis between rugosity and butterflyfish abundance showed low correlation coefficients that were statistically not significant, which may be caused by the confounding effect of interactions among fish species, territorial activities by fish species affecting reef structural complexity and low sample size. Read full article here.

scholarly journals Coral Restoration Effectiveness: Multiregional Snapshots of the Long-Term Responses of Coral Assemblages to Restoration

Diversity ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 153 ◽  
Author(s):  
Margaux Y. Hein ◽  
Roger Beeden ◽  
Alastair Birtles ◽  
Naomi M. Gardiner ◽  
Thomas Le Berre ◽  
...  
Keyword(s):  
Coral Cover ◽  
Structural Complexity ◽  
Reef Management ◽  
Growth And Survival ◽  
Coral Communities ◽  
Restoration Practices ◽  
Coral Health ◽  
Hard Coral Cover

Coral restoration is rapidly becoming a mainstream strategic reef management response to address dramatic declines in coral cover worldwide. Restoration success can be defined as enhanced reef functions leading to improved ecosystem services, with multiple benefits at socio-ecological scales. However, there is often a mismatch between the objectives of coral restoration programs and the metrics used to assess their effectiveness. In particular, the scales of ecological benefits currently assessed are typically limited in both time and space, often being limited to short-term monitoring of the growth and survival of transplanted corals. In this paper, we explore reef-scale responses of coral assemblages to restoration practices applied in four well-established coral restoration programs. We found that hard coral cover and structural complexity were consistently greater at restored compared to unrestored (degraded) sites. However, patterns in coral diversity, coral recruitment, and coral health among restored, unrestored, and reference sites varied across locations, highlighting differences in methodologies among restoration programs. Altogether, differences in program objectives, methodologies, and the state of nearby coral communities were key drivers of variability in the responses of coral assemblages to restoration. The framework presented here provides guidance to improve qualitative and quantitative assessments of coral restoration efforts and can be applied to further understanding of the role of restoration within resilience-based reef management.

scholarly journals Acclimatization to high-variance habitats does not enhance physiological tolerance of two key Caribbean corals to future temperature and pH

2016 ◽  
Vol 283 (1831) ◽  
pp. 20160442 ◽  
Author(s):  
Emma F. Camp ◽  
David J. Smith ◽  
Chris Evenhuis ◽  
Ian Enochs ◽  
Derek Manzello ◽  
...  
Keyword(s):  
Climate Change ◽  
Future Climate ◽  
Seagrass Beds ◽  
Metabolic Rates ◽  
Acropora Palmata ◽  
Climate Scenarios ◽  
Environmental Variance ◽  
Outer Reef ◽  
Porites Astreoides ◽  
Physiological Tolerance

Corals are acclimatized to populate dynamic habitats that neighbour coral reefs. Habitats such as seagrass beds exhibit broad diel changes in temperature and pH that routinely expose corals to conditions predicted for reefs over the next 50–100 years. However, whether such acclimatization effectively enhances physiological tolerance to, and hence provides refuge against, future climate scenarios remains unknown. Also, whether corals living in low-variance habitats can tolerate present-day high-variance conditions remains untested. We experimentally examined how pH and temperature predicted for the year 2100 affects the growth and physiology of two dominant Caribbean corals ( Acropora palmata and Porites astreoides ) native to habitats with intrinsically low (outer-reef terrace, LV) and/or high (neighbouring seagrass, HV) environmental variance. Under present-day temperature and pH, growth and metabolic rates (calcification, respiration and photosynthesis) were unchanged for HV versus LV populations. Superimposing future climate scenarios onto the HV and LV conditions did not result in any enhanced tolerance to colonies native to HV. Calcification rates were always lower for elevated temperature and/or reduced pH. Together, these results suggest that seagrass habitats may not serve as refugia against climate change if the magnitude of future temperature and pH changes is equivalent to neighbouring reef habitats.

scholarly journals Apparent stability of a low-density Diadema antillarum regime for Puerto Rican coral reefs

2018 ◽  
Vol 75 (6) ◽  
pp. 2193-2201 ◽  
Author(s):  
Ruber Rodríguez-Barreras ◽  
Alfredo Montañez-Acuña ◽  
Abimarie Otaño-Cruz ◽  
Scott D Ling
Keyword(s):  
Puerto Rico ◽  
Sea Urchin ◽  
Coral Cover ◽  
Live Coral ◽  
Low Density ◽  
Limited Evidence ◽  
Diadema Antillarum ◽  
Benthic Habitats ◽  
Stable Regime ◽  
Apparent Stability

Abstract Caribbean reefs have suffered decline in coral cover in recent decades due to recurrent anthropogenic and natural stressors. The regional collapse of the sea urchin Diadema antillarum, combined with overfishing, has contributed to a phase-shift of coral reef communities towards fleshy macroalgal dominance. Here, we examine the population dynamics of D. antillarum at five sites in Puerto Rico from 2011 to 2016 and determine trends between the sea urchin and local benthic habitats. The sea urchin population exhibited low but stable densities (with slight, but non-significant trend of increase), yet showed variability between sites. Large urchins (>60 mm test diam.) were the most abundant across sites and through time, followed by medium urchins (41–60 mm test diam.), whereas small individuals (<40 mm) were rare, indicating recruitment-limitation. Spatial and temporal differences in benthic habitats were not related to local D. antillarum abundances. Macroalgae cover declined at all sites over the 6 years, ranging 5–86%, whereas live coral cover also decreased across all sites (ranging 4–38%). Diadema antillarum populations in Puerto Rico appear stable with limited evidence for recovery trends back to pre-mass mortality densities. Full population recovery may take longer than expected; however, evidence indicates that the contemporary low-density D. antillarum population represents a novel stable regime.

scholarly journals New Scales to Guide the Assessment of Hard Coral Cover and Diversity in the Philippines

2020 ◽  
pp. 121-126
Keyword(s):  
Ecosystem Services ◽  
Coral Reefs ◽  
Coral Cover ◽  
Rapid Identification ◽  
The Philippines ◽  
Hard Coral ◽  
Hard Coral Cover ◽  
Assessment Scales

Coral reefs supply vital ecosystem services to the Philippines. Safeguarding these services requires the rapid identification of reefs that provide most services, and identification is best made by measuring hard coral cover and diversity and using updated and locally relevant assessment scales on these measurements. The use of these assessment scales has advantages and is recommended to update and improve Philippine laws.

scholarly journals River Streamflow, Remotely Sensed Water Quality, and Benthic Composition of Previously Undescribed Nearshore Coral Reefs in Northern Puerto Rico

2021 ◽  
Vol 8 ◽  
Author(s):  
Juan L. Torres-Pérez ◽  
Carlos E. Ramos-Scharrón ◽  
William J. Hernández ◽  
Roy A. Armstrong ◽  
Maritza Barreto-Orta ◽  
...  
Keyword(s):  
Water Quality ◽  
Puerto Rico ◽  
Coral Reefs ◽  
Coral Species ◽  
Coral Cover ◽  
Remotely Sensed ◽  
North Coast ◽  
Acropora Palmata ◽  
Chl A ◽  
Benthic Composition

Land-based sediment stress represents a threat to many coral reefs in Puerto Rico primarily as a result of unrestricted land cover/land use changes and poor best management practices. The effects of such stresses have been documented along most coasts around the island. However, little attention has been paid to reefs located on the north coast, and very little is known about their composition and current state. Here, we present a study characterizing riverine inputs, water quality conditions, and benthic composition of two previously undescribed coral reefs (Tómbolo and Machuca reefs) located just eastward of the Río Grande de Manatí outlet in north-central Puerto Rico. This study utilizes a time series of remotely sensed ocean color products [diffuse vertical attenuation coefficient at 490 nm (Kd490) and chlorophyll-a concentration (Chl-a) estimated with data from the Visible Infrared Imaging Radiometer Suite (VIIRS)] to characterize water quality in this coastal region. In general, the months with relatively high mean daily river streamflow also coincide with months having the highest proportion of eastward wave direction, which can promote the eastward influence of river waters toward the two coral reefs sites. Kd490 and Chl-a showed a higher riverine influence closer to the watershed outlet. Kd490 and Chl-a monthly peaks also coincide with river streamflow highs, particularly at those pixels closer to shore. Tómbolo Reef, located farther eastward of the river outlet, shows a well-developed primary reef framework mainly composed of threatened reef-building species (Acropora palmata, Pseudodiploria) and high coral cover (19–51%). The benthos of Machuca Reef, located closer to the river outlet, is dominated by macroalgae with a significantly lower coral cover (0.2–2.7%) mainly composed of “weedy” coral species (Porites astreoides and Siderastrea radians). Cover of major benthic components correlates with distance from the river outlet, and with gradients in Kd490 and Chl-a, with higher coral cover and lower macroalgal cover farther from the river outlet. Coral cover at Tómbolo Reef is higher than what has been reported for similar sites around Puerto Rico and other Caribbean islands showing its ecological importance, and as up until now, an unrecognized potential refuge of reef-building threatened coral species.

scholarly journals Associations between Benthic Cover and Habitat Complexity Metrics Obtained from 3D Reconstruction of Coral Reefs at Different Resolutions

2020 ◽  
Vol 12 (6) ◽  
pp. 1011 ◽  
Author(s):  
Atsuko Fukunaga ◽  
John H. R. Burns ◽  
Kailey H. Pascoe ◽  
Randall K. Kosaki
Keyword(s):  
Fractal Dimension ◽  
Coral Reefs ◽  
Habitat Structure ◽  
Coral Cover ◽  
Three Dimensional ◽  
Structural Complexity ◽  
Coralline Algae ◽  
Crustose Coralline Algae ◽  
Surface Areas ◽  
Abundance And Diversity

Quantifying the three-dimensional (3D) habitat structure of coral reefs is an important aspect of coral reef monitoring, as habitat architecture affects the abundance and diversity of reef organisms. Here, we used photogrammetric techniques to generate 3D reconstructions of coral reefs and examined relationships between benthic cover and various habitat metrics obtained at six different resolutions of raster cells, ranging from 1 to 32 cm. For metrics of 3D structural complexity, fractal dimension, which utilizes information on 3D surface areas obtained at different resolutions, and vector ruggedness measure (VRM) obtained at 1-, 2- or 4-cm resolution correlated well with benthic cover, with a relatively large amount of variability in these metrics being explained by the proportions of corals and crustose coralline algae. Curvature measures were, on the other hand, correlated with branching and mounding coral cover when obtained at 1-cm resolution, but the amount of variability explained by benthic cover was generally very low when obtained at all other resolutions. These results show that either fractal dimension or VRM obtained at 1-, 2- or 4-cm resolution, along with curvature obtained at 1-cm resolution, can effectively capture the 3D habitat structure provided by specific benthic organisms.

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