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 The gut microbiome stability of a butterflyfish is disrupted on severely degraded Caribbean coral reefs

2020 ◽  
Author(s):  
Friederike Clever ◽  
Jade M. Sourisse ◽  
Richard F. Preziosi ◽  
Jonathan A. Eisen ◽  
E. Catalina Rodriguez Guerra ◽  
...  
Keyword(s):  
Coral Reefs ◽  
Gut Microbiome ◽  
Habitat Degradation ◽  
Coral Cover ◽  
Live Coral ◽  
Ecological Communities ◽  
Core Microbiome ◽  
Habitat Gradient ◽  
Fermentative Bacteria ◽  
Fish Gut

AbstractEnvironmental degradation has the potential to alter key mutualisms that underline the structure and function of ecological communities. While it is well recognized that the global loss of coral reefs alters fish communities, the effects of habitat degradation on microbial communities associated with fishes remain largely unknown despite their fundamental roles in host nutrition and immunity. Using a gradient of reef degradation, we show that the gut microbiome of a facultative, coral-feeding butterflyfish (Chaetodon capistratus) is significantly more variable among individuals at degraded reefs with very low live coral cover (~0%) than reefs with higher coral cover (~30%), mirroring a known pattern of microbial imbalance observed in immunodeficient humans and other stressed or diseased animals. We demonstrate that fish gut microbiomes on severely degraded reefs have a lower abundance of Endozoicomonas and a higher diversity of anaerobic fermentative bacteria, which suggests a broader and less coral dominated diet. The observed shifts in fish gut bacterial communities across the habitat gradient extend to a small set of potentially beneficial host associated bacteria (i.e., the core microbiome) suggesting essential fish-microbiome interactions are vulnerable to severe coral degradation.

scholarly journals Filamentous calcareous alga provides a substrate for coral-competitive macroalgae in the degraded lagoon of Dongsha Atoll, Taiwan

2018 ◽  
Author(s):  
Carolin Nieder ◽  
Chaolun Allen Chen ◽  
Shao-Lun Liu
Keyword(s):  
Coral Reefs ◽  
Temporal Dynamics ◽  
Coral Cover ◽  
Northern South China Sea ◽  
Patch Reef ◽  
Live Coral ◽  
Percent Cover ◽  
Reef Site ◽  
Patch Reefs ◽  
Dongsha Atoll

AbstractBackgroundThe chemically-rich seaweed Galaxaura is not only highly competitive with corals, but also provides substrate for other macroalgae. Its ecology and associated epiphytes remain largely unexplored. To fill this knowledge gap, we herein undertook an ecological assessment to explore the spatial variation, temporal dynamics, and epiphytic macroalgae of G. divaricata on patch reefs in the lagoon of Dongsha Atoll, a shallow coral reef ecosystem in the northern South China Sea, repeatedly impacted by mass coral bleaching events.MethodsTwelve spatially independent patch reefs in the Dongsha lagoon were first surveyed to assess the benthic composition in April 2016, and then revisited to determine G. divaricata percent cover in September 2017, with one additional Galaxaura-dominated reef (site 9). Four surveys over a period of 17 months were carried out on a degraded patch reef (site 7) to assess the temporal variation in G. divaricata cover. Epiphytic macroalgae associated with G. divaricata were quantified and identified through the aid of DNA barcoding.ResultsPatch reefs in the Dongsha lagoon were degraded, exhibiting relatively low live coral cover (5-43%), but high proportions of macroalgae (13-58%) and other substrates (rubble and dead corals; 23-69%). The distribution of G. divaricata was heterogeneous across the lagoon, with highest abundance (16-41%) in the southeast area. Temporal surveys from site 7 and photo-evidence from site 9 suggested that an overgrowth by G. divaricata was still present to a similar extend after 17 months and 3.5 years. Yet, G. divaricata provides a suitable substrate some allelopathic macroalgae (e.g., Lobophora sp.).ConclusionsOur study demonstrates that an allelopathic seaweed, such as G. divaricata, can overgrow degraded coral reefs for extended periods of time. By providing habitat for harmful macroalgae, a prolonged Galaxaura overgrowth could strengthen negative feedback loops on degraded coral reefs, further decreasing their recovery potential.

scholarly journals KONDISI TERUMBU KARANG DI KAWASAN WISATA PULAU BOKORI, KENDARI, PROVINSI SULAWESI TENGGARA

OSEANA ◽  
2021 ◽  
Vol 46 (1) ◽  
pp. 23-29
Author(s):  
Ofri Johan ◽  
Jupri Jupri ◽  
Fella Pritian Cera ◽  
Ahmad Rezza Dzumalex ◽  
Ratna Diyah Palupi ◽  
...  
Keyword(s):  
Coral Reefs ◽  
Coral Cover ◽  
Live Coral ◽  
Percent Cover ◽  
City Center ◽  
Tourist Destination ◽  
Dead Coral ◽  
Dominant Type ◽  
Mushroom Coral ◽  
The City

Bokori Island has been a tourist destination managed by the Tourism Office of the Southeast Sulawesi Provincial since 2014. The location is close to the city center, making this island visited by many tourists. In addition to the beauty of the island, it is also necessary to maintain the beauty of coral reefs as objects for underwater recreation. The study was conducted on 24–25 July 2019 at three sites of observation. The research purpose was to determine the condition of coral reefs of the island, which is used as a tourist destination. The result indicates that the condition of coral reefs is categorized good by having coral cover about 50.67%. The dominant coral at the island is the foliose coral (CF) group with percent cover about 22%, followed by coral branching (CB) 10%, Acropora tabulate (ACT) 8.57%, mushroom coral (CMR) 6%, encrusting coral (CE) 2% and massive coral (CM) 1.33%. The dominant type of substrate was dead coral with algae (DCA) about 37.3%, and the damage due to explosion could still be seen in the location. The current condition of coral needs to be maintained and improved supervision so that live coral can improve so that the function to support underwater tourism can be achieved.

scholarly journals Microhabitats of sharknose goby (Elacatinus evelynae) cleaning stations and their links with cleaning behaviour

Coral Reefs ◽  
2021 ◽  
Author(s):  
Kathryn E. Whittey ◽  
Katie Dunkley ◽  
Grace C. Young ◽  
Jo Cable ◽  
Sarah E. Perkins
Keyword(s):  
Coral Reefs ◽  
Coral Cover ◽  
Marine Ecosystem ◽  
Three Dimensional ◽  
Structural Complexity ◽  
Live Coral ◽  
Cleaner Fish ◽  
Habitat Features ◽  
Anthropogenic Threats ◽  
Cleaning Stations

AbstractCoral reefs are renowned for the complexity of their habitat structures and their resulting ability to host more species per unit area than any another marine ecosystem. Dedicated cleaner fish, which acquire all their food resources through client interactions, rely on both the habitat structures (by using topological cleaning stations) and the wide diversity of fish species available on coral reefs, to function. As a result of natural and anthropogenic threats, coral reef habitat structures and their complexity are being lost—despite this threat it is unclear how important reef geometry is to key ecological interactions, like cleaning. Using an established Caribbean reef study site, three-dimensional constructions of discrete coral heads were used to investigate how fine-scale structural complexity traits (structural complexity—measured by rugosity and vector dispersion—height, volume, surface area, percentage live coral cover and refuge availability) relate to cleaner occupancy, abundance and their cleaning interactions with clients. Coral height was a particularly important trait for cleaning, correlating with both the occurrence of cleaning stations on a reef, and with increased cleaning durations and reduced cleaning frequencies/rates. Cleaning stations were also more structurally complex than non-cleaning coral heads, and the increased availability of uneven surfaces (creating cracks and crevices) and refuge availability linked with increased cleaning durations/rates. By understanding habitat features important to cleaner fish on a typical Caribbean fringing reef, we can gain a better understanding of how important reef geometry might be for governing the occurrence and dynamics of such mutualisms.

scholarly journals Status of Coral Reefs in the Water of Spermonde, Makassar, South Sulawesi

2021 ◽  
Vol 324 ◽  
pp. 03007
Author(s):  
Ni Wayan Purnama Sari ◽  
Rikoh Manogar Siringoringo ◽  
Muhammad Abrar ◽  
Risandi Dwirama Putra ◽  
Raden Sutiadi ◽  
...  
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Coral Cover ◽  
Public Awareness ◽  
Live Coral ◽  
Health Index ◽  
Point Count ◽  
Live Coral Cover ◽  
Reef Health ◽  
Index Value

Observations of the condition of coral reefs have been carried out in Spermonde waters from 2015 to 2018. The method used in this observation uses Underwater Photo Transect (UPT), and the data obtained is analyzed using CPCe (Coral Point Count with Excel Extensions) software. The results show that the percentage of coral cover has increased from year to year. The percentage of live coral cover in 2015 was 19.64%, 23.60 in 2016, 23.72% in 2017, and 27.83% in 2018. The increase in live coral cover from year to year is thought to occur due to the availability of nutrients. or increasing public awareness, considering this location is one of the most famous tourist attractions in Makassar. Coral reef health index values can be used to classify coral reef health. Through the analysis of the coral reef health index, an index value of 4 was obtained, which means that the condition of the coral reefs is in the “moderate” category.

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 SPATIAL COMPOSITION OF BENTHIC SUBSTRATE AROUND BONTOSUA ISLAND

2018 ◽  
Vol 4 (1) ◽  
Author(s):  
Muhammad Banda Selamat ◽  
Mahatma Lanuru ◽  
Amir Hamzah Muhiddin
Keyword(s):  
Reef Flat ◽  
Live Coral ◽  
Percent Cover ◽  
Small Islands ◽  
East Side ◽  
Coral Rubble ◽  
West Side ◽  
Spatial Composition ◽  
Index Ratio ◽  
Benthic Substrate

Coral reefs and seagrass are natural fortress for small islands from waves and ocean currents. The spatial distribution of these benthic substrate should be known and monitored regularly. This study aims were to map existing benthic substrates on the reef flat of Bontosua Island, determine the spatial composition and develop index ratio. Benthic substrates were surveyed using geotagging technique. Their distribution were estimate using Quickbird image that was rectified and classified using ISOcluster method and validate by 240 selected photos. The seagrass were surveyed at 8 stasions to record percent cover and species composition. Depth profiles were track along 10 reef flat line segment. Bontosua Island has an elongated shape from South to Northwest. This study had produced a benthic substrate distribution map with thematic accuracy 76%. Total area able to map were 54.2 hectares. About 43% benthic substrates at Bontosua were mixture of coral rubble, seagrass and algae, 20% was mixture of rubble and algae, 16% dominated by seagrass, 13% mixture of sand and seagrass and 8% substrate were dominated by live coral. There were eight seagrass species found with average percent cover 37.2 ± 12.5 percent. The spatial ratio of live coral, seagrass and mixed substrate for West side reef flat was 2:20:49 and 1:9:9 for East side. This indicate that the distribution of benthic substrates on the West side is much wider than on the East side. This approach potentially applied to study the relationship between benthic substrate composition and the deformation of small islands.

Crown-of-thorns starfish outbreak at Taiping Island (Itu Aba), Spratlys, South China Sea

2021 ◽  
Author(s):  
Wei Khang Heng ◽  
Ming-Jay Ho ◽  
Chao-Yang Kuo ◽  
Ya-Yi Huang ◽  
Chia-Ying Ko ◽  
...  
Keyword(s):  
South China Sea ◽  
Coral Reefs ◽  
South China ◽  
Coral Cover ◽  
Significant Decline ◽  
Live Coral ◽  
Sea Stars ◽  
China Sea ◽  
Regional Collaboration ◽  
First Time

Outbreak of crown-of-thorns sea stars, Acanthaster cf. solaris, were documented in coral reefs around Taiping Island, Spratlys for the first time. The outbreak might be thereason for the significant decline in live coral cover in 2021. Comprehensive monitoring through regional collaboration is needed.

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.

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.

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