scholarly journals Assessing health status of corals at a tropical marginal reef site through bleaching and decadal change in population parameters

2018 ◽  
Author(s):  
Lélis Carlos-Júnior ◽  
Carla Zilberberg ◽  
Amana Garrido ◽  
Fernanda Casares ◽  
Joel Christopher Creed ◽  
...  
Keyword(s):  
Health Status ◽  
Coral Cover ◽  
Anthropogenic Activities ◽  
Population Decline ◽  
Light Availability ◽  
Reef Site ◽  
Local Conditions ◽  
Frequency Distributions ◽  
Siderastrea Stellata ◽  
Marginal Reef

Scleractinian corals are key organisms in structuring reef habitats and coral cover is being lost due to local and global stressors caused and/or exacerbated by anthropogenic activities. Despite being hardly touched upon, studies of size-frequency distributions serve as snapshots of coral populations’ status and provide information on population decline or growth over time. In our study we have intermittently monitored two Brazilian scleractinians species, the endemic Mussismilia hispida and Siderastrea stellata, since 2000 in an important coral marginal reef site at Armação dos Búzios, Rio de Janeiro, Brazil. We measured length, width and arc of all colonies from both species found across transects at eleven sites. In total, over 5,000 colonies have been measured over the past 17 years. Although the frequency of small and medium colonies remained relatively constant, we observed a clear decline in the frequency of larger colonies (> 30 cm) for both species, particularly the most common S. stellata. Additionally, we have been monitoring colonies for bleaching in five of these sites throughout 2017 to assess health status. The relationship between observed bleaching prevalence/intensity and environmental variables (temperature, light availability and sedimentation) may elucidate how changes in local conditions influence coral health.

scholarly journals Assessing health status of corals at a tropical marginal reef site through bleaching and decadal change in population parameters

2018 ◽  
Author(s):  
Lélis Carlos-Júnior ◽  
Carla Zilberberg ◽  
Amana Garrido ◽  
Fernanda Casares ◽  
Joel Christopher Creed ◽  
...  
Keyword(s):  
Health Status ◽  
Coral Cover ◽  
Anthropogenic Activities ◽  
Population Decline ◽  
Light Availability ◽  
Reef Site ◽  
Local Conditions ◽  
Frequency Distributions ◽  
Siderastrea Stellata ◽  
Marginal Reef

Scleractinian corals are key organisms in structuring reef habitats and coral cover is being lost due to local and global stressors caused and/or exacerbated by anthropogenic activities. Despite being hardly touched upon, studies of size-frequency distributions serve as snapshots of coral populations’ status and provide information on population decline or growth over time. In our study we have intermittently monitored two Brazilian scleractinians species, the endemic Mussismilia hispida and Siderastrea stellata, since 2000 in an important coral marginal reef site at Armação dos Búzios, Rio de Janeiro, Brazil. We measured length, width and arc of all colonies from both species found across transects at eleven sites. In total, over 5,000 colonies have been measured over the past 17 years. Although the frequency of small and medium colonies remained relatively constant, we observed a clear decline in the frequency of larger colonies (> 30 cm) for both species, particularly the most common S. stellata. Additionally, we have been monitoring colonies for bleaching in five of these sites throughout 2017 to assess health status. The relationship between observed bleaching prevalence/intensity and environmental variables (temperature, light availability and sedimentation) may elucidate how changes in local conditions influence coral health.

scholarly journals Colony size-frequency distributions among different populations of the scleractinan coral Siderastrea stellata in Southwestern Atlantic: implications for life history patterns

2006 ◽  
Vol 54 (4) ◽  
pp. 213-223 ◽  
Author(s):  
Monica Moraes Lins de Barros ◽  
Débora de Oliveira Pires
Keyword(s):  
Life History ◽  
Colony Size ◽  
Large Scale ◽  
Environmental Changes ◽  
Size Structure ◽  
Growth Potential ◽  
Local Conditions ◽  
Frequency Distributions ◽  
Size Frequency ◽  
Siderastrea Stellata

Colony size-frequency distributions of reef corals may be used to infer growth potential and population responses upon environmental changes. The present paper compares the size structure of colonies of Siderastrea stellata Verrill, 1868,among 11 sites, six of them distributed along a gradient of sediment deposition in Abrolhos, Bahia, Brazil (18º S). Results indicated that the population structure is likely to be influenced by local conditions, rather than large scale factors, such as latitude. The 11 distributions, however, showed higher frequencies of small size classes. Class 1 (up to 2.5 cm diameter) was always present and the frequency of colonies from size class 3 (10 cm diameter) tended to decrease in all sites. Comparison among the six Abrolhos sites showed that S. stellata has advantages at sites with intermediate sedimentation, where colonies attain larger sizes, probably, reflecting a higher survivorship over time. The present study showed that, despite the influence of environmental conditions on parameters of the populations such as size of colony, the life history strategy of S. stellata reflects a local adaptation that allows its development and survivorship in shallow waters and horizontal substrates, sites characterized by high mortality rates.

scholarly journals Physiological and ecological consequences of the water optical properties degradation on reef corals

Coral Reefs ◽  
2021 ◽  
Author(s):  
Tomás López-Londoño ◽  
Claudia T. Galindo-Martínez ◽  
Kelly Gómez-Campo ◽  
Luis A. González-Guerrero ◽  
Sofia Roitman ◽  
...  
Keyword(s):  
Optical Properties ◽  
Population Decline ◽  
Light Availability ◽  
Potential Effect ◽  
Optical Quality ◽  
Light Penetration ◽  
Reef Corals ◽  
Orbicella Faveolata ◽  
Light Quantity ◽  
Reduced Light

AbstractDegradation of water optical properties due to anthropogenic disturbances is a common phenomenon in coastal waters globally. Although this condition is associated with multiple drivers that affect corals health in multiple ways, its effect on light availability and photosynthetic energy acquisition has been largely neglected. Here, we describe how declining the water optical quality in a coastal reef exposed to a turbid plume of water originating from a man-made channel compromises the functionality of the keystone coral species Orbicella faveolata. We found highly variable water optical conditions with significant effects on the light quantity and quality available for corals. Low-light phenotypes close to theoretical limits of photoacclimation were found at shallow depths as a result of reduced light penetration. The estimated photosynthetically fixed energy depletion with increasing depth was associated with patterns of colony mortality and vertical habitat compression. A numerical model illustrates the potential effect of the progressive water quality degradation on coral mortality and population decline along the depth gradient. Collectively, our findings suggest that preserving the water properties seeking to maximize light penetration through the water column is essential for maintaining the coral reef structure and associated ecosystem services.

scholarly journals Evaluation of coral reef carbonate production models at a global scale

2015 ◽  
Vol 12 (5) ◽  
pp. 1339-1356 ◽  
Author(s):  
N. S. Jones ◽  
A. Ridgwell ◽  
E. J. Hendy
Keyword(s):  
Coral Reef ◽  
Predictive Power ◽  
Numerical Models ◽  
Coral Cover ◽  
Light Availability ◽  
Global Scale ◽  
Data Set ◽  
Carbonate Production ◽  
Future Global Warming ◽  
Atmospheric Co2 Concentrations

Abstract. Calcification by coral reef communities is estimated to account for half of all carbonate produced in shallow water environments and more than 25% of the total carbonate buried in marine sediments globally. Production of calcium carbonate by coral reefs is therefore an important component of the global carbon cycle; it is also threatened by future global warming and other global change pressures. Numerical models of reefal carbonate production are needed for understanding how carbonate deposition responds to environmental conditions including atmospheric CO2 concentrations in the past and into the future. However, before any projections can be made, the basic test is to establish model skill in recreating present-day calcification rates. Here we evaluate four published model descriptions of reef carbonate production in terms of their predictive power, at both local and global scales. We also compile available global data on reef calcification to produce an independent observation-based data set for the model evaluation of carbonate budget outputs. The four calcification models are based on functions sensitive to combinations of light availability, aragonite saturation (Ωa) and temperature and were implemented within a specifically developed global framework, the Global Reef Accretion Model (GRAM). No model was able to reproduce independent rate estimates of whole-reef calcification, and the output from the temperature-only based approach was the only model to significantly correlate with coral-calcification rate observations. The absence of any predictive power for whole reef systems, even when consistent at the scale of individual corals, points to the overriding importance of coral cover estimates in the calculations. Our work highlights the need for an ecosystem modelling approach, accounting for population dynamics in terms of mortality and recruitment and hence calcifier abundance, in estimating global reef carbonate budgets. In addition, validation of reef carbonate budgets is severely hampered by limited and inconsistent methodology in reef-scale observations.

scholarly journals Potential Distribution of the Critically Endangered Chinese Pangolin (Manis pentadactyla) in Different Land Covers of Nepal: Implications for Conservation

2020 ◽  
Vol 12 (3) ◽  
pp. 1282 ◽  
Author(s):  
Hari Prasad Sharma ◽  
Bhagawat Rimal ◽  
Mingxia Zhang ◽  
Sandhya Sharma ◽  
Laxman Prasad Poudyal ◽  
...  
Keyword(s):  
Potential Distribution ◽  
Anthropogenic Activities ◽  
Land Use Changes ◽  
Population Decline ◽  
Species Conservation ◽  
Critically Endangered ◽  
Cultivated Land ◽  
Manis Pentadactyla ◽  
Suitable Habitats ◽  
Species Specific

Anthropogenic activities have driven many wildlife species towards extinction. Among these species, the geographic distributions of many are poorly documented, which can limit the effectiveness of conservation. The critically endangered Chinese pangolin (Manis pentadactyla) is experiencing population decline throughout its range due to land-use changes and illegal trade for food and traditional medicine. Using distribution records and maximum entropy modeling, we predicted the potential distribution of the Chinese pangolin across Nepal. Most suitable potential habitats of the Chinese pangolin occurred in forest areas of the mid-hill region in central and eastern Nepal, followed by cultivated land. Almost all potential suitable habitats of the Chinese pangolin occurred outside of protected areas, and most of them were encroached upon by cultivated land, human settlements, and infrastructure developments. The results from this study provide baseline information on the potential suitable habitats of the Chinese pangolin in Nepal, which helps to develop site- and species-specific management plans and to identify priority areas to minimize the current threats to the pangolin and enhance the stewardship of species conservation.

scholarly journals Preliminary Study of Coral Reef Conditions in Marine Park and Coral Reef Education Centre Plan Area, Seribu Islands National Park, Indonesia

2020 ◽  
Vol 4 (1) ◽  
pp. 1-9
Author(s):  
Hermansyah Hermansyah ◽  
Tatang Mitra Setia ◽  
Cipto Utomo ◽  
Annastasya Rahma Ramadhani ◽  
Sabihis Sabihis ◽  
...  
Keyword(s):  
Coral Reef ◽  
National Park ◽  
Coral Cover ◽  
Anthropogenic Activities ◽  
Live Coral ◽  
Dominant Form ◽  
Point Count ◽  
Massive Growth ◽  
Marine Park ◽  
Index Value

Marine waters surrounding Child-friendly Integrated Public Spaces (RPTRA) at Tanjung Elang still has the potential for highly productive coral reef resources, thus enabling the development of ecological-based tourism, education and conservation. Despite the potential, the coral reefs in the surrounding of  RPTRA Tanjung Elang has suffered damage caused by anthropogenic activities and natural factors. The aim of this research is to assess the initial condition of coral reef at the location of   marine park areal and coral reef education center plan, RPTRA Tanjung Elang Waters, Pramuka Island, Seribu Islands National Park, DKI Jakarta, Indonesia. This research used Underwater Photo Transect/UPT method were analyzed using CPCe 4.1. software (Coral Point Count with Excel extension). The results of physico-chemical parameters measurements showed that water quality in RPTRA Tanjung Elang Waters Pramuka Island, is still within tolerance limits for coral life. The percentage of live coral cover was in a bad category with a low value (5.35%). The most dominant form of coral growth was submassive (CS) with a percentage value 54.46%. Composition of hard coral genusis consists of 3 family, 5 genus, and 100 species.The most dominant of Porites was with submassive and massive growth form. The index value of diversity shows a low category (0.56). The dominance index value showed a medium category (0.75). Uniformity and mortality index value showed a low category (0.35 and 0.43).

scholarly journals Cross-Shelf Differences in the Response of Herbivorous Fish Assemblages to Severe Environmental Disturbances

Diversity ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 23 ◽  
Author(s):  
Eva McClure ◽  
Laura Richardson ◽  
Alexia Graba-Landry ◽  
Zoe Loffler ◽  
Garry Russ ◽  
...  
Keyword(s):  
Fish Assemblages ◽  
Coral Cover ◽  
Herbivorous Fish ◽  
Total Biomass ◽  
Hard Coral ◽  
Inner Shelf ◽  
Environmental Disturbances ◽  
Local Conditions ◽  
Thermal Bleaching ◽  
Hard Coral Cover

Cross-shelf differences in coral reef benthic and fish assemblages are common, yet it is unknown whether these assemblages respond uniformly to environmental disturbances or whether local conditions result in differential responses of assemblages at different shelf positions. Here, we compare changes in the taxonomic and functional composition, and associated traits, of herbivorous reef fish assemblages across a continental shelf, five years before and six months after two severe cyclones and a thermal bleaching event that resulted in substantial and widespread loss of live hard coral cover. Each shelf position maintained a distinct taxonomic assemblage of fishes after disturbances, but the assemblages shared fewer species among shelf positions. There was a substantial loss of species richness following disturbances within each shelf position. Total biomass of the herbivorous fish assemblage increased after disturbances on mid- and outer-shelf reefs, but not on inner-shelf reefs. Using trait-based analyses, we found there was a loss of trait richness at each shelf position, but trait specialisation and originality increased on inner-shelf reefs. This study highlights the pervasiveness of extreme environmental disturbances on ecological assemblages. Whilst distinct cross-shelf assemblages can remain following environmental disturbances, assemblages have reduced richness and are potentially more vulnerable to chronic localised stresses.

scholarly journals Size-frequency distribution of coral assemblages in insular shallow reefs of the Mexican Caribbean using underwater photogrammetry

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8957 ◽  
Author(s):  
Roberto C. Hernández-Landa ◽  
Erick Barrera-Falcon ◽  
Rodolfo Rioja-Nieto
Keyword(s):  
Species Richness ◽  
Frequency Distribution ◽  
Dominant Species ◽  
Coral Cover ◽  
Sampling Area ◽  
Size Frequency Distribution ◽  
Frequency Distributions ◽  
Size Frequency ◽  
Reef Health ◽  
Minimum Sampling Area

The characterisation of changes in coral communities depends heavily on systematic monitoring programs and the collection of necessary metrics to assess reef health. Coral cover is the most used metric to determine reef health. The current organizational shift in coral requires the evaluation of complementary metrics, such as colony size and frequency distributions, which help to infer the responses of the coral populations to local stress or larger scale environmental changes. In this study, underwater digital photogrammetry techniques were used to assess the live cover of all coral colonies ≥3 cm2 and determine the size-frequency distribution of the dominant species in the shallow reefs of the Cozumel Reefs National Park (CRNP). In addition, the minimum sampling area (m2) needed to obtain a representative sample of the local species pool was estimated. Areas between 550 and 825 m2 per reef were photographed to generate high-resolution digital ortho-mosaics. The live area of the colonies was digitised to generate community matrices of species and abundance. EstimateS software was used to generate accumulation curves and diversity (Shannon H′) at increasing area intervals. Chi-Square tests (χ2, p = 0.05) were used to compare the observed vs estimated species richness. Spearman’s coefficients (rs), were calculated to correlate the increase in sampling area (m2) vs H′, and the Clench’s function was used to validate the observed richness (R2 = 1 and R > 90%). SIMPER analysis was performed to identify dominant species. Comparisons in terms of abundance, coral cover and size-frequencies were performed with Kruskal-Wallis (H test, p = 0.05), and paired Mann-Whitney (U test, p = 0.05). In order to obtain 90% of the species richness, a minimum sampling area of 374 m2is needed. This sampling area could be used in shallow Caribbean reefs with similar characteristics. Twelve (mainly non-massive) species: Agaricia agaricites, A humilis, A. tenuifolia, Eusmilia fastigiata, Meandrina meandrites, Montastrea cavernosa, Orbicella annularis, Porites astreoides, P. porites, Pseudodiploria strigosa, Siderastrea radians andS. siderea, were dominant in terms of abundance and coral cover. A significant increase (p < 0.05) in the number of colonies and live coral (m2) was observed from north to south of the study area. Furthermore, a wide intraspecific variation of size-frequency, even between adjacent reefs, was also observed. The size-frequency distributions presented positive skewness and negative kurtosis, which are related to stable populations, with a greater number of young colonies and a constant input of recruits. Considering the increase in disturbances in the Caribbean and the appearance of a new coral disease, digital photogrammetry techniques allow coral community characteristics to be assessed at high spatial resolutions and over large scales, which would be complementary to conventional monitoring programs.

scholarly journals 3D HABITAT COMPLEXITY OF CORAL REEFS IN THE NORTHWESTERN HAWAIIAN ISLANDS IS DRIVEN BY CORAL ASSEMBLAGE STRUCTURE

2019 ◽  
Vol XLII-2/W10 ◽  
pp. 61-67 ◽  
Author(s):  
J. H. R. Burns ◽  
A. Fukunaga ◽  
K. H. Pascoe ◽  
A. Runyan ◽  
B. K. Craig ◽  
...  
Keyword(s):  
Coral Reef ◽  
Habitat Complexity ◽  
Coral Cover ◽  
Light Availability ◽  
Structural Complexity ◽  
Assemblage Structure ◽  
Natural Environments ◽  
Live Coral ◽  
Ecological Processes ◽  
Coral Assemblage

<p><strong>Abstract.</strong> Corals act as ecosystem engineers by secreting structurally complex calcium carbonate skeletons on the benthic substrate that provide habitat for a diverse array of associated reef organisms. Communities of living corals create large and dynamic benthic structures that directly affect ecological parameters such as habitat provisioning and light availability, thus influencing overall ecosystem function. Despite the important role 3D structural complexity plays in ecosystem biodiversity and productivity, the field of coral ecology has lacked accessibility to practical technology capable of quantifying 3D characteristics of underwater habitats. Advancements in the field of computer vision has led to Structure-from-Motion (SfM) photogrammetry, which provides a simple and cost-effective method for creating high-resolution and spatially accurate 3D reconstructions of natural environments. Integrating SfM approaches into coral reef research and monitoring has provided useful insight into the relationship between 3D habitat complexity and ecological processes. In this study, we examined the relationships among 2D estimates of live coral cover and several metrics of 3D habitat structural complexity among eleven long-term monitoring sites at French Frigate Shoals. Our findings show that coral assemblage structure acts as a significant driver of 3D structural complexity of coral reef habitats at this atoll. This study highlights the importance of diverse and abundant coral assemblages in supporting structurally complex coral reef habitats and provides a framework for future investigations into the ecological role of various coral morphotypes.</p>

scholarly journals Aquatic health indicators: holistic evaluation tools for sustainable management of a tropical oxbow lake ecosystem

2018 ◽  
Vol 65 (4) ◽  
Author(s):  
Dipankar Ghosh ◽  
Jayanta Kumar Biswas
Keyword(s):  
Health Status ◽  
Sustainable Management ◽  
Anthropogenic Activities ◽  
Health Indicators ◽  
Biological Properties ◽  
Oxbow Lake ◽  
Lake Ecosystem ◽  
Lake Ecosystems ◽  
Health Indices ◽  
Fish Productivity

Quantitative relationship of primary productivity and fish productivity and estimating aquatic health indices in tropical oxbow lake ecosystems remains to be addressed as predictors of fisheries yield in sustainable management. The aquatic health indicators and aquatic health status assessed with biological properties of phytoplankton, zooplankton, macroinvertebrates, macrophytes and fish in a semi-closed tropical oxbow lake ecosystem in the eastern India were studied along with socioecological and socio-economical aspects. Five ecological classes namely phytoplankton, zooplankton, macroinvertebrate, macrophyte and fish have been championed as effective biological indicators supported by physicochemical attributes. The established aquatic health indices registered the health status as moderate to poor. Organic loading and consequent nutrient enrichment and water quality deterioration during monsoon led to more homogeneous benthic biotic assemblage. With observed diverse nature of each trophic level of the ecosystem, there occurred a downstream ‘spillover’ of diversity along the food chain. The ‘structure affecting structure’ argument goes in tune with the theory of consumers controlling species diversity. Total 38 fish productivity regression equation models explained clearly that fish abundance and productivity were declining due to high anthropogenic activities of jute retting and indiscriminate uses of fishing gears of various mesh sizes during monsoon and thereafter, which need to be regulated.

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