scholarly journals Thermal stress-related spatiotemporal variations in high-latitude coral reef benthic communities

Coral Reefs ◽  
2020 ◽  
Vol 39 (6) ◽  
pp. 1661-1673
Author(s):  
Nicholas P. Jones ◽  
Joana Figueiredo ◽  
David S. Gilliam

AbstractHigh-latitude coral reef communities have been postulated as the first areas to undergo reorganisation under climate change. Tropicalisation has been identified in some high-latitude communities and is predicted in others, but it is unclear how the resident benthic taxa are affected. We conducted a long-term (2007–2016) assessment of changes to benthic community cover in relation to thermal stress duration on the Southeast Florida Reef Tract (SEFRT). Thermal stress events, both hot and cold, had acute (thermal stress duration affected benthic cover that year) and chronic (thermal stress duration affected benthic cover the following year) impacts on benthic cover. Chronic heat stress was associated with declines in cover of the reef-building coral families Acroporidae, Montastraeidae, Meandrinidae, Mussidae and Siderastreidae, which coupled with the absence of cold stress and rising annual temperatures boosted macroalgae cover. Cover of smaller, weedy coral families, Poritidae, Agariciidae and Astrocoeniidae, was either unaffected or positively related to heat stress duration and rising mean temperature. Thermal stress was related to spatiotemporal variations in benthic cover on the SEFRT, likely enhanced by local stressors, such as elevated nutrients and sedimentation. Coral and octocoral cover declined within four of six sub-regions, sponge cover increased in half of the sub-regions, and macroalgae cover increased in four sub-regions during the study. Under current conditions, increased macroalgae and weedy coral cover are anticipated to inhibit reef recovery.

2019 ◽  
Vol 20 (2) ◽  
pp. 570-575 ◽  
Author(s):  
IMAM BACHTIAR ◽  
TRI ARYONO HADI

Abstract. Bachtiar I, Hadi TA. 2019. Differential impacts of 2016 coral bleaching on coral reef benthic communities at Sekotong Bay, Lombok Barat, Indonesia. Biodiversitas 20: 570-575. Coral bleaching has been a major causal factor of coral mortality worldwide in the last two decades and it is therefore threaten food security. Understanding post-bleaching recovery is therefore very crucial to formulate strategy in promoting natural coral reef recovery. The present study documented coral reef communities both in pre- and post-bleaching event in early 2016. The results show that coral bleaching variably reduced coral and soft-coral covers. Sponge and other fauna cover considerably fluctuated. Since the individual number of soft-coral, sponge and other fauna were small, there is likely no big impact of coral bleaching. Among 12 study sites, 11 sites showed significant reduction of coral cover but one site showed only little fluctuation. Overall mean reduction of coral cover was about 18%. Consequently, algal cover increased by about 24%. The present study revealed differential coral bleaching impact between outer- and inner- reefs. At outer reefs, coral community suffered more severe mass coral mortality than those at inner reefs. This disparity is likely owing to initial coral cover and species composition of the coral communities. In the second year, there is still no visible coral recruitment from larvae. Cascade effects of land-clearing and overfishing due to increasing tourism development is very likely to be additional major stress that pause post-bleaching coral reef recovery at Sekotong Bay, Lombok Island, Indonesia.


Science ◽  
2013 ◽  
Vol 340 (6128) ◽  
pp. 69-71 ◽  
Author(s):  
James P. Gilmour ◽  
Luke D. Smith ◽  
Andrew J. Heyward ◽  
Andrew H. Baird ◽  
Morgan S. Pratchett

Coral reef recovery from major disturbance is hypothesized to depend on the arrival of propagules from nearby undisturbed reefs. Therefore, reefs isolated by distance or current patterns are thought to be highly vulnerable to catastrophic disturbance. We found that on an isolated reef system in north Western Australia, coral cover increased from 9% to 44% within 12 years of a coral bleaching event, despite a 94% reduction in larval supply for 6 years after the bleaching. The initial increase in coral cover was the result of high rates of growth and survival of remnant colonies, followed by a rapid increase in juvenile recruitment as colonies matured. We show that isolated reefs can recover from major disturbance, and that the benefits of their isolation from chronic anthropogenic pressures can outweigh the costs of limited connectivity.


2020 ◽  
Vol 25 (3) ◽  
pp. 121-126
Author(s):  
Ana Faricha ◽  
Isa N. Edrus ◽  
Sasanti R. Suharti ◽  
Rizkie S. Utama ◽  
Agus Budiyanto ◽  
...  

The coral reef environment has a strong influence on associated organisms such as fishes, mollusks, and others. Wherein, the butterflyfishes are marine fishes which closely associated with the tropic group as dietary specialization i.e. obligate coral feeder, facultative, and generalist. The obligate may respond only to change in preferred corals and not indicate others. However, generalist show in different response in habitat deteriorates and may allow switching feeding to a less preferred one. Many questions remain about food specific at the species level which may potentially as bio-indicator for coral conditions. Here, we studied the species composition among coral coverage. We explore the environmental degradation in Taka Bonerate National Park impact on food resources and fishes especially for butterflyfishes community. This study focused on family Chaetodontidae with UVC method and UPT method for coral cover. This study was carried out at Taka Bonerate National Park, South Sulawesi between May and June 2019. There were 342 individuals observed and dominated by Chaetodon kleinii, Hemitaurichthys polylepis, Heniochus chrysostomus, C. lunulatus, C. melannotus, C punctatofasciatus, and Forcipiger flavissimus. However, we found a site with diversity index and coral cover has across conditions. Whilst, these benthic communities mostly dominated by Acropora, which may be preferenced by specific species. Butterflyfishes have several types of foraging tasks and may impact in utilizing the coral reef and other social habitats used. The species composition and abundance of butterflyfishes had relations not only by coral coverage but also benthic compositions. However, factors that regulate its specific species distribution and species compositions are still under study.


2021 ◽  
Author(s):  
Mohit Arora ◽  
Kalyan De ◽  
Nandini Ray Chaudhury ◽  
Mandar Nanajkar ◽  
Prakash Chauhan ◽  
...  

Coral reefs are one of the most sensitive, productive, and invaluable biological resources on the earth. However, coral reefs are facing unprecedented stress due to ongoing climate changes and intensified anthropogenic disturbances globally. Elevated Sea Surface Temperature (SST) has emerged as the most imminent threat to the thermos-sensitive reef-building corals. The 2010–2014-2016 El Niño Southern Oscillation (ENSO) caused prolonged marine heat waves (MHWs) that led to the most widespread coral bleaching and mortality in the tropical Indi-Pacific regions. Coral bleaching prediction is vital for the management of the reef biodiversity, ecosystem functioning, and services. Recent decades, satellite remote sensing has emerged as a convenient tool for large-scale coral reef monitoring programs. As thermal stress is a critical physical attribute for coral bleaching hence, the present study examines the effectiveness of the elevated SSTs as a proxy to predict coral bleaching in shallow water marginal reefs. Advanced Very High-Resolution Radiometer (AVHRR) satellite data from the NOAA Coral Reef Watch’s (CRW) platform has been used for this study. Coral bleaching indices like Bleaching Threshold (BT), Positive SST Anomaly (PA), and Degree Heating Weeks (DHW) are computed to analyze the thermal stress on the coral reefs. The computed thermal stress from satellite-derived SST data over regions concurrence with the mass coral bleaching (MCB) events. This study concludes that in the last decades (2010 to 2019) the coral cover around these regions has dramatically declined due to higher SST, which indicates that the thermal stress induced recurrent bleaching events attributed to the coral loss.


2021 ◽  
Author(s):  
Oliver Selmoni ◽  
Gael Lecellier ◽  
Veronique Berteaux-Lecellier ◽  
Stephane Joost

Coral reefs around the world are under threat due to widespread decline of hard corals caused by anomalous heat waves. Coral taxa of different morphologies are known to have different sensitivities to heat stress. However, little is known about how long-term effects of heat exposure differ between coral taxa, nor in particular how such effects might drive adaptive processes. Here, we combined worldwide reef survey data with remotely sensed thermal anomalies to evaluate how local rates of taxa-specific coral cover were associated with heat stress. We found a negative association between coral cover and heat stress, where associations were weaker for corals with boulder-like morphology (massive corals), intermediate for corals with arborescent morphology (branching corals) and stronger for corals with encrusting or laminar morphology (plating corals). Additionally, we found that the negative association between branching coral cover and recent exposure to heat stress (measured as the year before a survey) was mitigated by the effect of long-term heat stress (measured since 1985), suggesting that adaptive processes occurred. In contrast, this "mitigating effect" of past heat-stress was not observed for either massive or plating corals. We hypothesize that these different responses to recent and past heat stress mirror different life history traits of coral taxa. For instance, branching corals are known to show higher sensitivities to heat stress and faster growth rates, two characteristics that might boost adaptive rates via evolutionary processes, when compared with other taxa. The results of this work suggest that all coral taxa, regardless of their morphology, will be "losers" of coral bleaching, and that conservation strategies should be adjusted to match taxa-specific responses to heat stress.


PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2084 ◽  
Author(s):  
Adam Suchley ◽  
Melanie D. McField ◽  
Lorenzo Alvarez-Filip

Long-term phase shifts from coral to macroalgal dominated reef systems are well documented in the Caribbean. Although the impact of coral diseases, climate change and other factors is acknowledged, major herbivore loss through disease and overfishing is often assigned a primary role. However, direct evidence for the link between herbivore abundance, macroalgal and coral cover is sparse, particularly over broad spatial scales. In this study we use a database of coral reef surveys performed at 85 sites along the Mesoamerican Reef of Mexico, Belize, Guatemala and Honduras, to examine potential ecological links by tracking site trajectories over the period 2005–2014. Despite the long-term reduction of herbivory capacity reported across the Caribbean, the Mesoamerican Reef region displayed relatively low macroalgal cover at the onset of the study. Subsequently, increasing fleshy macroalgal cover was pervasive. Herbivorous fish populations were not responsible for this trend as fleshy macroalgal cover change was not correlated with initial herbivorous fish biomass or change, and the majority of sites experienced increases in macroalgae browser biomass. This contrasts the coral reef top-down herbivore control paradigm and suggests the role of external factors in making environmental conditions more favourable for algae. Increasing macroalgal cover typically suppresses ecosystem services and leads to degraded reef systems. Consequently, policy makers and local coral reef managers should reassess the focus on herbivorous fish protection and consider complementary measures such as watershed management in order to arrest this trend.


2021 ◽  
Vol 8 ◽  
Author(s):  
Graham Kolodziej ◽  
Michael S. Studivan ◽  
Arthur C. R. Gleason ◽  
Chris Langdon ◽  
Ian C. Enochs ◽  
...  

Since the appearance of stony coral tissue loss disease (SCTLD) on reefs off Miami in 2014, this unprecedented outbreak has spread across the entirety of Florida’s coral reef tract, as well as to many territories throughout the Caribbean. The endemic zone reached the upper Florida Keys by 2016, resulting in partial or complete mortality of coral colonies across numerous species. Disease was first observed at Cheeca Rocks (Islamorada, Florida) in the beginning of 2018, with reports of coral mortality peaking mid-year. The disease was still present at Cheeca Rocks as of March 2020, however, to a lesser degree compared to the initial outbreak. Annual monitoring efforts have been ongoing at Cheeca Rocks since 2012, including repeated benthic photomosaics of a 330 m2 survey zone, spanning six replicate sites. As such, a repository of coral community composition data exists for before and after the disease outbreak that was analyzed to assess the impacts of SCTLD on reef communities at an upper Florida Keys inshore reef. Cheeca Rocks is hypothesized to be a resilient reef due to its persistent high coral cover despite its inshore location, which subjects corals to fluctuating water quality and marginal environmental conditions. Coral populations here have been shown to recover from bleaching events and heat stress with minimal coral mortality. Though colonies of coral species characterized as highly and moderately susceptible to SCTLD (e.g., Colpophyllia natans, Diploria labyrinthiformis, Pseudodiploria strigosa, Orbicella annularis, and O. faveolata) suffered mortality as a result of the outbreak with an average loss of 16.42% relative cover by species, the overall impacts on coral cover and community structure were relatively low, contributing to a loss of total coral cover of only 1.65%. Comparison of photomosaic data to other studies indicate Cheeca Rocks may not have been affected as severely as other sites on Florida’s coral reef tract, underlying this site’s potential role in coral resilience to stressors including bleaching events, land-based pollution, and disease epizootics.


PLoS ONE ◽  
2014 ◽  
Vol 9 (11) ◽  
pp. e113079 ◽  
Author(s):  
Tom C. L. Bridge ◽  
Renata Ferrari ◽  
Mitch Bryson ◽  
Renae Hovey ◽  
Will F. Figueira ◽  
...  

2020 ◽  
Author(s):  
Oliver Selmoni ◽  
Gaël Lecellier ◽  
Laurent Vigliola ◽  
Véronique Berteaux-Lecellier ◽  
Stéphane Joost

AbstractAs anomalous heat waves are causing the widespread decline of coral reefs worldwide, there is an urgent need to identify coral populations tolerant to thermal stress. Heat stress adaptive potential is the degree of tolerance expected from evolutionary processes and, for a given reef, depends on the arrival of propagules from reefs exposed to recurrent thermal stress. For this reason, assessing spatial patterns of thermal adaptation and reef connectivity is of paramount importance to inform conservation strategies.In this work, we applied a seascape genomics framework to characterize the spatial patterns of thermal adaptation and connectivity for coral reefs of New Caledonia (Southern Pacific). In this approach, remote sensing of seascape conditions was combined with genomic data from three coral species. For every reef of the region, we computed a probability of heat stress adaptation, and two indices forecasting inbound and outbound connectivity. We then compared our indicators to field survey data, and observed that decrease of coral cover after heat stress was lower at reefs predicted with high probability of adaptation and inbound connectivity. Last, we discussed how these indicators can be used to inform local conservation strategies and preserve the adaptive potential of New Caledonian reefs.


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