The coral communities of Yongle atoll: status, threats and conservation significance for coral reefs in South China Sea

Xisha Islands are in the central South China Sea and form one of the four large island groups in this region. They include more than 40 islands, reefs and cays, and have considerable ecological and biodiversity value, both intrinsically and as a source of larvae for coastal ecosystems throughout the South China Sea. Yongle atoll is the biggest and one of the most important atolls in the Xisha Islands. The detailed surveys of the marine habitats in the Yongle atoll were conducted from June to July 2013. This baseline survey revealed coral communities in a relatively healthy condition. Mean coral cover of different geomorphic habitats varied from 2 to 29%. Branching corals were most important, followed by encrusting and massive growth forms (48, 29 and 17% of coral cover). Pocillopora (29% of total cover in line transects), Porites (19%), Acropora (17%) and Montipora (16%) were the four dominant genera. Communities differentiated into four clusters, namely, lower reef slope, upper reef slope, outer reef flat, and inner reef flat and lagoon slope. This baseline investigation highlighted the ecological value of these reefs. Destructive fishing and overfishing are presently the most serious threats for these coral reefs. They should receive much more scientific and conservation attention.

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Using Landsat Data to Detect Change in Live to Recently (<6 Months) Dead Coral Cover in the Western Xisha Islands, South China Sea

Sustainability ◽

10.3390/su12135237 ◽

2020 ◽

Vol 12 (13) ◽

pp. 5237

Author(s):

Xiuling Zuo ◽

Fenzhen Su ◽

Junjue Zhang ◽

Wenzhou Wu

Keyword(s):

Remote Sensing ◽

South China Sea ◽

Coral Reefs ◽

South China ◽

Large Scale ◽

Coral Cover ◽

Dead Coral ◽

Reef Management ◽

Xisha Islands ◽

China Sea

The amount of live and dead coral is related to recruitment, but differentiating them by remote sensing techniques is difficult. We measured change in the amount of live, bleached, and recently (<6 months) dead coral cover (CCA6) for an island archipelago in the South China Sea. Six Landsat 4/7 ETM/8 OLI images from 1989–1990, 2005, and 2014 were analyzed to assess changes in CCA6 at 14 coral reefs in the western Xisha Islands. Satellite images were georectified and calibrated to remote sensing reflectance. Models for three shallow water (<6 m) geomorphic zones throughout the western Xisha Islands are proposed based on ground-truthed data collected in 2014 and satellite-determined spectral values for 2014 images. Nonlinear models based on Landsat image blue spectral bands for reef slope and lagoon habitats, and green bands for reef flat habitats, are determined as optimal models. Significant changes in CCA6 from 2005 to 2014, and changes in coral reefs and geomorphic zones, correlate with increased numbers of both crown-of-thorns starfish, and sea surface temperature in 2007. Detecting change in CCA6 by remote sensing can provide large-scale information of value for coral reef management, restoration, and protection.

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

Bulletin of Marine Science ◽

10.5343/bms.2021.0030 ◽

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.

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Impact on the coral reefs at Yongle Atoll, Xisha Islands, South China Sea from a strong typhoon direct sweep: Wutip, September 2013

Journal of Asian Earth Sciences ◽

10.1016/j.jseaes.2015.04.009 ◽

2015 ◽

Vol 114 ◽

pp. 457-466 ◽

Cited By ~ 8

Author(s):

Hongqiang Yang ◽

Kefu Yu ◽

Meixia Zhao ◽

Qi Shi ◽

Shichen Tao ◽

...

Keyword(s):

South China Sea ◽

Coral Reefs ◽

South China ◽

Xisha Islands ◽

China Sea

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Zircon SHRIMP U-Pb dating of the Neogene coral reefs, Xisha Islands, South China Sea: implications for tectonic evolution

China Geology ◽

10.31035/cg2018007 ◽

2018 ◽

Vol 1 (1) ◽

pp. 49-60 ◽

Cited By ~ 1

Author(s):

Hong Xu ◽

◽

Zhao-peng Ji ◽

Shan-ying Li ◽

Yan-qiou Yang ◽

...

Keyword(s):

South China Sea ◽

Coral Reefs ◽

South China ◽

Tectonic Evolution ◽

Xisha Islands ◽

China Sea

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Spatially Modeling the Synergistic Impacts of Global Warming and Sea-Level Rise on Coral Reefs in the South China Sea

Remote Sensing ◽

10.3390/rs13132626 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2626

Author(s):

Xiuling Zuo ◽

Fenzhen Su ◽

Kefu Yu ◽

Yinghui Wang ◽

Qi Wang ◽

...

Keyword(s):

Global Warming ◽

South China Sea ◽

Coral Reefs ◽

Sea Level Rise ◽

Sea Level ◽

South China ◽

The South China Sea ◽

Nansha Islands ◽

Xisha Islands ◽

China Sea

Global warming and sea-level rise (SLR) induced by rising atmospheric CO2 concentrations can cause coral bleaching, death, and submergence of the world’s coral reefs. Adopting the GIS and RS methods, we modeled how these two stressors combine to influence the future growth of the atolls and table reefs of three archipelagoes in the South China Sea (SCS), based on geomorphic and ecological zones. A large-scale survey of the coral communities in Xisha Islands in 2014, Dongsha Islands in 2014–2016 and Nansha Islands in 2007 provided zone-specific process datasets on the range of reef accretion rates. Sea surface temperature and extreme (minimum and maximum) SLR data above 1985–2005 levels by 2100 in the SCS were derived from the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) models forced with the Representative Concentration Pathways (RCPs). Our model projected that: (1) the Xisha Islands and Dongsha Islands may have a better growth status, because the reef flat biotic sparse zone may be recolonized with hard coral and become a biotic dense zone; (2) the southern Nansha Islands reefs have a risk of stopping growing due to their earlier annual bleaching years. The increasing of water depths of these reefs is stronger in the RCP with more emissions. Our approach offers insights into the best-case and worst-case impacts of two global environmental pressures on potential future reef growth under a changing climate.

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The Status of Coral Reefs and Its Importance for Coastal Protection: A Case Study of Northeastern Hainan Island, South China Sea

Sustainability ◽

10.3390/su11164354 ◽

2019 ◽

Vol 11 (16) ◽

pp. 4354 ◽

Cited By ~ 1

Author(s):

Meixia Zhao ◽

Haiyang Zhang ◽

Yu Zhong ◽

Dapeng Jiang ◽

Guohui Liu ◽

...

Keyword(s):

Coral Reef ◽

South China Sea ◽

Coral Reefs ◽

South China ◽

Hainan Island ◽

Coastal Protection ◽

China Sea ◽

Spatial Coverage ◽

The Status ◽

Coral Communities

This study evaluated the status of coral communities at the fringing reefs in the northern South China Sea, and their potential role in maintaining nearby coastline stability of northeastern Hainan Island (Puqian Bay, Hainan Bay). Thirty-nine coral species were recorded with mean coral cover of 5.3%, and are dominated by massive Galaxea, Platygyra and Porites. The coral communities were clustered into two groups (Clu-HNB and Clu-PQB) corresponding to different stable coastal conditions. Coral communities at the Hainan Bay with higher diversity and greater cover corresponded to relatively stable coastline, whereas those at the southern Puqian Bay (with the lowest coral diversity and spatial coverage) corresponded to severe coastline erosion. This work provides some direct evidence that declined coral reefs would weaken their functions to maintain a stable coastline, resulting in severe coastal erosion. It is also useful to help coastal managers and local people pay more attention to the importance of coral reefs in coastal protection and encourage them to change their ways to get sustainable use of coral reef resources. It may be beneficial to inspire or initiate coastal engineering to manage coasts with natural coral reef solution.

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Effects of sea-level variation and sedimentary noise variation on the development of biogenic reefs since the Pliocene among the Xisha Islands, South China Sea

Geological Society of America Bulletin ◽

10.1130/b36138.1 ◽

2021 ◽

Author(s):

Ke Zhao ◽

Xuebin Du ◽

Jixin Jia ◽

Xinong Xie ◽

Fang Hao ◽

...

Keyword(s):

South China Sea ◽

Coral Reefs ◽

Sea Level ◽

South China ◽

Oil And Gas ◽

Level Variation ◽

Carbonate Platforms ◽

Xisha Islands ◽

China Sea ◽

Sea Level Variation

Carbonate strata are a vital and favorable reservoir for global oil and gas exploration, and carbonate sedimentary systems record ancient oceanic and paleoclimatic conditions, including paleoenvironmental variations throughout geologic periods. Carbonate platforms are widely distributed among the Xisha Islands in the South China Sea and contain large amounts of oil and gas resources. Biogenic reefs are the dominant parts of the carbonate platforms in the Xisha Islands; however, research on the factors that control and affect biogenic reef development is lacking. In this study, a core from well XK-1, which is located on Yongxing Island in the Xisha Islands, a sedimentary noise model, and time-series analyses were used to determine the effects of sea-level fluctuations from 5.3 Ma to present. The results show that coral reefs in the Xisha Islands are sensitive to eustatic fluctuations and that a decrease in sea level essentially corresponds to an increase in sedimentation rate. Indexes of the East Asian monsoon and other environmental indexes show that the Pleistocene and Holocene were suitable for coral growth; however, the trends shown by these indexes and the sea-level variation indicate that the future growth of coral reefs will be at a disadvantage. Research on the controlling factors of biogenic reefs is of significance for understanding reef growth, performing global reef comparisons, and encouraging the future protection of coral reefs.

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