Long-Term Dynamics Influencing Recovery Processes under Environmental Constraints of Coral Reef Ecosystems in Southeast Asia, Phu Quoc, Vietnam (2014–2023)

Authors

  • Quang Thanh Le

    Forest Science Institute of South Vietnam, Ho Chi Minh City 70000,  Vietnam
  • Luom Thanh Thai

    Faculty of Natural Resources and Environmetn, Kien Giang University, Rach Gia 91000, Vietnam
  • Mo Danh

    Faculty of Natural Resources and Environmetn, Kien Giang University, Rach Gia 91000, Vietnam
  • Gieo Hoang Phan

    Faculty of Natural Resources and Environmetn, Kien Giang University, Rach Gia 91000, Vietnam
  • Au Hai Nguyen

    Institute of Environment and Resources, Vietnam National University, Ho Chi Minh City 70000, Vietnam
  • Trang Thi Phuong Huynh

    Center for Traffic Management and Technical Infrastructure, Ho Chi Minh City 70000, Vietnam
  • Lan Thi Phong Pham

    Phu Quoc Marine Reserve, Phu Quoc 92500, Vietnam

DOI:

https://doi.org/10.30564/re.v8i4.13522
Received: 17 May 2026 | Revised: 8 July 2026 | Accepted: 14 July 2026 | Published Online: 17 August 2026

Abstract

This study investigated the temporal changes in coral reef cover and seawater quality in the Phu Quoc Marine Protected Area, Vietnam, from 2014 to 2023. Based on long-term monitoring data, marine environmental parameters were evaluated according to Vietnamese standards, and trends in coral reef ecosystem health were assessed. Coral reef benthic communities, reef-associated benthic invertebrates, reef fish assemblages, and physicochemical water quality parameters were surveyed annually at the beginning of the rainy season and monitored during both the dry and rainy seasons. A Comprehensive Reef Ecosystem Condition (CREC) index integrating five key biological components was developed to evaluate the overall ecological status of the coral reef ecosystem. Mean live coral cover increased from 38.6% in 2014 to 58.0% in 2023, indicating substantial reef recovery. No outbreaks of the coral-feeding crown-of-thorns starfish (Acanthaster cf. solaris/planci) were recorded during the study period, while benthic invertebrate communities were dominated by long-spined black sea urchins (Diadema spp.), which may have contributed to macroalgal control and coral recovery. Water quality remained generally stable, with pH (7.85–7.95), dissolved oxygen (>5 mg/L), and most nutrient concentrations within Vietnamese regulatory thresholds for coral reef development. However, nitrate, ammonium, phosphate, and coliform concentrations were consistently higher during the rainy season than during the dry season. CREC values indicated a good ecological condition. The results suggest that stable water quality has supported coral reef recovery in Phu Quoc, whereas increasing nutrient inputs and microbial contamination during the rainy season may pose future risks. The proposed CREC framework provides a practical tool for long-term reef monitoring and supports evidence-based conservation and adaptive management of tropical coral reef ecosystems.

Keywords:

Coral Reef Health; Water Quality; Reef Fish Assemblages; Benthic Invertebrates; Long-Term Monitoring; Marine Protected Area; Phu Quoc; Vietnam

References

[1] IPCC, 2023. Climate Change 2021: The Physical Science Basis: Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press: Cambridge, UK. DOI: https://doi.org/10.1017/9781009157896

[2] Smith, K.E., Burrows, M.T., Hobday, A.J., et al., 2023. Biological impacts of marine heatwaves. Annual Review of Marine Science. 15, 119–145. DOI: https://doi.org/10.1146/annurev-marine-032122-121437

[3] Zhang, T., Chen, T., Liu, S., et al., 2023. Coral reef resilience persisted for a millennium but has declined rapidly in recent decades. Frontiers in Marine Science. 10, 1143728. DOI: https://doi.org/10.3389/fmars.2023.1143728

[4] Bruno, J.F., Valdivia, A., 2016. Coral reef degradation is not correlated with local human population density. Scientific Reports. 6, 29778. DOI: https://doi.org/10.1038/srep29778

[5] Kim, S.W., Sommer, B., Beger, M., et al., 2023. Regional and global climate risks for reef corals: Incorporating species-specific vulnerability and exposure to climate hazards. Global Change Biology. 29(14), 4140–4151. DOI: https://doi.org/10.1111/gcb.16739

[6] Hughes, T.P., Barnes, M.L., Bellwood, D.R., et al., 2017. Coral reefs in the Anthropocene. Nature. 546(7656), 82–90. DOI: https://doi.org/10.1038/nature22901

[7] Wicquart, J., Mathon, L., Petit, A., et al. (Eds.), 2025. Status and Trends of Caribbean Coral Reefs: 1970–2024. Global Coral Reef Monitoring Network (GCRMN): Canberra, Australia; International Coral Reef Initiative (ICRI): Townsville, Australia. DOI: https://doi.org/10.59387/BDHF9180

[8] Lapointe, B.E., Brewton, R.A., Herren, L.W., et al., 2019. Nitrogen enrichment, altered stoichiometry, and coral reef decline at Looe Key, Florida Keys, USA: A 3-decade study. Marine Biology. 166, 108. DOI: https://doi.org/10.1007/s00227-019-3538-9

[9] McClanahan, T.R., Darling, E.S., Beger, M., et al., 2024. Diversification of refugia types needed to secure the future of coral reefs under climate change. Conservation Biology. 38(1), e14108. DOI: https://doi.org/10.1111/cobi.14108

[10] Greiner, A., Andrello, M., Darling, E., et al., 2022. Limited spatial rescue potential for coral reefs lost to future climate warming. Global Ecology and Biogeography. 31(11), 2245–2258. DOI: https://doi.org/10.1111/geb.13571

[11] Wenger, A.S., Fabricius, K.E., Jones, G.P., et al., 2015. Effects of sedimentation, eutrophication, and chemical pollution on coral reef fishes. In: Mora, C. (Ed.). Ecology of Fishes on Coral Reefs. Cambridge University Press: Cambridge, UK. pp. 145–153. DOI: https://doi.org/10.1017/CBO9781316105412.017

[12] Uthicke, S., Doyle, J., Duggan, S., et al., 2015. Outbreak of coral-eating Crown-of-Thorns creates continuous cloud of larvae over 320 km of the Great Barrier Reef. Scientific Reports. 5, 16885. DOI: https://doi.org/10.1038/srep16885

[13] Veettil, B.K., Puri, V., 2025. Coral reefs in Vietnam: Current state of research and future perspectives. Estuarine, Coastal and Shelf Science. 326, 109554. DOI: https://doi.org/10.1016/j.ecss.2025.109554

[14] McClanahan, T.R., Donner, S.D., Maynard, J.A., et al., 2012. Prioritizing key resilience indicators to support coral reef management in a Changing Climate. PLoS ONE. 7(8), e42884. DOI: https://doi.org/10.1371/journal.pone.0042884

[15] Davey, M., Klein, C.J., Roelfsema, C., 2025. A review of the application of coral reef condition indicators in conservation planning. Ecological Indicators. 179, 114222. DOI: https://doi.org/10.1016/j.ecolind.2025.114222

[16] Borja, Á., Bricker, S.B., Dauer, D.M., et al., 2008. Overview of integrative tools and methods in assessing ecological integrity in estuarine and coastal systems worldwide. Marine Pollution Bulletin. 56, 1519–1537. DOI: https://doi.org/10.1016/j.marpolbul.2008.07.005

[17] OECD, 2008. Handbook on Constructing Composite Indicators: Methodology and User Guide. OECD Publishing: Paris, France. DOI: https://doi.org/10.1787/9789264043466-en

[18] Rice, J.C., Rochet, M.-J., 2005. A framework for selecting a suite of indicators for fisheries management. ICES Journal of Marine Science. 62(3), 516–527. DOI: https://doi.org/10.1016/j.icesjms.2005.01.003

[19] Souter, D., Planes, S., Wicquart, J., et al., 2021. Status of Coral Reefs of the World: 2020. Global Coral Reef Monitoring Network (GCRMN): Canberra, Australia; International Coral Reef Initiative (ICRI): Townsville, Australia.

[20] English, S., Wilkinson, C., Baker, V. (Eds.), 1997. Survey Manual for Tropical Marine Resources, 2nd ed. Australian Institute of Marine Science: Townsville, Australia.

[21] Hodgson, G., Hill, J., Kiene, W., et al., 2006. Reef Check Instruction Manual: A Guide to Reef Check Coral Reef Monitoring. Reef Check Foundation: Pacific Palisades, CA, USA .

[22] Intergovernmental Panel on Climate Change (IPCC), 2023. Climate Change 2022: Impacts, Adaptation and Vulnerability: Working Group II Contribution to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press: Cambridge, UK. DOI: https://doi.org/10.1017/9781009325844

[23] Walker, A.S., Kratochwill, C.A., van Woesik, R., 2024. Past disturbances and local conditions influence the recovery rates of coral reefs. Global Change Biology. 30, e17112. https://doi.org/10.1111/gcb.17112

[24] Goergen, E.A., Schopmeyer, S., Moulding, A.L., et al., 2020. Coral Reef Restoration Monitoring Guide: Methods to Evaluate Restoration Success from Local to Ecosystem Scales. NOS (National Ocean Service), NCCOS (National Centers for Coastal Ocean Science): Silver Spring, MD, USA. DOI: https://doi.org/10.25923/xndz-h538

[25] Casella, E., Lewin, P., Ghilardi, M., et al., 2022. Assessing the relative accuracy of coral reef heights reconstructed from drones and structure from motion photogrammetry on coral reefs. Coral Reefs. 41, 869–875. DOI: https://doi.org/10.1007/s00338-022-02244-9

[26] Burns, C., Bollard, B., Narayanan, A., 2022. Machine-learning for mapping and monitoring shallow coral reef habitats. Remote Sensing. 14(11), 2666. DOI: https://doi.org/10.3390/rs14112666

[27] Pierce, J., Butler, M.J., Rzhanov, Y., et al., 2021. Classifying 3-D models of coral reefs using structure-from-motion and multi-view semantic segmentation. Frontiers in Marine Science. 8, 706674. DOI: https://doi.org/10.3389/fmars.2021.706674

[28] Urbina-Barreto, I., Garnier, R., Elise, S., et al., 2021. Which method for which purpose? A comparison of line intercept transect and underwater photogrammetry methods for coral reef surveys. Frontiers in Marine Science. 8, 636902. DOI: https://doi.org/10.3389/fmars.2021.636902

[29] Cheal, A.J., Emslie, M.J., Currey-Randall, L.M., et al., 2021. Complementarity of reef fish measures from underwater visual census (UVC) and baited remote underwater video stations (BRUVS). Journal of Environmental Management. 289, 112375. DOI: https://doi.org/10.1016/j.jenvman.2021.112375

[30] Obura, D., Gudka, M., Rabi, F.A., et al., 2019. Coral Reef Status Report for the Western Indian Ocean (2017). Global Coral Reef Monitoring Network (GCRMN): Canberra, Australia; International Coral Reef Initiative (ICRI): Townsville, Australia.

[31] Matthews, S.A., Mellin, C., Pratchett, M.S., 2020. Larval connectivity and water quality explain spatial distribution of crown-of-thorns starfish outbreaks across the Great Barrier Reef. Advances in Marine Biology. 87(1), 223–258. DOI: https://doi.org/10.1016/bs.amb.2020.08.007

[32] Purcell, S.W., Mercier, A., Conand, C., et al., 2012. Sea cucumber fisheries: Global analysis of stocks, management measures and drivers of overfishing. Fish and Fisheries. 14(1), 34–59. DOI: https://doi.org/10.1111/j.1467-2979.2011.00443.x

[33] Sheppard, C.E., Williams, G.J., Exton, D.A., et al., 2023. Co-occurrence of herbivorous fish functional groups correlates with enhanced coral reef benthic state. Global Ecology and Biogeography. 32(3), 435–449. DOI: https://doi.org/10.1111/geb.13638

[34] Crisp, S.K., Tebbett, S.B., Bellwood, D.R., 2022. A critical evaluation of benthic phase shift studies on coral reefs. Marine Environmental Research. 178, 105667. DOI: https://doi.org/10.1016/j.marenvres.2022.105667

[35] Turicchia, E., Ponti, M., Rossi, G., et al., 2021. The Reef Check Mediterranean underwater coastal environment monitoring protocol. Frontiers in Marine Science. 8, 620368. DOI: https://doi.org/10.3389/fmars.2021.620368

[36] Kaijser, W., Lorenz, A.W., Hering, D., et al., 2022. The interplay of nutrients, dissolved inorganic carbon and algae in determining macrophyte occurrences in rivers. Science of the Total Environment. 781, 146728. DOI: https://doi.org/10.1016/j.scitotenv.2021.146728

[37] Huy, B., 2016. Statistical Informatics in Forestry. Vietnam Science and Technology Publishing House: Hanoi, Vietnam. Available from: https://baohuy-frem.org/vn/wp-content/uploads/sites/3/2021/07/Textbook-Informatic-Statistics-Final-all.pdf (in Vietnamese)

[38] Rice, E.W., Baird, R.B., Eaton, A.D., 2017. Standard Methods for the Examination of Water and Wastewater, 23rd ed. American Public Health Association: Washington, DC, USA; American Water Works Association (AWWA): Denver, CO, USA; Water Environment Federation (WEF): Alexandria, VA, USA.

[39] Nalley, E.M., Tuttle, L.J., Barkman, A.L., et al., 2021. Water quality thresholds for coastal contaminant impacts on corals: A systematic review and meta-analysis. Science of the Total Environment. 794, 148632. DOI: https://doi.org/10.1016/j.scitotenv.2021.148632

[40] Robinson, J.P.W., Williams, I.D., Yeager, L.A., et al., 2018. Environmental conditions and herbivore biomass determine coral reef benthic community composition: Implications for quantitative baselines. Coral Reefs. 37(4), 1157–1168. DOI: https://doi.org/10.1007/s00338-018-01737-w

[41] Hughes, T.P., Kerry, J.T., Álvarez-Noriega, M., et al., 2017. Global warming and recurrent mass bleaching of corals. Nature. 543(7645), 373–377. DOI: https://doi.org/10.1038/nature21707

[42] Claar, D.C., Starko, S., Tietjen, K.L., et al., 2020. Dynamic symbioses reveal pathways to coral survival through prolonged heatwaves. Nature Communications. 11, 6097. DOI: https://doi.org/10.1038/s41467-020-19169-y

[43] McClanahan, T., Polunin, N., Done, T., 2002. Ecological states and the resilience of coral reefs. Conservation Ecology. 6(2), 18.

[44] Wilkinson, C. (Ed.), 2008. Status of Coral Reefs of the World: 2008. Global Coral Reef Monitoring Network (GCRMN): Canberra, Australia; International Coral Reef Initiative (ICRI): Townsville, Australia.

[45] Bellwood, D.R., Hughes, T.P., Folke, C., et al., 2004. Confronting the coral reef crisis. Nature. 429, 827–833. DOI: https://doi.org/10.1038/nature02691

[46] Alongi, D.M., Murdiyarso, D., Fourqurean, J.W., et al., 2016. Indonesia’s blue carbon: A globally significant and vulnerable sink for seagrass and mangrove carbon. Wetlands Ecology and Management. 24(1), 3–13.

[47] Webb, A.E., de Bakker, D.M., Soetaert, K., et al., 2021. Quantifying functional consequences of habitat degradation on a Caribbean coral reef. Biogeosciences. 18(24), 6501–6516. DOI: https://doi.org/10.5194/bg-18-6501-2021

[48] Krajewski, J.P., Floeter, S.R., 2011. Reef fish community structure of the Fernando de Noronha Archipelago (Equatorial Western Atlantic): The influence of exposure and benthic composition. Environmental Biology of Fishes. 92, 25–40.

[49] Logan, C.A., Dunne, J.P., Ryan, J.S., et al., 2021. Quantifying global potential for coral evolutionary response to climate change. Nature Climate Change. 11, 537–542. DOI: https://doi.org/10.1038/s41558-021-01037-2

[50] Gudka, M., Obura, D., Treml, E.A., et al., 2024. Strengthening resilience potential assessments for coral reef management. Methods in Ecology and Evolution. 15(4), 612–627. DOI: https://doi.org/10.1111/2041-210X.14303

[51] Bellwood, D.R., Streit, R.P., Brandl, S.J., et al., 2019. The meaning of the term ‘function’ in ecology: A coral reef perspective. Functional Ecology. 33(6), 948–961. DOI: https://doi.org/10.1111/1365-2435.13265

[52] Mumby, P.J., Hastings, A., Edwards, H.J., 2007. Thresholds and the resilience of Caribbean coral reefs. Nature. 450, 98–101. DOI: https://doi.org/10.1038/nature06252

[53] Lam, V.Y.Y., Doropoulos, C., Bozec, Y.-M., et al., 2020. Resilience concepts and their application to coral reefs. Frontiers in Ecology and Evolution. 8, 49. DOI: https://doi.org/10.3389/fevo.2020.00049

[54] Graham, N.A.J., Wilson, S.K., Jennings, S., et al., 2006. Dynamic fragility of oceanic coral reef ecosystems. Proceedings of the National Academy of Sciences. 103(22), 8425–8429. DOI: https://doi.org/10.1073/pnas.0600693103

Downloads

How to Cite

Le, Q. T., Thai, L. T., Danh, M., Phan, G. H., Nguyen, A. H., Huynh, T. T. P., & Pham, L. T. P. (2026). Long-Term Dynamics Influencing Recovery Processes under Environmental Constraints of Coral Reef Ecosystems in Southeast Asia, Phu Quoc, Vietnam (2014–2023). Research in Ecology, 8(4), 250–275. https://doi.org/10.30564/re.v8i4.13522

Issue

Vol.8, Iss.4 (August 2026): In Progress

Article Type

Article

License

Copyright © 2026 Quang Thanh Le, Luom Thanh Thai, Mo Danh, Gieo Hoang Phan, Au Hai Nguyen, Trang Thi Phuong Huynh, Lan Thi Phong Pham

Creative Commons License

This is an open access article under the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) License.

Crossref
Scopus
Google Scholar
Europe PMC