A Bibliometric Review of Seagrass Research in the Philippines (2014–2024): Trends, Disciplinary Focus, and Future Directions

Abstract

Seagrass ecosystems contribute significantly to both ecological stability and economic resilience. They serve as crucial feeding habitats for dugongs, nurseries for young marine organisms, and significant natural carbon sinks that help mitigate climate change. Despite their importance, seagrass habitats face a range of natural and anthropogenic threats. Previous review papers highlighted regional knowledge gaps in seagrasses across Southeast Asia. However, these studies lack country-specific insights, which is important in developing strategies to address unique issues within a country. This review focuses on generating localized knowledge and providing insights vital for country-specific policies and management strategies. It evaluates trends in seagrass research in the Philippines from 2014 to mid-2024, retrieved from Google Scholar using the keyword “seagrass studies in the Philippines.” The collected articles were compiled in Microsoft Excel for analysis. A total of 123 published articles were identified, a significant increase compared to the last two to three decades. Most publications consist of research articles, followed by reviews and notes. Geographically, Mindanao is the most studied region, with natural sciences emerging as the dominant discipline. Ecology receives the most attention, while physiology, biology, and molecular studies remain significantly underexplored, highlighting the need for further research in these fields. Collectively, seagrass research trends in the Philippines show temporal fluctuations, possibly influenced by external factors that cause periodic increases and decreases in output. Directing research efforts toward underexplored areas is recommended for adaptive management of seagrasses.

Keywords

• Trends
• Seagrass
• Country-specific
• Gaps
• Philippines

References

1. Arbilo, A. M. L., Sayadi, I. J. M., & Lumogdang, L. P. (2023). Carbon sequestration potential of seagrasses species in the selected sites of Don Marcelino, Davao Occidental, Philippines. Davao Research Journal, 14(2), 84–92. doi:https://doi.org/10.59120/drj.v14i2.100 
2. Arriesgado, D. M., Kurokochi, H., Arriesgado, E. M., Roa, E. C., Gonzales, R. C., Perpetua, A. D., Bucay, D. M., Iwakiri, A., & Lian, C. (2023). Genetic diversity and structure of dominant seagrass species in the Southern Philippines for conservation and adaptive management. Philippine Journal of Science, 152(1), 57–71. doi:https://doi.org/10.56899/152.01.21
3. Arriesgado, D., Arriesgado, E., Roa, E., Perpetua, A., Gonzales, R., Acuña, R., & Sornito, M. (2024). Seagrass cover and associated macrobenthic marine invertebrates in Southern Philippines. Aquatic Ecology, 58, 643–657. doi:https://doi.org/10.1007/s10452-024-10095-5 
4. Arriesgado, D., Arriesgado, E., Sornito, M., & Bucay, D. (2024). Anthropogenic activities alter the seagrass ecosystem in Southern Philippines. Journal of Survey in Fisheries Sciences, 11(1), 84–90. doi:https://doi.org/10.53555/sfs.v11i01.1971 
5. Arriesgado, D. M., Kurokochi, H., Nakajima, Y., Matsuki, Y., Uy, W. H., Fortes, M. D., & Lian, C. (2015). Genetic diversity and structure of the tropical seagrass Cymodocea serrulata spanning its central diversity hotspot and range edge. Aquatic Ecology, 49, 357–372. doi:https://doi.org/10.1007/s10452-015-9529-0 
6. Arriesgado, D. M., Kurokochi, H., Nakajima, Y., Matsuki, Y., Uy, W. H., Fortes, M. D., & Lian, C. (2016). Population genetic diversity and structure of a dominant tropical seagrass, Cymodocea rotundata, in the Western Pacific region. Marine Ecology, 37(4), 786–800. doi:https://doi.org/10.1111/maec.12350 
7. Bennett, N. J., Roth, R., Klain, S. C., Chan, K., Christie, P., Clark, D. A., Cullman, G., Curran, D., Durbin, T. J., Epstein, G., Greenberg, A., Nelson, M. P., Sandlos, J., Stedman, R., Teel, T. L., Thomas, R., Veríssimo, D., & Wyborn, C. (2017). Conservation social science: Understanding and integrating human dimensions to improve conservation. Biological Conservation, 205, 93-108. doi:https://doi.org/10.1016/j.biocon.2016.10.006
8. Bertuol‐Garcia, D., Morsello, C., N. El‐Hani, C., & Pardini, R. (2018). A conceptual framework for understanding the perspectives on the causes of the science–practice gap in ecology and conservation. Biological Reviews, 93(2), 1032-1055. doi:https://doi.org/10.1111/brv.12385

9. Bongolan, V. P., Torres, G. M., & Branzuela, J. E. (2019). Modelling, simulation and visualization of a multispecific Philippine seagrass meadow. The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 42, 77-82. doi:https://doi.org/10.5194/isprs-archives-xlii-4-w19-77-2019
10. Brodie, G., Holland, E., De Ramon, N. Y. A., Soapi, K., & Hills, J. (2020). Seagrasses and seagrass habitats in Pacific small island developing states: Potential loss of benefits via human disturbance and climate change. Marine Pollution Bulletin, 160, 111573. doi:https://doi.org/10.1016/j.marpolbul.2020.111573
11. Capin, N. C., Pototan, B. L., Delima, A. G. D., & Novero, A. U. (2021). Distribution and abundance of seagrasses in the southwest coast of Davao Oriental, Philippines. Philippine Journal of Science, 150, 383-394. doi:https://doi.org/10.56899/150.s1.28
12. Celmar, J. M., Gabriel, A. D., Hung, C. C., & Bacosa, H. P. (2024). Microplastic pollution on seagrass blades in two coastal bays in Northern Mindanao, Philippines. Regional Studies in Marine Science, 77, 103636. doi:https://doi.org/10.1016/j.rsma.2024.103636
13. Cullen-Unsworth, L. C., Nordlund, L. M., Paddock, J., Baker, S., McKenzie, L. J., & Unsworth, R. K. (2014). Seagrass meadows globally as a coupled social–ecological system: Implications for human wellbeing. Marine pollution bulletin, 83(2), 387-397. vhttps://doi.org/10.1016/j.marpolbul.2013.06.001
14. Domínguez-Tejo, E., Metternicht, G., Johnston, E., & Hedge, L. (2016). Marine Spatial Planning advancing the Ecosystem-Based Approach to coastal zone management: A review. Marine Policy, 72, 115-130. doi:https://doi.org/10.1016/j.marpol.2016.06.023
15. Duarte, B., Martins, I., Rosa, R., Matos, A. R., Roleda, M. Y., Reusch, T. B. H., Engelen, A. H., Serrão, E. A., Pearson, G. A., Marques, J. C., Caçador, I., Duarte, C. M., & Jueterbock, A. (2018). Climate Change Impacts on Seagrass Meadows and Macroalgal Forests: An Integrative Perspective on Acclimation and Adaptation Potential. Frontiers in Marine Science, 5, 190. doi:https://doi.org/10.3389/fmars.2018.00190
16. Espadero, A. D. A., Nakamura, Y., Uy, W. H., Tongnunui, P., & Horinouchi, M. (2020). Tropical intertidal seagrass beds: An overlooked foraging habitat for fishes revealed by underwater videos. Journal of Experimental Marine Biology and Ecology, 526, 151353. doi:https://doi.org/10.1016/j.jembe.2020.151353
17. Fortes, M. D. (2018). Seagrass ecosystem conservation in Southeast Asia needs to link science to policy and practice. Ocean & Coastal Management, 159, 51-56. doi:https://doi.org/10.1016/j.ocecoaman.2018.01.028
18. Fortes, M. D. (2021). Seagrass factor in climate change mitigation in the Philippines. Philippine Journal of Science, 151, 195-206. doi:https://doi.org/10.56899/151.s1.13
19. Fortes, M. D., Ooi, J. L. S., Tan, Y. M., Prathep, A., Bujang, J. S., & Yaakub, S. M. (2018). Seagrass in Southeast Asia: A review of status and knowledge gaps, and a road map for conservation. Botanica Marina, 61(3), 269-288. doi:https://doi.org/10.1515/bot-2018-0008
20. Fourqurean, J. W., Duarte, C. M., Kennedy, H., Marbà, N., Holmer, M., Mateo, M. A., Apostolaki, E. T., Kendrick, G. A., Krause-Jensen, D., McGlathery, K. J., & Serrano, O. (2012). Seagrass ecosystems as a globally significant carbon stock. Nature Geoscience, 5(7), 505-509. doi:https://doi.org/10.1038/ngeo1477
21. Gaboy, S. M. M., Guihawan, J. Q., Leopardas, V. E., & Bacosa, H. P. (2022). Unravelling macroplastic pollution in seagrass beds of Iligan City, Mindanao, Philippines. Marine Pollution Bulletin, 185, 114233. doi:https://doi.org/10.1016/j.marpolbul.2022.114233
22. Grimm, K. E., Archibald, J. L., Bonilla-Anariba, S. E., Bood, N., & Canty, S. W. (2023). Framework for fostering just and equitable seagrass policy, management, and social-ecological outcomes: Lessons learned from Belizean marine resource managers. Marine Policy, 152, 105606. doi:https://doi.org/10.1016/j.marpol.2023.105606
23. Hemraj, H. (2020). Coral Reef Management: Analysis of the Management of the Coral Triangle Initiative within the Coral Triangle Region. (PhD), Queen’s University, Kingston, Ontario, Canada.
24. John, A., Raveen, B. N., Sheikh, H. I., Kamal, A. H. M., Vedharajan, B., Pandisamy, R., & Appadoo, C. (2023). Seagrass of Southeast Asia: Challenges, prospects, and management strategies. In B. Pathak & R. S. Dubey (Eds.), Climate change and urban environment sustainability (pp. 279-291). Springer. doi:https://doi.org/10.1007/978-981-19-7618-6_15
25. Korinek, J. and Ramdoo, I. (2017). Local content policies in mineral-exporting countries. OECD Trade Policy Papers, 209, 1-36. doi:http://dx.doi.org/10.1787/4b9b2617-en
26. Kurokochi, H., Matsuki, Y., Nakajima, Y., Fortes, M. D., Uy, W. H., Campos, W. L., & Lian, C. (2016). A baseline for the genetic conservation of tropical seagrasses in the western North Pacific under the influence of the Kuroshio Current: the case of Syringodium isoetifolium. Conservation Genetics, 17, 103-110. doi:https://doi.org/10.1007/s10592-015-0764-7
27. Leopardas, V. E. (2015). Variation in community structure of seagrass macrofauna across multiple spatial scales (PhD), Hokkaido University, Japan.
28. Llabrés, E., Mayol, E., Marbà, N., & Sintes, T. (2022). A mathematical model for inter‐specific interactions in seagrasses. Oikos, 2022(9), 1-10. doi:https://doi.org/10.1111/oik.09296
29. Mair, L., Mill, A. C., Robertson, P. A., Rushton, S. P., Shirley, M. D., Rodriguez, J. P., & McGowan, P. J. (2018). The contribution of scientific research to conservation planning. Biological Conservation, 223, 82-96. doi:https://doi.org/10.1016/j.biocon.2018.04.037
30. Masaya, Y., Nakamura, T., Tanaka, Y., Nakaoka, M., Watanabe, A., Miyajima, T., & Diego-McGlone, K. N. (2017). A dynamic model to assess mariculture-induced environmental impacts on seagrass beds along coasts of Bolinao and Anda, Philippines. Japan Geoscience Union and American Geophysical Union Joint Meeting, May 20, 2017, Makuhari Messe, Chiba, Japan. https://www.jpgu.org/meeting_e2017/
31. Mascariñas, H., & Otadoy, J. B. (2023). Potential impacts on seagrass ecosystem in Maribojoc Bay, Bohol, Philippines. Applied Ecology & Environmental Research, 21(6), 5827-5847. doi:https://doi.org/10.15666/aeer/2106_58275847
32. Mascariñas, H. J. (2022). Seagrass diversity and distribution in Maribojoc Bay, Bohol, Philippines. American Journal of Environment and Climate, 1(1), 12-19. doi:https://doi.org/10.54536/ajec.v1i1.217
33. Mascariñas, H. J. C., & Otadoy, J. B. (2023). Economic valuation of seagrass ecosystem in Maribojoc Bay, Bohol, Philippines. Biodiversitas Journal of Biological Diversity, 24(8), 4448-4456. doi:https://doi.org/10.13057/biodiv/d240826
34. Nakajima, Y., Matsuki, Y., Lian, C., Fortes, M. D., Uy, W. H., Campos, W. L., & Nadaoka, K. (2014). The Kuroshio Current influences genetic diversity and population genetic structure of a tropical seagrass, Enhalus acoroides. Molecular Ecology, 23(24), 6029-6044. doi:https://doi.org/10.1111/mec.12996
35. Nakajima, Y., Matsuki, Y., Arriesgado, D. M., Campos, W. L., Nadaoka, K., & Lian, C. (2017). Population genetics information for the regional conservation of a tropical seagrass, Enhalus acoroides, around the Guimaras Strait, Philippines. Conservation Genetics, 18, 789-798. doi:https://doi.org/10.1007/s10592-017-0927-9
36. Nakajima, Y., Matsuki, Y., Fortes, M. D., Uy, W. H., Campos, W. L., Nadaoka, K., & Lian, C. (2023). Strong genetic structure and limited gene flow among populations of the tropical seagrass Thalassia hemprichii in the Philippines. Journal of Marine Science and Engineering, 11(2), 356. doi:https://doi.org/10.3390/jmse11020356
37. Ooi, J. L. S., Kendrick, G. A., Van Niel, K. P., & Affendi, Y. A. (2011). Knowledge gaps in tropical Southeast Asian seagrass systems. Estuarine, Coastal and Shelf Science, 92(1), 118-131. doi:https://doi.org/10.1016/j.ecss.2010.12.021
38. Ordonio, A., Singson, A. G., Olmedo, A., Genova, E., & Canon, C. (2020). Community structure of the intertidal seagrass in Linaon, Cauayan, Negros Occidental, Philippines: A rapid assessment. TRIDENT, 12(1).
39. Orth, R. J., & Heck Jr, K. L. (2023). The dynamics of seagrass ecosystems: history, past accomplishments, and future prospects. Estuaries and Coasts, 46(7), 1653-1676. doi:https://doi.org/10.1007/s12237-023-01252-4
40. Pansini, A., Bosch-Belmar, M., Berlino, M., Sarà, G., & Ceccherelli, G. (2022). Collating evidence on the restoration efforts of the seagrass Posidonia oceanica: Current knowledge and gaps. Science of the Total Environment, 851, 158320. doi:https://doi.org/10.1016/j.scitotenv.2022.158320
41. Pazzaglia, J. (2022). Living with global changes: physiological and molecular mechanisms as the basis for seagrasses resilience in a changing world. (PhD), Università Degli Studi Di Trieste, Italy.
42. Phair, N. L. (2018). Vulnerability, resilience and adaptation: the future for the seagrass, Zostera capensis. (PhD), Stellenbosch: Stellenbosch University, South Africa.
43. Quevedo, J. M. D., Uchiyama, Y., & Kohsaka, R. (2023). Understanding rural and urban perceptions of seagrass ecosystem services for their blue carbon conservation strategies in the Philippines. Ecological Research, 38(4), 521-540. doi:https://doi.org/10.1111/1440-1703.12325
44. Reyes, A. G. B., Vergara, M. C. S., Blanco, A. C., & Salmo III, S. G. (2022). Seagrass biomass and sediment carbon in conserved and disturbed seascape. Ecological Research, 37(1), 67-79. doi:https://doi.org/10.1111/1440-1703.12272
45. Reyes, D. A., Mendoza, D. M., Briñas, K. B., Aquino, M. G., Tamayo, M. G., & Reyes, A. T. (2023). Assessment of seagrass beds and associated macrobenthic fauna in the intertidal areas of Dasol, Pangasinan, Philippines. Aquaculture, Aquarium, Conservation & Legislation, 16(5), 2454-2466.
46. Rossi, S. (2022). Conservation and Restoration-Large Scale Regeneration Plans. SDG 14: Life Below Water, (pp. 431–533). Cham: Springer International Publishing. doi:https://doi.org/10.1007/978-3-031-19467-2_6
47. Santacera, P. A. S., Famatid, T. A. G., Dalgado, S. P. Q., & Santander-de Leon, S. M. S. (2015). Biofouling on fish farm net enclosures, epifauna on seagrass blades, and benthic macrofauna in seagrass bed influenced by fish farm. Philippine Journal of Natural Sciences, 20(1), 5-15.
48. Saunders, M. I., Cannard, T., Fischer, M., Sheppard, M., Twomey, A., Morris, R., Bishop, M. J., Mayer-Pinto, M., Malcolm, F., Vozzo, M., Steven, A., Swearer, S. E., Lovelock, C. E., Pomeroy, A. W. M., McLeod, I., & Waltham, N. J. (2024). A roadmap to coastal and marine ecological restoration in Australia. Environmental Science & Policy, 159, 103808. doi:https://doi.org/10.1016/j.envsci.2024.103808
49. Short, F., Carruthers, T., Dennison, W., & Waycott, M. (2007). Global seagrass distribution and diversity: a bioregional model. Journal of experimental marine biology and ecology, 350(1-2), 3-20. https://doi.org/10.1016/j.jembe.2007.06.012
50. Simon, H. (2014). Case Study Research. The Oxford Handbook of Qualitative Research, 454–470. doi:https://doi.org/10.1093/oxfordhb/9780199811755.013.005
51. Snyder, H. (2019). Literature review as a research methodology: An overview and guidelines. Journal of Business Research, 104, 333–339. doi:https://doi.org/10.1016/j.jbusres.2019.07.039
52. Stankovic, M., Ambo-Rappe, R., Carly, F., Dangan-Galon, F., Fortes, M. D., Hossain, M. S., Kiswara, W., Van Luong, C., Minh-Thu, P., Mishra, A. K., Noiraksar, T., Nurdin, N., Panyawai, J., Rattanachot, E., Rozaimi, M., Soe Htun, U., & Prathep, A. (2021). Quantification of blue carbon in seagrass ecosystems of Southeast Asia and their potential for climate change mitigation. Science of the Total Environment, 783, 146858. doi:https://doi.org/10.1016/j.scitotenv.2021.146858
53. Thorhaug, A., Gallagher, J. B., Kiswara, W., Prathep, A., Huang, X., Yap, T. K., & Berlyn, G. (2020). Coastal and estuarine blue carbon stocks in the greater Southeast Asia region: Seagrasses and mangroves per nation and sum of total. Marine Pollution Bulletin, 160, 111168. doi:https://doi.org/10.1016/j.marpolbul.2020.111168
54. Tiquio, M. G. J. P. (2024). Responses of the sexual propagules of Enhalus acoroides (Lf Royle) to mariculture-derived changes in water quality. Journal of Nature Studies, 23(1), 1-17.
55. Turner, L. M., Bhatta, R., Eriander, L., Gipperth, L., Johannesson, K., Kadfak, A., Karunasagar, I., Karunasagar, I., Knutsson, P., Laas, K., Moksnes, P.-O., & Godhe, A. (2017). Transporting ideas between marine and social sciences: experiences from interdisciplinary research programs. Elementa: Science of the Anthropocene, 5, 14. doi:https://doi.org/10.1525/elementa.148
56. UN (2017). Sustainable Development Goal 14: Conserve and sustainably use the oceans, seas and marine resources. United Nations. https://sdgs.un.org/goals. Access date: 10.02.2024.
57. Unsworth, R. K. F., McKenzie, L. J., Collier, C. J., Cullen-Unsworth, L. C., Duarte, C. M., Eklöf, J. S., Jarvis, J. C., Jones, B. L., & Nordlund, L. M. (2018). Global challenges for seagrass conservation. Ambio, 48, 801-815. doi:https://doi.org/10.1007/s13280-018-1115-y
58. Vinson, N. S., Ante, S. C., Roxas, R. J. F. S., Salvio, S. M. C., Rabe, S. L. C., Torres, M. A. J., & Requieron, E. A. (2016). Correlation between water quality and seagrass distribution along intertidal zone in Sarangani Province, Philippines. Journal of Biodiversity and Environmental Sciences, 30, 30-35. ISSN: 2220-6663
59. Wagey, B. T. (2015). Morphometric study on the leaf width of the seagrass Halodule in relation to density, exposure, light, and temperature in the Central Visayas, Philippines. Asian Journal of Biodiversity, 6(1). doi:https://doi.org/10.7828/ajob.v6i1.694
60. Watai, M., Nakamura, Y., Honda, K. O., Bolisay, K., Miyajima, T., Nakaoka, M., & Fortes, M. D. (2015). Diet, growth, and abundance of two seagrass bed fishes along a pollution gradient caused by milkfish farming in Bolinao, northwestern Philippines. Fisheries Science, 81, 43-51. doi:https://doi.org/10.1007/s12562-014-0824-9
61. Waycott, M., Duarte, C. M., Carruthers, T. J. B., Orth, R. J., Dennison, W. C., Olyarnik, S., Calladine, A., Fourqurean, J. W., Heck, K. L., Hughes, A. R., Kendrick, G. A., Kenworthy, W. J., Short, F. T., & Williams, S. L. (2009). Accelerating loss of seagrasses across the globe threatens coastal ecosystems. Proceedings of the National Academy of Sciences, 106(30), 12377–12381. doi:https://doi.org/10.1073/pnas.0905620106
62. Yamamoto, T., Malingin, M. A. C. L., Pepino, M. M., Yoshikai, M., Campos, W., Miyajima, T., & Nadaoka, K. (2019). Assessment of coastal turbidity improvement potential by terrigenous sediment load reduction and its implications on seagrass inhabitable area in Banate Bay, central Philippines. Science of the Total Environment, 656, 1386-1400. doi:https://doi.org/10.1016/j.scitotenv.2018.11.243
63. York, P. H., Gruber, R. K., Hill, R., Ralph, P. J., Booth, D. J., & Macreadie, P. I. (2013). Physiological and morphological responses of the temperate seagrass Zostera muelleri to multiple stressors: investigating the interactive effects of light and temperature. PloS one, 8(10), e76377. doi:https://doi.org/10.1371/journal.pone.0076377
64. York, P. H., Smith, T. M., Coles, R. G., McKenna, S. A., Connolly, R. M., Irving, A. D., Jackson, E.L., McMahon, K., Runcie, J.W., Sherman, C.D.H., Sullivan, B.K., Trevathan-Tackett, S.M., Brodersen, K.E., Carter, A.B., Ewers, C.J., Lavery, P.S., Roelfsema, C.M., Sinclair, E.A., Strydom, S., Tanner, J.E., van Dijk, K., Warry, F.Y., Waycott, M., & Whitehead, S. (2017). Identifying knowledge gaps in seagrass research and management: an Australian perspective. Marine Environmental Research, 127, 163-172. doi:http://doi.org/10.1016/j.marenvres. 2016.06.006
65. Yoshikai, M., Nakamura, T., Tanaka, Y., Nakaoka, M., Watanabe, A., Herrera, E. C., Tsuchiya, T., Miyajima, T., San Diego-McGlone., M.L., Fortes, M.D., Blanco, A.C., Tamondong A.M. & Nadaoka, K. (2021). Modeling seagrass bed dynamics under environmental impacts of intensive mariculture activities in Bolinao and Anda, the Philippines. Estuarine, Coastal and Shelf Science, 250, 107152. doi:https://doi.org/10.1016/j.ecss.2020.107152