Fine‐scale distribution of tropical seagrass beds in Southeast Asia

Sudo, Kenji; Nakaoka, Masahiro

doi:10.1111/1440-1703.12137

Cited by 8 publications

(9 citation statements)

References 21 publications

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“…An increase in chlorophyll-a concentration may indicate the presence of an increased phytoplankton population in the water which may result in less light penetrating the water and reaching the seagrass beds. Fortunately, results from MODIS (2002( -2020( ), and SeaWIFS (1997, as shown in Figure 8, indicate a minimal increase in chlorophyll-a concentration in Busuanga with only 0.00013 mg/m 3 and 0.000037 mg/m 3 per decade, respectively. Because of lack of observation data, comparison of chlorophylla concentration between MODIS and SeaWIFS were examined (Figure 9).…”

Section: Chlorophyll-a Concentrationmentioning

confidence: 99%

“…Since 1980, seagrasses have been declining globally at a rate of 110 square kilometers per year and 29% of their known extent has disappeared since 1879 when they were first recorded (Waycott et al, 2009). However, these values may have been underestimated because the study did not include Southeast Asia, which is the global hotspot of seagrasses, because of lack of data (Sudo and Nakaoka, 2020). Recent analysis of seagrass beds in Southeast Asia show seagrass to be declining at an average rate of 10.9% per year since the late 1990s (Sudo et al, under review).…”

Section: Introductionmentioning

confidence: 99%

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Time Series Analysis for Monitoring Seagrass Habitat and Environment in Busuanga, Philippines Using Google Earth Engine

Tamondong

Nakamura

Quiros

et al. 2021

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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Abstract. Seagrasses are marine flowering plants which are part of a highly productive coastal ecosystem and play key roles in the coastal processes. Unfortunately, they are declining in area coverage globally, and seagrass losses can be attributed to climate change such as sea-level rise, increase in sea surface temperature, and decrease in salinity, as well as human-related activities. The objective of this research is to assess the historical changes in the seagrass habitat and environment of Busuanga, Philippines using time series data available in the Google Earth Engine (GEE) platform. These include satellite data such as MODIS, Landsat 5, 7, and 8, and SeaWIFS. Reanalysis data such as HYCOM was also utilized in this research. Results from HYCOM data show that there has been a 0.0098 °C increase in the sea surface temperature per decade in Busuanga while MODIS data indicates an increase of 0.0045 °C per decade. Moreover, HYCOM data also shows an overall average of 0.76 mm in sea surface elevation anomaly and a decreasing trend in salinity values at 0.0026 psu per decade. Chlorophyll-a concentration has a minimal increase based on results from MODIS and SeaWIFS. Aside from changes in water parameters, changes in the land also affect seagrasses. Forest loss may cause increased siltation in the coastal ecosystem which can lead to seagrass loss. Based on the results of Landsat satellite image processing, there has been forest cover loss in Busuanga with the highest loss occurring in 2013 when super typhoon Yolanda ravaged the island. Lastly, results from the linear spectral unmixing of 778 Landsat images from 1987–2000 show that the average percent cover of seagrasses in Busuanga were declining through the years.

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Section: Chlorophyll-a Concentrationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Time Series Analysis for Monitoring Seagrass Habitat and Environment in Busuanga, Philippines Using Google Earth Engine

Tamondong

Nakamura

Quiros

et al. 2021

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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“…In very recent years, the study trends of phycology and distribution of different seagrass species were discussed [77], and one new distribution of seagrass was reported [62]. Sudo and Nakaoka [78] described the distribution of South Asian seagrasses. The seagrass coverage [79] and meadow impact [80] in the Malaysian state of Sabah was reported recently.…”

Section: Biology and Distributionmentioning

confidence: 99%

Trends in Seagrass Research and Conservation in Malaysian Waters

Kamal

Asif

Idris

et al. 2023

J.Trop.Life.Science

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The seagrass ecosystems found in the marine and coastal areas, with substantial eco-nomic and ecological services and span all over the globe excluding the Antarctic region. The Coral Triangle and Southeast Asia are recognized as a worldwide hotspot of seagrass species and habitats, encompassing 10-21 species of seagrass in every na-tion, although the study, understanding, and quantity of publications on seagrass eco-systems are rather limited in the region, including Malaysia. Malaysia contains 18 seagrass species from three families, which occupy 16.8 km2of coastal area, where the study and discovery of seagrass species and meadows began in 1904 with the re-port of Beccari. All of the published papers reviewed reported on Malaysian seagrass-related research, which was divided into nine topic groups: biology and distribution, carbon sequestration, fauna, remote sensing, impact and pollution genetic study, res-toration, microbiological investigation, and others. The extensive study of the seagrass ecosystem began in 1993, and we have identified 183 published papers from Scopus, 141 publications from Web of Science, and 42 from Google Scholar. However, the average trend of the number of publications from 1993 to 1999 was 0.71 ± 0.36, while from 2000 to 2022 was 7.70 ± 1.16 followed by the average trend of the yearly number of publications was 6.78 ± 1.08. The highest number of publications was found on faunal categories (43.17%), followed by biology and distribution (21.85%). The num-ber of articles that were published on Malaysian seagrass meadows each year has been discovered to be rising, which indicates that the trends in seagrass study and publish-ing were progressively garnering the attention of researchers, academics, and the gov-ernment. However, to better understand the sustainable ecology and ecosystem ser-vices provided by seagrass habitats, an emphasis on certain research niches, such as the genetic study of flora and fauna in seagrass meadows, microbial ecology, and res-toration as well as conservation of seagrass species might be helpful.

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“…In total, we compiled more than 195 scientific papers and reports published after 2000. The data collected by 2018 were published as a data paper (Sudo and Nakaoka, 2020). In this paper, we added 88 literature and 719 data published by 2020 that was not included in the data paper (Supplementary Table 1).…”

Section: Data Collectionmentioning

confidence: 99%

Distribution, Temporal Change, and Conservation Status of Tropical Seagrass Beds in Southeast Asia: 2000–2020

et al. 2021

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Although Southeast Asia is a hotspot of global seagrass diversity, there are considerable information gaps in the distribution of seagrass beds. Broad-scale seagrass distribution has not been updated in the global seagrass database by UNEP-WCMC since 2000, although studies on seagrasses have been undertaken intensively in each region. Here we analyze the recent distribution of tropical seagrass beds, their temporal changes, causes of decline and conservation status in Southeast Asia (plus southern mainland China, Taiwan and Ryukyu Island of Japan) using data collected after 2000. Based on the 195 literature published since 2000, we identified 1,259 point data and 1,461 polygon data showing the distribution of seagrass beds. A large discrepancy was found in the seagrass bed distribution between our updated data and the UNEP-WCMC database, mostly due to inaccurate and low resolution location information in the latter. Temporal changes in seagrass bed area analyzed for 68 sites in nine countries/regions demonstrated that more than 60% of seagrass beds declined at an average rate of 10.9% year–1, whereas 20% of beds increased at an average rate of 8.1% year–1, leading to an overall average decline of 4.7% year–1. Various types of human-induced threats were reported as causes for the decline, including coastal development, fisheries/aquaculture, and natural factors such as typhoons and tsunamis. The percentage of seagrass beds covered with existing marine protected areas (MPAs) varied greatly among countries/regions, from less than 1% in Brunei Darussalam and Singapore to 100% in southern Japan. However, the degree of conservation regulation was not sufficient even in regions with higher MPA coverage. The percentage of seagrass beds within EBSAs (Ecologically and Biologically Significant Area determined by the Convention of Biological Diversity) was higher than that within MPAs because EBSAs cover a greater area than MPAs. Therefore, designating EBSAs as legally effective MPAs can greatly improve the conservation status of seagrass beds in Southeast Asia.

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Fine‐scale distribution of tropical seagrass beds in Southeast Asia

Cited by 8 publications

References 21 publications

Time Series Analysis for Monitoring Seagrass Habitat and Environment in Busuanga, Philippines Using Google Earth Engine

Time Series Analysis for Monitoring Seagrass Habitat and Environment in Busuanga, Philippines Using Google Earth Engine

Trends in Seagrass Research and Conservation in Malaysian Waters

Distribution, Temporal Change, and Conservation Status of Tropical Seagrass Beds in Southeast Asia: 2000–2020

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