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Satellite image analysis reveals changes in seagrass beds at Van Phong Bay, Vietnam during the last 30 years

Authors :
Khin Lau
Xuan-Vy Nguyen
Lawrence M. Liao
Trong-Thach Vo
Source :
Aquatic Living Resources. 33:4
Publication Year :
2020
Publisher :
EDP Sciences, 2020.

Abstract

Seagrass meadows are fragile ecosystems in the coastal zone. Natural disasters, land reclamation and various human activities seem to exert negative impacts on the distribution and biological performance of seagrass beds in Vietnam. In this present study, satellite Landsat TM/OLI image analysis was applied to determine changes in seagrass distribution at Van Phong Bay, Vietnam in the last 30 years. The maximum likelihood decision rule was used to extract seagrass bed distribution data. The error matrix using the in situ reference data for HLM image classification was 81–95% accurate, and Kappa coefficients were between 0.72 and 0.91. The results indicated that 186.2 ha (or 35.8%) of the original seagrass beds were lost in the last three decades at Van Phong Bay, and decline in each specific site may have been due to different causes. Typhoons may have caused the loss of seagrass beds at open-sea sites whereas aquaculture activities, excavation and terrigenous obliteration may have caused such losses in protected sites.

Details

ISSN :
17652952
Volume :
33
Database :
OpenAIRE
Journal :
Aquatic Living Resources
Accession number :
edsair.doi...........2e51b3a920e435d9e1536b44ea55ab46
Full Text :
https://doi.org/10.1051/alr/2020005