Decadal dynamics and challenges for seagrass beds management in Cu Lao Cham Marine Protected Area, Central Vietnam

Seagrass beds in central Vietnam plays an important role in the aquatic ecosystem. The area of seagrass beds in Cu Lao Cham Marine Protected Area (MPA), central Vietnam, has been reported to be declining in recent years. However, there has not been any study on assessing the changes in the area of seagrass beds in Cu Lao Cham MPA, especially by the application of remote sensing technology for evaluating temporal and spatial changes. The aim of this study is to establish the current status and document historical changes using maps of seagrass area in Cu Lao Cham MPA, central Vietnam, during the period of 2003–2017. This is the first study on assessing the temporal and spatial changes in the area of seagrass beds in central Vietnam using remote sensing technology. The study integrated field surveys, satellite remote sensing and GIS methods to analyse ALOS AVNIR-2 and Landsat satellite image data during the period of 2003–2017. The Kappa coefficients and overall accuracies of the years 2003, 2010 and 2017 were generally higher than 89% and 0.83, respectively, in all cases. Seagrass beds have mainly distributed near small islands such as Hon La, Hon Tai and Hon Dai. In particular, seagrass beds have almost disappeared at Bai Ong and Bai Huong in April 2017. In the period of 2003–2017, the area of the seagrass bed experienced significant changes. The seagrass area loss was 40.17 ha, and it gained 58.6 ha in the period of 2003–2010. In the period of 2010–2017, the loss of seagrass area was 68.76 ha, and the new addition was 7.27 ha. The study has identified a number of impacts of declining seagrass areas including marine pollution, changes in natural conditions and some other direct impacts from human activities and tourism. The results of this study could contribute to conservation of seagrass resources and sustainable livelihood development for the local community.