Coastal Reef and Seagrass Monitoring for Coastal Ecosystem Management

Abstract

The growth of human occupations in coastal areas and climate change impact have changed the dynamics of seagrass cover and accelerated the damage to coral reefs globally. For these reasons, coastal management measures need to be developed and renewed to preserve the state of seagrass beds and coral reefs. An example includes the improvement of spatial and multitemporal analyses. This study sought to analyze changes in seagrass cover and damages to coral reefs in Gili Sumber Kima, Buleleng Regency, Bali based on multitemporal Sentinel 2A-MSI imagery. The algorithms of a machine learning, Random Forest (RF), and a Support Vector Machine (SVM) were used to classify the benthic habitats (seagrass beds and coral reefs). Also, a change detection analysis was performed to identify the pattern and the extent to which seagrass beds had changed. The multispectral classification of, particularly, coral reefs was used to explain the condition of this benthic habitat. The results showed +-70% to +-83% accuracies of estimated seagrass cover, and the change detection analysis revealed three directions of change, namely an increase of 27.9 ha, a decrease by 86 ha, and a preserved state in 157 ha of seagrass cover. The product of coral reefs mapping had an accuracy of 42%, and the coral reefs in Gili Sumber Kima were split almost equally between the good (1505 ha) and damaged ones (1397 ha). With the spatial information on seagrass beds and coral reefs in every region, the ecological functions of the coast can be assessed more straightforwardly and appropriately incorporated as the basis for monitoring the dynamics of resources and coastal area management.

Teknologi Elektrolisis untuk Mempercepat Pembentukan Batu Kapur dalam Pertumbuhan Terumbu Karang

“…Beberapa faktor yang menyebabkan kerusakan terumbu karang di antaranya adalah meningkatnya okupasi manusiadi wilayah pesisir dan dampak perubahan iklim yang telah mengubah dinamika batu kapur sehingga mempercepat kerusakan terumbu karang secara global [4], pemanasan global, asam laut, peningkatan suhu air laut, pencemaran, penangkapan ikan yang tidak bertanggung jawab, dan aktivitas pariwisata yang tidak terkelola dengan baik. Selain itu, terumbu karang juga terancam oleh praktek-praktek eksploitasi seperti penangkapan ikan secara berlebihan, penggunaan bahan peledak dalam penangkapan ikan, pengambilan bahan-bahan dari terumbu karang untuk keperluan industri [5], penambangan timah di laut [6] serta eksploitasi kerang [7].…”

High-Resolution Seagrass Species Mapping and Propeller Scars Detection in Tanjung Benoa, Bali through UAV Imagery

“…In response to these issues, remote sensing techniques are being employed due to their high accuracy when detecting seagrass distribution [Yang & Huang, 2011]. A study by Lazuardi et al [2021] used images derived from Sentinel-2A MSI for the mapping of benthic habitat in Gili Sumber Kima, Bali, Indonesia and they classified seagrass cover with great accuracy, approximately 70% for the 2015 map and 83% for the 2019 map. This suggests that satellite images may well be utilized as a data source to accurately identify objects in the ocean.…”