Biodiversity, Zonation, and Conservation Status of Macrobenthic Algae in Barangay Sawang, Sibutad, Zamboanga Del Norte: An Ecological Assessment

Abstract

This study assessed the biodiversity, spatial distribution, and conservation status of macrobenthic algae in Barangay Sawang, Sibutad, Zamboanga del Norte, Philippines. A descriptive-exploratory research design was employed and field data was collected using transect-quadrat sampling. A total of 20 macrobenthic algal species were identified, consisting of 10 green algae (Chlorophyta), five brown algae (Phaeophyta), and five red algae (Rhodophyta). Five species dominated the algal community: Padina pavonica (Linnaeus) Thivy 1960, Amphiroa beauvoisii J.V. Lamouroux 1816, Sargassum hemiphyllum (Turner) C. Agardh 1820, Boergesenia forbessi (Harvey) Feldmann 1938, and Canistrocarpus cervicornis (Kützing) De Paula & De Clerck 2006, with the most dominant species to be P. pavonica with 57.89% cover and A. beauvoisii with 52.96% cover. Spatial analysis revealed that Barangay Sawang, Sibutad exhibited moderate species diversity, while the low intertidal zone served as the primary ecological refuge. A clear inner-to-outer bay gradient in seaweed cover was observed. Conservation assessments indicated that most recorded species are classified as Data Deficient (DD), highlighting significant knowledge gaps regarding their population trends and vulnerability. Furthermore, socio-economic surveys of local residents revealed the absence of macroalgal harvesting or utilization, despite the presence of considerable macroalgal biomass in the area. Overall, this study provides baseline ecological information that may support local marine resource management, biodiversity conservation initiatives, and climate change adaptation strategies for coastal communities in Barangay Sawang, Sibutad, Zamboanga del Norte.