Ecological evaluation of marine macroalgal communities on five islands of Korea in the Yellow Sea

Abstract

Macroalgae have long been used as biological indicators of marine ecosystem health worldwide due to their ecological importance and sensitivity to environmental stress. A number of previous studies have utilized macroalgal communities in monitoring surveys of environmental conditions. This study examined the characteristics and patterns of marine macroalgal communities in the Yellow Sea off the western coast of Korea. Macroalgae were analyzed for the number of species, biomass, and coverage ratio by macroalgal type. During the study period, 82 macroalgal species (10 green algae, 17 brown algae, and 55 red algae) were identified at the five study sites, with the highest number of species found at Gwanrido and Uido (both containing 41 species) and the lowest at Daeijakdo (27 species). The average biomass (via dry weight) was 98.63 g/m2, consisting of green algae (8.39 g/m2), brown algae (35.08 g/m2), and red algae (55.16 g/m2). The dominant macroalgae species in terms of biomass were Corallina pilulifera, Sargassum thunbergii, and Ulva australis in the intertidal zones, and Botryocladia wrightii and Gelidium elegans in the subtidal zones. Richness, evenness, and diversity indices based on the biomass of abundant species were 5.08, 0.65, and 2.30, respectively, over the entire study area. Based on the evaluation of the environmental states by the community indices, overall, the Ecological Evaluation Index of macroalgae communities in the study area was marked as “Good-Moderate”, but was determined as “Moderate-Low” at several sites during summer. The results can be a direct approach in the assessment of coastal habitats in which anthropogenic as well as climate change influences persist.