Abstract: We used the habitat suitability index (HSI) model to determine the habitat suitability of Sargassum muticum in Lidao bay, Shandong Province. Eight environmental factors, including temperature, salinity, depth, turbidity, sediment, inorganic nitrogen concentration, phosphate concentration, distance from seaweed bed, were used as input variables for HSI model. The weight of each factor was defined by the analytic hierarchy process (AHP). We implemented the distribution of S. muticum suitable habitat along the coast of Lidao bay with the HSI model, based on the investigation of the environmental factors in spring and autumn 2018. The results showed that most of the S. muticum natural habitats were identified as excellent habitat and suitable habitat, accounting for 14.2% in spring and 18.6% in autumn. The distribution of habitat hierarchies varied across seasons, while habitat hierarchies showed spatial intersections in different seasons. There were significant seasonal differences in the factor suitability indices of temperature and phosphate concentration, which accounted for the seasonal HSI variations of S. muticum in Lidao bay. The S. muticum HSI model could be used to detect the habitat hierarchies distribution of S. muticum, and also to find its potential suitable habitat, which could provide a reference for future resource conservation and artificial proliferation of S. muticum.

Key words: Sargassum muticum, habitat suitability, habitat suitability index (HSI), habitat hierarchy, spatial distribution, resource conservation