Abstract:
To further assess the distribution of seagrass resources in the coastal waters of Hainan Island, identify seagrass diversity hotspots, and analyze their spatial association with marine ranching. This study targeted three dominant tropical seagrass species:
Enhalus acoroides,
Thalassia hemprichii, and
Halophila ovalis. Three categories of data were adopted in the analysis. The datasets include field survey data collected from 2021 to 2023, historical species distribution records, and 20 marine environmental parameters. We first conducted Spearman correlation analysis and variance inflation factor (VIF) screening to filter collinear environmental variables. Afterwards, we constructed a maximum entropy (MaxEnt) model combined with a stacking ensemble algorithm. This model was applied to predict the potential uitable habitats of the three seagrass species and quantify the contribution of each environmental variable. We further carried out spatial overlay analysis to identify seagrass diversity hotspots and calculate their spatial overlap with both existing and planned marine ranches. The MaxEnt model exhibited outstanding predictive performance, with all AUC values higher than 0.8. The high-suitability areas of
E. acoroides and
T. hemprichii clustered along the eastern coast of Hainan Island. In comparison, highly suitable habitats for
H. ovalis were distributed in shallow waters near the northeastern and southwestern coasts. Among the three species,
H. ovalis possessed the largest total suitable area of 5,994.23 km
2. Dissolved oxygen and annual mean water temperature were the major environmental factors affecting the distribution of
E. acoroides and
T. hemprichii. Annual mean water temperature and salinity were the key limiting factors that determined the spatial pattern of
H. ovalis. Seagrass diversity hotspots presented obvious spatial overlap with existing and planned marine ranches in eastern Hainan. The results of this research can offer scientific support for seagrass conservation, restoration site selection, and the optimized spatial planning of marine ranches.
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