Distribution patterns of saline plant communities and their associations with environmental soil factors in the Circum-Bohai-Sea saline region, China

Questions The Circum-Bohai-Sea saline region possesses abundant halophytic plant resources; however, the specific composition and distribution patterns of these communities, as well as their complex associations with soil factors, remain insufficiently understood. This study aims to elucidate how plant community distribution and species diversity are associated with soil chemical properties in this region. Location The Circum-Bohai-Sea saline region, China. Methods We conducted extensive sample surveys across 245 sites. The data were analyzed using multiple comparisons, Two-Way Indicator Species Analysis (TWINSPAN), and Canonical Correspondence Analysis (CCA) to examine the relationships between plant species distribution and key soil chemical factors, including soil pH, total soluble salt (S), total nitrogen (TN), total phosphorus (TP), soil organic matter (SOM), and specific ions K + , Na + , Ca 2+ , Mg 2+ , Cl - , SO 4 2- , and HCO 3 - ). Results (1) A total of 145 species belonging to 107 genera and 43 families were recorded. These were classified into six communities: A ( Bolboschoenus planiculmis + Suaeda glauca ); B ( Typha orientalis + Bolboschoenus planiculmis ); C ( Phragmites australis - Suaeda glauca + Suaeda salsa ); D ( Suaeda salsa - Phragmites australis + Imperata cylindrica ); E ( Ambrosia artemisiifolia - Cynodon dactylon + Tournefortia sibirica ); and F ( Salsola komarovii - Tournefortia sibirica ). (2) CCA ordination showed that plant species distribution was associated with variation in S, TN, K + , Na + , Ca 2+ , Mg 2+ , SO 4 2− , and Cl − . (3) The diversity indices were significantly negatively correlated with S and the concentrations of the measured water-soluble ions. Conclusions Our findings indicate that soil salinity and the concentrations of certain water-soluble salt ions were important environmental factors associated with lower species diversity and differences in community composition. This study provides baseline ecological data that may inform vegetation restoration and soil ecological improvement in coastal saline–alkali lands.