The construction of ecological barriers and ecological security patterns is an important way of maintaining regional ecological security in landscape ecology. However, there is still no consensus on the concept and connotation of ecological barriers, and the zoning and adaptive management of ecological sources are rarely considered in the construction of ecological security patterns. This study uses the terrestrial ecosystem of Bohai Bay, China as a study area, and the identification and zoning of ecological sources in the ecological security pattern are achieved by combining an ecosystem service assessment with an ecological risk assessment, and on this basis, ecological barriers are identified to optimize the structure and function of ecological sources. The minimum cumulative resistance model is used to identify ecological corridors and ecological strategic nodes and to construct an ecological security pattern based on the modified ecological sources. The results demonstrate that firstly, 2873.25 km² was identified as the ecological source, accounting for 14.28% of the total. Secondly, there are three large ecological barrier zones and nine ecological barrier cells with a total area of 1173.06 km², accounting for 40.83% of the ecological sources. Thirdly, a total of 35 ecological corridors were extracted, and 32 ecological strategic nodes were marked, mainly distributed at the intersection and branches of important ecological corridors. An ecological security pattern construction system was formed with the collection of ecological source selection, ecological barrier identification, ecological resistance surface construction, and ecological corridor extraction. Fourthly, the concept and connotation of ecological barriers was analyzed, and the complementary relationship between ecological barriers and ecological security patterns in terms of structure and function is discussed. This study enriches the definition and connotation of ecological barriers, provides a new framework for identifying the ecological security patterns, and provides scientific guidance for ecological protection and management in coastal areas.

A Gram-stain-negative, aerobic, chitin-degrading, motile bacterial strain with a single polar flagellum, designated XS-10^T, was isolated from saline soil sampled from the rhizosphere of Suaeda salsa, Tumd Right Banner, Inner Mongolia, PR China. Strain XS-10^T grew at 10–40 °C (optimum, 35 °C), pH 5.0–9.0 (optimum, pH 8.0) and 0–12.5% NaCl (optimum 2.0 %). The phylogenetic analysis based on both the 16S rRNA gene and the phylogenomic tree revealed that strain XS-10^T formed a clade with Sphingomonas turrisvirgatae MCT13^T and Sphingomonas koreensis JSS-26^T, sharing 98.4 and 97.5 % 16S rRNA gene similarities to S. koreensis JSS-26^T and S. turrisvirgatae MCT13^T, respectively. Spermidine and Q-10 were the major polyamine and the major respiratory quinone, respectively. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, sphingoglycolipid, two unidentified lipids and an unidentified aminophospholipid. The major fatty acids were summed feature 8 (C_18 : 1  ω7c and/or C_18 : 1  ω6c), C_16 : 0 and C_17 : 1  ω6c. The genome of strain XS-10^T consisted of a 4 154 291 bp chromosome with a DNA G+C content of 65.5 mol%. The average nucleotide identity, average amino acid identity and digital DNA–DNA hybridization values of strain XS-10^T with S. turrisvirgatae MCT13^T and S. koreensis JSS-26^T were 77.8 and 78.6 %, 75.9 and 76.3 %, and 22.0 and 22.9 %, respectively. Based on the phylogenetic, phenotypic, and genotypic characteristics, strain XS-10^T is considered to represent a novel species of the genus Sphingomonas , for which the name Sphingomonas suaedae sp. nov. is proposed. The type strain is XS-10^T (=CGMCC 1.17078^T=JCM 33850^T).

A Gram-negative, strictly aerobic, gliding motility, none-spore forming, yellow, rods bacterial strain, designated XS-5^T, was isolated from rhizosphere soil of Suaeda salsa, in Tumd Right Banner, Inner Mongolia, PR China. A phylogenetic tree based on the 16S rRNA gene sequences and the phylogenomic tree both showed that strain XS-5^T clustered with Flavobacterium beibuense F44-8^T (shared 97.2 % of 16S rRNA gene similarity) and Flavobacterium rakeshii FCS-5^T (97.6 %), and shared <96.0 % of 16S rRNA gene similarities with all other type strains. Strain XS-5^T contained MK-6 as the major respiratory quinone. Its major polar lipids were phosphatidylethanolamine, an unidentified aminolipid and an unidentified lipid; and the major fatty acids were iso-C_15 : 0, iso-C_17 : 0 3-OH, C_16 : 0, iso-C_15 : 0 3-OH, Summed feature 3 (iso-C_15 : 0 2-OH and/or C_16 : 1  ω7c), and Summed feature 9 (iso-C_17 : 1  ω9c and/or C_16 : 0 10-methyl). The genome consisted of a 3 985 855 bp circular chromosome, with a G+C content of 37.9 mol%, predicting 3616 coding sequences genes, 45 tRNA genes and three rRNA operons. The average nucleotide identity, amino acid identity and digital DNA–DNA hybridization values of strain XS-5^T to F. beibuense F44-8^T and F. rakeshii FCS-5^T were 79.2 and 79.2 %, 81.7 and 81.6 %, 22.3 and 22.2 %, respectively. The results of phylogenetic, physiological and biochemical tests allowed the discrimination of strain XS-5^T from its phylogenetic relatives. Flavobacterium alkalisoli sp. nov. is therefore proposed with strain XS-5^T (=CGMCC 1.17077^T=KCTC 72459^T) as the type strain.