Most tidal areas in sihcao are distributed near the outlet to the sea where the salt content is low and water flows slowly . therefore , they are ideal habitats for animals and plants and nourish a wide variety of bathos , such as fish , shrimps and shells . when low tide comes , we can see flocks of birds and packs of fiddler crabs come seeking food in these areas 四草地区的潮间带多分布于出海口，因为此地位于河海交界，盐分较低、水流缓慢，适合动、植物栖息，孕育丰富的鱼虾贝类等底栖生物，退潮时经常吸引成群的鸟类及招潮蟹前来觅食。
Review russian history of western security maintenance , we can conclude that there are four action modes , including ( occupying strategic anportant places , scrambling for seaport , building up safety belt , and avoiding two - side campaign . we also can analyse the base of four ideologies including : " moscow - the third rome , " messianic , legitimism and conservation , pan - slavism , and orthodox churh united completcd , which influence russia western security policy nato ( north atlanhc treaty organization ) is the most dripoopt part of russia western security environment 回顾俄罗斯维护西部安全的历史，可以总结出俄罗斯维护西部安全的四种行为模式，即抢占战略要地、争夺出海口、构造安全带和避免两线作战，分析影响西部安全政策的四种意识形态基础： “莫斯科? ?第三罗马”和救世主说、正统主义和保守主义、泛斯拉夫主义以及全东正教统一思想。
