Abstract: From August 2010 to August 2011, an investigation was conducted on the macroalgae in the intertidal zone of Shengsi Archipelago. A total of 114 macroalgae species belonging to 53 genera of 3 phyla were identified, among which, 75 species of 33 genera belonged to Rhodophyta, 21 species of 13 genera belonged to Phaeophyta, and 18 species of 7 genera belonged to Chlorophyta. Rhodophyta, Phaeophyta, and Chlorophyta accounted for 65.8%, 18.4%, and 15.8% of the total, respectively. The macroalgae had the largest number (87 species) in Gouqi Island, followed by in Jinping Island (42 species), and in Maguan Island (26 species). 79.8% of the macroalgae were distributed in low intertidal zone, and 62.3% distributed in middle intertidal zone. The similarity value of the algae composition between the low and middle intertidal zone, the middle and high intertidal zone, and the low and high intertidal zone was 0.57, 0.15, and 0.06, respectively. The species number of macroalgae changed with season and in the order of summer (57 species) > winter (55 species) > spring (52 species) > autumn (46 species). The dominant species also differed with season. The dominant species in spring were Undaria pinnatifida, Ulva pertusa, Ulva linza, and Pachymenia carnosa, those in summer were Sargassum vachellianum,Chondria crassicaulis,Sargassum thunbergii and Alga eucheumae, those in autumn were Gracilaria verrucosa, Gigartina intermedia suring, Sargassum thunbergii, and Ulva lactuca, and the dominant species in winter were Scytosiphon lomentarius, Porphra suborbiculate, Sargassum thunbergii, and Polysiphonia japonica.

Key words: spatial pattern, vegetation NDVI, climate change, human activity, Xinjiang.