| Chongming Island, located at the estuary of the Yangtze River, 121°09'～ 121°54'E, 31°27'～31°51'N, is one of the biggest islands that formed with alluviation, most of which is governed by Shanghai. Chongming Island is prevalent in agriculture because of its subtropics monsoon climate, distinct four seasons, never insufficient rainfall and planus land. Since the island formed, it has been enlarging its domain in the past 1 000 years, which makes Chongming a specific islet. The bryophytes in the island has never been focused on and investigated systematically, what's less is the quantitive research on the diversity of the species. Through the research, the bryophytes species composition in Chongming Island could been known, which can supply basic information for bryophytes research in China, especially for island species. On the other hand, the results can also be referred when the problems about vegetative ecological system occur in the course during development of the island.The paper includes the researches to species diversity and ecosystem diversity of bryophytes in Chongming Island. The results were as followed:1. Based on two times' investigations, 1157 specimens at the area were collected. A total of 37 moss species belonging to 15 genera of 7 families and only 1 liverwort were identified. Among them, 13 moss species in 11 genera of 5 families were newly recorded in Shanghai.2. Most species were small, humicolous acrocarpous mosses, almost no other base materials. There were only 9 species owned by both Chongming Island and another adjacent island, Jinshan Island. It was the way the land utilized that cause the difference.3. It was shown that, by the statistics on the distribution of the mosses in 5 types of landscapes, Physcomitrium sphaericum and P. courtisii is the prevalent community in farm. The same to Physcomitrium sphaericum in woodland, Ditrichum pallidum in village, Weissia controversa and Bryum algovicum in wasteland, though not so prominent, as well as Tortula muralis and Bryum algovicum in roadside. The pattern of the distribution in the landscapes was related to the genealogical classification of the mosses in some degree.4. Of the 5 types of landscapes, woodland had the highest indexes for Shannon-Wiener, Simpson and Pielous, which were respectively 2.748, 0.9202 and 0.854. As for the lowest, wasteland, were 1.948, 0.7717 and 0.650. The indexes for diversity of village were of most convergence, while those in woodland were discrete among different sites.5. On niche width, some mosses, including Bryum algovicum, Tortula muralis, Physcomitrium sphaericum, Weissia controversa and Physcotnitrium courtisii, were all with Shaanon-Wiener indexes higher than 3.0. The pairs of species with high level of niche overlap were always proximate in genealogical classifications, which indicated that their accommodation to the environment resembled. In the view of niche, the distribution of the mosses in Chongming Island changed little between the seasons.6. The result of TWINSPAN and DCA showed that disposition of the species related to the types of landscapes. But no relationship could be seen while TWINSPAN and DCA were used to analyze the sites. The sites, representing heterogeneous landscapes, didn't disclose any characteristic on the richness and abundance of the species, which illustrated that environment factors of the landscapes were of approximation.
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