Studies On Flora And Ecology Of Bryophytes In Suzhou And Yixing City, Jiangsu Province, China

Suzhou and Yixing not only are the most important cities in the delta of Yangtz River and Tai Lake area, but also are well known for their tourism and cultural history. There is no special research focusing on biodiversity and ecology of bryophytes in the two cities. Based on field investigation and sampling, by means of analysis methods of biodiversity and quantitative ecology, the flora and ecology of bryophytes in Suzhou and Yixing were systematically studied for the first time. The main results are as follows:1. Characteristics of bryophytes diversity in Suzhou and Yixing(1) Based on the investigation and identification of more than 2500 specimen of bryophytes from Suzhou, 154 species in 73 genera and 33 families of bryophytes in Suzhou were reported. Of these, 13 species, belonging to 10 genera and 13 families, were liverworts. 141 species, belonging to 25 genera and 63 families, were mosses. And 33 families, 65 genera and 118 species of bryophytes in Yixing were recorded, including 9 families 9 genera 13 species of liverworts and 24 families 56 genera 105 species of mosses. Six species and three genera are new to Jiangsu province. The characteristics of the habitat and dominant families, genera, species were also analyzed.(2) Compared with composition of the bryophytes in Shanghai, Wuxi and Hangzhou, the percentages of genus similarity between Suzhou, Yixing and Wuxi were the highest, owing to their similar geography location of bordering on the Tai Lake and the similar climate characteristics. The comparison results showed that Pottiaceae, Bryaceae, Thuidiaceae, Brachytheciaceae and Hypnaceae were the common dominant families and Brachythecium was the common genus among the five cities.2. Floristic analysis of bryophytes in Suzhou and Yixing(1) The bryoflora in Suzhou and Yixing could be divided into ten and eight geographical elements respectively. Of those, they both had a dominant majority of east Asian elements (36.59%, 46.15%) and a proportion of temperate elements(24.39%, 26.37%), which reflected a typical East Asian trait and obvious temperate characteristic. It implied that the bryoflora of Suzhou and Yixing had a transitional characteristic from sub-tropic to northern temperate zone.(2) The comparison of R/T value in the five cities reflected the bryoflora of Suzhou, Shanghai and Wuxi were extreme similar and the value of Yixing was a little lower, which showed similar temperate characteristic.The R/T value of Hangzhou was obviously higher than the others. In general, the R/T value matched with the latitude of the five cities.3. Characteristics of bryophytes in Suzhou Gardens(1) Based on the field investigation in 11 major gardens of Suzhou, 90 species in 42 genera and 23 families of bryophytes were reported. Of these, 4 species, belonging to 3 genera and 3 families, were liverworts. 86 species, belonging to 20 genera and 39 families, were mosses. Compared with normal cities and gardens, the proportion of epixylophyte(53.3%)and petrophyte(40.0%)species in Suzhou Gardens was higher. It was characterized by 36 species of bryophytes on rockry and 22 species on bonsai recorded in Suzhou Gardens.(2) The dominant families and genus were mainly anti-jamming species with wide niche breadth. Eleven gardens could be divided into 5 groups by cluster analysis based on bryophyte diversity, related to their area, patterns and habitats. Studies and applications of bryophytes in gardens should be enhanced.4. Ecological studies on bryophytes of the Karst caves in Yixing(1) Based on investigating and sampling the coverage of bryophytes in four sites of Karst caves in Yixing, 20 families, 35genus, 59species of bryophytes were studied by ecology analysis. The abundance index indicated that the diversity of bryophytes had less correlation with the horizontal distance away from the mouth of the cave, but the diversity of Zhanggong Cave was highly related to the vertical distance.(2) By combining the coverage data of the bryophytes in five plots, it could be discovered that the dominant families changed from Hypnaceae(Taxiphyllum), Pottinales to Anomodon and Thuidiaceae with the increase of the distance from the mouth of cave and Brachytheciaceae held a clear dominance on every distance grades.(3) Detrended Correspondence Analysis (DCA) was used to analyze the distribution patterns of bryophytes in the caves. The result showed that the 59 bryophytes could be divided into 4 groups, which corresponded the communities of region 0-3m, 4-9m, 10-14m and 15m above, respectively. As the matter of fact, 15m from the mouth of cave might be regarded as the"isolating line"which were influenced by some physical factors such as the light , humidity, pH and temperature.In addition, based on literature available to us, an annotated checklist of mosses in Jiangsu province (including Shanghai) was completed. 354 species, 1 subspecies and 15 varieties in 131 genera and 38 families were accepted as valid taxa. The checklist provided the useful information for future biodiversity study in Jiangsu province and China.