赣抚平原农田沟渠植物多样性及生态化学计量特征研究-生态学专业论文.docxVIP

ABSTRACT  PAGE 6 ABSTRACT Ditches are important corridor of farmland landscape ecosystem and plants grown in ditches play an important role in mataining the biodiversity and ecological security of farmland ecosystem. In this study, we explored the floristic composition, diversity and mechanism of community construction, as well as stoichiometry of leaf C, P and N of plants grown in farmland ditches of GanFu plain through investigation of typical functional triats and measurement of total N, P, C content of farmland ditch associated plants from substantial community plots in these plains. The main obtained results are as follows: Analysis of the floristic characteristic and geographic distribution of farmland ditch associated plants in GanFu plain region indicated that there were 127 species of plants in the farmland ditches we studied, belonging to 56 families and 115 genera, including 13 invasive species. Specifically, plants belonging to big family accounted for 4% of the total, with composition of rich species. On the contrary, small family contained less genuses than the big family did, taking 96% of the total plants. The geographical distibutions of genera were complicated and the R/T value was 1.61, implying a nature close to that of the tropic. Floristic charatersitic was examined with cluster analysis and the results indicated that ecological system of farmland ditches in GanFu plain region was similar to wetland as well as river ecosystem, partly proved to be a special type of wetland ecology system. Ditches were classified based on their width and the flow patterns of water. Community of Leptochloa chinensis (L.) Nees was the most common in these ditches. Diversity index of α and β were calculated from different grades of ditches of three plots in GanFu plain. Analysis showed that ditches of the first grade contained the greatest number of individuals, with the fourth grade the smallest. The third grade ditches exhibited the greatest species richness an