Structure and dynamics of natural populations of the endangered plant Euryodendron excelsum H. T. Chang

Abstract

Euryodendron excelsum H. T. Chang is an endangered species of the family Theaceae endemic to China. It is listed as a second-class endangered plant for state protection in the Red Data Book of Plants in the People’s Republic of China. The species is restricted to one remnant population with less than 200 individuals in the Bajia region of Yangchun County, Guangdong Province. This study was conducted to determine the status of the population, analyze the past population structure and forecast the future population dynamics of E. excelsum. The size structure and height structure of the population of E. excelsum were tabulated and analyzed. Based on these data, we estimated the values of the parameters such as survival curve, mortality curve and life expectancy. Population dynamics was predicted by a time-sequence model. The size distribution of the whole population generally fit a reverse “J” type curve, suggesting a stable population. The number of young individuals was larger than that of middle-aged and old individuals. The analysis of life table and survival curves show that under environmental screening and human disturbance, the population had one peak of mortality in size class II and only 11.43% individuals could survive from size class II to size class III. The life expectancy of E. excelsum was the highest in size class IV. The survival curve of the population belongs to the Deevey-III type. Time-sequence models for E. excelsum population predict that the number of different size classes will increase after two and five years. As a result, the crucial factors for the natural regeneration and restoration of E. excelsum are the protection of living individuals and their habitat.

Key words： population structure; life table; survival curve; time sequence analysis; Euryodendron excelsum H. T. Chang

Acknowledgements

This study was supported by National Natural Science Foundation of China (Grant No. 30560017).

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