| Pseudolarix amabilis belongs to genus Pseudolarix of family Pinaceae, which is single speciesendemic to China. It has been included in the list of rare and endangered plants in China as national IIlevel protection species, scattered in Jiangsu province, Zhejiang province, Fujian province, Anhuiprovince, Henan province, Jiangxi province, Hubei province, Hunan province and Sichuan province, ect.Type specimens were collected from Zhejiang Province, and it’s one of the world’s five most excellentcourtyard ornamental tree species with Sequoiadendron giganteum, Araucaria araucana,Sciadopitys verticillata and Cedrus deodara. In this study, resources of wild P. amabilis in ZhejiangTianmu Mountain National Nature Reserve were conducted a field reconnaissance by using the methodof typical sample and examining every individual within. In this study, resources of wild P. amabilis inZhejiang Tianmu Mountain National Nature Reserve were conducted a field reconnaissance by usingthe method of typical sample and examining every individual within. And the community features andpopulation dynamics of P. amabilis were studied by using the method of survey on the relatedliterature review combined with inquiries. Draw the following conclusions:（1）The environment and the floristic composition of P. amabilis community. The P. amabiliscommunity in Tianmu Mountain area are scattered in w arm, humid, plentiful rainfall, deep soil, steepmountain and deep valley area. The plant species are rich in this community, that occurs262vascularspecie belonging to190genera84families. Floristic composition of North Temperate distribution type,East Asia-North America discontinuous distribution type and East Asia distribution type are dominant,followed by extensive tropical distribution type. Genera of old world tropical distribution type and EastAsia-North America discontinuous distribution type arise in the community flora, indicating that thecommunity flora has a higher ancient quality and extensive contacts in the genera level.（2）The appearance and structure of P. amabilis community. Raunkiaer’s life form spectrumrevealed that middle phanerophytes, climbers and hemicryptophytes are the main part of the P.amabilis community in Tianmu Mountain area, and small phanerophytes and dwarf phanerophytes alsooccupy a certain ratio. Vertical structure of the P. amabilis community in Tianmu Mountain area canbe divided into tree layer, shrub layer, herb layer and interlayer plant. Species in tree layer are single,while individuals in shrubs layer are relatively more rich, and plants in herb layer are the most rich. Andit’s hard for P. amabilis to form the dominant population, so the co-dominant species or secondary species always compose mixed forest with other broadleaf species. Community composition mainlycompose of deciduous trees, and relative similarity exists in every sample plot.（3）The species diversity of the P. amabilis community. Shannon-Wieners indices (H’) in herblayer (2.31~3.63) is the highest, followed by the shrub layer (1.79~3.15). Simpson dominance indices (λ)in herb layer (0.05~0.44) is the highest, followed by the shrub layer (0.06~0.27). Pielo evenness index(E) in herb layer (0.80~0.97) is the highest, followed by the tree layer (0.75~0.94). Study in diversity ofP. amabilis community in different altitude showed that: changes in altitude has less impact on speciesrichness index in tree layer and shrub layer but more on herb layer. As the altitude changes, the changeof Shannon-Wiener index in tree layer, shrub layer and herb layer is small, and the trend is more gentle.With the decreasing of altitude, Simpson dominance indices in ree layer showed a first increasing andthen decreasing, finally ascending trend. With the decreasing of altitude, Pielo evenness index has asmall change, and the shrub layer showed a downward trend after the first rise. Overall the speciesdiversity of the P. amabilis community is richer.（4）The dynamic characteristics of the P. amabilis population. The analysis of size structure,height structure, Static life table and survival of the P. amabilis population in Tianmu Mountain areashowed that the size structure and height structure are rendered as the inverted pyramid, indicating thatthe P. amabilis population in Tianmu Mountain is in a recession phase. The survival curve of P.amabilis population belongs to Deevey-I type, and the mortality rate curve and the disappearance ratecurves are approximately coincident, reflecting the the dynamic change trend of P. amabilis populati-on on the whole. Four survival function curve indicates that the P. amabilis population has the chara-cteristics of declining sharp in earlier stage, tending to be stable in interim stage and recession in laterstage. The survival rate trend of the population showed monotonically decreasing, while the cumulativemortality trend showed monotonically increasing,and both complement eac h other. The raise and fall ofsurvival curve and cumulativ mortality curve of the P. amabilis population in Tianmu Mountain areaare more gentle, since there is no sharp drop and surge. |
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