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西藏沙棘(Hippophae tibetana)是沙棘属中最进化的种类,也是青藏高原上分布较广的沙棘种类.但是目前几乎未见关于西藏沙棘的基础生态学研究报道.根据珠穆朗玛峰绒布沟沿海拔梯度进行的西藏沙棘群落样方调查,采用二元指示种分析(TWINSPAN)法和去势对应分析(DCA)法,研究了海拔梯度下西藏沙棘的生境类型、影响其分布的环境主导因子和表型变异规律.结果表明,珠峰绒布沟西藏沙棘生境可以分为5个类型:河边砾石滩地、河谷灌丛草地、沙石滩地、草甸和柳树林缘.DCA排序结果反映其群落的分布和生长主要受海拔和土壤湿度两种环境主导因子的影响.通过有关数据的回归分析发现,西藏沙棘植株的叶宽、基径、高度和盖度都随海拔的升高呈显著减小的趋势,但叶片长度与海拔不显著相关.西藏沙棘的盖度随样方与河水实际距离的增大而减小.图3表2参31
Hippophae tibetana is the most evolutionary species in the genus Hippophae and is also the species of seabuckthorn widely distributed in the Qinghai-Tibet Plateau. However, there are few reports on the basic ecology of seabuckthorn in Tibet at present. According to the elevation gradient of the Rongbu ditch in Mount Everest, Using the TWINSPAN and DCA methods, the habitat types of Tibetan seabuckthorn and their environmental dominance and phenotypic variation were studied by means of quadrat analysis and quadrat analysis. The results showed that the seabuckthorn habitat of the Rongbugou Tibetan Plateau can be divided into five types: river gravel beach, valley shrub grassland, sand beach, meadows and willow forest margin.The results of DCA rankings reflect the distribution and growth of the main community Which was influenced by the two environmental factors of elevation and soil moisture.The regression analysis of the data showed that the leaf width, basal diameter, height and coverage of H. tabulaeformis plants in Tibet showed a decreasing trend with elevation, but the leaves Length and altitude were not significantly related to the coverage of Tibetan seabuckthorn with the actual distance between the sample and the river decreases.Figure 3 Table 2 参 参 31