【摘要】 在黄土高原丘陵沟壑区对阳坡,半阳坡,半阴坡,阴坡四个生境条件下,对经过13年发育的沙棘种群动态、大小结构等进行了系统研究,编制了静态生命表,分析了存活曲线和死亡曲线.结果表明,黄土高原丘陵沟壑区不同生境的沙棘种群基本属于进展型或稳定型,幼龄个体多,中老龄个体少.不同生境的种群密度存在差异,其中阴坡种群密度最大;不同坡向种群生命表显示,种群在、径级时死亡率较高,随着年龄增加,死亡率逐渐降低,但到了,径级,由于生理衰老死亡率又上升;种群期望寿命在、径级较高,随着年龄增加,期望寿命逐渐下降;不同坡向的沙棘种群的存活曲线均接近于Deevey型.沙棘种群动态是环境因素与生物学特性共同作用的结果,其中土壤含水量、人为干扰、土壤有机质影响较大.在黄土高原丘陵沟壑区,沙棘人工种群应该以保护为主,适当抚育的措施,促进群落持续发育.更多还原

【Abstract】 The dynamics and sizes and structures of Hippophae rhamnoides populations, which had grew for 13 years in the habitats sitting on sunny slopes, semi sunny slopes, semi shady slopes and shady slopes, were systematically studied and their static life tables and survival curves and death curve of the populations were accordingly worked out. The results showed that Hippophae rhamnoides populations in different habitats standing in hilly loess regions basically belonged to a progressive or stable type contain more young population members and less middle aged or old population members. The population density differed among different habitats with its highest point appearing in the habitats on sunny slopes; the life tables of Hippophae rhamnoides population on slopes with different aspects indicated that the death rates of the populations was relatively high at diameter classes Ⅰand Ⅱ but the expected life span of the populations gradually declined as the population ages increased; the survival curve of Hippophae rhamnoides populations on different slopes with different aspects approached to Deevey Ⅲ. The dynamics of Hippophae rhamnoides populations resulted from the interactions between their environmental factors and biological characteristics of which soil moisture, manmade interferences and soil organic matter exerted more influences. In hilly and gully regions of the Loess Plateau, protective measures should be mainly adopted in combination with proper tending practices to enhance sustainable population development.更多还原