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对塔里木河下游荒漠河岸林退化程度不同的4个典型断面胡杨种群结构和空间分布格局进行了研究,结果表明:①胡杨种群密度从英苏断面的8.01株/(25 m×25 m)下降至依干不及麻断面的0.62株/(25 m×25 m),同时伴生种数量和种类不断减少。②胡杨种群整体分布不均匀,幼苗和小树缺乏,中龄和老龄植株所占比例较高。随着退化程度的加剧,幼苗和小树所占比例不断降低,而中龄和老龄植株所占比例明显增加。③胡杨种群整体分布格局为聚集分布,聚集度Moristia指数Iδ从英苏断面的1.67增至依干不及麻断面的4.99,并且幼苗和小树发育阶段的胡杨种群分布格局因植株数量的不断减少,逐渐由聚集分布过渡为随机分布,而中龄和老龄发育阶段的胡杨种群均为聚集分布。④影响胡杨种群结构和分布格局变化的主要因子是地下水埋深,浅层土壤含水率对其影响不大。
The Populus euphratica population structure and spatial distribution pattern of 4 typical Populus euphratica Populations with different degree of degradation of desert riparian forests in the lower reaches of the Tarim River were studied. The results showed that: (1) Populus euphratica population density decreased from 8.01 plants / (25 m × 25 m) 0.62 plants / (25 m × 25 m) at the same time as those of the hemp section, while the number and species of concomitant species decreased continuously. ② Populus population unevenly distributed, lack of seedlings and young trees, middle-aged and older plants accounted for a higher proportion. As the degree of degradation aggravated, the proportion of seedlings and young trees continued to decrease while the proportion of middle-aged and aged plants increased significantly. ③ Populus euphratica population distribution pattern is aggregated distribution, aggregation degree Moristia index Iδ increased from 1.67 in the British Soviet-Soviet cross section to 4.99 in the dry trunk less than the hemp section, and Populus euphratica population distribution pattern in the seedling and young tree development stage due to the continuous decline in the number of plants, Gradually from the distribution of the distribution of a random distribution of distribution, and middle-aged and aged Populus population are aggregated distribution. ④ The main factor that affected Populus euphratica population structure and distribution pattern was groundwater depth, and the shallow soil moisture had little effect on it.