石羊河下游天然与人工柠条种群分布格局和数量特征研究

Distribution pattern and quantity characteristic of natural and artificial Caragama microphylla species in Shiyang River

以地处典型干旱地区的石羊河下游天然(红敖包、阿拉古山天然林)和人工(扎子沟人工林)柠条种群为研究对象,通过调查柠条种群分布、密度、盖度及其个体大小等指标,分析研究区柠条种群空间分布格局、数量结构特征.结果表明:石羊河下游天然与人工柠条种群空间分布均为聚集分布类型,但聚集度存在一定差异;红敖包和阿拉古山天然林柠条种群密度接近,均略小于扎子沟人工柠条林;扎子沟人工柠条林盖度是红敖包和阿拉古山天然柠条种群的2～3倍;2个天然柠条林的平均地径与扎子沟人工林间未见显著差异(P<0.05),不同柠条种群分枝数和新梢长度差异显著,红敖包天然林柠条的新梢长度明显大于阿拉古山和扎子沟柠条林,而分枝数相反;种群结构大小的调查显示,2个天然林都处于增长阶段,而扎子沟人工林暂无法确定.

The research took the natural and artificial Caragama microphylla of the downstream of Shiyang River which is located in the typical arid region as the research object. The population distribution, spatial distribution pattern, quantity structure and characteristic of Caragama rnicrophylla among the three different regions were analyzed, meanwhile the density, coverage and its individual size were also studied. The results showed that in the different regions of the downstream Shiyang River, natural and arti- ficial C. microphylla population spatial distribution were all the congregating distribution types, but the aggregated degree were different in some degree. The difference of the two natural C. microphylla popula- tion＇s density was small and less than that of the artificial population. The coverage of Zhazigou artificial population was about two or three times than that of the two natural population, and ground diameter char- acteristics showed there was little difference among the three regions;but the differences of the density, coverage and ground diameter were all not very obvious though analysis of variance, and ground diametercharacteristics showed there was certain difference among the three regions, but the difference was not very obvious though analysis of variance. The new branches length of Haoaobao was obviously more than that of the other two C. microphylZa population,but the number of branches was opposite exactly. The population structure size was surveyed and it showed that the two natural forests were in the growth stage and had de- velopment potential,while Zhazigou plantation temporarily was unable to determine.