北京山区典型流域不同海拔椴树种群的空间点格局分析

采用点格局分析法对不同海拔的椴树（Tilia miqueliana Maxim.）种群进行分布格局及其种间关系进行了研究。结果表明：整体上群落内以中龄树个体数为最多,小树次之,成年树个体最少。随着海拔的增加可以看出：小树（d≤5 cm）随着海拔的增加而减少,中树（5 cm20 cm）的规律不明显;椴树种群的空间分布格局与空间尺度（25 m内）有密切关系,在较小的空间尺度上倾向于非随机分布,具有明显的空间相关性;在〉15 m或25m的某临界尺度时却倾向于随机分布,同时空间关联变得微弱。随着海拔的增加,各物种聚集分布的尺度有逐渐减小的趋势。种间关系随着海拔的增加,物种间的正相关尺度有增加的趋势。

Spatial pattern analysis on individuals of Tilia tuan Szyszyl.at different altitudes in typical watershed of Beijing mountainous area

In this paper,spatial pattern analysis of individuals in different altitudes of Tilia tuan Szyszyl.and the spatial association between them were studied by spatial point pattern analysis.The results showed that middle aged are the most,young ones are letter,and the old are the least in the population from the whole aspect.With the altitude elevation,the young trees are decreased,and the middle aged ones are increased.while the old ones have no obvious rule.The spatial pattern of different altitude Tilia tuan Szyszyl and the spatial association between individuals in different altitude Tilia tuan Szyszyl depend on spatial scale.In small scale,the individuals of all altitude Tilia tuan Szyszyl tend to clumping distribution,and the spatial association between individuals in different altitude Tilia tuan Szyszyl is considerably strong.By contrast,if the scales enlarge beyond these points,the individuals of all altitude Tilia tuan Szyszyl will disperse randomly,and their spatial association will loosen greatly.With the altitude elevation,the scale of the clumping distribution tends to decrease.And the scale of positive association tends to increase.