天然毛竹林竞争空间关系分析

以浙江天目山天然毛竹(Phyllostachys edulis)林为研究对象, 在毛竹林样地测量和调查的基础上, 利用地理信息系统和空间分析方法, 从天然毛竹林生存竞争的微观视角, 研究毛竹林生存竞争的空间自相关分布特征、竞争强度与毛竹密度和年龄的关系、竞争强度各向异性及与其所在样地坡向间的关系。研究结果发现: 毛竹林竞争呈现出空间自相关的特征, 竞争强度呈现出高与高、低与低集聚生长的特点; 天然毛竹林的空间分布密度与竞争强度呈现出正相关的趋势, 高强度竞争区域的毛竹密度显著大于低强度竞争区域的密度; 年龄在不同竞争强度区域的分布具有差异, 分布在低强度竞争区域上的毛竹年龄显著低于中、高强度竞争区域的年龄; 生长在中、高强度竞争区域上的毛竹年龄之间没有显著差异; 天然毛竹林竞争强度呈现出各向异性的特点且与其所在坡向相互垂直, 垂直于坡向方向上的竞争强度高于平行于坡向方向的竞争强度。通过研究表明, 空间分析方法能够有效地应用于研究天然毛竹林的生长规律, 为毛竹的合理经营与采伐提供指导意义。

Spatial analysis of competition in natural Phyllostachys edulis community

Spatial analysis of competition is an effective method to understand trend, variability and distribution patterns of plant communities. The objective of this study was to improve our understanding of autocorrelation distribution, the relationship between competition intensity and density and age of Phyllostachys edulis, and the relationship between competition intensity anisotropy and the aspect of sample plots. Based on data collected from natural P. edulis forest plots located in Tianmu Mountain of Zhejiang Province, we calculated Hegyi competition index in Geographic Information System (GIS). ESDA (exploratory spatial data analysis) was used to analyze the spatial distribution of the Hegyi competition index to identify the spatial distribution. Spatial semivariogram and standard deviation ellipse were used to study regionalized spatial variability of variables. The results showed that the spatial densities and the competition intensity of natural P. edulis forest was autocorrelated: Phyllostachys edulis density was higher in area of high competition intensity. The age of P. edulis was also different between areas of different competition intensities: Phyllostachys edulis was younger in plots of low competition intensity than in plots of high competition intensity. The anisotropy of the competition intensity was higher in the vertical direction than in the horizontal direction.