岷江柏四个地理种群分布格局比较研究

岷江柏是我国特有珍稀树种,其种群分布格局一直缺乏必要的研究。采用Greig-Smith的相邻格子样方调查法,调查了四川西部四个岷江柏地理种群,用方差/均值比率法和聚集度指标法分析了种群空间并进行了比较。结果表明,岷江柏种群分布格局与取样尺度有关。在2m×2m、4m×4m、6m×6m、8m×8m四个取样尺度下,小金种群均表现为集群分布,马尔康种群均表现为随机分布,金川种群和理县种群却随着取样尺度的增大,表现出聚集分布→均匀分布→随机分布的变化趋势。四个取样尺度中以2m×2m取样尺度来分析岷江柏种群空间分布格局时效果最好。方差/均值比率法运用统计方法确定T值的显著性,数学推导严密,运算简单,在分布格局分析中是一种较可靠的方法。

Distribution Patterns of Cupressus chengiana S.Y.Hu Populations in Four Geographical Areas

Cupressus chengiana S. Y. Hu, is a vulnerable tree endemic to China. There was limited understanding and protection of this population due to lack of comprehensive investigation. This work was conducted in the western Sichuan and four Cupressus chengiana H. populations in different counties, Xiaojin, Jinchuan, Barkam and Lixian, were investigated. Their distribution patterns were analyzed and compared. The results showed that sampling scale affects distribution pattern of Cupressus chengiana H. population. Four sizes of sampling scale, 2 m × 2 m, 4 m × 4 m, 6 m × 6 m and 8 m× 8 m, Xiaojin population all belong to clump distribution, Maerkan population all belong to regular distribution, the spatial pattern of Jinchuan population and Lixian population proceed from the clumped distribution to regular distribution, and from the regular distribution to random distribution. The results revealed that optimal sampling size is 2 m × 2 m for pattern detection. T - value is used to employ to test statistically for the significance of the difference （i. e. Variance/Mean Method）. It＇s mathematical inference is rigorous and calculation process is simple. Therefore, the Variance/Mean Method is better than others.