黑石顶自然保护区森林次生演替过程中群落主要种的种间协变分析

采用2×2列联表，通过Pearson积矩相关系数和Speaman秩相关系数对黑石顶森林次生演替过程中各阶段群落优势种的种间协变进行了定量分析。结果表明，在演替初期的裸地恢复阶段，显著种间协变的种对较多，有14对(正协变9对负协变5对)，在针阔混交林阶段，显著种间协变的种对较少，仅有5种。全为正协变，表现为主要种间对群落环境的相同要求，并形成了主要种间的竞争格局，在阳生性常绿阔叶林阶段。显著种间协变的种对最少，只有4对，其中3对为负协变，这是主要种之间对群落环境相同要求的激烈竞争结果，在中生性常绿阔叶林阶段，显著种间协变的种对最多有20对，19对为正协变，主要表现为群落上层种和中下层种间形成了大量的正协变，但群落上层主要种间无显著的种间协变。

Interspecies covariation analysis of dominant tree species in secondary succession of forest communities in Heishiding Natural Reserve,Guangdong Province

Based on a 2 x 2 contingency table, the Pearson product-moment correlation coefficient and Spearman rank correlation coefficient were used to analyses the interspecies covariation of dominant tree species in different communities of secondary succession series in Heishiding Natural Reserve, Guangdong Province. In early succession stage, 14 pairs of tree species showed a significant interspecies covariation, and 9 pairs of species showed a negative coraviation, indicating that the species pairs needed the same habitats, while five pairs of species showed a positive covariation, which indicated that the species pairs needed different habitats. In the stage of needle broad-leaved mixed forest, only 5 pairs of species showed a significant interspecies covariation, and they were all positive covariation, which indicated the main species needed the same habitats and the interspecies competition were going. In the stage of evergreen broadleaved forest dominated by heliophytes, 4 pairs of species showed a significant interspecies covariation, which was the least one in secondary succession series. Three pairs of them showed a positive covariation. It was the result of interspecies competition that the species pairs needed the same habitats. In the stage of evergreen broadleaved forest dominated by mesophytes, 20 pairs of species showed a significant interspecies covariation, which was the most one in secondary succession series. Nineteen pairs of them showed a positive covariation. It showed positive covariation between species in upper tree layer and in middle or lower tree layer, but dominant species in upper tree layer had no significant interspecies covariation.