海南岛尖峰岭次生热带山地雨林树种间的联结动态

DYNAMICS OF ASSOCIATIONS BETWEEN TREE SPECIES IN A SECONDARY TROPICAL MONTANE RAIN FOREST AT JIANFENGLING ON HAINAN ISLAND

应用方差检验法和基于 ２×２联列表的分析手段，对海南岛尖峰岭热带山地雨林采伐后 ２５～３５年次生群 落 ２４００ ｍ２固定样地中胸径≥７． ０ ｃｍ林木的种间联结动态进行了研究，结果如下：１）群落内的树种总体呈正联结， 但未达到显著水平。联结指数Ｖ界于１．００～１．２１之间，接近无联结假设条件下的Ｖ值（Ｖ＝１），证实了作者关于 “种的分布相对独立”的假说；２）种间联结的比例和强度随演替进程而下降，群落朝种间无联结方向发展的趋势较 为明显；３）群落早期建群种与后期入侵种种间没有负联结，两类树种之间有２６％的种对呈正联结，但均不显著，说 明他们不仅可通过分割资源而和谐共处，而且更趋于独立存在。后期入侵种种间也不存在负联结，所有正联结（占 总种对数４．４％）均达到显著水平，表明他们对环境条件的要求和适应明显相似。

The pattern of association of tree (DBH>7. 0 cm) species was examined in forty-eight 10 m X 5 m permanent plots during 10 years of succession in a secondary-growth tropical montane rain forest at Jianfengling on Hainan lsland using the variance test and 2 X 2 contingency table methods. Field observations commenced in 1989 when the forest was 25 years old. Three hypothesies were tested concerning the dynamics of species interactions through succession and the following results were obtained. 1)The variance test reveals that all tree species in the forest showed a non-significant pattern of positive association. The observed index of species association (V) ranged from 1. 00 to 1. 21 (close to V= 1 under the null hypothesis of no association) over the 10 years of succession suggests that tree species were mostly independently distributed. 2) The proportion of species pairs showing positive and negative associations compared to those showing no associations declined with time. In addition, while the level of significance of negative associations remained unchanged, that of positive associations declined with time. 3) No negative associations were found between the early-established species (pioneer or canopy species) and the later invading species (tolerant or subcanopy species), or between the later invading species. All positive associations between the early-established species and the later invading species were not significant, while those between the later invading species were significant.