海南岛尖峰岭次生热带山地雨林的边缘效应

Edge Effects in Two Secondary Tropical Montane Rainforests at Jianfengling, Hainan Island of China

对海南岛尖峰岭热带山地雨林采伐迹地次生林及周围的保留林进行了群落调查,组建了一个基于分割线段模型的边缘效应测度公式:Y=a+e0[1-(D Dmax)](式中Y为与边缘垂直距离D处的测定指标值,e0为边缘效应强度的最大值,Dmax为边缘效应作用的最大距离,a为常数),研究了热带山地雨林群落的边缘效应,结果表明:(1)用组建的测度公式来分析热带山地雨林采伐迹地边缘的次生林及保留林的边缘效应强度及其作用距离,结果是有效和可靠的;(2)热带山地雨林采伐后形成的边缘,其效应的作用距离一般都不超过15m;(3)边缘对保留林和次生林的效应没有显著差异。

The strength and distance of edge effects in two secondary tropical montane rainforests at Jianfengling, Hainan Island of China were predicted with a newly proposed model:Y=a+e_0[1-(D/D_(max))],where Y was the value of a variable measured;e_0 was the maximum value of edge effects;D was the distance from the edge to a point at which Y was recorded; D_(max) was the distance from the edge to the point at which edge effects reached zero;and α was a constant. The species richness of plants with diameter at breast height less than 5 cm obtained from 44 plots of 4 m^2 in two forests each containing a secondary forest after clear-cut and a remined forest was used to fit the model and the following results were obtained.The edge effects in the tropical montane rainforests were well described by the proposed model;The maximum distance (D_(max)) at which edge effects reached zero was,in general,less than 15 m;and at the same plot,the edge effects on species richness of the remaining forests and on that of the secondary-forests after clear cut were not significantly different.