影响季风常绿阔叶林幼苗定居的主要因素

FACTORS AFFECTING SEEDLING ESTABLISHMENT IN MONSOON EVERGREEN BROAD-LEAVED FOREST

摘要:

对鼎湖山季风常绿阔叶林的试验观测结果表明：除去灌木草本层能增加新的幼苗定居的机会，对灌木草本层小规模的破坏能很快得到恢复。由于凋落物对种子与地面土壤的接触具有阻隔作用，因此除去凋落物层对幼苗的定居有利，但不能增加其幼苗物种丰富度。降雨量的大小对幼苗的死亡率影响极大．冠层叶面积指数的大小影响光照强度而导致各样地幼苗定居数量和物种丰富度的差异．当样地土壤湿度增大时，其幼苗的密度随之增加，显示土壤湿度大有利于种子萌发，并能提高幼苗成活率。

Abstract:

The experiments were conducted in Dinghushan Biosphere Reserve, Guangdong Province, in monsoon evergreen broad-leaved forest community with species of Castanopsis chinensis, Schima superba and Cryptocarya concinna in & plots with 5m×5m each. In four of the & plots the shrub and herb layers were removed, and in the other four these layers were retained as control. Another 4 plots with 2m ×5m each were used in the experiment for investigation of the effect of cleaning litter. Measurements were made in September and December every year during 1994 to 1998 to investigate the speoes number，the number of individuals，and the height of all newly appeared seedlings The results showed that the seedling establishment increased in plots removing shru b and herb layer or cleaning the litter， but the species richness of seed lings did not increase． High mortality of seed lings appeared in dry season and in plots with high light intensity Precipitaiton is a key factor affecting the establishment of seed lings．Moist soil condition could promote seed germination and seedling establishment．