人为干扰对鼎湖山马尾松林种群动态的影响

通过处理（根据当地居民习惯收割凋落物和林下）和保护（停止人为干扰，无任何人类活动）样地的比较在五年内（9190－1995年）研究了人为干扰对鼎湖山马尾松林植物种群动态的影响。结果表明，保护样地的林下层和灌木层盖度逐年上升，而处理样地相对较稳定。保护样地的草本层盖度略上升至1992年后，呈显著下降的变化，处理样地的变化则与保护样地的相反。保护样地的林下层植物种数逐年下降（从1990年的41种降至1995年的30种，减少11种），处理样地变化不大（从1990年的36种降至1995年的34种，仅减少2种）。小径级（≤13cm)的马尾松胸径增长速率保护样地高于处理样地，且径级越小，增长速率越大，然而，径级大于13cm的植株，则没有显示出这种规律性的变化。以上现象表明，适度的人为干扰对稀疏马尾松林的自然更新及林下植物种类多样笥具有一定的维持或促进作用，但不利于马尾松的生长。同时对稀疏马尾松－灌木－草本群落在停止人为干扰后的演替途径作了预测和探讨。

Population Dynamics of Human-impacted Masson Pine Plantation in Dinghushan

Plant population dynamics of a human-impacted masson pine (Pinus massoniana) plantation was studied in Dinghushan Biosphere Reserve in Guangdong for 5 years from 1990. Twenty paired plots with total area of 4 000 m2 were investigated in plots of harvesting under-story, ground cover, and litter as the local peasants did for fuel annually once or twice, and in undisturbed plots as control. The results indicated that understory coverage and the shrub coverage in undisturbed plots increased annually, but those in disturbed plots remained little changed. However, the coverage of herbs was slightly increased before 1992, and then decreasedmarkedly in undisturbed plots, while that in disturbed plots was on the contrary. The coverage of main shrub and herb species was also measured. Species number of understory plants decreased annually from 41 to 30 in undisturbed plots, but that in disturbed plots remained more or less stable, only 2 species lost. The result showed that appropriate disturbance in understory of masson pine plantation could maintain species abundance, and exhibited positive effect on natural regeneration of pine tree, but negative impact on pine growth. The possible succession of open masson pine forest toward pine-broadleaved mixed forest is discussed.