松嫩平原羊草草原凋落物层群落学作用的研究

STUDY ON EFFECT OF LITTER LAYER ON COMMUNITY IN ANEUROLEPIDIUM CHINENSE GRASSLAND IN SONGNEN PLAIN

植物的萌发数量与凋落物量呈抛物线型 ,峰值出现在 2 0 0 g· m- 2处 ,凋落物对植物萌发影响主要是通过影响地表温度和土壤水分而起作用。群落的物种数随着凋落物量增加而增加 ,峰值出现在 80 0 g· m- 2 处 ,种饱和度达 14种· m- 2 ,峰值后略有下降。群落优势种羊草 (Aneurolepidium chinense)的密度、平均高度、盖度和地上生物量随凋落物量的变化趋势基本相同 ,峰值出现在 6 0 0 g· m- 2左右。凋落物层对群落的演替动态有一定的影响 ,凋落物量相近的样地差异较小 ,随着凋落物量的增加 ,群落间差异越来越大。群落地上和地下生物量随凋落物量的变化呈单峰曲线 ,地上生物量峰值出现在 6 0 0 g· m- 2处 ,地下生物量出现在 70 0 g· m- 2处 ,地下生物量 /地上生物量值随凋落物量变化呈 V字型 ,最小值出现在 5 5 0 g· m- 2 左右。

Seasonal change in litter weight and number of germinating plants showed a parabolic form. The peak number germinating was 200 g·m -2 . Litter effected germination via its influence on surface temp eratu re and soil water.The number of species present in the community increased with increasing litter weight up to a peak value of 800 g·m -2 : species saturat ion occurred at 14·m -2 ,then decreased. Changes in the density,average height,coverage and aboveground b iomass of dominant species with litter weight were basically similar and each pe aked at around 600 g·m -2 .The litter layer had a strong influence upon the dynamics of community succession. The difference between plots in which litter weight was low was sma ll,while communities diverged as litter weight increased. The changes of abovegr ound biomass and underground biomass of community with litter weight showed a si ngle peak at 600 g·m -2 and 700 g·m -2 respectively. Underground and aboveground biomass both varied with litter weight in a ‘V’ type pattern with the lowest value around 550 g·m -2 .