高原湿地纳帕海周边山地不同植被类型枯落物持水特性

Water Holding Characteristics of Litters of Different Species in Mountainous Area of Napahai Plateau Wetland

对高原湿地纳帕海周边山地8种不同植被类型枯落物持水特性进行了研究。结果表明,(1)8种植被类型枯落物储量和总持水量均表现出半分解+分解层>未分解层的变化趋势;枯落物储量呈现从乔木林到灌木林和荒草地逐渐降低的总体趋势;高山柳+白桦混交林最大总持水量最大,受人为干扰较为严重的高山松纯林总持水量最小。(2)初始1h内不同植被类型不同层次枯落物持水量均迅速增大,在浸水6～10h后,枯落物持水量基本达到饱和。(3)枯落物在浸水前0.5h内吸水速率最大,6～10h时下降速度明显减缓。(4)不同植被类型枯落物失水速率有一致性,随着失水时间延长而逐渐变小,呈近直线下降。综合分析得出,高山柳+白桦混交林枯落物持水量最大,调节洪峰能力最强,失水过程最佳,补给水源能力最好,其水文生态效应是8种植被类型中最好的。

The water holding capacity was characterized for the litters from eight plantation types in the mountainous area of Napahai Plateau Wetland.The results show that,for all the eight plantation types,the semi-decomposed and decomposed layer had higher litter storage and water reserving capacity than the freshly-littered layer.The litter storage decreased from highwood,shrub to waste grassland.Specifically,the litter storages of natural Picea asperata Mast,mixed forest of Pinus densata Mast and Rhododendron simsii Planch,mixed forest of Salix cupularis Rehd and Betula platyphylla Suk,Crataegus pinnatifida Bge and waste grassland demonstrated a capacity of 36.60,30.67,26.63,25.61 and 5.30 t/hm2,respectively.Comparatively,mixed forest of Salix cupularis Rehd and Betula platyphylla Suk had the highest water holding capacity,and seriously human-disturbed Pinus densata Mast had the lowest.The water holding capacity of the litters increased rapidly during the initial first hour,and then slightly increased after 6~10 hour saturation.The highest water absorption rates were observed in the first 30 minute saturation time,and thereafter the rates decreased substantially.Water loss rates were similar for all the litters,showing a linear decreasing trend.Systematic analysis indicated that the litter of mixed forest of Salix cupularis Rehd and Betula platyphylla Suk had the highest water holding capacity,the strongest flood-adjusting capacity,the most ideal water loss process and the highest water supply capacity,and the best hydro-ecological effect among the eight plantation types.