黄土高原丘陵区典型退耕灌木液流速率对环境因素的响应差异研究

The Response of Sap Flow Density to Environmental Factors of Two Typical Shrub Species in the Hilly Loess Plateau of China

植树造林为黄土高原的水土流失问题做出了重要贡献,但大规模的植被恢复对有限土壤水分的过度消耗,影响到了黄土高原生态恢复的可持续性,因此有必要阐明典型恢复物种的耗水特征。本文以黄土高原典型丘陵沟壑区延安羊圈沟小流域两种典型的人工植物种——引入种沙棘和本地种绣线菊为研究对象,通过分析两物种液流速率以及它们在不同尺度上对环境因子响应的特征与差异,探究两物种对水分的利用状况与对环境的适应特点。研究主要结论有:沙棘的液流速率显著大于绣线菊且两种植物液流速率在不同时间尺度上对环境因子的响应存在差异。绣线菊在对环境的适应性上表现出与沙棘不同的特征。研究表明,黄土高原引入物种与本地物种在耗水特征以及对当地环境适应方式上有很大差异,引入物种沙棘在增加黄土高原植被覆盖率的同时也增加了对当地土壤水分的消耗,但关于两物种在黄土高原生态恢复中的影响还需要多方面的分析评价。

Vegetation afforestation has made important contribution to the soil and water loss in the Loess Plateau,but the large-scale vegetation recovery work has been overconsumed by the soil water,which has been harmful to the sustainability of the ecological restoration of the Loess Plateau.Therefore,it is necessary to elucidate the water consumption characteristics of typical restored species.The aim of this study was to explore the water utilization and environmental adaptation of typical re-vegetation species-the introduced species Hippophae rhamnoides L.(HR),and the native species Spiraea pubescens Turcz(SP).We analyzed the characteristics of the sap flow density(Fd)of two typical cultivated species in the Yangjuangou catchment,Yan'an,a typical hilly and gully region of the Loess Plateau,and illuminated the response of sap flow density to environmental factors at different time scales.The main conclusions are as follows:The sap flow rate of HR was significantly higher than that of SP,and the fluctuation range of flow rate of HR was greater than that of SP.There existed discrepancy of the response of sap flow density to environmental factors at different time scales.This showed different adaptation characteristics of the two species to the semiarid environment.The introduction of HR increased the vegetation coverage on the Loess Plateau and also increased the consumption of local soil water.However,the effects of the two species on the ecological restoration of the Loess Plateau still need to be analyzed and evaluated in the future.