| 摘要: |
| 【目的】针对延河流域人工植被建造存在植被退化的问题，比较了自然植被与人工植被地上生物量的差异及其土壤水分效应，探寻人工植被退化的原因，为延河流域植被恢复重建提供理论支持。【方法】共采集57个气象站点1980-2000年的气候数据，并根据降雨和温度变化，将延河流域划分为17个环境梯度单元，测定了自然植被地上生物量及0～500 cm土层土壤含水量，分析自然植被的空间变化及其影响因素，对自然植被与人工植被地上生物量及相应的土壤水分变化进行比较分析。【结果】延河流域自然植被地上生物量在空间上存在明显差异，从西北向东南呈现逐渐递增的变化趋势。自然植被地上生物量与年均总降雨量呈正相关关系，与年均生长季温度呈负相关关系；相同气候区的自然植被地上生物量随坡位和坡向的变化差异均很大。以自然植被为参照，人工植被地上生物量最大超载可达30 425.83 g/m2，最小超载为118.93 g/m2，平均为6 668.00 g/m2，说明人工植被地上生物量明显超出了自然状态下所能承载的范围。与自然植被相比，人工植被土壤水分最大亏缺量可达80.5 g/kg，说明人工植被地上生物量的超载引起平均土壤含水量显著低于自然植被，出现了不同程度的土壤干层，进而导致人工植被群落的衰退或死亡。【结论】生物量超载是引起土壤水分耗竭、植被退化的主要原因。植被恢复重建规划时，必须充分考虑特定立地环境条件下潜在生物量的制约，而不是盲目地选择不适宜的物种。 |
| 关键词: 自然植被 人工植被 地上生物量 空间变化 气候因素 土壤含水量 |
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| 基金项目:国家自然科学基金项目“黄土丘陵区潜在植被格局及其对未来气候变化的响应”（40871246）；国家科技支撑课题“植被优化配置与可持续建设技术”（2006BAD09B03）；中国科学院“西部之光”联合学者项目（2010y236） |
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| Differences of above-ground biomass and comparisons of its effect on soil moisture between natural vegetation and artificial vegetation in Yanhe basin |
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| Abstract: |
| 【Objective】Above-ground biomass and soil moisture between natural and artificial vegetation,were compared to explore the reason of artificial vegetation degeneration,vegetation restoration planning and decision support in Yanhe basin.【Method】We collected climate data of 57 meteorological stations from the year 1980-2000,and divided the Yanhe basin into 17 environmental gradient units according to rainfall and temperature changes.Above-ground biomass of the natural vegetation and 0-500 cm soil moisture content were measured.The spatial variation of natural vegetation and its influence factors were analyzed,and the changes of above ground biomass and soil moisture content between the natural vegetation and artificial vegetation were compared.【Result】The results showed that above ground biomass of natural vegetation in space had significant differences,and above ground biomass increased gradually from northwest to southeast in Yanhe basin.Above ground biomass of natural vegetation had a positive correlation with annual total precipitation（P<0.05）,and it showed a negative correlation with growing seasonal temperature;the above ground biomass changed significantly with the different terrain or slope in the same climate.With natural vegetation as reference,the maximum overloading of artificial vegetation above ground biomass was 30 425.83 g/m2,the minimum 118.93 g/m2,and the average 6 668.00 g/m2,artificial vegetation above ground biomass significantly exceeded the extent of natural vegetation carrying capacity.Compared with natural vegetation,the biggest deficit of artificial vegetation’s soil moisture could reach 80.5 g/kg,so it indicated that average of artificial vegetation was significantly lower than the natural vegetation (P<0.05),appearing different degrees of dry soil layer which led the artificial vegetation communities to decline or death.【Conclusion】Finally,the main reason for soil moisture depletion and vegetation degeneration was overloaded biomass.When restoring and reconstructing vegetation,we must consider the potential biomass restriction under specific site conditions,rather than choose blindly unsuitable species. |
| Key words: natural vegetation artificial vegetation above-ground biomass spatial variation climatic factors soil moisture |
