This paper analyzes the monitored data of the 4 times of stream water conveyances to the river section where the stream flow was cut-off, of 9 groundwater-monitoring sections and 18 vegetation plots in the lower reach...This paper analyzes the monitored data of the 4 times of stream water conveyances to the river section where the stream flow was cut-off, of 9 groundwater-monitoring sections and 18 vegetation plots in the lower reaches of Tarim River. The results show that the groundwater depth in the lower reaches of Tarim River rose from 9.87 m before the conveyances to 7.74 m and 3.79 m after the first and second conveyances, 3.61 and 3.16 m after the 2 phases of the third conveyance, and 2.66 m after the fourth conveyance. The transverse response scope of groundwater level was gradually enlarged along both sides of the channel of conveyances, i.e., from 450 m in width after the first conveyance to 1050 m after the fourth conveyance, but the response degree of groundwater level was reduced with the increase of the distance away from the channel of conveyances. The composition, distribution and growth status of the natural vegetation are directly related to the groundwater depth. The indexes of Simpson’s biodiversity, McIntosh’s evenness and Margalef’s richness, which reflect the change of the quantity of species and the degree of biodiversity, are reduced from 0.70, 0.48 and 0.90 to 0.26, 0.17 and 0.37 re- spectively along with the drawdown of groundwater level from the upper reaches to the lower reaches. After the stream water conveyances, the natural vegetation in the lower reaches is saved and restored along with the rise of groundwater level, the response scope of vegetation is gradually enlarged, i.e., from 200— 250 m in width after the first conveyance to 800 m after the fourth conveyance. However, there is still a great disparity to the objective of protecting the “Green Corridor”in the lower reaches of Tarim River. Thus, it is suggested to convey the stream water in double-channel way, combine the conveyance with water supply in surface scope, or construct the modern pipe-conveyance network systems so as to save the natural vegetation in an intensive way, achieve the efficient water consumption and speed u展开更多
基金supported by the National Natural Science Foundation of China(Grant No.90102007)the Knowledge Innovation Project of the Chinese Academy of Sciences(Grant No.KZCX1-08-03).
文摘This paper analyzes the monitored data of the 4 times of stream water conveyances to the river section where the stream flow was cut-off, of 9 groundwater-monitoring sections and 18 vegetation plots in the lower reaches of Tarim River. The results show that the groundwater depth in the lower reaches of Tarim River rose from 9.87 m before the conveyances to 7.74 m and 3.79 m after the first and second conveyances, 3.61 and 3.16 m after the 2 phases of the third conveyance, and 2.66 m after the fourth conveyance. The transverse response scope of groundwater level was gradually enlarged along both sides of the channel of conveyances, i.e., from 450 m in width after the first conveyance to 1050 m after the fourth conveyance, but the response degree of groundwater level was reduced with the increase of the distance away from the channel of conveyances. The composition, distribution and growth status of the natural vegetation are directly related to the groundwater depth. The indexes of Simpson’s biodiversity, McIntosh’s evenness and Margalef’s richness, which reflect the change of the quantity of species and the degree of biodiversity, are reduced from 0.70, 0.48 and 0.90 to 0.26, 0.17 and 0.37 re- spectively along with the drawdown of groundwater level from the upper reaches to the lower reaches. After the stream water conveyances, the natural vegetation in the lower reaches is saved and restored along with the rise of groundwater level, the response scope of vegetation is gradually enlarged, i.e., from 200— 250 m in width after the first conveyance to 800 m after the fourth conveyance. However, there is still a great disparity to the objective of protecting the “Green Corridor”in the lower reaches of Tarim River. Thus, it is suggested to convey the stream water in double-channel way, combine the conveyance with water supply in surface scope, or construct the modern pipe-conveyance network systems so as to save the natural vegetation in an intensive way, achieve the efficient water consumption and speed u
文摘为探讨不同区段金沙江下游山地失稳性坡面土壤有机碳(soil organic carbon,SOC)含量特征,选择典型流域内温带湿润山岭区、亚热带和暖温带半湿润区和亚热带干热河谷区为研究对象,在各气候区失稳性坡面的不同区段(稳定区、失稳区、堆积区)设置样地,测定不同区段0-20 cm SOC含量,并结合中国科学院东川泥石流观测研究站多年的气象资料,分析气候、区段因素与SOC含量的相关性.结果显示:(1)金沙江下游山地失稳性坡面SOC含量与年均温、夏季均温、冬季均温均存在显著负相关关系(P<0.05),与年降水量、夏季降水量存在显著正相关关系(P<0.05);温带湿润山岭区水热条件良好,整体上各区段SOC含量均高于亚热带和暖温带半湿润区、亚热带干热河谷区;(2)温带湿润山岭区与亚热带干热河谷区SOC含量整体上随着区段稳定程度的降低而下降,呈现稳定区>失稳区>堆积区的变化趋势;(3)金沙江下游山地失稳性坡面SOC含量还受到坡向的影响,具体表现为温带湿润山岭区和亚热带干热河谷区各区段SOC含量均呈现出"阴坡">"阳坡"的变化趋势;(4)气候与区段的交互作用显著影响SOC含量,具体表现为查菁沟阳坡堆积区的SOC含量显著低于温带湿润山岭区与亚热带和暖温带半湿润区(P<0.05).本研究表明气候与区段共同对金沙江下游山地失稳性坡面SOC含量产生影响,且人类活动的干扰作用也不可忽视,具体表现为人类干扰频繁的亚热带和暖温带半湿润区稳定区SOC含量显著低于亚热带干热河谷区(P<0.05),且3个区段SOC含量差异不显著(P>0.05).以上结论可为研究该区域失稳性坡面土壤碳演变规律提供数据支撑和理论参考,同时为生态脆弱区的生态恢复规划提供相应的理论依据.(图2表4参43)
