【作者】 康义；

【导师】 郭泉水；

【作者基本信息】 中国林业科学研究院 ， 植物学， 2010， 博士

【摘要】 世界高度关注三峡水利枢纽工程,其中库区生态环境问题是最重要的方面,而其重点是消落带的生态环境问题。三峡水库水位变化受水库调度所调控,水位涨落导致消落带周期性出没于水陆交替之中。在这种变化过程中,消落带的土壤不仅受到水位涨落造成的重力侵蚀和水浪的冲击,而且在消落带出露成陆期还会受到雨水冲刷的影响,长期持续的结果必将导致消落带土壤性状发生巨大改变;原生长在消落带的陆生植物,大多数也因难以在短期内改变在长期系统发育过程中形成的生物学和生态习性而受到生存威胁。为了减轻乃至消除消落带的生态环境问题,立足于三峡库区消落带实地特情,按消落带水位高程,因地制宜,选择适宜的植物种类,并进行科学的结构配置,开展消落带的植被恢复和重建,是三峡库区实现充分利用消落带资源,改善消落带生态环境状况,促进库区经济社会可持续发展的重要目标。而揭示三峡水库运行后,消落带土壤理化性质和植被的时空动态变化规律及发展趋势,是实现这一目标的最关键的环节。本文基于连续3年对秭归和巫山消落带监测样地土壤理化性状和植被动态的定位观测,对消落带不同水位高程土壤的理化性质和植被动态变化进行研究。结果表明:(1)三峡库区消落带受水位涨落影响后,土壤物理性状发生了很大改变。在消落带海拔156-172m区段,不同土层经历1个水位涨落周期的影响后,土壤密度增加了2.69-16.72%,总孔隙度降低了1.73-16.25%、毛管孔隙度降低了7.09-22.82%、非毛管孔隙度降低了16.26-48.21% ,最大持水量降低了2.79-14.66%、毛管持水量降低了9.31-15.87%、田间持水量降低了5.05-22.71%,0-10cm土层的粗砂粒含量增加了29.43%,细沙粒含量减少了9.17 %,粉砂粒含量减少了10.94%,粘粒含量减少了17.60%。在消落带海拔145-156m区段,不同土层经历3年水位涨落影响和经历2年水位涨落影响后的测定结果比较,土壤密度增加了3.58-8.48%,总孔隙度降低了3.59-20.20%、毛管孔隙度降低了5.05-22.65%、非毛管孔隙度降低了12.19-41.60%,最大持水量降低了4.63-26.29%、毛管持水量降低了2.61-28.64%、田间持水量降低了3.30-25.49%。0-10cm土层的粗砂粒含量增加了47.10%,细沙粒含量增加了25.37%,粉砂粒含量减少了64.83%,粘粒含量减少了43.88%。方差分析结果表明,土壤表层(0-10cm)受到水位涨落的影响最为显著。(2)基于监测样地调查结果表明:受水位涨落的影响,消落带土壤养分含量总体呈下降趋势,但不同养分测定指标的下降速率有所不同。在消落带海拔156-172m区段,经历1个水位涨落周期后,不同土层的速效N含量减少了41.53-59.87%,速效P含量减少了5.34-36.57%,速效K含量减少了3.55-45.46%,全N含量减少了5.75-40.11%,全P含量基本上没有变化,全K含量略有减少,有机质含量减少了12.15-37.83%。pH值趋于中性化,变化幅度为1.82-9.53%。与未受影响时比较,土壤速效N含量和土壤有机质含量在p<0.05水平上达到差异显著程度。在消落带海拔145-156m区段,对经历2个和3个水位涨落周期影响后的测定结果比较,不同土层的速效N含量减少了34.6 -59.63%,速效P含量减少了30.97-70.32%,速效K含量减少了6.10-17.58%,全N含量减少了14.02-45.60%,全P含量减少了1.34-40.13,全K含量略有减少,土壤有机质含量减少了10.82-34.43%。土壤pH值继续向中性发展,变化幅度为1.63-5.29%。0-10 cm土层,经历2个和经历3个水位涨落影响后的土壤速效N、速效P和全效N含量等,在p<0.05水平上达到差异显著程度。(3)在消落带海拔156-172m区段,经历1个水位涨落周期影响后,消落带植物种类数量急剧减少,减少幅度因监测样地而异,总的变化范围在28.30-34.55%,平均约为34%。植物生活型组成发生了较大变化。其中,草本植物种类增加了13.56%,灌木树种减少了72.63%,乔木树种减少了84.62%;受水位涨落影响前后,各监测样地中植物的重要值发生了显著变化,一些较适应的草本植物在样地的重要地位得到提升。草本植物的Shanon-winner多样性指数,Sinmpson优势度指数,PIE种间相遇几率,Pielou均匀度指数等均表现出下降的趋势。对消落带海拔145-156m区段所有监测样地的调查资料进行统计的结果表明,2007年(经历1个水位涨落周期)消落带出现了114种植物,2008年(经历2个水位涨落周期)时减少到95种,2009年(经历了3个水位涨落周期)减少到31种。从2007年到2009年植物种类的减少幅度为72.81%。截止2009年调查时,消落带生存下来的物种基本上都是草本植物。随着水位涨落周期的增加,多年生草本所占比例在逐年下降,而一年生草本所占比例逐年增加。消落带草本植物的物种多样性总体仍呈现下降趋势。(4)基于监测样地保存植物重要值大小的排序,初步认为以下植物可以作为三峡库区消落带不同海拔区段植被恢复和建设中比较适宜的植物材料:在消落带海拔156-172 m区段(消落带的中浅水位区)可供选择的草本植物是:香附子、狗尾草、旱莲草、毛马唐、铁苋菜、斑茅、柔弱斑种草、野茼蒿、粽叶狗尾草、地瓜藤、雾水葛、鼠麴草、马唐、白背莓、青蒿、少花龙葵、狼把草、野菊、酢浆草、矶雉草、野塘蒿、合基苔草、蜈蚣蕨、青葙、雀稗;灌木树种是:君迁子、白毛桐、江南越橘、金樱子、湖北算盘子、马桑、黄荆、盐肤木、假奓苞叶、铁仔、马棘、华东葡萄;乔木树种是:乌桕、复羽叶栾树。在消落带海拔145-156 m区段(消落带的深水位区)可供选择的草本植物是:三数马唐、马唐、金色狗尾草、牛鞭草、香附子、狼把草、碎米莎草、苍耳、旱莲草、水牛草、雾水葛、野茼蒿、野塘蒿、狗尾草、苦蘵、粽叶狗尾草、旱稗、狗牙根、空心莲子草、荩草、牛筋草、龙葵、红果黄鹌菜、绿苋。由于此区段淹水时间最长,淹水深度最深,监测结果表明,目前尚未发现可供选择的乔木和灌木树种。更多还原

【Abstract】 The Three Gorges Project is paid attention in the worldwide, and the ecological environment problems in reservoir area especially in hydro-fluctuation belt is the most important aspect. Changes in the Three Gorges reservoir water level is regulated by the scheduling, and periodic appeared alternating in hydro-fluctuation belt. is caused by water level fluctuations. During the changing progress, the soil in hydro-fluctuation belt is effected not only by gravitational erosion and water wave impact which is caused by fluctuation of water level, but also by rainfall erosion. The long and continuously influence will cause the altering of soil, and most of the terrestrial plants in hydro-fluctuation belt which can not change their biological and ecological habit will get survival crisis. In order to reduce even eliminate the ecological environment problems in hydro-fluctuation belt, based on the fact in Three Gorges reservoir hydro-fluctuation belt, according to water level in hydro-fluctuation belt, local conditions, choosing suitable plants, structure configuration scientifically, developing restoration and reconstruction, which are important goals in making full use of resource in Three Gorges reservoir hydro-fluctuation belt, improving the ecological environment condition and promoting economic and social sustainable development in reservoir ares. Revealing temporal dynamic change law and development trend of soil physical and chemical properties and vegetations in hydro-fluctuation belt after reservoir is the most key problem. This research is based on located monitoring of soil physical and chemical properties and vegetations in Zigui and Wushan hydro-fluctuation belt in the past three years. The result shows that:(1) The Three Gorges area of the hydro-fluctuation belt was affected by water level fluctuations, soil physical properties have changed a lot. In hydro-fluctuation belt 156-172 m above sea level section, different layers after 1 year of water level fluctuating, soil density increased 2.69-16.72%, total porosity decreased 1.73-16.25%, capillary porosity deceased 7.09-22.82%, non-capillary porosity decreased 16.26-48.21%, maximum moisture capacity decreased 2.79-14.66%, capillary moisture capacity decreased 9.31-15.87%, field capacity decreased 5.05-22.71%,and in the layer of 0-10cm, thick sand content increased by 29.43% and the fine sand, silly sand and clay content decreased by 9.17%,10.94% and 17.60% separately.In hydro-fluctuation belt 145-156 m above sea level section, different layers after 3 years of water level fluctuating, soil density increased 3.58-8.48%, total porosity decreased 3.59-20.20%, capillary porosity deceased 5.05-22.65%, non-capillary porosity decreased 12.19-41.60%, maximum moisture capacity decreased 4.63-26.29%, capillary moisture capacity decreased 2.61-28.64%, field capacity decreased 3.30-25.49%, and in the layer of 0-10 cm, thick sand content increased by 47.10% and the fine sand, silly sand and clay content decreased by25.37%,64.83% and 43.88% separately. The variance analysis showed that the effect of water level fluctuating is most significant in the layer of 0-10 cm,(2) The result shows that: the By the influence of water level fluctuating, soil nutrient had reduced in hydro-fluctuation belt generally, but the drawdown speed of each testing index were different.In hydro-fluctuation belt 156-172 m above sea level section, different layers after 1 year of water level fluctuating, available N decreased by 41.53 -59.87%, available P decreased by 5.34-36.57%, available K decreased by 3.55-45.46%, total N decreased by 5.75-40.11%, total P had no change generally, total K had decreased a little, content of organic material decreased by 12.15-37.83%, pH value turned to neutral, changed by 1.82-9.53%. Compared with the non-submerged zones, after one year of water level fluctuating, the difference of available N and organic material, was significant at 0.05 level.In hydro-fluctuation belt 145-156 m above sea level section, different layers after 3 years of water level fluctuating,, available N decreased by 34.6 -59.63%%, available P decreased by 30.97-70.32%, available K decreased by 6.10-17.58%, total N decreased by 14.02-45.60%, total P decreased by1.34-40.13%, total K had decreased a little, content of organic material decreased by 110.82-34.43%, pH value turned to neutral, changed by 1.63-5.29%. Compared two years of water level fluctuating zones, after three years of water level fluctuating, the difference of available N, P and total N in layer 0-10 cm, was significant at 0.05 level.(3) In hydro-fluctuation belt 156-172 m above sea level section, after 1 year of water level fluctuating, the number of plant species had decreased a lot. Each monitoring plot had decreased differently by 28.3-34.55%, mean by about 34%. The life form of plant had changed o lot, herbs increased by 13.56%, shrubs decreased by 72.63%,trees decreased by 84.62%. After 1 year of water level fluctuating, importance value of plants had changed significantly The herbs which were suitable in hydro-fluctuation belt were more important. The diversified index of Shanon-winner,Sinmpson,PIE, and Pielou of herbs were all decreased.In all monitoring plots in hydro-fluctuation belt 145-156 m above sea level section, in 2007(after 1 year of water level fluctuating) appeared 114 species of plants, 2008(after 2 years of water level fluctuating) appeared 95 species of plants, 2009(after 3 years of water level fluctuating) appeared 31 species of plants. From 2007 to 2009, the species of plants had decreased by 72.81%. The most of plants were herbs till 2009. And by the increase of water level fluctuating cycle, perennial herbs had decreased, annual herbs had increased by years. The diversified index of herbs in hydro-fluctuation belt were still decreased.(4) Based on the importance value of plants in monitoring plots, preliminarily considered the following plants can be options in restoration and reconstruction in Three Gorges reservoir hydro-fluctuation belt. In hydro-fluctuation belt 156-172 m above sea level section(the shallow and middle level), the herbs are: Cyperus rotundus , Bidens tripartita, Setaria viridis, Crassocephalum crepidioides, Eclipta prostrata, Digitaria chrysoblephara, Acalypha australis ,Oxalis corniculata, Saccharum arundinaceum, Bothriospermum tenellum ,Crassocephalum Setaria, crepidioides palmifolia, Ficus tikoua, Conyza bonariensis, Pouzolzia zeylanica, Gnaphalium affine, Digitaria sanguinalis, Rubu innominatu, Artemis caruifolia, Solanum americanum, Chrysanthemum indicum, Leptochloa panicea, Carex sclerocarpa, Pteris vittata, Paspalum thunbergii. The shrubs are:Diospyros lotus, Mallotus barbatus, Vaccinium mandarinorum, Rosa laevigata, Glochidion wilsonii, Coriaria sinica, Vitex negundo, Koelreuteria bipinnata, Rhus chinensis, Discocleidion rufescens, Myrsine africana , Broussonetia papyrifera, Indigofera pseudotinctoria, Vitis pseudoreticulata. The trees are: Sapium sebiferum, Koelreuteria bipinnata. In hydro-fluctuation belt 145-156 m above sea level section(the deep level), the herbs are: Digitaria ternata, Digitaria sanguinalis, Setaria glauca, Hemarthria altissima, Cyperus rotundus, Bidens tripartita,Cyperus iria, Xanthium sibiricum, Eclipta prostrata, Hemarthria compressa, Pouzolzia zeylanica, Crassocephalum crepidioides, Conyza bonariensis, Setaria viridis, Physalis angulata, Setaria palmifolia, Echinochloa crusgalli var hispidula, Cynodon dactylon, Alternanthera philoxeroides, Arthraxon hispidus, Eleusine indica, Solanum nigrum, Youngia erythrocarpa, Amaranthus hybridus. Because of the longest under water time and the deepest water level in this area, the suitable shrubs and trees are not found yet.更多还原