【作者】 刘金根；

【导师】 卞新民；

【作者基本信息】 南京农业大学 ， 生态学， 2007， 博士

【摘要】 据科学考察发现,在所有开发建设活动中,农林开发、公路铁路、城镇建设、露天煤矿、水利水电等造成的水土流失最为严重。公路、铁路、水利等工程建设与自然环境密切相关,其工程规模大、项目多、涉及面广,土石填挖工程形成的大量土石裸露边坡,破坏了既有植被,对当地生态环境影响较大,因此,项目开发与环境保护兼顾成为当前经济可持续发展的重大课题。以往通常采用单纯的工程防护技术措施,如浆(干)砌片石、喷锚防护等,这些工程措施导致原有植被破坏、生态景观效果差等一系列生态环境问题,同时工程建设造价高和后期草坡退化严重、维护成本高的问题突出。目前,边坡治理已经发展到防护和生态恢复阶段,但由于生态恢复研究一般需要较长时间,而我国刚刚把恢复生态学理论引入到边坡恢复中,这方面的论文很少,且都只是概念性的引入,研究成果也很少。因此,需要对边坡防护和绿化进一步探讨边坡的物质能量循环、恢复过程等,从生态系统层次认识植被对边坡稳定的作用,用生态经济学理论,考察边坡防护与生态恢复的经济问题。近年来,国內外香根草在工程护坡方面的研究与应用正如火如荼地展开,但多偏重应用研究,缺乏系统、深入的理论研究与总结。作为护坡先锋外来植物种,香根草在恢复中扮演的角色还难以正确判断与定位,目前仍不清楚其在群落演替中的作用与地位,以及其对演替方向和进程影响的内在机制。工程边坡大多坡体高陡,秋冬季干旱、夏伏季炎热,土体养分逐渐流失,土壤肥力降低,如何解决边坡呈现的无土、缺水,缺肥的状态及边坡植被面临的干、热威胁,将直接影响到边坡最终绿化效果和生态效益的发挥。因此对坡地自然环境信息和植物生理生态特性的了解,是植被护坡能否成功的关键。本研究就植被护坡中主要限制因子温度、水分和光照条件及刈割措施等人为因素对香根草生长的影响展开生理生态研究,藉此确定香根草对这些因子的耐性阈值,同时作为解释群落演替特征的理论依据。研究结果显示:在夏季高温干旱条件下香根草可耐55℃高温,停水持续时间可达24～42天,高温干旱引起植株地上部和地下部根系外部形态和内部生理生态性质的变化,不但抑制香根草地上部生长,引起叶片形态发生相应形态变化,还影响叶片的正常生理功能,导致叶绿素下降,叶片伤害率加重。尽管高温干旱起初可以小幅促进根系生长,但随着高温干旱持续发展,根系生长亦会明显受到抑制,根体积和根生物量将处于停滞状态。在冬季低温耐旱试验中,香根草也表现出较强的耐旱性,持续耐旱时间达4个月之久。试验中也显示出温度和水分互作效应明显,高温条件下土壤水分含量高香根草耐高温能力就强;低温下土壤水分过多或过少均不利于香根草春季返青及其后续生长发育。在实际工程边坡防护时,只要调查掌握边坡所在位置的温度等自然因素和坡面土壤水分的时空分布规律,就可以据此预测和判断该边坡是否适宜种植香根草。遮光对香根草的不同生育性状指标影响不同,即使是同一性状,在不同发育时期所受的影响也是变化的。试验结果表明:香根草春季移栽后缓苗期较长,约两个月后成活率才基本稳定,遮光对存活率有影响,但不显著;在香根草栽后两个月缓苗期内遮光对分蘖几乎没有影响,但此后遮光对分蘖影响极其显著;遮光对生长前期株高影响不大,后期影响较大;遮光对根茎比影响较大,但这种影响比较复杂。适度刈割(7月中旬～9月中旬刈割一次)有利于香根草的生长发育,但过度刈割或不刈割均不利于香根草的生长。植物护坡实践中,由于受工期的限制,对边坡植被状况缺少长期的观察和系统的研究,验收合格的工程边坡植被防护体系几年后的状况却常常难以令人满意。因此,只有对这些问题作详尽的调查研究分析,才能正确指导施工,否则边坡的植物生长将无法实现人工强制绿化向原始植物群落的顺利演替。本研究连续两年分春、秋两季对调查坡面植物群落采用样方法进行群落特征指标观测与调查,记录每样方内各植物的种类、盖度、高度、密度、地上部生物量和统计群落內各物种的出现频度等群落特征指标值。从香根草种群动态、群落内物种组成及生活型、群落质量特征值(丰富度指数、多样性指数、均匀度指数、优势度指数、相似系数)、生态位宽度及生态位重叠值等方面研究各类坡面植物群落的演替规律。坡向与坡位是影响香根草护坡植物群落特征的重要自然因素。通过对不同区域类型的3个边坡植被群落调查结果分析,发现:①香根草护坡植物群落演替不但受坡向(光照、温度差异)的影响,还受坡位(水肥等差异)的影响,其中坡向的影响更为关键。②同一坡向上不同坡位的群落相似性系数高于不同坡向中两群落的相似性系数。③向阳坡或受光较好的坡位上香根草种群优势明显,背阳坡或受光不足的坡位上香根草种群随时间退化,水土保持效果也会下降。④群落质量特征值与群落中香根草种群的特征值密切相关,群落质量特征指标与群落中香根草种群的物种优势度存在一定的相关性。当香根草种群优势明显时,香根草物种优势度与群落丰富度指数、群落多样性指数、群落均匀度指数呈负线性相关,香根草物种优势度与群落优势度指数呈正线性相关。但是当坡面植物群落退化,群落中香根草种群优势不明显时,群落中香根草种群的物种优势度与群落质量特征指标就不存在相关性。坡度也是影响香根草护坡植物群落特征的另一重要自然因素。通过对两不同坡度边坡上植物群落调查资料分析,结果发现:①两坡面上香根草护坡植物群落建植两年后出现分化倾向,坡度小(近20°)有利于香根草种群的发展,但同时也有利于乡土物种的着生定居。②春季坡度大(近30°)的边坡上植物群落丰富度指数高于坡度小的边坡上植被群落,坡度小的植物群落多样性指数大于坡度大的植被群落,秋季时结果則相反。但从时间序列上看,坡度小的植被群落多样性指数呈上升趋势;坡度小的边坡上植物群落均匀性指数小于坡度大边坡上的植被群落;坡度小的边坡上植物群落优势度指数高于大坡度边坡上的植物群落,但这种趋势会随时间下降。③香根草物种优势度与群落丰富度指数R1、群落多样性指数H′、群落多样性指数SW、群落均匀度指数J′、群落优势度指数C′均呈负线性相关。研究结果显示,人为控制群落演替方向与进程是可行的。香根草护坡植物群落建植初期香根草种群优势不明显,尤其是生境恶劣的工程坡地上,但可以通过人为控制措施快速建立人工植被。当然,这种控制必须是科学的,否则会适得其反,因此研究适当的人类行为对植物群落演替规律的影响是有意义的。刈割对植物群落演替发展方向与进程影响很大,研究表明:①刈割频率高,群落丰富度指数高,但会降低群落优势度指数值,春季表现得尤为明显。②2次刈割/年(分别在4月上旬和6月上旬)对群落演替发展方向与进程影响大,能增加群落中定居的物种数,有助于减小群落内部香根草种群与其它植物种之间的生态位重叠值,提高群落多样性指数。③香根草物种优势度与群落丰富度指数R1呈正显著线性相关,与群落丰富度指数R2呈正极显著线性相关;香根草物种优势度与群落多样性指数SW呈负显著线性相关;香根草物种优势度与群落均匀度指数J′呈负极显著线性相关;香根草物种优势度与群落优势度指数C′呈正显著线性相关。④刈割有利于植被截流涵水功能的发挥。施肥对植物群落演替影响也较大,研究发现:①施肥能增加群落中定居的物种数,但也会加剧群落內部物种之间的竞争关系。②施肥可以提高群落丰富度指数,秋季表现得尤为明显;③重施肥处理(3次,分别在6月初、7月初、8月初,每次用量225kg/hm~2)群落多样性指数最高,较重施肥(2次,分别在6月初和7月初,每次用量225kg/hm~2)有利于提高优势度指数值。④施肥处理群落坡面上位土壤含水量均高于中位土壤含水量,而未施肥处理群落則相反。⑤不施肥处理与重施肥处理植被群落差异大。⑥香根草物种优势度与群落丰富度指数R2呈正显著线性相关;香根草物种优势度与群落多样性指数SW呈负显著线性相关;香根草物种优势度与群落均匀度指数不相关;香根草物种优势度与群落优势度指数SN呈负显著线性相关。香根草与紫穗槐复种模式比较试验表明:①香根草种群在群落中的影响比紫穗槐大。②在阳坡上,香根草与紫穗槐间作对香根草生长不利,但有利于紫穗槐。在阴坡上,香根草与紫穗槐间作有利于香根草种群。③阳坡上紫穗槐与香根草间作,紫穗槐性状明显好于阳坡单作的紫穗槐,但在阴坡上紫穗槐与香根草间作时,紫穗槐性状比起阴坡上单种的紫穗槐优势并不明显。④阳坡上紫穗槐植株高,茎杆粗,但萌枝少,而阴坡上則相反。⑤香根草物种优势度与群落丰富度指数不相关;香根草物种优势度与群落多样性指数H′呈负极显著线性相关;香根草物种优势度与群落均匀度指数J′和群落均匀度指数PW均呈负极显著线性相关,但与群落均匀度指数J′相关性更好;香根草物种优势度与群落优势度指数C′和群落优势度指数SN均呈正极显著线性相关,但与群落优势度指数C′相关性更好。研究结果还显示:菊科、禾本科、豆科类植物最早定居于边坡上,物种数所占比例最低27.78%,最高可达92.86%;春季与秋季植物群落特征值表现差异较大,春季群落特征值规律表现相对复杂,秋季植被群落特征规律表现相对明显。因此,在秋季香根草滞长期进行植被群落调查效果较理想;群落质量特征值与群落中香根草种群优势度密切相关,但群落特征值的不同计算方法得出的结果可能存在差异。因此,对于群落质量特征分析来说,选择适当的评价方法至关重要,需要进一步探讨总结。生态系统恢复的不可确定性,迄今为止已提出了许多生态系统恢复的标准,生态系统恢复要求综合考虑生态、经济和社会因素,但对时间、空间上异质性的生态系统而言实在太难。对于生态系统恢复的时间到底要持续多长,目前的科学研究还不能确切地回答这个问题,还有待于开展可重复的和长期的试验和观测。更多还原

【Abstract】 According to scientific investigation,among all developments and construction activities,famrming and forest exploitation,road construction,town construction,coal mining,irrigation works and power generation cause the most serious soil erosion.The construction of roads,railways and irrigation works,which are not only large on scale and rich in number,but also widely involved and closely related to natural environment.The large amount of bare slopes resulted from soil and stone excavation and stuffing destroy original vegetation,and these all have negative effect on local entironment.Therefore,the combination of project development and environment protection has become an important task for sustainable economic development.In the past,simple protection techniques such as wet or dry brick-laying and spraying protection techniques were used,which caused destroyed vegetation,poor ecological scenery and other ecological problems.At the same time,the problems of high cost for project construction,latter vegetation of slope deterioration and high conservation cost are outstanding.At present,slope treatment has developed to the stage of slope protection and ecological restoration,but ecological restoration needs a relatively long time and in our country the theory of restoration ecology has just been introduced in slope restoration recently,so there are few papers in this respect,and they are only notional introduction,few study results have been known.Therefore,further exploration into substance and energy recycle,restoration process,etc in slope protection and virescence are needed to learn the functions of vegetation in slope stabilizing on the level of ecosystem and consider economic problems in slope protection and ecology restoration with ecology-economic theory.In recent years,the study on and the application of Vetiveria zizanioides are carded out very widely both domestic and abroad.But they emphasized on applied study,lacking systemic,deep study and summary.As a pioneer introduced species,it is difficult to tell and determine Vetiveria zizanioides succession role in restoration.At present,its function and role in community succession and the mechanics of its effect on succession orientation and process are still unknown.Most engineering slopes are highly steep,dry in autumn and in winter and hot in summer,and nutrients in the soil gradually leak,causing low soil fertility,thus,how to solve the problems of no soil,shortness of water and fertility and the threat of dryness and hotness that the slope vegetation is faced with will directly effect the final virescence results and the function of ecology effectiveness.Therefore,to learn the natural environment information on the slope and the physiological and ecological characters is the key to the success of plant slope protection.This study was designed to address a physiological and ecological exploration based on the effects of main limiting factors in vegetation slope protection such natural factors as temperature,moisture,light,etc.and such artificial measure as cutting on virescence growth,which the tolerance thresholds of these factors were determined by and used as the theory gist of community succession characters.The study results showed that under the hot and wet conditions in summer, vetiver tolerated 55℃,and water stress time may last 24 to 42 days.The exterior configuration changes and interior physiological and ecological changes in the aboveground parts and the underground root system resulted from high temperature and dryness not only suppressed the growth of aboveground parts,but also caused relative changes in leaf shape.In addition,it affected the normal physiological functions of the leaves,resulting in decrease in the value of SPAD and increase in leaf injure rate.Despite initial growth improvement in root system as a result of high temperature and dryness,as the hot and dry condition continued,the root growth was obviously suppressed.In winter low temperature water-stress experiment,Vetiveria zizanioides showed fairly strong dryness tolerance,continuous dryness lasted up to 4 months.Vetiveria zizanioides also showed obvious interactive effect.Under high temperature,higher soil moisture resulted in better high temperature tolerance.Under low temperature,excessive or inadequate soil moisture limits Vetiveria zizanioides’revival in spring and its latter growth and development.In actual engineering slope protection,investigation of natural factors such as temperature of the slope site the temporal and spatial distribution regulation of slope soil moisture are needed to predict and judge whether the slope is suitable for Vetiveria zizanioides planting. Shading has different effects on different growth indexs,even the same growth character was influenced differently during various growth stages.The experiment results indicated that the recovery time is long after transplanting,with stable survival rate after 2 months. Shading affects survival rate,but not significantly.Shading in the recovery stage of 2 months after transplanting hardly affected tillers,but later,shading influences tillers very significantly.Shading hardly affects prophase height,but affects later height more strongly. Shading has a rather strong effect on root -stem ratio,which is complex.In mid-growth stage,large amounts of tillers were produced while root system developed rapidly.A proper cutting measure(Cutting one time between the middle decades of July and the middle decades of September) is beneficial to growth and development of Vetiveria zizanioides,but excessive cutting or no cutting is disadvantage to its growth.In actual slope protection practice,because of time limit,vegetation protection system will not be satisfactory after several years,although it was qualified when checked and accepted.Lacking of long- time observation and systemic study causes great difference between the situations when accepted and those years later.Only when these problems have been investigated and studied particularly,can construction be conducted properly. Otherwise,the succession of slope vegetation from enforced artificial virescence to primitive plant communities cannot be successfully realized.In this study,community character indexes of the investigated slope plant communities are observed and investigated by the same means in springs and autumns of two continuous years.Community character indices such as the species,coverage,height,density,aboveground biomass of each plant and frequency were recorded.The succession laws of all types of slope plant communities are studied through Vetiveria zizanioides population dynamic,species composition of each community and their life styles,community quality characteristics,richness index,diversity index,evenness index,ecological dominance,similarity coefficient,niche breadth and niche overlap.Slope orientation and slope location treatments are important nature factors,which influences the community features with vetiver for slope-protection.By Anlysing the investigation data of plant communities in different three type sites,the results indicates that:①Vetiveria zizanioides for slope-protection community succession is affected not only by Slope orientation(difference in light and temperature),but also by slope location(difference in soil moisture and fertility) among which light is of most importance.②Comparability coefficient between the communities at the different locations on the same slope site is greater than that between the two communities at the different slope orientation sites.③On the slope exposed to sun or slope location with preferable sun light,Vetiveria zizanioides population dominance is significant,while on the slope backed to sun or slope location with lacking sun light Vetiveria zizanioides population degrades with time,and its water and soil conservation function decreases.④Community qulity eigenvalues are closely related to the population features of vetiver,and community qulity eigenvalues are some relatively with species dominance of vetiver.When population dominance of vetiver is significant,species dominance of vetiver is negative in linearity correlation with community richness index,community diversity index,community evenness index,yet species dominance of vetiver is positive in linearity correlation with community ecological dominance index.When the population dominance of vetiver is no significant,species dominance of vetiver exists no correlation with community qulity eigenvalues.Gradient is another important nature factors,which influences the community features with vetiver for slope-protection.By Anlysing the investigation data of plant communities on different gradient slopes,the results indicates that:①They began to put up with differentiation tendency when after the two plant communities with vetiver for slope-protection on the different gradient slopes were built for two years.Less gradient slope(approximate 20°) is propitious to the development of vetiver population,at the same time it is also useful to the native plant species for settling and living.②In spring the plant community richness index of more gradient slope(approximate 30°) is greater than that of less gradient slope(approximate 20°),and community diversity index of less gradient slope (approximate 20°) is greater than that of more gradient slope(approximate 30°),but the result is reverse in autumn.In time sequence,community diversity index of less gradient slope(approximate 20°) is put up with ascend tendency;community evenness index of less gradient slope is less than that of more gradient slope;community ecological dominance index of less gradient slope is greater than that of more gradient slope,but tendency is decreased with time.③species dominance of vetiver is all negative in linearity correlation with community richness index R1,community diversity index H’,community diversity index SW,community evenness index J’ and community ecological dominance index C’.We found that artificial controlling direction and course of community succession, which is scientific,is feasible.So the artificial action is significative for the laws of community succession.Cutting treatment makes a great effect on developing direction and process of community succession.The result points out that①The tendency that high frequency of cutting and high richness index can be seen in the whole,but decreases the index of ecological dominance index,it is especially obvious in spring.②The treatment of cutting twice(in the fast ten days of April and June,respectively) could make a great effect on developmenting direction and process of community succession,it also could increase the number of species in community,and decrease niche overlap between Vetiveria zizanioides and other species and enhance the index of community diversity index.③Species dominance of vetiver is significant positive in linearity correlation with community richness index R1,being significant positive in linearity correlation with community richness index R2(0.01 level),being significant negative in linearity correlation with community diversity index SW,being significant begative in linearity correlation with community evenness index J’,being significant positive in linearity correlation with community ecological dominance index c’.④Cutting treatment is useful to water conversation function of vegetation.The fertilizing also has a great effect on developing direction and process of community succession.The fertilizing experiment showes that:①Fertilizing could also increase the number of species in community,but it may enhance the competition effect among species.②Fertilizing also could advance the richness index of community,which is especially obvious in autumn.③Most fertilization(three times,on the earlier days in June,July and Auguest,respectively.225kg/hm~2.time) makes the community diversity index highest.More fertilization(twice times,on the earlier days in June and July, respectively.225kg/hm~2.time) is useful to increase the community ecological dominance index.④The soil moisture of fertilized community at top part of slope is higher than that at its middle part,while the unfertilized one is apt to the opposite situation.⑤The community with no fertilizing treatment is great different with that with fertilizing treatments.⑥Species dominance of vetiver is significant positive in linearity correlation with community richness index R2,being significant negative in linearity correlation with community diversity index SW,being no significant with community evenness index,yet being significant negative in linearity correlation with community ecological dominance index SN.Vetiveria zizanioides and Amorpha fruticosa Linn multiple cropping model experiment revealed that:①The population of Vetiveria zizanioides has a greater influence than that of Amorpha.fruticosa Linn.in the community.②It is harmful to Vetiveria zizanioides and helpful to Amorphafruticosa Linn.at the solar slope,while at the lunar slope we got the opposite result.③The characters of Amorpha.fruticosa Linn.were better than Vetiveria zizanioides evidently when they were intercropped at the solar slope,but the advantage was not obvious at the lunar slope.④Amorpha.fruticosa Linn.develop tall stands,thick stems with less tillers on the solar slope,on the opposite slope we got the opposite result.⑤Species dominance of vetiver is no significant in linearity correlation with community richness index,being significant negative in linearity correlation with community diversity index H’(0.01 level),being significant negative in linearity correlation with community evenness index J’(0.01 level) and community evenness index PW(0.01 level),but preferring in linearity correlation with community evenness index J’.Species dominance of vetiver is significant positive in linearity correlation with community ecological dominance index C’(0.01 level) and community ecological dominance index SN(0.01 level),but preferring in linearity correlation with community ecological dominance index C’.The results also showes that composite,gramineousness,leguminousness firstly intruded the slopes,and they all pressessed lagre proportion from 27.78%to 92.86%;There were rather great differences between community characteristics in spring and those in autumn.The community characteristics regulations in spring are complex,while the ones are comparatively obvious,so the results of investigating the plant communities is ideal when vetiver grows slowly in autumn;community characteristic values is closely related to species dominance of vetiver in the community,but different computing method of community characteristics may cause different results,so suitable assessment method is also important for community characteristics analysis and it needs further exploration.The uncertainty of eco-system restoration has already put up many levels of eco-system restoration,the ecosystem restoration requested synthetically consideration of ecology and economy and society,but it was difficult for heterogeneity of time and space. Because of the restriction of impersonality factor,the result was only on its phase.The sustaining time of ecological restoration is uncertain.It still need long-term and repeated experimentation and observation.更多还原