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1.
Abstract. Marked increases in growth and nitrogen content were found with Gunnera tinctoria Molina (Mirbel) plants infected (+ Nostoc ) with the cyanobacterium Nostoc punctiforme L., in comparison to uninfected (— Nostoc ) plants and this was attributed to N2-fixation by the phycobiont. Whilst host and symbiont can be grown separately, preliminary data indicates that the host plant is reliant on the cyanobacterium to meet its nitrogen requirements because it has little capacity to assimilate nitrate. Although the maximum light-saturated rate of photosynthesis was higher in the + Nostoc plants, there was no reduction in photosynthetic efficiency under lightlimiting conditions, despite marked differences in plant nitrogen status. Differences in photosynthetic rate were implicated as the major reason for the differences in plant productivity. Stomatal conductance was insensitive to changes in plant nitrogen status and did not parallel the variation in photosynthetic rates. The ecological significance of the largely invariant stomatal response and the consequences of differences in water and nitrogen-use efficiencies between + and — Nostoc plants is discussed.  相似文献   

2.
智利大叶草(Gunnera tinctoria)是一种不同寻常的固氮植物,已入侵到了世界各地,通常入侵到低蒸发需求和/或高降雨的环境。 在许多可以解释其作为一个成功的引入物种的机制中,差异性的物候特征可能起重要作用,但这可能取决于在次优化条件下生长和利用 营养物质的能力。我们研究了智利大叶草在物候和固氮能力方面是否具有优势,并将其与受智利大叶草入侵影响最大的本地物种灯芯草 (Juncus effusus)进行了比较。2016–2017年,我们每周或每两周对爱尔兰阿奇尔岛的长期种群进行物候学评估。在测量土壤温度,湿度和氧化还原电位的同时,收集了叶和花序数,叶总面积,光截获和地上生物量的数据。利用δ 15N 同位素并结合原位乙炔还原测量的方法评估了用于支持季节生长的固氮能力的重要性。研究结果表明,2016–2017年,智利大叶草和灯芯草开始生长的时间不同,智利大叶草叶片出现和展叶的时间较早,水分利用率较高时地上生物量最大。智利大叶草的早期生长依赖于预先形成的结构,5月下旬冠层发育达到最大,并且早于灯芯草。虽然在3月份观察到固氮作用,但这对冠层发育后期的生长有更显著的贡献。基于δ 15N 同位素分析结果表明,早期生长主要与根状茎的氮转移有关,而幼苗主要依赖于固氮作用。这一发现强调了养分调动对早期生长的重要性,并表明固氮能力的重要性可能在不同的发育过程中有所不同,并且其在入侵过程的不同阶段也是如此。  相似文献   

3.
4.
天然东北红豆杉土壤种子库研究   总被引:6,自引:2,他引:6  
刘彤  胡林林  郑红  周志强 《生态学报》2009,29(4):1869-1876
在黑龙江省穆棱东北红豆杉自然保护区内,对10株天然东北红豆杉结实母树冠下的土壤种子库进行了调查分析.结果表明:东北红豆杉土壤种子库中的种子数量在垂直方向和水平方向上都表现出明显的规律性.在不同深度土层中的种子数量差异显著(p<0.05).枯枝落叶层及0~5cm土层集中了最大量的种子,占总量的84%,随土层深度的增加,种子数量逐渐减少,15cm以下极少有种子出现.土壤种子库中具有活力的种子数量极少,不到总量的1%.种子丧失活力的首要原因是被昆虫和啮齿类动物啃食,占损失量的52%,其次是腐烂,占29%.在水平方向上,东北红豆杉种子具有近母株分布的特点,且在不同方向上种子数量差异极显著(p<0.01).当年下落到地面的东北红豆杉种子,按远离母株的顺序,种子数量逐渐减少;在围绕母株的八个方向上,东向的种子数量最多,其次是东北、北和东南方向,西面的种子数量最少.当年下落的3%的完好种子补充到土壤种子库中.自然条件下,东北红豆杉以种子繁殖,土壤种子库是其自然更新及种群恢复的重要基础,本研究结果对于东北红豆杉濒危机制的探索及种群恢复具有重要的理论意义.  相似文献   

5.
This study tested the efficacy of smokewater to determine the potential germination from soil seed bank in three management sites of the same National Park: a forest site prior to restoration, an ex‐pine plantation site and an ex‐mine site. This will provide further information to land managers so that more accurate planning can occur. Results showed that smokewater significantly increased the germination from the soil seed bank, and significant differences in the level of germination of weed species from the soil seed bank were seen between the three management sites. This use of smokewater may be a useful tool to help predict differences in the soil seed bank compared with predicting soil seed bank based on land‐use history and recent condition.  相似文献   

6.
为了解全球气候变化背景下森林草原过渡带持久土壤种子库对未来降水减少的响应,本研究以呼伦贝尔森林草原过渡带为研究区域,沿降水梯度采集0~10 cm土层的持久土壤种子库样本,研究种子库密度、物种组成、多样性及其与地上植被的关系,并利用结构方程模型研究年降水量对持久土壤种子库的直接影响及其通过地上植被和土壤有效氮、有效磷、土壤pH值产生的间接影响。结果表明: 随着降水量的降低,种子库密度和物种丰富度有增加趋势,森林草原过渡带草地土壤种子库物种多样性高于森林。土壤种子库与地上植被相似性整体较低。结构方程模型结果显示,年降水量对种子库的密度和物种丰富度的总效应为负效应,标准路径系数为-0.051和-0.122。年降水量对种子库的密度和物种丰富度的直接效应为正效应,降水量通过土壤全氮对种子库密度和物种丰富度产生显著的间接正效应,通过土壤pH和土壤有效磷对种子库物种丰富度产生显著的间接负效应,通过土壤pH对种子库密度产生显著的间接负效应。气候变化下降水减少会改变植物应对风险的策略,森林草原过渡带的持久土壤种子库对应对未来可能发生的降水减少具有一定的缓冲作用。  相似文献   

7.
Giant ragweed (Ambrosia trifida, L. henceforth referred to as GR), an annual non‐native invasive weed, may cause health problems and can reduce agricultural productivity. Chemical control of GR in grasslands may have irreversible side effects on herbs and livestock. In an attempt to propose a solution to the harmful effects of GR on grasslands, this study explores the fate of its soil seed bank (SSB) and considers the physical control of its SSB reduction. By studying GR distributed in grasslands of the Yili Valley, Xinjiang, China, we measured the spatial and temporal changes in seed density, seed germination, dormancy, and death. We analyzed seed germination, dormancy, and death following different storage periods. The study analyzed population characteristics over time, including seed fate, and examined physical control methods for reducing the SSB density. The SSB of GR occurs in the upper 0–15 cm of soil in grasslands. Seed density in the SSB decreased by 68.1% to 82.01% from the reproductive growth period to the senescence period. More than 98.7% of the seeds were rotten, eaten, germinated, dispersed, or died within one year after being produced. The seed germination rate of the SSB decreased with the number of years after invasion. When stored for 0.5 or 3.5 years, seed germination rates fell by 40%, during which time seed death rate increased by almost 40%. When GR was completely eradicated for two consecutive years, the SSB and population densities decreased by >99%. The vast majority of GR seeds germinated or died within one year; the germination rate decreased significantly if the seeds were stored dry at room temperature for a long time. Newly produced seeds are the main source of seeds in the SSB. Therefore, thoroughly eradicating GR plants for several years before the seeds can mature provides an effective control method in grasslands.  相似文献   

8.
持久土壤种子库研究综述   总被引:24,自引:3,他引:24  
土壤种子库是指存在于土壤上层凋落物和土壤中全部存活种子,简单地可分为短暂土壤种子库和持久土壤种子库。即使给予理想的萌发条件如季节、温度、湿度等,土壤种子库中也仍有部分种子保持休眠状态,休眠的种子组成了持久土壤种子库。持久土壤种子库具有在承受了空间或时间上不可预测的干扰的植被中发挥繁殖能力的潜势,因此,其在植被承受干扰后的恢复、管理和重建中常常起关键作用。研究持久土壤种子库能丰富生物多样性的内容,同时,可以为深入了解植被更新提供更多的信息。本文从持久土壤种子库的研究方法、分类方法、指示因子、生态意义,以及持久土壤种子库研究中存在的问题和今后的工作进行综述,试图为将来的工作奠定基础。  相似文献   

9.
围封沙质草甸土壤种子库与幼苗库的特征   总被引:8,自引:1,他引:7  
赵丽娅  李锋瑞 《西北植物学报》2003,23(10):1725-1730
采用野外定点取样和萌发实验相结合的方法,研究了科尔沁沙地围封沙质草甸土壤种子库和幼苗库的特征.结果表明:土壤种子库总密度为13854±1651有效种子数/m2,而幼苗库的总密度为808±164株/m2,仅为土壤种子库总密度的6%,土壤种子库与幼苗库总密度之间存在显著的差异 F=36.0,n=219,P<0.001 .土壤种子库与幼苗库的植物种数分别为37和44,其中一、二年生草本植物分别占种子库与幼苗库植物种数的62%和50%,而多年生草本植物所占的比例分别为24%和41%,灌木所占的比例很小,分别为14%和9%.土壤种子库与幼苗库种类组成上的相似性系数为0.667,表现出较小的异质性.土壤种子库密度与幼苗库密度之间存在显著的相关性,其间关系可用三次曲线来描述.  相似文献   

10.
生物土壤结皮对荒漠土壤种子库和种子萌发的影响   总被引:6,自引:0,他引:6  
研究了腾格里沙漠东南缘在不同自然条件(风、温度、水分)下,人工固沙植被区(24龄、41龄、50龄)和相邻天然植被区的两种生物土壤结皮对荒漠土壤种子库和种子萌发的影响。结果表明,荒漠土壤种子库在苔藓结皮上的储量显著高于藻类结皮。随着生物土壤结皮的发育,种子萌发量在苔藓结皮上增加,在藻类结皮上减少。生物土壤结皮层的含水量对种子萌发有显著的影响(p〈0.05),植物种子在湿润处理的生物土壤结皮上的萌发量高于干燥处理的生物土壤结皮上的种子萌发量。生物土壤结皮表层温度和亚表层温度对荒漠植物种子萌发无显著影响(p〉0.05),但总体而言,对于苔藓结皮,植物种子在较高温度下的萌发量略高于在较低温度下的萌发量,而对于藻类结皮,植物种子在较低温度下的萌发量略高。  相似文献   

11.
安太堡露天煤矿排土场土壤种子库   总被引:2,自引:0,他引:2  
采用种子萌发法研究了安太堡露天矿排土场的土壤种子库,共统计到17种植物种子,分属5科,以1年生草本植物种子为主.排土场土壤种子库具有极大的时空异质性,地上植被与土壤种子库群落组成上的相似性程度较低,复垦后期土壤种子库间相似性系数较低.随着复垦时间、复垦模式或立地条件的不同,土壤种子库的种类、密度各不相同.选择正确的复垦模式,有利于土壤种子库自我更新能力的增加和排土场生态系统稳定,对排土场的土地复垦和生态重建具有重要意义.  相似文献   

12.
土壤种子库作为地上植被更新的潜在种源,在植被自然恢复和演替过程以及生态系统建设中起着重要作用。以宁夏盐池县荒漠草原区4种植物群落为研究对象,通过对封育16年后植物群落土壤理化性质的变化与其土壤种子库的特征之间的关系的探讨,揭示荒漠草原植物群落的土壤种子库分布特征和演替趋势,以及土壤质量的改变如何影响土壤种子库特征。研究结果表明:(1)不同植物群落土壤种子库物种组成及种子密度不同,同一物种在不同植物群落土壤种子库中出现时种子密度也存在差异;禾本科、菊科、藜科植物种在4种植物群落土壤种子库中出现比例均较高,分别占到26.19%、21.43%和19.05%,占总物种数的66.7%;灰绿藜、冰草、碱蓬在4种植物群落土壤种子库中均有出现。(2)4种植物群落土壤种子库中多年生植物和一年生植物种子居多,灌木、半灌木植物种较少。(3)4种植物群落土壤种子库中物种数和种子密度均表现为:芨芨草群落 > 苦豆子群落 > 油蒿群落 > 盐爪爪群落;且随着土层的加深,4种植物群落土壤种子库中物种数和种子密度均呈递减趋势。(4)4种植物群落土壤种子库中Shannon-Wiener指数、Simpsin指数、Pielou指数和Patrick指数均表现为芨芨草群落 > 苦豆子群落 > 油蒿群落 > 盐爪爪群落。此外,芨芨草群落土壤种子库与油蒿群落土壤种子库相似性最高,油蒿群落与盐爪爪群落的最低。(5)土壤种子库物种多样性特征指数与土壤pH、含水量、碱解氮呈正相关,与土壤电导率呈负相关,其中土壤pH和电导率对种子库物种多样性的影响较大。荒漠草原封育以后,土壤种子库中植物种数、种子密度和物种多样性均呈增加趋势,且以多年生植物和一年生植物种子居多;禾本科和豆科植物的物种数和种子密度大于菊科和藜科,这表明围封后牧草品质改善,植物群落正向演替。  相似文献   

13.
Much of our current understanding of the impact of invasive species on plant communities is based on patterns occurring in the above-ground vegetation, while only few studies have examined changes in soil seed banks associated with plant invasions, despite their important role as determinants of vegetation dynamics. Here, we reviewed the literature on the impact of plant invasions on the seed bank and we provide a quantitative synthesis using a meta-analysis approach. Specifically, (1) we quantified the impact of 18 invasive alien plants on (i) species richness and (ii) density of the seed banks of invaded communities, based on 58 pair-wise invaded-uninvaded comparisons (cases); we identified (2) the invasive taxa that are responsible for the largest changes in the seed bank; and (3) the habitats where substantial changes occur. Our study showed three major findings: (1) species richness (68% of cases) and density (58% of cases) were significantly lower in native seed banks invaded by alien plants; (2) species richness and density of native and alien species were remarkably lower in seed banks invaded by large, perennial herbs compared to uninvaded sites; and (3) invaded seed banks were often associated with a larger richness and/or abundance of alien species. This study indicates a need for additional seed bank data in invasion ecology to characterize species-specific and habitat-specific impacts of plant invasions, and to determine whether changes in the seed banks of native and alien species are a symptom of environmental degradation prior to a plant invasion or whether they are its direct result. The findings of this study help improve our capacity to predict the long-term implications of plant invasions, including limitations in the recruitment of native species from the seed bank and the potential for secondary invasions by seeds of other alien species.  相似文献   

14.
Questions: Are soil seed banks affected by invasions of alien plants? How can we rigorously assess alterations in seed bank communities associated with invasive species and account for the high spatial variability of seed bank data? How do multivariate approaches compare with more traditional approaches based on analysis of variance? Location: Three riparian sites, Ireland. Methods: A protocol based on a combination of multivariate techniques was used to characterize soil seed bank communities associated with the herbaceous invasive species Heracleum mantegazzianum in May and October. Permutational multivariate analysis of variance (PERMANOVA) was used to test the effects of the factors “invasion”, “site”, “plot” and “depth” on the soil seed bank, while multivariate analysis of dispersion (PERMDISP) provided a measure of the variability of seed bank data at different spatial scales. Similarity percentages analysis (SIMPER) was used to identify the species that contributed most to the differences between invaded and uninvaded communities. A comparison between the results of PERMANOVA and ANOVA analyses was also made. Results: The composition of seed bank communities invaded by H. mantegazzianum differed significantly from that of uninvaded seed banks. Invaded seed banks were less diverse and had reduced abundance, and were dominated by only a few species, such as Urtica dioica and Juncus effusus. Such patterns were recorded at each of three depth categories, indicating that invasive plants can affect both the transient and the more persistent component of the soil seed bank. Seed bank variability was significantly higher within uninvaded areas, supporting the notion that invasions tend to lead to more homogeneous communities. Conclusion: The analytical protocol used in this study was effective in quantifying the effect of plant invasions, at different spatial scales, providing a statistically robust analysis of alterations in soil seed bank communities. Compared to ANOVA, this protocol provided more biological information and was more appropriate for analysis of the data. This approach is therefore recommended in soil seed bank and invasion ecological studies.  相似文献   

15.
金沙江干热河谷山地植被恢复区土壤种子库和地上植被研究   总被引:10,自引:0,他引:10  
罗辉  王克勤 《生态学报》2006,26(8):2432-2442
土壤种子库在植物种群动态中起着重要作用。土壤种子库可缓解种群的灭绝过程,保存群落中植物种的表现特征,是植被天然更新的物质基础。通过对金沙江干热河谷山地植被恢复区(包括水平阶、自然坡面、沟底)和未恢复区(包括放牧地)的土壤种子库和地上植被的组成、大小及多样性进行比较研究表明,植被恢复区土壤种子库和地上植被的密度、丰富度、多样性及均匀度均大于未恢复区。恢复区地上生物量要远大于未恢复区。水平阶和各类型间的土壤种子库密度与地上植被密度差异显著。土壤种子库中草本植物占很大比例。孔颖草和扭黄茅是土壤种子库和地上植被的两大优势种,两者的个体数量、重要值及生物量最大。土壤种子库和地上植被有较高的相似性,且随着恢复程度的加深,相似性有增高的趋势;土壤种子库密度和地上植被密度之间关系可以用二次和三次曲线拟合。  相似文献   

16.
腾格里沙漠东南缘苔藓结皮对荒漠土壤种子库的影响   总被引:3,自引:0,他引:3  
对腾格里沙漠东南缘沙坡头人工植被区和天然植被区苔藓结皮种子库进行了研究.结果表明,土壤种子库密度随着苔藓结皮的发育呈现增加的趋势,天然植被区是24年生人工植被区的3.4倍.种子库中共发现12种植物种子,分属于6科,其中1年生草本植物占70%以上.人工植被区未发现有多年生草本的植物种子,天然植被区多年生草本占20%,半灌木植物在人工植被区和天然植被区分别占20%和10%.人工植被区土壤种子库物种丰富度指数相对较低,而天然植被区物种丰富度指数是人工植被区的2倍;人工植被区土壤种子库物种多样性指数随着结皮的发育略有下降,天然植被区的多样性指数最高,为0.693;人工植被区土壤种子库物种相似性指数为1,相对较高,而人工植物区与天然植被区的物种相似性指数为0.4.苔藓结皮的出现增加了地表粗糙度,有利于对种子的捕获,同时显著地改善了土壤环境,有利于更多植物的定居.  相似文献   

17.
长白落叶松是东北地区主要的用材树种,其种子雨和种子库研究鲜见报道。在辽东山区用收集器收集的种子分析了长白落叶松种子雨组成、质量和扩散距离,每隔2个月调查1次种子库数量,并结合靛蓝染色法测定每次种子的活力来分析土壤种子库动态。结果表明,辽东山区的长白落叶松种子雨从8月中旬开始,9月末到10月初达到高峰期,11月初结束。在起始期,种子雨以干瘪的不完整种子为主,而从高峰期开始,种子雨以完整种子为主。整个长白落叶松种子雨中不完整种子约占种子雨总量的45%,这些不完整种子由被动物取食、空粒和病虫害危害种子组成。完整种子的平均生活力为56.4%,即有活力的种子仅占整个种子雨的30%。种子雨集中在母树周围,在林缘1次扩散距离一般不超过1.5倍树高。种子雨到达地面之后,主要分布在枯枝落叶层,土壤0—5em层有少量分布,土壤5em以下没有种子分布;土壤种子库的种子主要在翌年雪融化后开始萌发、被取食、搬运以及腐烂,其中腐烂种子数占45.4%,动物取食为30.0%。种子库的种子数量和活力在冬季没有明显变化,而在翌年,种子数量和活力明显减少,4、6月和8月份种子数量分别为(506.3±35.56)粒m^-2,(267.1±17.47)粒m^-2和(143.6±9.83)粒m^-2,对应的活力分别为47.8%±4.68%,19.4%±3.39%和0%,这表明长白落叶松种子不能在地面形成连续的种子库。  相似文献   

18.
Abstract The soil seed bank and its relation to the extant vegetation in a Eucalyptus regnans F. Muell. forest in the Central Highlands of Victoria were examined. The average seed density was 430 germinable seeds m?2 to a depth of 2 cm. There was a polynomial regression relationship between the density and species richness of seeds in soil and forest age (0. 6–54 years). Species richness was not significantly different among soil depths (0- 2 , 2- 5 , 5–10 and 10–20 cm) in the forest stand of 54 years old. More seeds germinated from the 5–10 cm depth than from the other depths. Forbs accounted for 73% of the total germinable seeds and there was no germination of E. regnans. The number of species, particularly woody plant species, germinating from the soil seed bank were significantly lower than in the extant vegetation. However, almost all species present in the soil seed bank were present in the vegetation. The soil seed bank provides an important source for the rapid regeneration of understorey vegetation following clear-cutting and slash-burning in the E. regnans forest. The rapid understorey establishment may play an important role in protecting soil from erosion, in nutrient conservation, replacement and redistribution. The soil seed bank may also be a necessary source of maintaining genetic diversity in the forest over the long term.  相似文献   

19.
为了探明多年免耕下农田恶性杂草发生的机理,提高保护性耕作下作物对农田恶性杂草持久稳定的抑制效果,依据陕西安塞田间4a的定位试验, 采用小区调查取样和室内实验相结合的方法,从物种组成、密度特征、多样性以及相似性特征等方面,研究了黄土丘陵旱作农区大豆(Glycine max)、玉米(Zea mays)、红小豆(Semen Phaseoli)、马铃薯(Solanum tuberosum)在翻耕化肥(CF)、翻耕有机肥(CM)、翻耕无肥(CN)、免耕化肥(NF)、免耕有机肥(NM)、免耕无肥(NN)等水平下的农田土壤种子库.结果表明: (1) 4种作物24种土样中共萌发出12个物种1965株幼苗,隶属于7科12属.1年生杂草占94%,棒头草(fugax nees ex steud)、苋菜(Acalypha australis)、马唐(Digitaria sanguinalis)、早熟禾(Poa sphondylodes)为优势种,占87%.(2)在0~20cm土层不同处理间,土壤种子库的密度变动于(282.9±63.4)~(7482.5±1078.3)粒·m- 2,其中,红小豆小区>马铃薯小区>大豆小区>玉米小区;翻耕小区>免耕小区;有机肥小区>化肥小区>无肥小区,差异极显著. (3)土壤种子库密度NM红小豆最高,NN玉米最低;丰富度指数CF大豆为2.30;NN红小豆为0.29;多样性指数NN大豆为5.56,CF红小豆为0.45;生态优势度NF玉米为1.35,CF大豆为0.17.玉米、大豆是黄土丘陵沟壑旱作农区免耕下农田抑制杂草最为适宜的作物, NM玉米、NF大豆和NM大豆是黄土丘陵沟壑旱作农区较优的耕作管理方式,其农田的生态效应是能够竞争性抑制恶性杂草的蔓延,优化土壤环境,杂草的多样性高且比较均衡,杂草的土壤种子库密度低.  相似文献   

20.
Luo H  Wang K Q 《农业工程》2006,26(8):2432-2442
Soil seed bank plays an important role in the composition of different plant communities, especially in their conservation. Although soil seed bank, aboveground vegetation and their relationship have been the subject of much recent attention, little is known about the size and species composition of the soil seed bank and about the aboveground vegetation in the semiarid hillslope grasslands. There is limited understanding of how these components interact to determine the importance of seed banks in regeneration. In this study, the size and species composition of a soil seed bank and aboveground vegetation have been assessed in an experiment using 36 vegetation quadrats and 108 soil samples in terrace, slope, gully, and grazing land. This land represents a range of habitats within a hillslope grassland in Jinshajing hot-dry river valley of Yunnan, China. Terrace, slope, and gully represent restored sites and grazing land typifies unrestored sites. Twenty-one taxa in the seed bank were identified with a median and median density of 7 species/m2 and 5498 seeds/m2, respectively, whereas in the aboveground vegetation, 19 species were observed with a median and median density of 6 species/m2 and 1088 plants/m2, respectively. Both seed bank density and aboveground vegetation density among grazing land, gully, slope, and terrace differed significantly. There was an absolutely high proportion of herbaceous species in the seed bank and aboveground vegetation. Gramineae predominated over both seed bank and vegetation. The most frequent seeds and plants were Bothriochloa pertusa (L.) A. Camus and Heteropogon contortus (L.) Beauv that had the highest individual number, importance value, and biomass. In the seed bank, the seeds of Bothriochloa pertusa (L.) A. Camus and Heteropogon contortus (L.) Beauv accounted for 50.68% and 33.10% of the total seeds, respectively. In the aboveground vegetation, the individual number of Bothriochloa pertusa (L.) A. Camus and Heteropogon contortus (L.) Beauv accounted for 55.66% and 29.86% of the total, respectively. The biomass of Bothriochloa pertusa (L.) A. Camus and Heteropogon contortus (L.) Beauv accounted for more than 70% of the total, reaching 206.71 g/m2 and 147.76 g/m2, respectively. Bothriochloa pertusa (L.) A. Camus and Heteropogon contortus (L.) Beauv had the highest importance value of 193.01 and 159.99, respectively. Density, biomass, species richness, species diversity, and evenness were the highest in terrace land, whereas these were lowest in grazing land. Similarities between the seed bank and the aboveground vegetation were moderately high and not very different among slope, gully, and terrace lands, while for grazing land, they tended to increase when the restorative stage progressed. This result contrasts with some other studies where the seed bank contributes very little to the seedling flora and the vegetative growth clearly overwhelms sexual reproduction. The hypothesis about significant functional correlation between soil seed bank density and aboveground vegetation density is conformed. Correlation between soil seed bank density and aboveground vegetation density can be described in quadratic and cubic curves. The strong similarity between the vegetation and the seed bank is attributed to a large proportion of the species Bothriochloa pertusa (L.) A. Camus and Heteropogon contortus (L.) Beauv., which are seed profusive and whose seeds have a significant viability in the ground. The high density, biomass, species richness, species diversity, and uniformity of the reclaimed site are related to the sufficiency of heat and water supplies for species establishment and growth in the site, which partly reflects the effective efforts for hillslope grassland restoration. It is believed that the efforts for vegetation restoration have altered the microhabitat conditions of the site and have provided a favorable habitat for species to establish and grow.  相似文献   

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