西南喀斯特山地森林群落土壤种子库研究综述

土壤种子库作为喀斯特山地研究的重要组成部分,其研究成果在深入探讨喀斯特地区植被结构、功能与动态方面具有十分重要而独特的作用.本文系统介绍了该地区种子库的研究方法及主要内容.在对已有成果进行综合分析的基础上,就目前喀斯特土壤种子库研究中亟待解决的一些问题进行了探讨,认为今后应加强森林群落中优势种或建群种土壤种子库动态变化,外来入侵物种土壤种子库动态及其对群落物种多样性的影响机理和土壤种子库在退化植被恢复中的作用与潜力等领域的研究工作,以期为从事西南喀斯特地区土壤种子库研究和该地区植被群落恢复实践提供理论指导.     

中国矿区土壤种子库研究的必要性与挑战

土壤种子库是土壤及其表面凋落物中所有具生命活力的种子,可反映区域特有的生物多样性特征,其多数存在于表层土壤.作为植被恢复生长的基础和潜在的绿化材料,表土和土壤种子库是矿区不可再生的有限资源.土壤种子库研究是我国矿区土地复垦与生态重建领域的热点之一.由于矿业生产的特殊性,矿区土壤种子库研究不能仅仅关注土壤种子库中种子类型、数量及其与地表植被相互关系等常规静态内容,还需要借鉴特殊生境下土壤种子库的研究成果,并结合矿区土地利用特征,在研究体系和思路上寻求突破.本文总结了矿区土壤种子库研究的特殊性及相关研究进展,综述了特殊生境下土壤种子库的研究进展及启示,并提出了我国矿区土壤种子库研究所面临的挑战,为强化我国矿区土壤种子库研究、提高我国矿区土地复垦中表土及土壤种子库利用效率、加快植被恢复进程提供参考.     

黄土丘陵区延河流域潜在植被分布预测与制图

潜在植被的分布预测与制图对植被恢复规划具有重要的指导价值.利用广义相加模型（generalized additive model,GAM）,结合GIS空间分析技术和环境梯度分层采样技术,为延河流域24个地带性物种建立了分布模型,并在考虑群落内部物种种间关系及其分布概率的基础上,对物种分布进行运算,模拟预测了延河流域37种植物群落的分布状况和延河流域的潜在植被分布.结果表明: 研究区植被分布预测值与实际调查值间的差异不显著,预测的植被空间分布较好地反映了延河流域潜在的植被分布状况,表明该模型具有较好的预测能力,对于区域植被恢复的目标设定和恢复规划具有重要意义.     

铁矿采矿迹地不同恢复年限的植被特征

1997-2011年利用覆盖客土、覆盖客土+生态植被毯措施对北京首云铁矿尾矿库进行植被恢复,本研究调查了不同恢复年限的植被特征,并与周边自然植被进行对比分析.结果表明:恢复植被以禾本科、豆科和菊科植物为主,占植物物种总数的58％;采用客土+生态植被毯恢复的植被多度、物种丰富度和Shannon指数均接近周边未扰动植被,高于仅覆盖客土恢复的植被;客土+生态植被毯恢复植被的地上和地下部分生物量显著高于仅覆盖客土的植被,与对照差异不显著;采用客土+生态植被毯措施恢复植被的枯落物生物量第6年达到对照水平.采矿迹地植被快速重建对北京市生态涵养发展区的潜在生态功能发挥具有重要的意义,为类似采矿迹地植被重建提供可借鉴的案例.     

基于遥感数据对中国表土花粉进行植被覆盖度定量估算的研究

本文主要探讨利用现代类比法将表土花粉数据定量转换为植被覆盖度的方法,以及该方法在中国复杂地貌和气候环境中应用的可行性和可信度.陆地植被覆盖使用了卫星遥感MODIS 500×500m分辨率的栅格数据,覆盖度分类为乔木、草地和裸地三种.使用的表土花粉数据共1 127个样点,其地理分布基本能够覆盖中国的各种植被类型.用于现代类比法定量计算的化粉变量类型共64个.研究结果表明,计算获得的每个样点的植被覆盖度与MODIS实际观测值具有很好的对应性,基于花粉的覆盖度估算值与遥感实际观测值之间的相关性很高,其中裸地达到0.99,乔木达到0.97,草地为0.95.从空间分布看,利用花粉定量转换的植被覆盖样点可以清楚地识别从裸地向草地和乔木的变化区间,并且与植被分布的实际情况吻合.本研究证明,基于中国表土花粉数据对植被覆盖度的定量恢复足可行的.此外,研究发现乔木覆盖度较高的对应特征花粉较多,主要是松属、栲属、栎属(含青冈栎)、桦属、桤木属、杨梅属、冷杉属,云杉属等,而草地的对应特征花粉类型有莎草科、禾本科、蒿属、蔷薇科、豆科等,裸地主要为麻黄属和藜科等.     

表土在彭湖高速公路低缓边坡生态恢复中的应用

选取江西省彭泽至湖口高速公路沿线5个典型低缓边坡试验点,利用表土生态恢复,采用样线法调查1年后的试验边坡植物的生长情况。结果表明:在彭湖高速公路低缓边坡利用表土资源进行边坡生态恢复是可行的,各种利用表土的试验设计均取得了较好的恢复效果,其中,边坡覆盖7～10cm中层厚度表土后采取人工撒播恢复方式,边坡植物群落的Simpson多样性指数(平均0.80)及Pielou均匀度指数(平均0.84)相对较高,恢复效果较好;同时,此试验条件下生物量的积累值(平均446g.m-2)和木本植被的群落重要值(平均14.5)都显著高于其他恢复方式,这有利于群落结构的稳定和延续。     

云南亚热带南部表土孢粉组合与植被间的定量关系

以云南亚热带南部沿温度带分布的35个表土孢粉样品和7个植被样方调查为基础,计算了代表性孢粉类型的百分比和孢粉浓度,及常见孢粉的R值,并分析了影响R值的因素;同时,研究了植物群落和样方内孢粉组合的相似度。结果表明,云南亚热带南部表土样品孢粉产量丰富,蕨类植物孢子产量较高,具有典型的亚热带特征,且山地垂直分异显著;木本、草本植物花粉基本代表了区域内乔木和草本植物特征,蕨类植物孢子则具有超代表性;表土孢粉组合与植物群落间的相似系数绝大部分都在70％以上,表土孢粉组合基本上可以反映植物群落面貌;表明云南亚热带地区表土孢粉与现代植被之间具有较好的对应关系,这对在该区利用化石孢粉资料定量恢复古植被和重建古气候有重要意义。     

基于响应面分析法土壤种子库植被恢复的因素优化

表土厚度、覆盖物厚度、引用乔木种子数是土壤种子库应用于植被恢复工程中应考虑的重要因素.为了确定最优工程条件,利用Box-Behnken中心组合设计进行3因素3水平试验,用Design Expert进行响应面优化,以获取最优模型及各因素最优水平.结果表明: 本次响应面优化应采用二次模型,模型具有较好的统计学意义（P<0.0001）,能够很好地反映全体自变量和因变量的关系.响应模型的最优点为:表土厚度为4.3 cm,覆盖物厚度为2 cm,引入乔木种子数为224 ind·m^-2,种子库萌发个体总数可以高达6222 株·m^-2.土壤种子库幼苗萌发过程中,表土厚度与覆盖物厚度、表土厚度与引入乔木种子数交互作用显著,而覆盖物厚度与引入乔木种子数的交互作用不显著.表土厚度的响应曲线陡峭,且回归方程的标准化系数最大,是影响土壤种子库萌发物种个体总数的最重要因素.     

寒温带湿地火后植被恢复的影响因子

寒温带湿地在维护区域生态平衡方面发挥着重要作用.火是湿地的重要干扰因子.重度火烧会导致湿地生态功能明显退化.火后植被恢复,特别是火后早期植被的恢复是生态系统功能恢复的前提和基础.本文对火后湿地植被恢复影响因子的国内外研究进展进行了综述.寒温带湿地火后植被恢复受到火强度、火面积、火前植被类型、物种更新特性、立地条件等多因子的制约.寒温带湿地火后恢复的长期监测、植被恢复的关键影响因子、冻土层在植被恢复过程中的作用、植被恢复的理论与技术将是今后研究的重要方向.     

南京紫金山现代植被表土孢粉的初步研究

 选择南京紫金山现代植被进行植被调查和表土孢粉分析。结合中国东部不同气候带下的几个地点表土孢粉分析,把孢粉百分含量、孢粉组合及孢粉优势种、标志种与植被的各项参数进行对比,找出植被与孢粉之间的关系。为恢复古植被、古生态和古气候提供科学依据。     

Natural revegetation on forest topsoil and subsoil along roadsides in boreal forest

Questions: Does natural revegetation from indigenous soil improve the restoration success of roadside areas? What are the effects of topsoil, subsoil and fertilization on natural revegetation? Location: Akershus county, SE Norway (10°25′ E, 59° 44′ N). Methods: We used a recently constructed road through a boreal coniferous forest for a three year (2000–2002), fully replicated revegetation experiment (six replications). Treatments were soil type (two levels; one topsoil and one subsoil type) and fertilization (two levels; NPK and unfertilized control). Ordination methods, constrained ordination methods as well as univariate statistical methods, such as Wilcoxon's signed‐rank test and correlation analysis, were used to assess the relative importance and significance of treatments on the plant species composition. Results: There was no fertilization effect on species composition. The species composition on both soil types was stabilised by the second year. The species dominating the topsoil were more in accordance with the indigenous vegetation than was the case on the subsoil. The significant difference in species composition among blocks, persisting for the entire study period, indicated that local factors are important determinants of the outcome of revegetation. Conclusions: Unfertilized topsoil provides a revegetation result in better accordance with the indigenous vegetation than does subsoil.     

石林风景区不同石漠化人工修复方式对木本植物群落组成及种群生态位的影响

石漠化是我国西南喀斯特地区生态修复最严重的障碍,植被恢复是石漠化治理的重要途径。近50年来,我国开展了大量石漠化植被恢复的实践与研究,包括自然恢复与人工修复。但是,长期以来缺乏对已完成人工修复的植被的演替特征和修复效果的研究,而人工修复植被的效果评价能为石漠化生态修复提供理论依据与实践经验。以石林风景区中两类人工修复植被——栽植植被(PV)与飞播植被(ASV)为研究对象,以地带性自然植被(ZNV)为对照,研究人工修复植被中木本植物群落组成、群落多样性和种群生态位特征,以期揭示不同人工修复方式下的植被构成规律以及对有限资源的利用程度。结果表明:(1)在地带性自然植被、栽植植被和飞播植被3种植被类型中分别记录到木本植物92种(45科80属)、138种(50科101属)与44种(26科37属),3种植被类型中的共有种12种。(2)3种植被类型的Patrick丰富度指数与Shannon-Wiener多样性指数排序均呈现为地带性自然植被栽植植被飞播植被(P0.01),栽植植被与地带性自然植被之间的Jaccard相似性指数为0.14,飞播植被与地带性自然植被之间的Jaccard相似性指数为0.12;(3)3种植被类型中任意两者之间的生态位宽度均存在较大差异,但是清香木(Pistacia weinmannifolia)在3种植被类型中生态位宽度排位均靠前,利用资源能力较强;(4)生态位重叠程度的排序为地带性自然植被飞播植被栽植植被。综上,与地带性自然植被相比,人工修复植被物种多样性较低,但是人工修复植被的优势种中乡土植物占89.33%,乡土植物生态位较广,生态位重叠值偏低,植被较为稳定。在人工修复植被中,栽植植被的修复效果优于飞播植被。研究结果对未来喀斯特石漠化地区进行人工植被修复的物种规划与群落构建时具有重要的参考价值。     

Roadfill Revegetation in Semiarid Mediterranean Environments. Part II: Topsoiling, Species Selection, and Hydroseeding

Erosion is one of the main problems in roadfill restoration. Revegetation is widely used as a method to reduce erosion rates, and it is often carried out through hydroseeding. In semiarid Mediterranean conditions, this approach to revegetation often produces poor results due to climatic limitations. We evaluated whether (1) spreading topsoil and (2) hydroseeding with local rather than commercial species mixtures could improve the vegetative cover of roadfills. The study was carried out in 24 plots over a 20‐month period. At the end of the study, vegetation cover was higher in topsoiled plots (38.8%) than in nontopsoiled plots (21.5%). Locally selected species produced higher vegetative cover (61.1%) than did standard commercial species (52.2%). After 20 months, the erosion index was not different among any treatment probably due to the low sensitivity of this variable. These results suggest that amendment of soils through the addition of topsoil is an important technique in roadfill revegetation in Mediterranean environments. Additionally, hydroseeding with local species will produce better vegetative cover on roadfills than does hydroseeding with available commercial species.     

露天煤矿排土场边坡植被组成特征及其群落稳定性评价

研究植被恢复过程中植物群落组成、结构及稳定性的变化,可进一步了解到植物群落的演替过程及规律。采用空间代时间的方法对内蒙古锡林郭勒盟北电胜利露天煤矿4个排土场边坡人工恢复植被进行群落调查,在此基础上采用多样性指数与优化后的M.Godron稳定性指数对植物物种组成、物种多样性及其群落稳定性进行分析,探究不同恢复年限排土场边坡植被在恢复过程中群落特征及稳定性变化特征。结果表明：（1）排土场边坡植物物种组成共有16科44属56种,植物群落组成较简单,其中禾本科种类最多,生长型以草本植物为主。（2）随着恢复年限的增加,植物生活型由一、二年生转变为多年生,坡面优势种由人工种植植物转变为本土植物。（3）整体看,随着恢复年限增加,物种多样性呈下降趋势,群落稳定性整体呈上升趋势。（4）由于不同坡向土壤微环境差异,北坡恢复效果及稳定性好于南坡。本研究在一定程度上可为露天煤矿排土场边坡人工修复过程中植物物种及合理配置模式的选择提供科学依据。     

云南南涧干热退化山地人工植被恢复初期生物量及土壤环境动态

 研究了云南南涧干热河谷退化山地人工恢复植被初期阶段(3～5年)主要植物群落的地上生物量和恢复植被后土壤水分及养分的相关动态。结果表明,几种外来植物的适应性强,早期生长迅速并能很快郁闭。人工群落生物量都高于当地次生的坡柳灌草丛。引进种的地上生物量和总平均生长量分别是坡柳的3～16倍和5～20倍,其生长速度也高于乡土树种云南松。雨季人工植被下土壤含水量比光坡地增加约100％,表土层则增加2倍以上。但在旱季,林地土壤含水量与光坡地相近甚至低于光坡地。植被的恢复使土壤养分朝着良性循环转变。土壤有机质、速效钾含量提高,全氮含量稍有降低但不明显,速效磷含量降低,pH值有所下降。这些变化主要发生在土壤表层,人工植被及其土壤生态系统的恢复仍处于不稳定状态。     

Seed Stores for Restoration of Species-Rich Shrubland Vegetation Following Mining in Western Australia

The extreme species richness of native shrubland vegetation (kwongan) near Eneabba, Western Australia, presents a major problem in the restoration of sites following mineral sand mining. Seed sources available for post-mining restoration and those present in the native kwongan vegetation were quantified and compared. Canopy-borne seeds held in persistent woody fruits were the largest seed source of perennial species in the undisturbed native vegetation and also provided the most seeds for restoration. In undisturbed vegetation, the germinable soil seed store (140–174 seeds · m^?2) was only slightly less than the canopy-borne seed store (234–494 seeds · m^?2), but stockpiled topsoil provided only 9% of the germinable seeds applied to the post-mining habitat. The age of stockpiled soil was also important. In the three-year-old stockpiled topsoil, the seed bank was only 10.5 seeds · m^?2 in the surface 2.5 cm, compared to 56.1 to 127.6 seeds · m^?2 in fresh topsoil from undisturbed vegetation sites. In the stockpiled topsoil, most seeds were of annual species and 15–40% of the seeds were of non-native species. In the topsoil from undisturbed vegetation, over 80% of the seeds were of perennial species, and non-native species comprised only 2.7% of the seed bank. Additional seeds of native species were broadcast on restoration areas, and although this represented only 1% of the seed resources applied, the broadcast seed mix was an important resource for increasing post-mining species richness. Knowledge of the life-history characteristics of plant species may relate to seed germination patterns and assist in more accurate restoration where information on germination percentages of all species is not available.     

Waterproofing Topsoil Stockpiles Minimizes Viability Decline in the Soil Seed Bank in an Arid Environment

Topsoil is a valuable resource for revegetation of mine sites as it contains seeds of plant species indigenous to the local environment. As mine site restoration is undertaken after the completion of mining, it is a common practice to stockpile topsoil in preparation for restoration activities. While many studies have found a decrease in seedling emergence with increasing stockpile age in temperate regions around the world, a few examine the effect of stockpile age on topsoil seed bank and seedling recruitment in arid environments. Seed longevity is promoted under dry conditions whereas viability loss is increased under warm and moist conditions. Here in a study in Australia's Great Sandy Desert, the effect of topsoil storage age and method of storing topsoil (under‐cover and exposed) on seedling recruitment was examined for a major gold mining site. There was a trend for lower seedling emergence (68% lower) and species richness (30% lower) from topsoil stored for 2 years than from topsoil direct returned and topsoil stored for 1 year. Seedling emergence from topsoil stockpiled for 2 years was more than 3.5‐fold higher from covered topsoil stockpiles than uncovered topsoil stockpiles. For two ecologically dominant species, after 2 years of storage, seedling emergence of the grass Triodia basedowii was 13% of direct returned topsoil and seedling emergence of the shrub Acacia stellaticeps was 68% of direct returned topsoil. The implication of the decline in seedling emergence from topsoil stockpiling on mine site revegetation in a biodiverse arid region is discussed.     

植被重建对露天煤矿排土场土壤酶活性的影响

植被重建是露天煤矿排土场生态恢复的关键措施,深入了解植被建设对土壤酶活性的影响,对于合理选择适宜于矿区生态恢复的人工植被和加速矿区土壤生态恢复具有重要意义。通过野外调查采样和室内分析,研究了黑岱沟露天煤矿排土场植被重建和恢复对浅层(0—20 cm)土壤酶活性(包括3种氧化还原酶:过氧化氢酶、多酚氧化酶、脱氢酶,4种水解酶:蔗糖酶、脲酶、磷酸酶、纤维素酶)的影响。结果表明:相比未进行植被建设的新排土场裸地,植被重建显著改善了土壤酶活性和理化性质,建植18a后土壤酶活性可恢复到天然植被区的65%—76%,水解酶恢复速率(平均为86.9%)快于氧化还原酶(平均为42.7%),其中土壤磷酸酶恢复速率最快(平均为天然植被区的154.7%),其次为蔗糖酶(74.3%)、纤维素酶(59.9%)、脲酶(58.5%)、过氧化氢酶(52.1%)和脱氢酶(38.1%),多酚氧化酶恢复最慢(为37.8%)。植被恢复进程中,建植10a期土壤酶活性年均恢复速率最快(平均为6.0%/a),15a变缓(4.8%/a),18a迅速降低(3.2%/a)。同时植被配置类型对土壤酶活性影响显著,土壤酶活性与土壤主要理化因子具有较高的相关性。上述结果反映了植被重建能显著改善矿区排土场的土壤酶活性,植被恢复进程中水解酶恢复速率快于氧化还原酶,恢复初期快于后期,但土壤酶活性的恢复需要一个漫长的过程。     

Establishment of woody species across 26 years of revegetation on a Queensland coal mine

The establishment success of woody plant species at 56 revegetation sites, four to 26 years old, across the Meandu open‐cut coal mine in south‐east Queensland was assessed. The revegetation process involved returning stockpiled topsoil, deep ripping and mechanical sowing of a mix of native seeds. Blakes Wattle (Acacia blakei) and less often Black Wattle (A. leiocalyx), both primarily derived from respread topsoil seed, dominate the vegetation canopy at 59% and 20% of revegetation sites, respectively. The additional sowing of seeds of many tree and shrub species within the sites has had limited success with most failing to persist or grow well. Revegetation management, for example selective thinning of acacias (Acacia spp.) saplings within the first 5 years is recommended to release the competition pressure on the poorly performing tree species. This will also allow opportunities for other less well represented shrub and herb species to persist. This study has shown that a range of tree and shrub species, including Eucalyptus spp., are performing poorly under the current revegetation regime, suggesting adjustments to revegetation species selection and/or methodologies are needed. The natural colonization of woody native species within the sites from nearby remnant vegetation is shown to be limited to only four species, and therefore is unlikely to significantly supplement the species diversity of the revegetation.     

Evaluation of topsoil inversion in U.K. habitat creation and restoration schemes

Habitat creation and restoration schemes on former agricultural soils can be constrained by high residual soil fertility, a weedy seed bank, and a lack of suitable species in the seed rain. Topsoil inversion has been trialled across the United Kingdom as a novel technique to address these constraints. We investigated 15 topsoil inversion sites ranging in age (time since inversion) from 6 months to 5 years. We assessed surface soil fertility compared to adjacent noninverted soil, and vegetation composition with respect to the species introduced at each site. Soil organic matter, total and extractable N and P were lower in topsoil inversion surface soils, demonstrating that topsoil inversion can successfully reduce surface soil fertility prior to habitat creation and restoration. This reduction was maintained over the timescale of this study (5 years). Cornfield annual nurse crops provided instant visual appeal and gave way to grassland species over time. Sown species varied widely in their establishment success, and sowings were more successful than plug plantings. Grasses colonized naturally following sowing forb‐only seed mixes, allowing introduced forbs to establish early on with reduced competition from the seed bank. Plant communities did not yet resemble seminatural communities, but all were in the early stages of community development. Results indicate that topsoil inversion can successfully lower surface soil fertility and reduce competition between sown species and agricultural weeds.