安塞黄土丘陵沟壑区退耕地的土壤种子库特征

 采用野外调查取样和室内实验相结合的方法,研究安塞黄土丘陵沟壑区退耕地土壤种子库的物种组成、密度特征、物种多样性以及相似性特征。结果表明:阴、阳坡12个样地的土样中,共萌发了28种2442株幼苗,隶属于11科23属;05 cm土层的土壤种子库密度变动于（900.1±351.3）6 466.8±1 708.4粒.m-2之间,510cm土层的值变动于（116.7±61.4）2466.7±914.4粒.m-2之间;随着退耕年限的增加,土壤种子库的总密度都呈明显的递减趋势;阳坡的土壤种子库密度为阴坡的2.23.4倍;猪毛蒿和臭蒿是退耕地阳坡样地土壤种子库的优势物种,阴坡样地的优势物种是猪毛蒿;随着退耕年限的增加,土壤种子库的均匀度与退耕年限呈显著正相关,丰富度和多样性基本上呈上升趋势,生态优势度则呈下降趋势,说明随着退耕年限的增加,优势种趋向不明显;样地种子库组成成分的相似性分析表明,退耕演替的过程基本上也是土壤种子库空间异质性加大的过程。     

不同林龄刺槐和栓皮栎群落土壤种子库研究

为揭示土壤种子库在植被恢复中的作用,以太行山低山丘陵区的刺槐和栓皮栎2种乔木群落为研究对象,研究不同林龄刺槐、栓皮栎群落土壤种子库的组成、多样性特征以及种子库物种与地上植被的关系。结果表明:1)各群落草本层的共有科为菊科和禾本科,且所占比例较大;刺槐(30 a)群落地上物种的科数和种数最多,栓皮栎(20 a)最少,物种科数和种数随生长年限的增加而提高;多年生草本是刺槐(10、20、30 a)和栓皮栎(20、30、40 a)6个群落的主要生活型,群落间相似性系数为0～1.0。2)芸香科和禾本科在各群落土壤种子库中占有较大比例;种子库密度随林龄的增加而提高。刺槐群落土壤种子库的多样性随林龄增加而升高,而栓皮栎则呈现降低的趋势。3)土壤种子库中植物的科数和物种数都低于地上,且与地上物种类型不尽相同;土壤种子库对地上植被更新和演替贡献不大。     

汶川地震不同次生地质灾害类型区土壤种子库特征

为了解地震后次生地质灾害土壤种子库特征及其植被恢复特点,在四川省北川县采用野外取样和在当地自然环境下萌发相结合的办法,研究了5种不同灾害类型(包括滑坡、崩塌、泥石流、落石及堰塞湖)土壤种子库大小、物种组成及其与地上植被之间的关系。研究结果表明,不同灾害类型土壤种子库密度介于30133.33±6776.03~93383.33±26499.81粒/m2方差分析显示,只有落石损毁类型种子库密度与其它几种灾害类型差异显著,各灾害类型土壤种子库种子密度在0-5cm和5-10cm土层之间无明显分层区别。土壤种子库中一年生和多年生草本所占比例为90.48%,灌木所占比例为9.52%,没有观察到乔木种。各土壤种子库之间Sorensen相似性指数较高,为0.529~0.714土壤种子库与相应样地地上植物之间相似性不高,相关性也不密切,其相似性指数介于0.167~0.292。建议灾害损毁地植被恢复以自然恢复为主,若采取简易的水土保持措施和适量客土措施,将会促进种子的萌发和植被的更新种子库中缺乏乔木种,快速乔木化需要人工输入种子雨。     

黄土丘陵沟壑区红砂灌丛土壤种子库及其自然更新潜力评估

[目的]对黄土丘陵沟壑区红砂灌丛植被土壤种子库的特征及红砂灌丛植被自然更新潜力进行分析和评估,以说明红砂灌丛土壤种子库在植被恢复与重建中的重要作用。[方法]采用土壤种子库"萌发法"(每个地段10个2m×2m样方内分表土层0—2cm和2—5cm土层采集土样)及野外植被调查方法,对黄土丘陵沟壑不同坡位红砂灌丛土壤种子库进行研究。[结果]黄土丘陵沟壑区红砂灌丛植被土壤种子库发芽试验共观察到的4 251株幼苗,分属于9个物种。土壤种子库密度在100~1 000粒/m2,物种数在0.8~1.2种/0.01m2,下坡段的土壤种子库平均种子密度和平均物种数均比上坡段高。3个坡段的2个层次的平均种子密度和平均物种数均随土层加深而减小。3个坡段土壤种子库和地上植被的组成物种多为草本植物和红砂灌丛,地上植被与其土壤种子库的密度及物种数均呈不显著相关;物种组成的Sorensen相似性指数较高,均达到0.60以上,且土壤种子库比地上植被具有更高的物种丰富度。[结论]黄土丘陵沟壑区红砂灌丛具有依靠土壤种子库实现自然更新的潜力,但由于物种组成种类较少,现存灌丛植被一旦遭到破坏,仅靠土壤种子库恢复现存植被是困难的,需要在对自然恢复潜力评估的基础上,积极采取人工保护促进自然恢复的策略。     

汶川地震灾区典型区不同植被类型土壤种子库特征——以北川县苏保河、魏家沟流域为例

为了解汶川地震灾区典型区不同植被类型土壤种子库特征及其与灾害受损程度间的关系,采用野外调查取样和室内试验相结合的方法,研究了北川县苏保河与魏家沟流域4种植被类型(未受损林地、受损林地、灾后恢复草地和灾后裸地)土壤种子库的物种组成、种子密度、多样性及其与地上植物群落的关系。结果表明:4种植被类型样地中,土壤种子库密度为212.5~1 758.3个·m-2,每样带(200 m2)平均物种数为4.3~14.7个。4种植被类型土壤种子库的组成物种多为多年生或一年生草本植物,土壤种子库与相应地上植被的物种数仅受损林地与灾后恢复草地中呈显著相关;物种组成的Sorensen相似指数除裸地低于0.250外,其余均高于0.250。基于以上分析结果,在灾区进行植被恢复,需要考虑次生灾害对植被的持续破坏可能性,采用工程措施及人为引种的方式增加成活率和延续性。     

石羊河上游干旱草原阴山扁蓿豆群落土壤种子库

土壤种子库是地上植被补充更新的源泉,土壤种子库的研究已成为植物种群生态学研究中相当活跃的领域.在石羊河上游干旱草原选择阴山扁蓿豆草地群落,研究了草地土壤种子库的物种组成、密度、多样性特征以及与地上植被的关系.结果表明,阴山扁蓿豆草地群落土壤种子库共有20个物种,分属12科.随阴山扁蓿豆分盖度减小,土壤种子库密度和种类在水平方向上增加,种子库密度垂直分布呈现0-5cm>10-15 cm>5-10 cm土层,物种数量随深度而减少;在阴山扁蓿豆分盖度>60%的草地群落未发现其种子库的存在.土壤种子库的Margalef丰富度指数、Shannon-Wiener多样性指数和Pielow均匀度指数随阴山扁蓿豆盖度减小呈上升趋势,生态优势度由0.46下降至0.24;各草地群落土壤种子库与地上植被的相似性系数在0.29～0.58之间.     

塔里木河下游土壤种子库的季节差异分析

以因不合理的水土资源开发而出现严重生态退化的典型区--塔里木河下游为研究区,通过在塔里木河下游开展的土壤种子库实验,分析了塔里木河下游土壤种子库的基本特征和种子库密度、物种组成上的季节差异,并从土壤种子库的角度探讨了塔里木河下游生态恢复的可行性.(1)塔里木河下游土壤种子库的季节差异较大,如果排除放牧的影响,3月份土壤种子库的密度和物种丰富度总体上要小于8月份的土壤种子库;(2)从物种组成上看,3月份物种组成以一年生草本占优势,而胡杨和柽柳的种子基本上都出现在8月份的土壤种子库中;(3)随塔里木河下游地上植被群落退化程度的加重,种子库的密度和物种数均呈现明显的下降趋势;(4)鉴于土壤种子库无论在物种还是密度上均要远丰富于地上植被群落的事实,认为通过激活土壤种子库来实现下游生态的局部恢复在理论上是可行的.考虑到主要建群植物的生态恢复,建议今后的输水时间应该选择在8月到11月之间.     

汶川地震生态治理区土壤种子库及其与地上植被的关系

为了比较地震灾区不同气候类型植被恢复区土壤种子库时空分布特征,采用野外调查取样和室内试验相结合的方法,研究了四川省汶川县威州镇和绵竹市汉旺镇4类生态治理区[干旱干暖河谷受损治理区(DHD)、干旱干暖河谷未受损区(DHU)、亚热带湿润季风气候受损治理区(HMD)、亚热带湿润季风气候未受损区(HMU)]土壤种子库的萌发动态、数量特征、物种组成、多样性特征及其与地上植被之间的关系。结果表明:未受损区具有2个萌发高峰期,受损治理区只有1个萌发高峰期,不同气候类型治理区土壤种子库在不同土壤深度表现出不同的萌发潜力;4类治理区土壤种子库平均密度为192~1 544粒·m?2,表层密度和平均密度均为未受损区受损治理区,干旱干暖河谷气候区亚热带湿润季风气候区;4类治理区共有50种植物萌发,草本植物占显著优势;HMU、HMD、DHU、DHD地上植被与土壤种子库物种组成的S?rensen相似性系数分别为26.23%、44.9%、30.77%、16.00%,Jaccard相似性系数分别为15.09%、28.95%、18.18%、9.09%;不同类型样地土壤种子库特有种和共有物种均表现出不同的生活型格局。基于以上分析结果,在灾区进行植被恢复时,应该考虑治理区的气候环境,因地制宜的进行人工引种和制定恢复措施。     

天津地区湿地土壤种子库及其在受限空间中的植被演替研究

湿地土壤种子库运用对植被恢复的研究具有重要意义。从植被演替的角度出发,设置相对封闭的受限空间,持续监测土壤种子库萌发及其后续植物群落的演替情况,记录物种组成、群落多样性指数和群落覆盖度等参数的变化规律,评估了采用湿地土壤种子库进行植被恢复的效果。并对地面植被、土壤种子库及其演替植被的群落相似性指数进行了对比分析。结果发现:(1)土壤种子库恢复后期的植被与地面植被相似度较低(小于0.25);(2)植被恢复过程中,群落多样性指数呈现先降低后升高的趋势,而恢复3a后的植被群落多样性指数均接近于地面植被;(3)生长期的群落覆盖度高于90%,能够满足天津地区滨海盐碱型湿地植被恢复的要求。     

风沙黄土区排土场不同恢复类型植物群落与土壤种子库特征

风沙黄土区排土场作为一种人造生态系统,自然条件恶劣,土壤贫瘠,植被恢复困难。为了探明有效的人工促进植被恢复措施,采用植被调查与种子库萌发试验相结合的方法,通过研究不同植被类型地上植物群落与土壤种子库特征及二者的关系,探讨了其植被恢复效益及潜力。结果表明:研究区人工植被恢复下地上植物群落中共47种植物,分属16科40属,土壤种子库共14种植物,分属5科13属,其中均以禾本科、菊科、藜科、豆科占主导地位; 灌木植被的地上植被和土壤种子库的物种多样性均表现为最优; 地上植被与土壤种子库密度的变化范围为88.48～495.47株/m²,74.74～1422.91粒/m²,且均在草地类型下最大。土壤种子库和地上植被的相似性普遍较低,相似性系数仅为0.16～0.23。因此,风沙黄土区排土场的植被恢复与重建需要加强保护与管理,可以考虑构建以草灌配置为主的人工植被恢复模式,保障群落的恢复潜力,并提高群落多样性与稳定性,亦可考虑引入外源种子库提升群落恢复的潜力。     

元谋干热河谷山地植被修复区土壤种子库研究

 为了解干热河谷不同植被修复方法的土壤种子库的变化模式,采用对不同处理地段(包括水平阶间坡面、自然坡面、沟底)和对照(放牧地)的土壤种子库组成、大小进行比较研究的方法,研究元谋干热河谷山地植被修复区的土壤种子库。结果表明:1)植被修复区土壤种子库密度、丰富度均大于对照区;2)修复区内第2年土壤种子库密度、丰富度均大于第1年;3)水平阶间坡面和各类型间的土壤种子库密度差异显著;4)种子库中草本植物占很大比例;5)孔颖草和扭黄茅是种子库2大优势种。研究项目所采取植被修复措施在很大程度上改善土壤种子库的数量结构和物种组成。     

金安桥水电站弃渣场土壤种子库与地面植被的关系

通过研究金安桥水电站废弃渣场种子库和周边群落种子库以及渣场地面和周边群落地面植被的变化特征,结果表明：①周边群落土壤种子库和地面植物的物种丰富度大于渣场,从地面与种子库的物种组成分析得出,渣场植被恢复正处于由一年生草本植物向多年生草本植物过渡的阶段;②周边群落地面植物与土壤种子库的物种丰富度（30,33）及数量（186,1962）,渣场地面植物与土壤种子库的物种丰富度（10,12）及数量（35,1784）;③由于植物种子寿命短,加之土壤环境差,导致周边群落地面植物与种子库相似度（0．09）和渣场地面植物与种子库的相似度（0）差异性大。     

The Vertical Distribution of Soil Seed Bank and Its Restoration Implication in an Active Sand Dune of Northeastern Inner Mongolia,China

Although the functions and characteristics of soil seed banks in topsoil layers have been described for various ecosystems, the spatiotemporal pattern of the seed bank in deep soil and its ecological implications for vegetation restoration of active sand dune have not been fully explored. In 2007 and 2008, seed densities with regard to dune position, soil depth and season were investigated on an active and a stabilized sand dune of northeastern Inner Mongolia, China. Seeds in the 0–10 cm topsoil layer accounted for 60% of total soil seed bank on the stabilized sand dune, while more than 40% of seeds were stored in the 50–100 cm layers on the active sand dune. Seed density declined significantly with soil depth on the stabilized sand dune, but it was relatively constant across the 0–100 cm soil profile on the active sand dune. Seed density fluctuated with soil depth on the active sand dune suggesting that seeds were either relocated upward or downward over time. Seeds of annual non‐psammophytic species accounted for the majority of soil seed bank on the stabilized sand dune, while pioneer psammophytes contributed more to the soil seed bank of the active sand dune. Our data suggest that seeds in the deep soil layers of active sand dunes account for a large proportion of the whole soil seed bank. Because of the effect of wind erosion, seeds in deep soil could be gradually exposed to shallow soil layers and potentially contribute to population recruitment and vegetation restoration on active sand dunes. Copyright © 2015 John Wiley & Sons, Ltd.     

SOIL SEED BANK CHARACTERISTICS BENEATH AN AGE SEQUENCE OF CARAGANA MICROPHYLLA SHRUBS IN THE HORQIN SANDY LAND REGION OF NORTHEASTERN CHINA

To understand how shrub cover affects the spatiotemporal patterns of the soil seed bank and to assess the role of vegetation in the restoration of desertified land in a semi‐arid region of China, we investigated the species composition and seed density of the soil seed bank under and outside the canopies over two seasons for an age sequence of Caragana microphylla shrubs in the Horqin Sandy Land region, Inner Mongolia. The results showed that a total of 24 plant species seeds were present in the soil seed bank, of which 20 were annuals or biennials. The seed densities in the soil seed bank were in the range of 830 – 13882·5 seeds m⁻² at 10 cm depth. Species richness in the soil seed bank did not increase as the shrubs aged, whereas the seed densities increased significantly. Five annual species: Setaria viridis, Eragrostis pilosa, Chenopodium acuminatum, Chenopodium glaucum and Corispermum acuminatum, contributed above 90 per cent of the seeds to the soil seed bank. On the basis of seed characteristics and seed reduction amount during the growing season, we concluded that it represents a mixture of persistent and transient seeds in different proportions. More seeds accumulated under the canopies than outside the mature shrub cover, but no significant difference was found the younger cover. These results suggest that shrub size and age had an important role in augmenting seed abundance of the soil seed bank but not the species richness. We confirmed the important effects of shrub cover on seed accumulation and vegetation recovery, especially the value of more mature age vegetation for countering land degradation. Copyright © 2012 John Wiley & Sons, Ltd.     

北京山区不同质地类型自然边坡土壤种子库特征

为了解北京山区土质边坡和土石边坡土壤种子库特征,在北京市鹫峰、百花山和云蒙山采用野外调查和室内萌发试验相结合的办法,研究这3个区域中土质边坡和土石边坡土壤种子库大小、物种组成及其与地上植被之间的关系。各个研究区的土壤种子库共包含54种植物,隶属于26科53属,其中有30种灌木,23种草本,1种蕨类,未观察到乔木种;土壤种子库密度介于(16 166.67±2 165.16)~(20 612.50±2 717.32)粒/m~2;各个试验地0—5cm土壤层与5—10cm土壤层种子库的种子数量垂直分布有一致的规律性,0—5cm土壤层种子库密度略高于5—10cm土壤层;土壤种子库与相应样地地上植被之间相似性指数介于0.390~0.492。通过研究发现,所选地区土壤种子库中包含大量植物种子,在合适的环境条件下,可以顺利萌发,能够满足一般情况下的生态修复要求,可以考虑作为客土在北京山区的环境修复中发挥作用。     

Soil seed bank compositional change constrains biodiversity in an invaded species-rich woodland

Relationships between plant invasion and the soil seed bank in highly diverse fire adapted mediterranean woodlands are poorly understood, yet critical for that ecosystem’s conservation. Within the biodiversity hotspot of southwest Australia we investigated the composition and diversity of the Banksia woodland soil seed bank in good condition (GC), medium condition (MC) and poor condition invaded by the South African perennial species Ehrharta calycina (PCe) and Pelargonium capitatum (PCp). The investigation assessed three questions: (1) Do soil seed banks of invaded sites have fewer germinants of native species and more germinants of introduced (non-native) species than sites with minimal invasion? (2) Do soil seed banks show shifts in ecological functional types with invasion? (3) Is the soil seed bank of introduced species persistent? Native species germinants, mainly shrubs and perennial herbs, were highest in GC sites and least in poorer condition sites suggesting a reduction in their numbers had occurred over time. Introduced germinants were dominated by perennial and annual grasses, and annual herbs. E. calycina had the greatest seed density (8328 germinants m⁻²). More introduced than native germinants occurred in the litter. Rapid germination of introduced species (30% in week 1) compared to native species (4% in week 1) provides the capacity for their early dominance. A limited native soil seed bank and dominant persistent introduced soil seed bank represent great challenges for the structural and functional conservation and restoration of woodland ecosystems. This study provides key new knowledge, applicable to a wide range of ecosystems, to help formulate conservation protocols to control dominant introduced species and conserve and restore biodiverse-rich woodlands.     

Seed bank development after the restoration of alluvial grassland via transfer of seed-containing plant material

In the attempt to ensure long-term-conservation of flood meadows along the northern Upper Rhine transfer of seed-containing plant material was successfully applied since 2000. In this highly dynamic habitat, many typical plant species rely on a persistent seed bank for re-establishment after disturbance. But in contrast to the re-established above ground vegetation, seed bank composition remains unknown. Thus the main aims of the study were to elucidate the current seed bank composition and to assess patterns of seed and species traits. To this end we sampled above ground vegetation and seed bank on plant material plots and on control plots left to natural recruitment.Although the seed bank was still dominated by agrestal and ruderal plant species, it already contained seeds of transferred species. Analyses revealed that on the plant material plots seed density of plant material species declined significantly with soil depth, just as similarity between above ground vegetation and seed bank declined. In contrast, the seed bank on control plots comprised significantly lower numbers of transferred species. We found a vertical pattern of seed bank composition: in general, the upper seed bank layer comprised more elongated and large seeds of long-lived, competitive species able to build up transient seed bank. The lower soil layer was dominated by seeds of short-lived, agrestal and ruderal species, producing small, round and long-term persistent seeds.The present study shows that the build up of a seed bank typical of flood meadows is a time-consuming process. Thus restorative management in the early phase of vegetation development should focus on fostering high seed production of transferred species.