Comparison of Pioneer and Native Woodland Species Growing on Top of an Engineered Landfill,Hong Kong: Restoration Programme

This study dealt with a restoration project conducted at South‐East New Territories Landfill in Hong Kong, in order to screen suitable tree and shrub species (both native and pioneer species) for revegetation. For engineered landfills, landfill gas migration and leachate contamination to the topsoil are rarely problematic, but the lack of nutrients and moisture and poor physical soil conditions may jeopardize potential woodland establishment. The growth performance of 25 woody plant species subjected to 12 different soil amelioration and seedlings planting methods was compared. The results showed that the general performance (mortality rate, apical height, crown diameter and basal diameter) of pioneer species (notably Acacia species) was much better than that of native species in all blocks of woodland mix and scrub mix. The notch planting method was effective in helping seedling roots to have better contact with soil for water uptake, which subsequently increased the survival rates of seedlings, leading to a better tree coverage. Soil ameliorations (horticultural soil with fertilizer and horse and pig manure) generally increased the seedling survival rate and improved plant growth. Tree coverage on all the plant trial blocks was mainly established by the three Acacia species. A planting distance of 1 m was recommended for woodland establishment, and such dense seedlings planting would achieve a better tree coverage under a shorter period of time (than the distance of 3 m). Difficulties in woodland establishment were discussed, and the strategies for achieving a better tree growth were recommended. Copyright © 2015 John Wiley & Sons, Ltd.     

Exotic vs. native plant dominance over 20 years of old-field succession on set-aside farmland in Argentina

Exotic plants are major constituents of species pools in modern landscapes. Managing succession for restoration of degraded ecosystems thus requires an understanding of novel trajectories unfolding in mixed, native/exotic plant assemblages. We examined trends in native and exotic species abundance over 20 years of old-field succession on set-aside farmland in the Inland Pampa, Argentina. Changes in plant cover and species richness were annually monitored on adjacent permanent plots established in different years (1978-1989). Both native and exotic species occurred in early, mid and late successional stages, exhibiting similar life-form replacement patterns, from annual forbs, through annual to perennial grasses. Exotic plant richness declined with plot age. Yet, four exotic grasses remained dominant through succession (50-70% cover), with plots initiated in later years showing increased exotic cover. While native perennial grasses occurred from the onset of succession, increasing from 5 to 12 spp/plot, they only showed transient peaks below 30% cover. Cluster analysis of 113 plot-year samples identified alternative community states for early, mid and late successional stages, which were connected by a complex network of interweaving dynamic pathways. Depending on the plot, vegetation dynamics comprised directional temporal trajectories as well as nondirectional pathways, and arrested community states dominated by exotic grasses. Our results illustrate the overwhelming role of exotic species in modern old-field succession, and their potential to hinder recovery of native communities on former agricultural land. Community states with novel, native/exotic plant mixtures could be managed to deliver specific ecosystem services (e.g. forage production, carbon sequestration). However, meeting conservation goals may require active restoration measures, including exotic plant removals and native grass seeding.     

Evaluation of alternative approaches to rainforest restoration on abandoned pasturelands in tropical North Queensland,Australia

The lag time for natural recruitment of tropical rainforest species in abandoned pastureland is very long, therefore artificial restoration techniques have been employed to accelerate natural seedling recruitment. The objectives of this study were to investigate: (1) the success/failure of establishment 502 seedlings belonging to 15 species from 11 families planted approximately ten years ago; and (2) the influence of different restoration techniques on enhancing natural recruitment during this period. The study was conducted in the wet tropical rainforest region of northeast Queensland, Australia as a completely randomized block design involving five treatments with two replicates. In each plot, 63 tropical rainforest seedlings from one or a combination of species were planted randomly. Two control plots were laid out where no seedlings were planted. Survival, height and diameter data were taken on the seedlings ten years after planting. Each 11×17 m² plot was further divided into 187, 1×1 m² subplots. Within each subplot all seedlings recruited were located and identified. Canopy cover was estimated using belt transects 1 m apart that ran in an east–west direction across the plots. Within each plot the percentage of grass, and the crown cover were estimated using the Braun‐Blanquet cover abundance scale. Survival rate of planted seedlings varied across the treatment plots. The survival rate ranged from 65 to 75 per cent for primary‐promoter species, 85 to 100 per cent in middle‐phase species and 42 to 57 per cent for mature‐phase species. No Pilidiostigma tropicum seedlings survived in any treatment. Fourteen species recruited naturally across the treatment plots. A total of 410 seedlings were naturally recruited from 11 different families in the ten‐year‐old reforested site. The highest natural recruitment (236 seedlings) occurred in Treatment 3, where Omalanthus novo‐guineensis seedlings were planted with eight primary‐promoter species, followed by 99 in Treatment 5 where a group of primary‐promoters, middle phase species and mature‐phase species were planted together, 36 in Treatment 4 (Alphitonia petriei planted with eight primary‐promoter species), 10 in Treatment 2 where only Omalanthus novo‐guineensis seedlings were planted, and 13 in control plots. Grass cover declined with increasing species diversity and increased canopy cover. The results indicate that the diversity of species used in restoration had a major influence on natural recruitment. Copyright © 2004 John Wiley & Sons, Ltd.     

Soil Organic Carbon Accumulation in Abandoned Croplands on the Loess Plateau

The Grain to Green Program in China which began in 1999 led to the conversion of 0.64 million ha of cropland to grassland on steep sloping landscapes. However, the pattern of natural vegetation succession following cropland has not been well represented in previous regional syntheses of land use change effects on soil organic carbon (SOC). A chronosequence study focusing on the vegetation succession and soil carbon stocks was conducted in the center of the Loess Plateau. The chronosequence included fields of 0, 2, 5, 8, 9, 10, 12, 15 and 25 years of self‐restoration after cropland abandonment, as well as a natural grassland reference. Plant coverage, species richness and plant biomass increased significantly with time of cropland abandonment. Over time, the species composition more nearly resembled a natural grasslands community. Cropland abandonment replenished SOC stocks by 3.6 kg C m⁻² during the 25‐year self‐restoration, but the SOC accumulation was restricted to the upper soil profiles (0–60 cm). SOC accumulation rate was 88 g C m⁻² y⁻¹ in 0–30 cm and 55 g C m⁻² y⁻¹ in 30–60 cm soil depth, respectively. These carbon stocks were still significantly lower than those found in the natural grassland soil. Our results suggest that the recovery of plant communities and SOC stocks appears to be slow in this semiarid environment without revegetation effort along with appropriate field management, although the post‐agricultural soils have a high potential for carbon sequestration. Copyright © 2016 John Wiley & Sons, Ltd.     

Recovery of Soil C and N in a Tropical Pasture: Passive and Active Restoration

Soil degradation by deforestation and introduction of exotic grasses is a grave consequence of land‐use change in tropical regions during the last decades. Soil restoration following natural succession (i.e., passive restoration) is slow because of low tree establishment. Introduction of tree plantings by human intervention (i.e., active restoration) results in a promising strategy to accelerate forest succession and soil recovery in tropical region. The present research was carried out to explore the restoration of soil properties after cattle exclusion and of grazing combined with native tree planting introduction (legumes and nonlegumes) in a tropical pasture in Veracruz, southeast Mexico. Results indicate that land‐use changes decreased soil C and N pools in both litter and mineral soil. In addition, soil heterogeneity increased by land‐use changes at both temporal and spatial scales. In the short term, passive succession (i.e., cattle exclusion) favors the recovery of C and N content in labile soil pools, indicated by the increase in litter C and N masses as well as C and N concentrations in soil microbial biomass. Soils under active restoration showed trends to recover the N cycling, such as a greater accumulation of N in litter, in soil total N concentrations, soil microbial biomass N concentrations, rates of net N transformations, and extractable water and microbial biomass C:N ratios mainly under legumes species. Active restoration including legume introduction is a key factor for rapid recovery of soil fertility. Copyright © 2013 John Wiley & Sons, Ltd.     

Using landscape and depth gradients to decouple the impact of correlated environmental variables on soil microbial community composition

Simultaneously assessing shifts in microbial community composition along landscape and depth gradients allows us to decouple correlations among environmental variables, thus revealing underlying controls on microbial community composition. We examined how soil microbial community composition changed with depth and along a successional gradient of native prairie restoration. We predicted that carbon would be the primary control on both microbial biomass and community composition, and that deeper, low-carbon soils would be more similar to low-carbon agricultural soils than to high carbon remnant prairie soils. Soil microbial community composition was characterized using phospholipid fatty acid (PLFA) analysis, and explicitly linked to environmental data using structural equations modeling (SEM). We found that total microbial biomass declined strongly with depth, and increased with restoration age, and that changes in microbial biomass were largely attributable to changes in soil C and/or N concentrations, together with both direct and indirect impacts of root biomass and magnesium. Community composition also shifted with depth and age: the relative abundance of sulfate-reducing bacteria increased with both depth and restoration age, while gram-negative bacteria declined with depth and age. In contrast to prediction, deeper, low-C soils were more similar to high-C remnant prairie soils than to low-C agricultural soils, suggesting that carbon is not the primary control on soil microbial community composition. Instead, the effects of depth and restoration age on microbial community composition were mediated via changes in available phosphorus, exchangeable calcium, and soil water, together with a large undetermined effect of depth. Only by examining soil microbial community composition shifts across sites and down the soil column simultaneously were we able to tease apart the impact of these correlates environmental variables.     

Successional Trajectory Over 10 Years of Vegetation Restoration of Abandoned Slope Croplands in the Hill‐Gully Region of the Loess Plateau

Revegetation has been the primary management approach for solving the problems caused by severe soil erosion in the Loess Plateau. The objectives of this work were to explore the successional trajectory of the different types of restoration and discuss their potential effectiveness for the control of soil erosion. The presence and coverage of plants in 40 permanent plots were investigated during two periods (2003–2006 and 2013). The naturally and artificially revegetated communities studied in the two surveys were classified using two‐way indicator species analysis, and their relationships were analyzed using detrended correspondence analysis. Under natural revegetation, the communities succeed in the following order: annual plants → perennial plants → short rhizome tufts and subshrubs. Under artificial revegetation, succession was interrupted by artificial planting, and a Gramineae herb layer persisted through the years with few changes in species composition. Additionally, species richness, diversity, and evenness increased, while ecological dominance decreased during succession in both revegetation types. Succession rate was rapid at the initial stage and then slowed down gradually. Succession followed different trajectories under natural and artificial revegetation, and based on the potential effects of the two approaches on soil erosion and soil desiccation, we suggest that natural revegetation is preferable over artificial revegetation. Copyright © 2015 John Wiley & Sons, Ltd.     

林木超深栽在沙地造林中的应用效果分析

[目的]探讨林木超深栽在沙地造林中的可行性,为提高干旱半干旱沙地造林效果提供依据。[方法]在对永定河下游沙地不同深度土壤水分含量进行监测的基础上,以白榆为造林树种,开展了深根苗与普通苗的不同栽植深度﹝1m(超深栽),0.6m(深栽),0.3m(常规)﹞的造林试验。[结果](1)沙地下层土壤的水分含量较高并相对保持稳定;(2)沙地林木超深栽显著提高了造林成活率40%以上(p0.01)。特别是使用林木深根苗进行超深栽时,即使在无灌水的条件下亦取得了很好的造林效果(成活率94%);(3)林木超深栽显著提高了苗木的高生长,但对胸径生长的促进作用仅在使用深根苗时观察到。[结论]超深栽技术适用于干旱半干旱沙地造林,建议予以推广应用。     

桂西北喀斯特人为干扰区植被自然恢复与土壤养分变化

为促进桂西北喀斯特退化生态系统的恢复与重建,采用全面调查和样方调查方法,以自然保护区的顶级群落为对照,研究了桂西北喀斯特人为干扰区自然恢复22a后植被的演替规律与土壤养分变化。结果表明,干扰区物种丧失严重,种类仅有自然保护区的26.6%,随着群落由草丛→草灌丛→灌丛→藤刺灌丛→乔灌丛→顶级群落的顺向演替和发展,群落的高度、生物量和物种多样性、土壤有机质、养分、阳离子交换量和硅、铁、铝、钛等矿质全量逐步增加,钙、镁全量显著减少,pH值降低,土壤质量随着植被的恢复呈波折性提高。     

Rehabilitation of desurfaced soils by afforestation in La Plata County,Argentina

Removal of topsoil, mainly for making bricks, is one of the main causes of soil loss around large urban centres of the Humid Pampa, Argentina. In about 7 per cent of La Plata County, the 20–40 cm thick A‐horizon has been removed for that purpose. Most of the affected areas were originally prime farmland; however, with removal of the A‐horizon they became unsuitable for agriculture, including grazing, since the exposed Bt‐horizon is unsuited for plant growth due to its high clay content (45–65 per cent) and the low nutrient levels. Since trees survive better on poor soils than do agricultural crops, the possibility of afforestating desurfaced soils has been studied. Eucalyptus are one of the major species used in tree planting programmes aimed at reclaiming degraded soils since they are fast growing and can grow to commercial size in a wide range of soils and climatic conditions. The work reported here was done in a desurfaced Vertic Argiudoll and a similar non‐desurfaced soil (control). Three Eucalyptus species were tested, i.e. E. camaldulensis, E. viminalis and E. dunnii. Their height and diameter (dbh) growth were 47.9 to 75.8 per cent less and timber volume 86.5 to 98.5 per cent less on the desurfaced soil. E. camaldulensis grew best in all the parameters in the desurfaced soil. Although tree growth was poor, afforestation may be an alternative use for desurfaced soils where agriculture and livestock breeding are not possible. Copyright © 2002 John Wiley & Sons, Ltd.     

Evolution of the soil humus status on the calcareous Neogene clay dumps of the Sokolov quarry complex in the Czech Republic

The development of the soil profile and the humus substance system was described for two chronosequences of soil restoration on the Neogene clay dumps. The chronosequences differed in the restoration type of vegetation: self-overgrowing or overgrowing intensified by planting tree seedlings (rehabilitation). It was found that the regeneration rates of the soil and humus profile were much higher in the case of the land rehabilitation than during the self-overgrowing of the dumps. The acceleration of the ecogenetic succession and the symbiotic nitrogen fixation in the soils of the plots with seedlings planted resulted in the accumulation of humus and nitrogen and increased the degree of organic matter humification. The enrichment of the organic matter in nitrogen and its increased input were the main reasons for the more intense humification under the rehabilitation conditions.     

Effect of vegetation manipulation of abandoned arable land on soil microbial properties

 The effect of vegetation composition on various soil microbial properties in abandoned arable land was investigated 2 years after agricultural practice had terminated. Microbial numbers and processes were determined in five replicate plots of each of the following treatments: continued agricultural practice (monoculture of buckwheat in 1997), natural colonization by the pioneer community (arable weeds), and manipulated colonization from low (four species, three functional groups: grasses, forbs and legumes) or high diversity (15 species, three functional groups) seed mixtures from plant species that are characteristic of abandoned fields in later successional stages. The results indicated that differences in above-ground plant biomass, plant species composition and plant species diversity had no significant effect on soil microbial processes (net N mineralization, short-term nitrification, respiration and Arg ammonification), microbial biomass C and N (fumigation-incubation) or colony-forming units of the major microbial groups. Hence, there were no indications that soil microbial processes responded differently within 2 years of colonization of abandoned arable land by later successional plants as compared to that by plants from the natural pioneer weed community. Therefore, it seems that during the first few years after arable field abandonment, plants are more dependent on the prevailing soil microbiological conditions than vice versa. Received: 8 April 1999     

Nutrient‐enriched soils and native N‐fixing plants in New Zealand

Approximately 40% of New Zealand's land mass is fertilized grassland with entirely non‐native plants, but currently there is substantially increased interest in restoration of native plants into contemporary agricultural matrices. Native vegetation is adapted to more acid and less fertile soils and their establishment and growth may be constrained by nutrient spillover from agricultural land. We investigated plant–soil interactions of native N‐fixing and early successional non N‐fixing plants in soils with variable fertility. The effects of soil amendments of urea (100 and 300 kg N ha^?1), lime (6000 kg CaCO₃ ha^?1), and superphosphate (470 kg ha^?1) and combinations of these treatments were evaluated in a glasshouse pot trial. Plant growth, soil pH, soil mineral N, Olsen P and nodule nitrogenase activity in N‐fixing plants were measured. Urea amendments to soil were not inhibitory to the growth of native N‐fixing plants at lower N application rates; two species responded positively to combinations of N, P and lime. Phosphate enrichment enhanced nodulation in N‐fixers, but nitrogen inhibited nodulation, reduced soil pH and provided higher nitrate concentrations in soil. The contribution of mineral N to soil from the 1‐year old N‐fixing plants was small, in amounts extrapolated to be 10–14 kg ha^?1 y^?1. Urea, applied both alone and in conjunction with other amendments, enhanced the growth of the non N‐fixing species, which exploited mineral N more efficiently; without N, application of lime and P had little effect or was detrimental. The results showed native N‐fixing plants can be embedded in agroecology systems without significant risk of further increasing soil fertility or enhancing nitrate leaching.     

黄河源区人工草地植被群落和土壤养分变化

[目的]研究黄河源区不同年限人工草地植被群落特征和土壤养分的动态变化,揭示高寒地区人工草地稳定机制与演替规律,为退化高寒草甸(湿地)的近自然恢复和缩短退化草地恢复时间提供理论依据。[方法]选择黄河源区青海省玛沁县3,11,17 a单播垂穗披碱草人工草地,对植被与土壤养分特征进行调查。[结果]随着种植年限增加,人工草地优势种垂穗披碱草盖度降低,植物总盖度、生物结皮盖度、杂类草盖度以及生殖枝数量呈倒"V"型变化,而原生植被莎草科植物盖度、物种多样性逐渐增加,17 a人工草地中莎草科植物的盖度是3,11 a的10倍;人工草地土壤养分中全氮、全钾、速效氮、速效钾以及有机质随年限增加呈现积累趋势,土壤pH值逐渐趋于中性。土壤全氮含量在不同恢复年限之间差异最大,平均准确率降低度为25.71,有机质含量次之,其平均准确率降低度为18.55,而全钾含量及均匀度指数最小,平均准确率降低度均小于5。[结论]高寒地区人工草地群落结构和土壤营养随着建植时间的延长在逐渐恢复,建植17 a的人工草地土壤全氮、有机质含量仅是原生高寒草甸土壤的50%左右,因此,17 a人工草地土壤养分完全恢复还需要较长时间。     

Fungal diversity in set-aide agricultural soil investigated using terminal-restriction fragment length polymorphism

As part of the restoration of biodiversity on former agricultural land there has been focused on methods to enhance the rate of transition from agricultural land towards natural grasslands or forest ecosystems. Management practices such as sowing seed mixtures and inoculating soil of later successional stages have been used. The aim of this study was to determine the effects of a managed plant community on the diversity of soil fungi in a newly abandoned agricultural land. A field site was set up consisting of 20 plots where the plant diversity was managed by either sowing 15 plant species, or natural colonization was allowed to occur. The plant mixture contained five species each of grasses, legumes and forbs that all were expected to occur at the site. A subset of the plots (five from each treatment) was inoculated with soil cores from a late successional stage. The plant community composition was subject to a principal component analysis based on the coverage of each species. Five years after abandonment, soil samples were taken from the plots, DNA was extracted and the ITS region of the rDNA gene was amplified using fluorescently labelled fungal specific primers (ITS 1F/ITS 4). The PCR products were digested using HinfI and TaqI and sequenced. Results from both restriction enzymes were combined and a principal component analysis performed on the presence/absence of fragments. Also the fungal diversity expressed as number of restriction fragments were analysed. There was significantly higher fungal species richness in the experimental plots compared to the forest and field soils, but no differences between sown and naturally colonized plots. The different plant treatments did not influence the below ground fungal community composition. Soil water content on the other hand had an impact on the fungal community composition.     

黄土丘陵区典型草地演替中植物群落特征与土壤储水量关系

[目的]阐明草地植被演替过程中植被生产力、植物多样性等生态学特征与土壤储水量的关系,为探明黄土高原地区植被恢复的生态环境效应提供一定的科学依据。[方法]采用时空互代的方法对宁夏回族自治区固原市云雾山保护区自然恢复3,8,13,46,66,89a的样地进行取样,分析0—100cm土层土壤储水量的分布及其与地上地下植物生物量、物种多样性的关系。[结果]随着草地演替的进行,植被群落盖度、生物量和物种多样性指数在恢复13a之前显著增加,之后渐趋稳定;土壤含水量逐渐增加,容重逐渐降低。植被群落演替对0—40cm土层土壤储水量没有显著影响,但演替后期对40cm以下土层水分有明显消耗。植被群落生物量及物种多样性指标与表层0—10cm水分呈显著正相关。[结论]草地演替过程中,植被群落生物量和物种多样性的增加与表层土壤储水能力的提升密切相关,但深层根系生物量的增加对下层土壤储水的消耗也逐渐增大。     

黄土高原半干旱地区撂荒地次生植被演替过程中土壤微生物活性研究

To show the vegetation succession interaction with soil properties, microbial biomass, basal respiration, and enzyme activities in different soil layers (0--60 cm) were determined in six lands, i.e., 2-, 7-, 11-, 20-, 43-year-old abandoned lands and one native grassland, in a semiarid hilly area of the Loess Plateau. The results indicated that the successional time and soil depths affected soil microbiological parameters significantly. In 20-cm soil layer, microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), MBC/MBN, MBC to soil organic carbon ratio (MBC/SOC), and soil basal respiration tended to increase with successional stages but decrease with soil depths. In contrast, metabolic quotient (qCO2) tended to decrease with successional stages but increase with soil depths. In addition, the activities of urease, catalase, neutral phosphatase, β-fructofuranosidase, and carboxymethyl cellulose (CMC) enzyme increased with successional stages and soil depths. They were significantly positively correlated with microbial biomass and SOC (P < 0.05), whereas no obvious trend was observed for the polyphenoloxidase activity. The results indicated that natural vegetation succession could improve soil quality and promote ecosystem restoration, but it needed a long time under local climate conditions.     

The Role of Legumes in Plant Community Succession of Degraded Grasslands in Northern China

Legume species were more and more commonly introduced to degraded grassland for human‐aided restoration. This study aimed to test whether the natural spread of legume contributes to reversal of grassland degradation through making an extensive grassland vegetation and soil survey in Inner Mongolia of China. The results showed that legume biomass increased along a gradient of soil coarsening that was also a gradient of grassland degradation. The total biomass rather than legume biomass was limited by mean annual precipitation at plot level. The presence of legumes increased species richness in degraded steppe vegetation. Constancy of intermediate and climax species of vegetation succession at sites with legumes was higher than that at sites without legumes, implying that legumes might contribute positively to the reversal of grassland degradation. Our study suggests that naturally distributed legumes could benefit the reversal of grassland degradation through promoting plant community succession rather than total plant biomass. Planting legumes would be an effective measure to accelerate the recovery process of degraded grassland with coarsened soil in regions similar to our study region. Copyright © 2015 John Wiley & Sons, Ltd.     

Is Direct Seeding a Biologically Viable Strategy for Restoring Forest Ecosystems? Evidences from a Meta‐analysis

Ecological restoration has become an important technique for mitigating the human impacts on natural vegetation. Planting seedlings is the most common approach to regain lost forest cover. However, these activities require a large economic investment. Direct seeding is considered a cheaper and easier alternative technique, in which tree seeds are introduced directly on the site rather than transplanting seedlings from nurseries. To evaluate the effectiveness of direct seeding, we conducted a comprehensive search of the literature using ‘restoration’, ‘direct seeding’ and ‘sowing’ as keywords, and we performed a meta‐analysis using 30 papers and 89 species. We used two different measures of restoration success: seed germination probability and success probability (the chance that a seed germinates and survives until the end of the experiment). In general, restoration attempts using direct‐seeding techniques were relatively unsuccessful. On average, seed germination and success probability were 0·239 and 0·114, respectively, and were not affected by climate, species successional group or the application of pre‐germinative treatments. Germination and success probability increased with seed size, and the use of physical protections resulted in a nearly twofold increase in germination probability, but this effect faded by the end of the experiments. Because of the low rate of seedling success, we suggest the use of direct seeding as a complementary technique to reduce restoration costs, particularly for species with large seeds and known high germination rates, but our results do not support direct seeding as a substitute for seedling planting. Copyright © 2015 John Wiley & Sons, Ltd.     

Effect of earthworm on growth of late succession plant species in postmining sites under laboratory and field conditions

Earlier studies of postmining heaps near Sokolov, Czech Republic (0–46 years old) showed that massive changes in plant community composition occur around 23 year of succession when the heaps are colonized by the earthworms Lumbricus rubellus (Hoffm.) and Aporrectodea caliginosa (Savigny). The aim of the current study was to test the hypothesis that the introduction of earthworms into a postmining soil enhances growth of late succession plant species. In a laboratory experiment, earthworms significantly increased biomass of Festuca rubra and Trifolium hybridum grown in soil from a 17-year-old site. The biomass increase corresponded to a significant decrease in pH and an increase in oxidable C, total N, and exchangeable P, K, and Ca content. A second laboratory experiment showed higher biomass production of late successional plant community (Arrhenatherum elatius, Agrostis capillaris, Centaurea jacea, Plantago lanceolata, Lotus corniculatus, and Trifolium medium) in soil from late successional stage (46 years old); the introduction of earthworms into soil from an early successional stage (17 years old) increased biomass production. In a field experiment, introduction of L. rubellus to enclosures containing a 17-year-old soil not colonized by earthworms significantly increased the biomass of grasses after 1 year. The results support the hypothesis that colonization of postmining areas by earthworms can substantially modify soil properties and plant growth.