Natural Secondary Succession Research Articles

Shifts in fungal community diversity and potential function under natural forest succession and planted forest restoration in the Kunyu Mountains, East China.

Soil fungi participate in various ecosystem processes and are important factors driving the restoration of degraded forests. However, little is known about the changes in fungal diversity and potential functions under the development of different vegetation types during natural (secondary forest succession) and anthropogenic (reforestation) forest restoration. In this study, we selected typical forest succession sequences (including Pinus densiflora Siebold & Zucc., pine-broadleaf mixed forest of P. densiflora and Quercus acutissima Carruth., and Q. acutissima), as well as natural secondary deciduous broadleaved mixed forests and planted forests of Robinia pseudoacacia on Kunyu Mountain for analysis. We used ITS rRNA gene sequencing to characterize fungal communities and used the FUNGuild database to predict fungal functional groups. The results showed that forest succession affected fungal β-diversity, but not the α-diversity. There was a significant increase in Basidiomycota and a decrease in Ascomycota in the later successional stage, accompanied by an increase in the functional groups of ectomycorrhizal fungi (ECM). Conversely, planted forests exhibited decreased fungal α-diversity and altered community compositions, characterized by fewer Basidiomycota and more Ascomycota and Mucoromycota. Planted forests led to a decrease in the relative abundances of ECM and an increase in animal pathogens. The TK content was the major factor explaining the distinction in fungal communities among the three successional stages, whereas pH, AP, and NH4 + were the major factors explaining community variations between natural and planted forests. Changes in vegetation types significantly affected the diversity and functional groups of soil fungal communities during forest succession and reforestation, providing key insights for forest ecosystem management in temperate forests.

Plant secondary succession and soil degradation in humid red beds areas, South China

In South China, large amounts of strongly eroded badlands that are difficult for natural recovery formed in red beds soft rock, posing serious environmental hazards. This process is thought to be related to a unique nutrient cycle and plant-soil feedback in alkaline soil. In this study, we investigated 44 plant communities and some soil samples to explore the reasons for this erosion from the perspective of secondary succession and its driving factors. The results showed that the natural secondary succession (NSS) in red beds soft rock is the sequence of primary forest to scrub grass, xerophytes, and badlands. Masson pine and Masson pine/Schima superba communities have formed under the efforts of artificial intervention restoration. The community ecological gradient (CEG) and deciduosity rate substantially increased along the NSS, whereas the biomass, and diversity index rapidly decreased. The plantation community showed the opposite trend with increasing recovery years. Limitations in terms of soil water content, pH value, and available nitrogen (AN) for the community markedly increased, and we confirmed these were the largest contributors to redundancy analysis at the community scale. Compared with acidic soil, alkaline soil with a rough texture and high pH could not maintain enough water for plants during dry seasons, which inhibited the absorption of AN by plants. Therefore, in primary forests, the CEG and deciduosity rates need to be increased so that the plant community can adapt to harsh environments. plantation forests achieved soil acidification through litter accumulation. In the scrub grass and xerophyte, continuous reduction in litter and the intensification of soil erosion destroyed the balance between red argillaceous rock bed erosion and species invasion, leading to community degradation. Therefore, much attention should be given to primary forest protection and limiting factors mitigation in degraded communities.

Allelopathic Effect of Black Cherry (Prunus serotina Ehrh.) on Early Growth of White Mustard (Sinapis alba L.) and Common Buckwheat (Fagopyrum esculentum Moench): Is the Invader a Threat to Restoration of Fallow Lands?

Abandoned agricultural land present in most European countries constitutes a resource of land that can be restored to agricultural production. Fallow colonization by invasive plant species contributes to changes in the course of natural secondary succession. This may modify the possibilities of returning fallow lands to agriculture, which constitutes an issue that needs to be investigated. In this study, the phytotoxic effect of invasive black cherry (Prunus serotina Ehrh.) on two crop plants commonly used for fallow land utilization, white mustard (Sinapis alba L.) and common buckwheat (Fagopyrum esculentum Moench), was assessed. The influence of water extracts from P. serotina litter and the soil collected under the individuals of this species was investigated. Sinapis alba was found to be more sensitive to allelochemicals released by P. serotina than F. esculentum. Litter extracts and soil with residues of P. serotina significantly inhibited both germination and growth of S. alba seedlings, estimated with length and mass of the above-ground and underground parts. In the case of F. esculentum, a negative effect of the tested extracts and soil on root mass reduction was observed. Preliminary results of our laboratory tests suggest that cultivation of white mustard should be avoided in the reclamation of fallows with black cherry.

Microbial diversity regulates ecosystem multifunctionality during natural secondary succession

Abstract Natural forest succession after disturbances is one of the most important restoration strategies. However, the responses of ecosystem multifunctionality during natural forest succession remains poorly understood in forest ecosystem. Here we evaluated how the ecosystem multifunctionality including nutrient cycling, carbon stocks, water regulation, decomposition, wood production and symbiosis develops using a chronosequence, and identified the key factors contributing to the variations in the ecosystem multifunctionality during natural forest succession. We provide evidence that the ecosystem multifunctionality gradually increased along with succession stages. The individual functions of carbon stocks and water regulation also exhibited increasing patterns with stand development. The microbial diversity were more principal factors than plant diversity and soil properties for the explanation of changes in the ecosystem multifunctionality. The regression analysis showed that the diversity of bacteria, general fungi, actinomycetes, nematodes, G+ bacteria and G− bacteria significantly and positively associated with ecosystem multifunctionality. Soil nematodes exhibited significantly positive correlation with most of the individual functions. Synthesis and applications. Taken together, our results demonstrate that natural forest restoration plays a key role in promoting ecosystem multifunctionality, and emphasize the importance of soil microbial diversity for the maintenance of ecosystem functions and health.

Afrotropical secondary forests exhibit fast diversity and functional recovery, but slow compositional and carbon recovery after shifting cultivation

AbstractQuestionsHuman disturbance is increasingly affecting forest dynamics across the tropics. Forests can recover via natural secondary succession to pre‐disturbance levels of biodiversity, species composition, and ecosystem carbon stocks. Central Africa will be subject to increasingly high shifting‐cultivation pressure in the next decades, but succession trajectories of these ecosystem properties are still poorly known for the Congo basin. We addressed two questions: (1) how does taxonomic and functional composition and diversity shift during secondary succession; and (2) how fast do above‐ground carbon stocks recover during secondary succession in tropical forests?LocationCentral Congo basin.MethodsWe conducted an inventory of trees (diameter at breast height [DBH] ≥ 10 cm), measured species traits and soil texture and carbon content in 18 plots, located along six secondary succession stages (i.e., from agricultural to old growth forest sites). We measured tree diameter, height for 20% of trees distributed across diameter classes, wood traits from all species, and leaf traits from species that contributed to 85% of the plot basal area.ResultsWe showed that secondary forests recover relatively fast in terms of tree species diversity, alpha functional diversity, and fine‐root carbon, with near‐old‐growth forest values after six decades past disturbance, while floristic composition exhibited slower recovery. Secondary forests only partially shifted from acquisitive to a conservative life history, with shifts in leaf traits being largely decoupled from wood traits. Only 43% of above‐ground carbon recovered after 60 years of forest regrowth, potentially through a slow recovery of the large‐sized tree stems that dominate carbon stocks of old‐growth forests.ConclusionsOur findings underline the capacity of Afrotropical forests to recover species and alpha functional diversity after clear‐cutting through shifting cultivation. Simultaneously, old‐growth forests harbor a particular floristic community and store a large quantity of carbon with much longer recovery trajectories, stressing the need for conservation of these forests in the Congo basin.

Macro- and Micronutrient Contents in Soils of a Chronosequence of Naturally Regenerated Birch Stands on Abandoned Agricultural Lands in Central Poland

Abandoned agricultural lands in Central and Northern Europe undergo a quite rapid secondary succession of woody species, especially silver birch (Betula pendula Roth.) as a pioneer tree species. Such a process is desirable both from natural and economic point of views, as afforestation involves a change to the entire ecosystem and, in particular, the transformation of anthropogenic habitats typical for agriculture into habitats similar to a natural forest. In the present study, we report the chemical properties of soils under birch stands that naturally regenerated on abandoned agricultural lands and answer the question of whether silver birch modifies the chemical properties of soils over a (relatively short—17 years) time and with depth in the soil profile. The research investigated the natural secondary succession of silver birch on 28 study plots established as a chronosequence in seven locations in Central Poland. The age of the stands ranged from 2 to 17 years. We analysed the contents of selected micro- and macroelements and heavy metals at three depths in the soil profile. The chemical properties of former agricultural soils covered with newly established silver birch stands, taking into account the depth in the soil profile, demonstrated tendencies to change over the time. In the first age class of birch stands, the stock of investigated nutrients in the soil was higher compared to the following age classes. Statistically significant differences were noted in the case of Cu and Cr. Along with the age of birch stands (age class IV), there was a tendency for stock of the analysed nutrients to grow, which can be associated with an increase in aboveground biomass and root system development. The changes in the contents of the macro- and microelements, as well as heavy metals, were characterised by a gradual increase of the elements analysed in the upper layer of the soil that, in the years following the birch influence on the soil, starts having an effect on the deeper layers. In the case of Cu, Pb, Cd, Ni and Cr, there was a statistically significant change in the depth of the soil. Longer chronosequences should be observed to see a clear trajectory in soil chemistry changes with birch stand ages.

ANALISIS KADAR AIR SERASAH KELAKAI (Stenochlaena palustris Burm. Bedd) TERHADAP PELUANG TERJADINYA KEBAKARAN DI KAWASAN EKOWISATA BEKANTAN PT. ANTANG GUNUNG MERATUS KALIMANTAN SELATAN

Bekantan ecotourism area is a peat area that had caught fire in 2015 resulting in the loss of existing vegetation. Naturally, areas of burned peat have the ability to repair themselves by natural (secondary) succession. This succession is usually marked by the presence of pioneer plant types which will eventually form vegetation of shrubs, one of which is kelakai (Stenochlaena palustris Burm. Bedd) which dominates in the bekantan ecotourism area. It is possible to become one of the forest fuels if the area burns again. The aim of this study is to calculate the level of water litter (Stenochlaena palustris Burm. Bedd) and analyze the effect of water content of litter (Stenochlaena palustris Burm. Bedd) on the chance of a fire in Bekantan Ecotourism Area of PT. Antang Gunung Meratus, Kalimantan Selatan. The study was conducted in Bekantan Ecotourism Area PT. Antang Gunung Meratus, Kalimantan Selatan, for 3 months, from June to August 2019. The data obtained were calculated on the water content and determined the level of fire hazard. The results of this study the water content of litter under the shade of 11.6%. So that the water content under the shade is at a rate <20%. In accordance with the statement of the Ministry of Forestry and Forestry (1999) for peatlands, the water content in the observation plots is categorized as prone to fire.Keywords: Fire; Kelakai; Water content

Ecoenzymatic stoichiometry and nutrient limitation under a natural secondary succession of vegetation on the Loess Plateau, China

AbstractSoil ecoenzymatic stoichiometry reflects the nutrient flow of ecosystems. While knowledge exists on how the secondary succession of plants affects soil physicochemical properties and soil ecoenzymatic activity, less is known about how soil ecoenzymatics change during this process. We investigated five typical stages of the entire succession process of vegetation on the Loess Plateau, China. These stages included: (1) farmland stage (0 years), (2) grassland stage (30 years), (3) shrub land stage (60 years), (4) the pioneer forest stage (100 years), (5) the climax community stage (160 years). Soil ecoenzymatic activity, microbial biomass, and soil physicochemical properties were measured. Our research showed secondary succession significantly changed soil enzyme activity, and the metabolic activity of soil microorganisms significantly declines as secondary succession progresses. N limitation in the soil microbial community was weak initially and then gained strength. P nutrient limitation was strong initially, and then weakened. Soil ecoenzymatic C : N : P acquisition ratios deviated from 1 : 1 : 1. Thus, secondary succession on the Loess Plateau is nutrient dependent, but not homeostatic. Soil physicochemical properties and plants were important factors for soil enzyme activities. In addition, soil available nutrients were better than soil total nutrients to reveal changes in soil ecoenzymatic activities and stoichiometry. This study demonstrated the regularity of soil nutrient cycling during the secondary succession of vegetation, providing new insights on the mechanisms of nutrient flow.

Recovery of amphibian, reptile, bird and mammal diversity during secondary forest succession in the tropics

In tropical regions, many studies have focused on how vegetation and ecosystem processes recover following the abandonment of anthropogenic activities, but less attention has been given to the recovery patterns of vertebrates. Here we conduct a meta‐analysis (n = 147 studies) of amphibian, reptile, bird and mammal recovery during tropical secondary forest succession (i.e. natural regeneration). For each taxonomic group, we compared changes in species richness and compositional similarity during natural secondary succession to reference forests (mature or old growth forest). In addition, we evaluated the response of forest specialists and the change in bird and mammal functional groups during natural secondary succession in the tropical moist forest biome. Overall, species richness of all groups reached levels of the reference forests during natural secondary succession, but this was not the case for species compositional similarity. The delay in recovery of forest specialists may be the reason for the delay in recovery of species compositional similarity. Overall, vertebrate recovery increased with successional stage, but other potential predictors of diversity recovery, such as, the geographical setting (amphibian and reptile species compositional similarity recovered more rapidly on islands), rainfall (mammal species richness and compositional similarity recovered faster in regions of low rainfall), and the landscape context (amphibian, reptile and mammal species compositional similarity recovered faster in regions with more forest patches) influenced vertebrate recovery. These results demonstrate the important role of secondary forests in providing habitat for many vertebrates, but the slow recovery of species compositional similarity, forest specialists and some functional groups (e.g. insectivorous birds) highlighted the challenge of secondary forest persistence, and strongly argues for the continued protection of old growth/mature forest as habitat for forest specialists and as sources for secondary forest sites.

Vegetation dynamics of abandoned paddy fields and surrounding wetlands in the lower Tumen River Basin, Northeast China.

On the temperate lowland plain of the lower Tumen River, agricultural development has converted most marshland into paddy fields. However, the locations of old paddy fields in the lowland temperate zone, where the vegetation structure is dominated by herbs adapted to seasonally wet or waterlogged conditions, are poorly known, and the impact of land use history on marshland diversity and shifts in plant functional groups has been scantly researched. In this study, we used a chronosequence approach to investigate herbaceous wetland communities in different recovery phases (<5 years, 5–15 years, and >15 years), as well as natural wetland as a reference. We assessed their ecological characteristics, species composition and diversity to determine how they change during natural succession. Plant species composition and dominance in the abandoned fields changed markedly during natural secondary succession. Initially, the annual weeds Echinochloa crus-galli and Bidens tripartita were dominant. Later, communities gradually became dominated first by Polygonum thunbergii and then by tussock-forming Carex rostrata. Species diversity was higher in abandoned fields than in natural wetlands and decreased with time. The partition of β-diversity components revealed that replacement was the prominent process structuring plant communities in paddy field at different times since abandonment. Our results suggest that the vegetation of abandoned paddy fields could be restored effectively through natural succession, although there were some differences in plant functional group traits. Abandoned paddy fields may be good sites for restoration of wetland species and conservation of wetland habitat.

Stable and radio-isotopic signatures reveal how the feeding habits of ants respond to natural secondary succession in a cool-temperate forest

Ants are known to have various feeding habits and play important roles in many terrestrial ecosystems. However, little is known about how the feeding habits of each ant species are affected by the environmental changes associated with forest succession. In this study, we examined how feeding habits as well as the species composition and food preference of ants would respond to 105-year-old natural secondary succession of a cool-temperate forest. Stable carbon and nitrogen isotopes and radiocarbon were used to infer the feeding habits. The species richness was not affected by forest stand age. Redundancy analysis indicated that stand age, litter N concentration, and soil microbial respiration had significant relationships with the ant species composition. The bait experiments showed that honey bait became more attractive to ants relative to tuna bait in late succession. This was probably associated with changes in available food resources, such as nectar, during succession. Although the isotopic signatures differed significantly among the sample types (i.e., ant species, canopy leaves, and leaf litter), they were not significantly affected by forest stand age or by the interaction between sample types and stand age. This indicates that the ants showed consistent differences in feeding habits among the species during succession. Our results suggest that despite great changes in vegetation, each ant species would maintain functional roles in C and N flows during forest succession.

豫西丘陵坡地弃耕农田植被演替对土壤碳、氮库的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 豫西丘陵坡地弃耕农田植被演替对土壤碳、氮库的影响 DOI: 10.5846/stxb201709261739 作者: 作者单位: 河南科技大学,河南科技大学,河南科技大学,河南科技大学,河南科技大学 作者简介: 通讯作者: 中图分类号: 基金项目: NSFC-河南人才培养联合基金（U1304306）；中国科学院战略性先导科技专项（XDA05050402）；河南科技大学第六届研究生创新基金（CXJJ-2016-ZR12） Effects of vegetation succession on soil carbon and nitrogen storage in abandoned hilly farmlands of the Western Henan Region Author: Affiliation: Henan University of Science and Technology,,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:在豫西丘陵坡地弃耕农田中，设置一个时间梯度为1，3，8，15，25 a的弃耕演替系列，调查其群落数量特征、物种组成、植被与土壤的碳、氮储量，分析群落的自然次生演替过程，并探讨土壤碳库与氮库对植物群落演替的响应机制。结果表明，弃耕农田群落演替缓慢，阶段性不明显，大致可划分为一、二年生草本→多年生草本+灌木两个阶段。定植物种的多样性变化与附近的原生植被有关。在25 a的演替进程中，草本植物始终占据优势，旱生植物数量约是中生植物的4倍，C3植物数量逐渐增多；群落α多样性指数呈先增大后减小趋势，Margalef丰富度指数、Pielou均匀度指数与Shannon-Wiener综合多样性指数最大值分别为1.53、0.95、2.18，表明弃耕农田的自然演替促使群落结构更加复杂并趋向稳定。群落植物的碳、氮储量随着生物量的增加而增加，在25 a时分别达到313.14 g/m2和11.69 g/m2。土壤碳储量与氮储量的变化相反，在演替后期（25 a）土壤碳储量增加到960.98 g/m2，而氮储量则降低至27.08 g/m2，表明豫西弃耕农田土壤具有"固碳放氮"的生态现象。RDA分析表明，群落盖度、密度和生物量是影响土壤碳、氮储量的主要因子。从群落的生态功能变化分析，按照弃耕演替时间推进，土壤碳储量逐渐增大，有利于生态系统碳固定；而土壤氮库的缩减则不利于群落的稳定，建议增加群落中豆科植物的丰富度，从而促进土壤氮素固定，缓解氮素流失。 Abstract:Understanding the vegetation, soil status, and their relationship on abandoned farmland plays an important role in the determination of future land use. In this study, five hilly farmlands abandoned for different periods of time (1, 3, 8, 15, and 25 years) were selected as a series of successive abandonments in the Western henan region to investigate the quantitative characteristics and species composition of the plant community and the carbon and nitrogen storage in vegetation and the soil, to analyze the natural secondary succession process of the plant community, and to discuss how the soil carbon and nitrogen pool responded to the plant community succession. The main results indicated that:The abandoned farmland communities that possessed a slow succession progress and generally included two indistinct succession stages, from annual or biennial herbs to perennial herbs and shrubs. The plant species diversity was closely related to the surrounding native vegetation. Over 25 years, herbs in the community always had an advantage status, the number of xerophytes was more than four times that of mesophytes, and the quantity of C3 plants increased gradually. The α diversity index first increased and then decreased, and the maximum values of the Margalef, Pielou and Shannon-Wiener indices were 1.53, 0.95, and 2.18, respectively. These data could provide proof that the community structure became more complex and stable after a natural succession process of 25 years. Both plant carbon storage and nitrogen storage increased as the community biomass constantly accumulated, reaching values of 313.14 g/m2 and 11.69 g/m2, respectively, at the 25-year succession stage. The soil carbon storage trend opposed that of soil nitrogen storage. In the climax stage (25 a), the soil carbon storage increased to 960.98 g/m2, whereas the soil nitrogen storage was reduced to 27.08 g/m2. Therefore, the changes in the soil property of the abandoned farmlands in the Western henan region resulted in the ecological phenomenon of "carbon fixation and nitrogen release". Redundancy analysis (RDA) showed that the community coverage, density and biomass were the main factors affecting soil carbon and nitrogen storage. The analysis of the ecological function changes of these communities showed that soil carbon storage gradually increased as the time since abandonment increased, which was beneficial to the carbon fixation of the ecosystem. However, the reduction in soil nitrogen storage in abandoned farmlands did not, contribute to the stability of the ecosystem. Thus, an increase the richness of leguminous plants in the community was suggested to promote biological immobilization of soil total nitrogen and alleviate soil nitrogen loss. 参考文献 相似文献 引证文献

Long-term succession of Collembola communities in relation to climate change and vegetation

The successional dynamics of Collembola communities on a rubble and debris dump in Bremen, Germany were studied between 1980 and 2000 in two experimental plots. One plot (SUC) was left undisturbed for natural secondary succession, the other plot (REC) was recultivated with rotary-tilling and sowing of grass. The mean Collembola abundance varied between 4 and 119 thousand ind. m−2 on SUC and between 6 and 92 thousand ind. m−2 on REC. In the two plots individual numbers peaked in the first decade, thereafter they decreased. Number of species varied from 9 to 17 on SUC with a very slight increase over time and from 8 to 17 on REC with only a temporary depression in 1998. The alpha diversity calculated as Shannon-Weaver and Simpson-indices increased in both plots. The lowest species turnover rate occurred between 1990 and 1994 on SUC and between 1981 and 1982 on REC, indicating the lowest diversity in species composition. During the whole succession, species composition changed more or less irregular in the two plots. With 74%, the dominance similarity (Renkonen index) of the Collembola communities between SUC and REC was greatest two years after the beginning of succession. As a result from CCA analysis, confirmed by linear regression analyses, Collembola total abundance and species composition (dominances) were significantly affected by annual (Oct-Sep) mean air and soil temperature (−10cm), increasing over the study period of twenty years. Ordination scores of Collembola species abundance on the CCA axes revealed four climatic groups of Collembola: cold-dry, cold-wet, warm-wet and warm-dry. A correlation of Collembola species abundance with vegetation cover was not found. Nevertheless, stronger effects of climatic variables were found on REC, which had a shorter vegetation than SUC, creating a different microclimate. Successional dynamics of Collembola communities in the studied plots are correlated with temporal shifts of species between early and late years of succession, but are also significantly influenced by soil temperature.

Differences in early dynamics and effects of slope aspect between naturally regenerated and planted Pinus sylvestris woodland on inland dunes in Poland

Abstract: There is little knowledge of the effects of landform relief on early growth dynamics and competitive interactions of Pinus sylvestris (Scots pine) stands on inland dunes, which could potentially be substantial. The goal of this study was to examine and compare early dynamics (based on growth parameters and properties of the understorey vegetation) and the effects of slope aspect in naturally regenerated and pine-planted woodland on inland dunes in northern Poland. Growth parameters, tree density, and understorey vegetation were monitored on north- and south-facing slopes in a 26.3 ha post-fire area with natural secondary succession and eight even-aged pine-planted stands, 5-34 years old. Clear differences were detected between the woodland types, in both growth parameters of pines with similar ages and effects of slope aspect on the pines. In the natural regeneration area north-facing slopes provided favorable conditions for natural encroachment by pines. Tree density was higher, and the pines were taller and thicker, on north-facing than on south-facing slopes. In contrast, in the pine-planted area pines were larger on south-facing slopes, although growth conditions were less favorable than on north-facing slopes. However, in the pine-planted area the north-facing slopes had significantly higher herb cover, dominated by Deschampsia flexuosa, indicating that even the presence of a relatively low grass species can impede early growth of Scots pine. The understorey species composition differed in the natural regeneration area, being dominated by Calluna vulgaris on north-facing slopes and Corynephorus canescens on south-facing slopes. The results reveal that interactions between landform, natural dynamics, planting practices, and competitive interactions in woodlands on inland dunes are complex, and should be considered in efforts to manage them efficiently.

Effects of management on vegetation dynamics and associated nutrient cycling in a karst area, Yunnan, SW China

The legacies of land use (such as plantations, pastures and coppices) in the Shilin karst area of central Yunnan, SW China have strongly influenced the plant communities' structure, dynamics, species diversity, litter nutrients inputs, and soil chemical properties. To evaluate the effects of various restoration approaches on ecosystem recovery in the area, we analyzed vegetation characteristics of a Pinus plantation, natural successional plant communi- ties (the shrubland, the secondary forest and the natural premature forest), and their leaf litter nutrients and soil chemical properties. The natural successional plant com- munities had better regeneration, higher species diversity, higher litter nutrient input, and higher soil fertility as com- pared with the Pinus plantation. The results indicate that the natural secondary succession facilitates regeneration to young and old secondary forests, promotes recovery of plant diversity and cycling of litter-soil-nutrients, yielding greater ecological benefits. The study will provide guidance for restoration of the vegetation and for forest management planning in this fragile mountainous ecosystem.

Root biomass and soil carbon distribution in hybrid poplar riparian buffers, herbaceous riparian buffers and natural riparian woodlots on farmland

The objectives of this study were to compare coarse root (diameter > 2 mm) and fine root (diameter < 2 mm) biomass, as well as distribution of soil carbon stocks in 3 types of riparian land uses across 4 sites located in farmland of southern Québec, Canada: (1) hybrid poplar buffers (9th growing season); (2) herbaceous buffers; (3) natural woodlots (varying in tree species and age). For all land uses most of the root biomass was within the 0–20 cm depth range. Total coarse root biomass, to a 60 cm depth, ranged from 8.8-73.7 t/ha in woodlots, 0.6-1.3 t/ha in herbaceous buffers, and 9.2-27.3 t/ha in poplars. Total fine root biomass ranged from 2.68-8.64 t/ha in woodlots, 2.60-3.29 t/ha in herbaceous buffers, and 1.86-2.62 t/ha in poplars. Total root biomass was similar or higher in poplar buffers compared to a 27 year-old grey birch forest. This indicates that poplar buffers accelerated riparian soil colonisation by roots compared to natural secondary succession. Generally, fine root biomass in the surface soil (0–20 cm) was lower in poplar than in herbaceous buffers; the reverse was observed at greater depth. Highest coarse root biomass in the 40–60 cm depth range was observed in a poplar buffer, highlighting the deep rooted nature of poplars. On average, total soil C stocks (0–60 cm) were greater in woodlots than in riparian buffers. On most sites, soil C stocks tended to be lower in poplar buffers compared to adjacent herbaceous buffers, especially in surface soil, probably because of lower fine root biomass in poplar buffers. Across all sites and land uses, highest soil C stocks at the different soil depths were found in the soil layers of woodlots that also had the greatest fine root biomass. Strong positive linear relationships between fine root biomass and soil C stocks in the 0–20 cm depth range (R2 = 0.79, p < 0.001), and in the whole soil profile (0–60 cm) (R2 = 0.65, p < 0.01), highlight the central role of fine root biomass in maintaining or increasing soil C stocks.

Physicochemical and Biochemical Reclamation of Soil through Secondary Succession

Conversion of forest to agricultural fields has become a common practice in India. Very often these fields have been abandoned due to lack of sustainable production. In course of time these fallow lands undergo natural secondary succession. Present study was carried out to find out the restoration of soil physicochemical and biochemical properties in a chronosequence of 2 yr, 4 yr, 6 yr, 11 yr, and 15 yr fallow lands. Soil enzyme activities play key roles in the biochemical functioning of soils, including soil organic matter formation and degradation, nutrient cycling, and reflect the change in soil management and land use. There was gradual improvement in the physical condition and nutrient status along with increase in soil amylase, cellulase, dehydrogenase, phophatase, and urease activity in the present study with the progress of fallow age which indicates the importance of natural secondary succession in soil restoration. However the PCA analysis indicated that natural vegetational succession could reclaim the soil quality and promote ecosystem restoration but it required a long time under the present local climatic condition.

喀斯特峰丛洼地不同生态系统的土壤肥力变化特征

PDF HTML阅读 XML下载 导出引用 引用提醒 喀斯特峰丛洼地不同生态系统的土壤肥力变化特征 DOI: 10.5846/stxb201208161154 作者: 作者单位: 中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室,中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室,中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室,中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室,中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室,中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室,中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室,江西农业大学,广西大学林学院 作者简介: 通讯作者: 中图分类号: 基金项目: 中国科学院西部行动计划资助项目（KZCX2-XB3-10）；国家科技支撑计划资助项目（2011BAC09B02）；中国科学院战略性先导科技专项资助项目（XDA05070404，XDA05050205）；国家自然科学基金资助项目（31370485，31370623，U1033004，31100329）；桂科攻（1123001-9C）资助项目；广西“特聘专家”资助项目 Characteristics of soil fertility in different ecosystems in depressions between karst hills Author: Affiliation: Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences,,Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences,,,,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:基于喀斯特峰丛洼地坡耕地、草丛、灌丛、人工林、次生林、原生林6种典型生态系统的土壤主要养分、矿质养分和微生物这3组变量共计20个指标的调查、取样和分析，运用多重比较分析、主成分分析和典范相关分析探讨了其土壤肥力变化特征、主要影响因子及两两之间的相互关系。结果表明，喀斯特峰丛洼地土壤pH值为6.60-7.75，土壤主要养分、微生物种群数量和微生物生物量明显高于同纬度地区地带性红壤，矿质养分含量相对较低，其中SiO2、Al2O3、Fe2O3占矿质全量的90%以上。土壤肥力的总体趋势为原生林 > 次生林 > 灌丛 > 草丛 > 坡耕地 > 人工林。喀斯特石漠化地区实行林草结合的退耕还林还草模式更有利于土壤生态系统的环境改善，坡耕地应多施有机肥和氮肥，人工林应多施氮肥。原生林植物与养分之间达到了良好的平衡状态，主要应加强森林抚育管理，改善森林环境，保障植物、土壤养分及微生物之间的良好协调关系。确保土壤资源的合理利用，促进喀斯特峰丛洼地乃至整个西南喀斯特区域植被的迅速恢复和生态重建。 Abstract:The main soil nutrients, soil mineral nutrients, and soil microbes were investigated, sampled, and analyzed in farmland, grassland, scrub, plantation forest, secondary forest, and primary forest in depressions between karst hills. Multiple comparison analysis, principal component analysis, and canonical correlation analysis were used to study the soil characteristics and the main factors affecting soil fertility as well as the relationships between those three factors: the main soil nutrients, soil mineral content, and soil microbes. Soil pH ranged from 6.60 to 7.75 in depressions between karst hills. Across the different ecological systems, from farmland to primary forest soil, pH varied from acidic to alkaline. The soil nutrient content varied in different ecological systems, and changes in soil nutrient content can be modeled during the process of ecological succession. In the process of secondary succession soil organic matter (SOM), total nitrogen (TN), total phosphorous (TP), available nitrogen (AN), and available phosphorous (AP) content increased gradually. The soil nutrient levels were highest in primary forest and follow the sequence of primary forest > secondary forest > shrub > grassland. The soils of these habitats were all significantly or very significantly different. When the landuse type was changed from a landscape with natural secondary succession to farmland or plantation forests, soil TP and TK content increased significantly. The content of the main soil nutrients (SOM, TN, TP, TK, AN, AP, AK), microbial populations, and the soil content of C, N, and P in microbial biomass (Cmic, Nmic, Pmic, respectively), were obviously higher in the karst area than that in the red soil region at the same latitudes. The content of mineral nutrients was relatively low and the sum of SiO2, Al2O3, and Fe2O3 accounted for more than 90% of the total mineral nutrients. Although the supply of Ca and Mg were adequate, serious shortages of other mineral nutrients limited plant growth and development. Many types of ecological systems in depressions between karst hills were not obviously showing signs of rocky desertification, although a strong potential for rocky desertification still exists. All ecosystems studied here had high soil microbial populations, and primary forest had highest total microbial populations, bacteria populations and Actinomyces population while plantation forest had the lowest. Soil fertility can be ranked in the order of primary forest > secondary forest > scrub > grassland > farmland > plantation forest. The landscape in this karst area is strongly heterogeneous; the ecological systems are complex because numerous factors affect the ecosystems and different ecological systems are influenced by different factors. Therefore, the practice of returning farmland to forests or grassland tends to improve the soil ecosystem environment in karst areas which have undergone rocky desertification. Farmland requires more organic and nitrogenous fertilizers and plantation forests require more nitrogenous fertilizer than other ecosystems. In the primary forest, plants and soil nutrients reach a state of dynamic equilibrium, and land management should focus on strengthening and improving the forest environment and balancing the relationships among plants, soil nutrients and microbes. Assuring that soil resources are used rationally will be helpful in improving the results of ecological restoration and accelerate vegetation rehabilitation in depressions between karst hills or even in the entire karst region of southwest China. 参考文献 相似文献 引证文献

English

&nbsp; In order to assess the dynamics of microbial-diversity through vegetation successions, sample sites for soil investigation at the 10a, 25a, 40a, 75a natural secondary&nbsp;Pinus tabulaeformis&nbsp;Carr.&nbsp;forests were established in the forest region of Loess Plateau, China. With the succession extension, soil microbial biomass carbon (MBC), moisture content,&nbsp;soil organic carbon (SOC) as well as total N also exhibited an increase before decreasing trend with succession gradient. Soil indexes of the soil shannon diversity index (H), which incorporates both richness and evenness of all soil microbial-species observed in the plots according to T-RFs peaks composition determined by terminal restriction fragment length polymorphism (T-RFLP), also exhibited a similar trend with soil physicochemical properties during the succession. In the late-succession of 75a, its soil fertility and microbial-community structure is distant from other three stages, suggesting that it may be a specific stage to the recession succession. The result of a dendrogram of hierarchical cluster of the microbial-community structure of four succession stages showed that 75a was distant to the other three sample sites, and 25a and 40a represented the most similar microbial-community structure of all stages. It was concluded that the underground succession of natural secondary P. tabulaeformis&nbsp;Carr.&nbsp;forests in the forest region of Loess Plateau, China, is significantly linked to its aboveground. We infer that natural secondary succession of&nbsp;P. tabulaeformis&nbsp;Carr forest will be replaced by the&nbsp;Qercu sliaotungensis&nbsp;in the coming centuries in the forest region of Loess Plateau, China.&nbsp;&nbsp; &nbsp; Key words:&nbsp;Soil microbial-community; natural secondary succession, T-RFLP, Loess Plateau.

Dynamic of soil microbial-community: Terminal restriction fragment length polymorphism analysis on natural secondary succession of Pinus tabulaeformis Carr. in the forest region of Loess Plateau, China

Optimization of a chromium biosorption process was performed by varying three independent variables pH (0.5 to 3.5), initial chromium ion concentration (10 to 30 mg/L), and Yarrowia lipolytica dosage (2 to 4 g/L) using a Doehlert experimental design (DD) involving response surface methodology (RSM). For the maximum biosorption of chromium ion in an aqueous solution by Y. lipolytica , a total of fifteen experimental runs were set and the experimental data fitted to the empirical second-order polynomial model of a suitable degree. The analysis of variance of the quadratic model demonstrates that the model was highly significant. The model showed that chromium uptake in aqueous solution was affected by all the three variables studied. The optimum values of the variables were found to be 2.07, 18.76 mg/L and 3.39 g/L for pH, initial chromium ion concentration and biomass dosage, respectively at contact time of 30 min. At these optimal conditions, the maximum percentage biosorption of chromium was predicted to be 41.59. The experimental values were in good agreement with predicted values and the correlation coefficient was found to be 0.9891. Therefore, it is apparent that the DD involving RSM not only gives valuable information on interactions between the variables but also leads to identification of feasible optimum values of the studied variables. Keywords: Biosorption, Doehlert experimental design, response surface methodology, Yarrowia lipolytica African Journal of Biotechnology , Vol 13(12), 1413-1422