Soil faunas account for 23%of known animal species and play a crucial role in ecosystem processes such as mineralizing nutrients,regulating microbial community composition,forming soil aggregates,and enhancing primary...Soil faunas account for 23%of known animal species and play a crucial role in ecosystem processes such as mineralizing nutrients,regulating microbial community composition,forming soil aggregates,and enhancing primary productivity.However,due to global climate change,population density,community composition,and distribution patterns of soil fauna vary.Understanding the responses of soil fauna to major environmental change facilitate the conservation of biodiversity.Therefore,a review work of recent researches for analysing the effects of key environmental factors on soil fauna,such as warming,drought,food quality,and soil physical-chemical properties was studied.For most species,warming may exert a positive effect on their abundance and population development,however,it can inhibit the survival and reproduction of hibernating species.Drought leads to low soil porosity and water holding capacity,which reduces soil fauna population and changes their community composition.Drought also can reduce the coverage of flora and alter microclimate of the soil surface,which in turn indirectly reduces fauna abundance.Climate warming and elevated atmospheric carbon dioxide can reduce litter quality,which will force soil fauna to change their dietary choices(from higher-quality foods to poor quality foods)and reduce reproduction for survival.However,it is still predicted that enhanced species richness of plant(or litter)mixtures will positively affect soil fauna diversity.Habitat loss caused by the deterioration of soil physical-chemical property is primary factor affecting soil fauna.We mainly discuss the threats of increased salinity(a major factor in arid land)to soil fauna and their potential responses to anthropogenic disturbance in saline soils.The increase in soil salinity can override other factors that favour habitat specialists,leading to negative effects on soil fauna.Moreover,we find that more studies are needed to explore the responses of soil fauna in saline soils to human activities.And the relationship of important ecological processes with soil fauna density,community structure,and diversity needs to be redefined.展开更多
A field-scale experiment arranged in a complete randomized block design with three N addition treatments including a control (no addition of N), a low N (5 g m-2 year-1), and a medium N (10 g m-2 year-1) was performed...A field-scale experiment arranged in a complete randomized block design with three N addition treatments including a control (no addition of N), a low N (5 g m-2 year-1), and a medium N (10 g m-2 year-1) was performed in each of the three typical forests, a pine (Pinus massoniana Lamb.) forest (PF), a pine-broadleaf mixed forest (MF) and a mature monsoon evergreen broadleaf forest (MEBF), of the Dinghushan Biosphere Reserve in subtropical China to study the response of soil fauna community to additions of N. Higher NH4+ and NO3- concentrations and a lower soil pH occurred in the medium N treatment of MEBF, whereas the NO3- concentration was the lowest in PF after the additions of N. The response of the density, group abundance and diversity index of soil fauna to addition of N varied with the forest type, and all these variables decreased with increasing N under MEBF but the trend was opposite under PF. The N treatments had no significant effects on these variables under MF. Compared with the control plots, the medium N treatment had significant negative effect on soil fauna under MEBF. The group abundance of soil fauna increased significantly with additions of higher N rates under PF. These results suggested that the response of soil fauna to N deposition varied with the forest type and N deposition rate, and soil N status is one of the important factors affecting the response of soil fauna to N deposition.展开更多
The Liangshui Natural Reserve in Heilongjiang Province of China was selected as the study area. The authors collected the samples of forest litter (Tilia amurensis, Fraxinus mandshurica, Pinus koraiensis, Acer mono, B...The Liangshui Natural Reserve in Heilongjiang Province of China was selected as the study area. The authors collected the samples of forest litter (Tilia amurensis, Fraxinus mandshurica, Pinus koraiensis, Acer mono, Betula costata, and mixed litter), soil in humus horizon (0-5cm) and soil horizon (5-20cm), and soil macrofauna (Oli-gochaeta, Geophiloporpha and Juliformia) from 2001 to 2002. The role of soil macrofauna in the material cycle was analyzed through comparing the macro-element contents among various parts of the subsystems and using enrichment index (EI). The results indicate that dynamic changes of various litters are very complicated. The contents of Fe in each kind of litter increase firstly, and then decrease in the study period. The changes of macro-element contents are greater in the broad-leaf litter than in the coniferous litter, and the mixed litter is in the middle level, but the differences among them are not significant. The contents of Mg and Fe in humus are higher than those in soil, but the contents of Ca in soil are higher than that in humus. The dynamic changes of macro-element contents in soil and soil fauna are not consistent with those in litter. The diplopod presented obvious enrichment of Ca and Mg (EI>1), but it does not significantly enrich Fe. Earthworm has a stronger enrichment ability of Fe than diplopod and scolopendra, but EI<1. Soil fauna can make great influences on the material cycle of the subsystems.展开更多
In a field experiment, the populations of major soil fauna groups including earthworms, enchytraeids,arthropods and nematodes were examined in conventional tillage (CT) and no-tillage (NT) red soil ecosystems to evalu...In a field experiment, the populations of major soil fauna groups including earthworms, enchytraeids,arthropods and nematodes were examined in conventional tillage (CT) and no-tillage (NT) red soil ecosystems to evaluate their responses to tillage disturbance. Earthworms, macrry and micro-arthropods were stimulated under NT with earthworms showing the highest population increase by four times, while enchytraeids and nematodes favored CT system, predicting certain adaptability of these animals to plow-disturbed soil environment. On the basis of relative response index it was found that soil fauna was more sensitive to tillage than soil resource base (C and N pools) and microflora. The population structure of soil fauna was also affected by tillage treatments. Analysis on nematode trophic groups showed that bacteria-feeding and plant parasitic nematodes were more abundant in CT soil whereas the proportions of fungivores and omnivorepredators increased in NT soil. Possible reasons for the differentiation in both size and structure of the fauna population were discussed and the ecological significance involved in these changes was emphasized.展开更多
Litter decomposition is the key process in nutrient recycling and energy flow. The present study examined the impacts of soil fauna on decomposition rates and nutrient fluxes at three succession stages of wetland in t...Litter decomposition is the key process in nutrient recycling and energy flow. The present study examined the impacts of soil fauna on decomposition rates and nutrient fluxes at three succession stages of wetland in the Sanjiang Plain, China using different mesh litterbags. The results show that in each succession stage of wetland, soil fauna can obviously increase litter decomposition rates. The average contribution of whole soil fauna to litter mass loss was 35.35%. The more complex the soil fauna group, the more significant the role of soil fauna. The average loss of three types of litter in the 4mm mesh litterbags was 0.3-4.1 times that in 0.058mm ones. The decomposition function of soil fauna to litter mass changed with the wetland succession. The average contribution of soil fauna to litter loss firstly decreased from 34.96% (Carex lasiocapa) to 32.94% (Carex meyeriana), then increased to 38.16% (Calamagrostics an- gustifolia). The contributions of soil fauna to litter decomposition rates vary according to the litter substrata, soil fauna communities and seasons. Significant effects were respectively found in August and July on C. angustifolia and C. lasiocapa, while in June and August on C. meyeriana. Total carbon (TC), total nitrogen (TN) and total phosphorus (TP) contents and the C/N and C/P ratios of decaying litter can be influenced by soil fauna. At different wetland succession stages, the effects of soil fauna on nutrient elements also differ greatly, which shows the significant difference of influencing element types and degrees. Soil fauna communities strongly influenced the TC and TP concentrations of C. meyeriana litter, and TP content of C. lasiocapa. Our results indicate that soil fauna have important effects on litter decomposition and this influence will vary with the wetland succession and seasonal variation.展开更多
Microorganisms are nutritious resources for various soil fauna.Although soil fauna grazing affects microorganism composition and decomposition rate,the responses of soil fauna and leaf litter decomposition to added mi...Microorganisms are nutritious resources for various soil fauna.Although soil fauna grazing affects microorganism composition and decomposition rate,the responses of soil fauna and leaf litter decomposition to added microorganism is little understood.In this study,in the coniferous and broad-leaved mixed forest of Tahe County in the northern Da Hinggan Mountains,China,three sampling sites(each has an area of 10 m2) were selected.The first two sites were sprinkled with 250 times(EM1) and 1000 times(EM2) diluted effective microorganism(EM) preparations evenly,and the third site was sprinkled with the same volume of water as a control site.The responses of soil fauna structure and leaf litter decomposition to EM treatment were conducted during three years.The results revealed that EM treatment resulted in significant increase of soil organic matter.The number of soil fauna in the EM1 and EM2 sites increased by 12.88% and 2.23% compared to the control site,and among them springtails and mites showed the highest increase.However,the groups of soil fauna in the EM1 and EM2 sites decreased by 6 and 9,respectively.And the changes in the diversity and evenness index were relatively complicated.EM treatment slowed the decomposition of broad-leaved litter,but accelerated the decomposition of coniferous litter.However,the decomposition rate of broad-leaved litter was still higher than that of coniferous litter.The results of this study suggested that the added microorganisms could help individual growth of soil fauna,and this method led to a change in the process of leaf litter decomposition.This paper did not analyze the activity of soil microorganisms,thus it is difficult to clearly explain the complex relationships among litter type,soil fauna and soil microorganisms.Further research on this subject is needed.展开更多
Objective Faunal health is largely dependent on their soil environment and available litter quality. So the effects of different soil habitats and pesticides on citrate synthase (CS) activity of soil fauna and its pop...Objective Faunal health is largely dependent on their soil environment and available litter quality. So the effects of different soil habitats and pesticides on citrate synthase (CS) activity of soil fauna and its population were studied. Methods The soil animals were collected from different pedoecosystems for habitat study. Whereas Vigna radiata based system was selected for pesticidal observations. The field was divided into five equal plots for control and treatment of γ-BHC, quinalphos, carbaryl and cypermethrin. Soil fauna was collected by quadrat method and extracted by Tullgren funnel. Individuals of a species having similar sizes were collected for the estimation of CS activity. They were homogenized and fractions were obtained by differential centrifugation. The activity of CS was assayed spectrophotometrically. Results Citrate synthase (CS) activity of beetle (Rasphytus fregi), woodlouse (Porcellio laevis) and centipede (Scolopendra morsitans) varied significantly with respect to changes in different soil habitats. Though the CS activity of R. fregi, P. laevis, and S. morsitans differed among themselves but the highest activity of CS in these animals was in V. radiata and lowest in A. nilotica based pedoecosystem. The aerobic capacity of centipede was maximum followed by woodlouse and beetle. The treatment of γ-BHC, quinalphos, carbaryl and cypermethrin significantly reduced the CS activity of these animals. γ-BHC showed maximum reduction in CS activity indicating highly toxic effect of organochlorine on aerobic metabolism of soil fauna. However, minimum reduction was observed in response to carbaryl (in beetle) or cypermethrin (in woodlouse/centipede) leading to impairment of aerobic capacity. The differences in pesticide effects might be assigned to the differences in chemical nature of pesticides and their interactions with below-ground fauna. Treatment of γ-BHC and quinalphos reduced the population of Acari, Coleoptera, Collembola, other arthropods as well as total soil fauna. Acari was least affected by γ-BHC and maximally affected (72%) in response to quinalphos. The effect of γ-BHC was fairly similar on Coleoptera, Collembola, other arthropod and total soil fauna suggesting almost similar sensitivity to this pesticide. Likewise, quinalphos was similarly effective on Collemobola and other soil arthropods. Application of carbaryl decreased Acari and Coleoptera population but increased Collembola, other arthropods and total faunal populations. However, application of cypermethrin significantly reduced the population of Acari, Coleoptera, Collembola and total soil fauna and increased the population of other soil arthropods. In both the cases, acarine population was least affected. Conclusion The observations show the habitat-specific variation in aerobic capacity of soil fauna. However, pesticide-dependent loss in population might be due to impairment of aerobic capacity of soil inhabiting animals in desert.展开更多
Forest gaps are important in forest dynamics and management, but little is known about how soil fauna influence the degradation of recalcitrant litter components in different-sized forest gaps. This investigation uses...Forest gaps are important in forest dynamics and management, but little is known about how soil fauna influence the degradation of recalcitrant litter components in different-sized forest gaps. This investigation uses litterbags with two different mesh sizes (0.04 and 3 mm) to control the meso- and microfauna entering the bags to quantify the contribution of soil fauna to the degradation of recalcitrant components (including condensed tannins, total phenol, lignin and cellulose) during litter decomposition. The experiment was conducted in seven different forest gap sizes in Pinus massoniana plantations over 1 year. One closed-canopy site (CC) and forest gap sizes of 100, 225, 400, 625, 900, 1225 and 1600 m^2 were created in a P. massoniana plantation in the Sichuan basin of China;the CC was treated as the control. Cinnamomum camphora foliage from local native trees was used in all forest gap experiments. We found the following:(1) Gap size had significant effects on the degradation rates (E) of condensed tannins and lignin and on the contributions of soil fauna;medium-sized gaps also presented high degradation rates. Soil fauna obviously contributed to the degradation of recalcitrant foliar litter components in medium-sized gaps.(2) The highest contribution to degradation (40.98%) was recorded for lignin, and the lowest contribution (0.29%) was recorded for condensed tannins. The results indicate that medium-sized gaps (900 m^2) were conducive to the degradation of recalcitrant litter components by soil fauna.展开更多
Cunninghamia lanceolata(Lamb.) Hook. is economically the most important tree species in southern China and has been cultivated in plantations on a large scale. This species is widely used in construction, furniture, u...Cunninghamia lanceolata(Lamb.) Hook. is economically the most important tree species in southern China and has been cultivated in plantations on a large scale. This species is widely used in construction, furniture, utensils and shipbuilding. Soil fertility of C. lanceolata stands affects soil structure, porosity and nutrient availability, which causes changes in fauna activity. During January to February 2008,an ice storm caused extensive damage to C. lanceolata stands.Despite the environmental importance of soil fauna, basic information on the distribution and diversity of soil fauna in C.lanceolata stands after ice storm damage is lacking. To assess the response of soil fauna diversity and distribution to forest gaps following the ice storm, five small gaps(each 30–40 m^2),five large gaps(each 80–100 m^2) and five canopy cover plots were selected within a 2-ha C. lanceolata stand. Soil samples were collected from 0 to 10 cm depth in March 2011 to measure soil fauna diversity and abundance. The abundance and community composition of the soil fauna varied with gap size. In canopy cover sites, the number of individuals was 2.0 and 5.2 times greater than in the small gaps and large gaps.Three taxa(Nematoda, Oribatida and Insecta) of soil invertebrates occurred commonly, and Nematoda dominated the communities in all three habitat types. The Shannon–Wiener diversity index, Margalef diversity index, and Pielou evenness index were high in the small gaps, indicating that they harbored the most species, with the most even distribution, and the highest diversity. Our results indicated that gap size apparently affected abundance and community composition of the soil fauna.展开更多
From March 2014 to February 2015, the soil fauna community in the karst cave wetland of Maolan Nature Reserve was investigated. A total of 3,820 soil fauna was obtained, belonging to 31 orders, 11 classes, and 3 phyla...From March 2014 to February 2015, the soil fauna community in the karst cave wetland of Maolan Nature Reserve was investigated. A total of 3,820 soil fauna was obtained, belonging to 31 orders, 11 classes, and 3 phyla. The dominant groups were Araneae, Coleoptera and Hymenoptera, accounting for 48.90% of the total catch. There were 18 common groups and 10 rare groups. The diversity analysis showed that the Banzhai karst cave wetland had the largest soil fauna community diversity index and evenness index and that the Dongsai karst cave wetland had the largest number of groups and individuals. The seasonal variation of the soil fauna in the karst cave wetlands was analyzed: the number of soil fauna individuals showed a downtrend in summer, autumn, spring and winter; there were the highest number of phytophagous soil fauna, followed by predatory soil fauna and saprophagous soil fauna.展开更多
The relationship between long-term fertilization and cropland soil fauna was studied at the station’s experiment research network for soil fertility and fertilizers in Loess soil of Shannxi Provincefrom Jul. 2001 to ...The relationship between long-term fertilization and cropland soil fauna was studied at the station’s experiment research network for soil fertility and fertilizers in Loess soil of Shannxi Provincefrom Jul. 2001 to Oct. 2002. Six types of long-term fertilizer were carried out for this study including non-fertilizer (CK), abandonment (ABAND), nitrogenous and phosphors and potassium fertilizers combined (NPK), straw and NPK (SNPK), organic material and NPK (MNPK) and 1.5 times MNPK (1.5MNPK). 72 soil samples were collected and 5 495 species of cropland soil fauna obtained by handsorting and Cobb methods at 4 times, belonging to 6 Phyla, 11 Classes, 22 Orders, 2 Superfamilies, 61 Families and 35 Genera. The result showed that different fertilizer had significantly impacted on the cropland soil fauna (F = 2.24, P<0.007). The number of the cropland soil fauna was related to the soil physicochemical properties caused by long-term fertilization. The result by principal component analysis, focusing on the number of 15 key soil fauna species group’s diversity, evenness of community and the total soil fauna individuals indicated that the effects of SNPK, NPK, MNPK and 1.5MNPK were significantly different from that of the cropland soil fauna, in which, SNPK and NPK had the positive effect on cropland soil fauna, and MNPK and 1.5 MNPK had the negative affect, others could not be explained. By principal component Ⅰ, the synthetic effect of different fertilization on the total soil fauna individuals and the group was most significant, and the effect was little on evenness and diversity. By value of eigenvectors, the maximum one was 9.6248, and the minimum one was -1.0904, that means the 6 types of fertilization did not affect evenly the cropland soil fauna.展开更多
The response of soil fauna to the litter decomposition process has received considerable attention,but this effect has not been fully examined in agroforestry systems.A 1-year in situ decomposition experiment was carr...The response of soil fauna to the litter decomposition process has received considerable attention,but this effect has not been fully examined in agroforestry systems.A 1-year in situ decomposition experiment was carried out in a pure ginkgo plantation and two ginkgo agroforestry systems using a litterbag method(11 different treatments were tested in three systems).We found that the application of different organic materials(crop residues)produced positive effects on the number of soil fauna in the ginkgo planting systems;the mixture of ginkgo leaves and corn leaves was the best performing treatment.Collembola and Acarina were the predominant groups in the litter bags and were mainly responsible for the differences among the treatments.Litter mixing promoted the abundance,richness,and diversity of soil fauna,and significant differences regarding the Shannon–Wiener index of the soil fauna were observed among the 11 treatments in July.Significantly higher soil MBC(microbial biomass carbon)and MBN(microbial biomass nitrogen)were observed in agroforestry systems than in pure ginkgo plantations.These results suggest that the practice of intercrop residue application plays an important role in enhancing soil ecosystem function in ginkgo agroforestry systems and may ultimately contribute to sustainable intercrop production,soil fertility,and local economic diversity.展开更多
Soil fauna decompose litter, whereas land use changes may significantly alter the composition and structure of soil fauna assemblages.However, little is known of the effects of land-use on the contribution of soil fau...Soil fauna decompose litter, whereas land use changes may significantly alter the composition and structure of soil fauna assemblages.However, little is known of the effects of land-use on the contribution of soil fauna to litter decomposition.We studied the impacts of soil fauna on the decomposition of litter from poplar trees under three different land uses(i.e.poplar-crop integrated system, poplar plantation, and cropland), from December2013 to December 2014, in a coastal area of Northern Jiangsu Province.We collected litter samples in litterbags with three mesh sizes(5, 1 and 0.01 mm, respectively) to quantify the contribution of various soil fauna to the decomposition of poplar leaf litter.Litter decomposition rates differed significantly by land use and were highest in the cropland, intermediate in the poplar-crop integrated system, and lowest in the poplar plantation.Soil fauna in the poplar-crop integrated system was characterized by the highest numbers of taxa and individuals, and highest Margalef's diversity, which suggested that agro-forestry ecosystems may support a greater quantity, distribution,and biodiversity of soil fauna than can single-species agriculture or plantation forestry.The individuals and groups of soil fauna in the macro-mesh litterbags were higher than in the meso-mesh litterbags under-the same land use types.The average contribution rate of meso-and micro-fauna to litter decomposition was18.46%, which was higher than the contribution rate of macro-fauna(3.31%).The percentage of remaining litter mass was inversely related to the density of the soil fauna(P < 0.05) in poplar plantations; however, was unrelated in the poplar-crop integrated system and cropland.This may have been the result of anthropogenic interference in poplar-crop integrated systems and croplands.Our study suggested that when land-use change alters vegetation types, it can affect species composition and the structure of soil fauna assemblages, which, in turn, affects litter decomposition.展开更多
Introduction:Wetland soil fauna support material cycling and restoration processes in wetland ecosystems.In our study,we observed variations in wetland soil fauna on the shores of Lake Taihu,China.We examined the rela...Introduction:Wetland soil fauna support material cycling and restoration processes in wetland ecosystems.In our study,we observed variations in wetland soil fauna on the shores of Lake Taihu,China.We examined the relationships between fauna and major environmental factors,and looked at the short-and long-term changes in reed wetlands under restoration and in the natural reed lakeshore.Outcomes:We identified 93 groups of soil fauna in different wetlands and found significant differences in the lakeshore wetlands’soil fauna assemblages,depending on the length of the restoration period.By analyzing the soil fauna community evenness,dominance,number of taxa,and diversity,we found minimal seasonal variation in the soil fauna community diversity and abundance.The abundance of soil fauna in the sites under restoration decreased with depth below the soil surface.The reed restoration was obvious in the succession of the soil fauna groups in the long-term site.Although the restoration had an overall positive long-term effect on the soil fauna communities,there were no obvious short-term changes in the number of individuals.Conclusion:The study explored various potential measures to restore soil fauna in the Lake Taihu wetland and developed a theoretical basis for restoring the lakeshore wetland ecosystem.展开更多
Root and foliar litter inputs are the primary sources of carbon and nutrients for soil fauna and microorganisms,yet we still lack a quantitative assessment to evaluate the effects of root and foliar litter on various ...Root and foliar litter inputs are the primary sources of carbon and nutrients for soil fauna and microorganisms,yet we still lack a quantitative assessment to evaluate the effects of root and foliar litter on various groups of soil organisms across terrestrial ecosystems.Here,we compiled 978 paired observations from 68 experimental sites to assess the directions and magnitudes of adding and removing foliar and root litter on the soil faunal density and microbial biomass that was evaluated by phospholipid fatty acids(PLFAs)across forests and grasslands worldwide.We found that litter addition had only a marginal effect on soil faunal density but significantly increased the soil total microbial-,fungal-and bacterial-PLFAs by 13%,14%,and 10%,respectively,across ecosystems,suggesting that the soil microbial community is more sensitive to carbon source addition than soil fauna,particularly in soils with low carbon to nitrogen ratios.In contrast,removing litter significantly decreased the soil faunal density by 17%but had few effects on soil microorganisms.Compared with foliar litter,root litter input had a more positive effect on the development of soil fungal taxa.The effect of both litter addition and removal on soil faunal density and microbial biomass did not differ between humid and arid regions,but a greater influence was observed in grasslands than in forests for soil microbial community.Our results highlight that the increasing litter production under a global greening scenario would stimulate microbial activity in grasslands more than in forests,and this stimulation would be greater for soil microbes than soil fauna.展开更多
The underlying mechanisms of the relationships between tree species and the soil micro-food web in forest ecosystems remain uncertain,primarily ascribed to an insufficient understanding on how tree functional traits d...The underlying mechanisms of the relationships between tree species and the soil micro-food web in forest ecosystems remain uncertain,primarily ascribed to an insufficient understanding on how tree functional traits drive soil nematode communities,including in subtropical forests.We investigated the impacts of seven subtropical tree species(evergreen:Pinus massoniana,Mytilaria laosensis,Ilex chinensis,Michelia macclurei;and deciduous:Liquidambar formosana,Quercus acutissima,and Betula luminifera)on the soil nematode communities.We found that the abundance of soil nematodes was not affected by mycorrhizal types,but it was around 83%higher under the deciduous trees than the evergreen trees,indicating the importance of leaf phenology to the abundance of soil nematodes.Nonetheless,both the evergreen and the arbuscular mycorrhizal trees increased soil nematode diversity,resulting from changes in root traits and soil properties.Furthermore,root traits(root C,root N,and root C:N ratio),and soil properties(total C,total N,moisture content,and bulk density)were the best predictors of the community composition of soil nematodes,indicating a key role of resource quality and soil microhabitat in regulating soil nematodes.In contrast,the ectomycorrhizal trees had lower plant parasite and Wasilewska indices,and evenness,whereas the evergreen trees slightly improved the evenness of soil nematodes.This study suggests that tree species affect the soil food web through changes in soil conditions and plant functional traits in subtropical forests.展开更多
In the Niger Delta region of Nigeria, oil explorations and exploitations abound, causing environmental pollution with serious consequences on soil ecosystem and its biodiversity. In spite of the relationship between m...In the Niger Delta region of Nigeria, oil explorations and exploitations abound, causing environmental pollution with serious consequences on soil ecosystem and its biodiversity. In spite of the relationship between microbes and fauna in soil ecosystem, such that both organisms can metabolize certain range of petroleum hydrocarbon substrates with the fauna influencing the remediation potentials of bacteria, yet soil fauna is still not fully considered in bioremediation. The influence of earthworm;Lumbricus terrestris on the remediating potentials of soil bacteria in petroleum hydrocarbon contaminated soils was investigated. Eighteen pots were filled with 700 g of soil each, with nine treated with mixture of 3 levels crude oil and remediated with earthworm, while the other nine had no earthworm. The total petroleum hydrocarbon (TPH), soil physical, nutrient compositions, and TPH degrading bacteria biodiversity were determined before contamination or commencement of study and thirty days after. The results showed a decrease in TPH concentration of 55.58%, 62.57% and 67.07% in 1 ml, 2 ml and 3 ml crude oil contaminated soil, respectively. Species richness and abundance of bacteria organisms increased with high relative abundance in soils remediated with earthworms, hydrocarbon utilizing bacteria increased from less than 0.1 cfu/g to 0.4 cfu/g, and total heterotrophic bacteria 1.6 cfu/g at the end of the study. Earthworms increased rate of remediation potentials of bacteria, such that within 30 days post remediation treatment, 34.14% of reduced concentration was achieved over soil samples without earthworms at 3 ml, and 25.14% at 2 ml concentration. Reduction in pH levels in remediated soils was between 6.39 to 6.17 and 6.74 to 6.72 in unremediated soils, while moisture content was 6.73% to 6.77% unremediated and 5.85% to 6.62% in earthworm remediated soils. Total organic carbon, nitrates in soils inoculated with earthworms were lower in concentration than those without earthworms. Reverse was the case with potassium, phosphate and phosphorous concentrations which were above those without earthworms. Results indicate statistically, significant difference between reduction in TPH in earthworm remediated soils and unremediated soils, pointing out that earthworm is a good candidate for facilitation of bacteria remediation-petroleum hydrocarbon contamination.展开更多
A number of basic and applied questions in ecology and environmental management require the characterization of soil and leaf litter faunal diversity. Recent advances in high-throughput sequencing of barcode-gene ampl...A number of basic and applied questions in ecology and environmental management require the characterization of soil and leaf litter faunal diversity. Recent advances in high-throughput sequencing of barcode-gene amplicons ('metabarcoding') have made it possible to survey biodiversity in a robust and efficient way. However, one obstacle to the widespread adoption of this technique is the need to choose amongst many candidates for bioinformatic processing of the raw sequencing data. We compare three candidate pipelines for the processing of 18S small subunit rDNA metabarcode data from solid substrates: (i) USEARCH/CROP, (ii) Denoiser/UCLUST, and (iii) OCTUPUS. The three pipelines produced reassuringly similar and highly correlated assessments of community composition that are dominated by taxa known to characterize the sampled environments. However, OCTUPUS appears to inflate phylogenetic diversity, because of higher sequence noise. We therefore recommend either the USEARCH/CROP or Denoiser/UCLUST pipelines, both of which can be run within the QIIME (Quantitative Insights Into Microbial Ecology) environment.展开更多
基金supported by the National Natural Science Foundation of China (31971448, U1803233)the Foundation of Science & Technology Department of Xinjiang Uygur Autonomous Region, China (2019XS28)the Youth Innovation Promotion Association of Chinese Academy of Sciences (2020433)
文摘Soil faunas account for 23%of known animal species and play a crucial role in ecosystem processes such as mineralizing nutrients,regulating microbial community composition,forming soil aggregates,and enhancing primary productivity.However,due to global climate change,population density,community composition,and distribution patterns of soil fauna vary.Understanding the responses of soil fauna to major environmental change facilitate the conservation of biodiversity.Therefore,a review work of recent researches for analysing the effects of key environmental factors on soil fauna,such as warming,drought,food quality,and soil physical-chemical properties was studied.For most species,warming may exert a positive effect on their abundance and population development,however,it can inhibit the survival and reproduction of hibernating species.Drought leads to low soil porosity and water holding capacity,which reduces soil fauna population and changes their community composition.Drought also can reduce the coverage of flora and alter microclimate of the soil surface,which in turn indirectly reduces fauna abundance.Climate warming and elevated atmospheric carbon dioxide can reduce litter quality,which will force soil fauna to change their dietary choices(from higher-quality foods to poor quality foods)and reduce reproduction for survival.However,it is still predicted that enhanced species richness of plant(or litter)mixtures will positively affect soil fauna diversity.Habitat loss caused by the deterioration of soil physical-chemical property is primary factor affecting soil fauna.We mainly discuss the threats of increased salinity(a major factor in arid land)to soil fauna and their potential responses to anthropogenic disturbance in saline soils.The increase in soil salinity can override other factors that favour habitat specialists,leading to negative effects on soil fauna.Moreover,we find that more studies are needed to explore the responses of soil fauna in saline soils to human activities.And the relationship of important ecological processes with soil fauna density,community structure,and diversity needs to be redefined.
基金Project supported by the National Natural Science Foundation of China (NO. 30270283)the "100-Talent" Project of the Chinese Academy of Sciences (CAS)the Director Foundation of South China Institute of Botany, CASthe Innovation Priority Project of CAS (No. KSCX2-SW-120).
文摘A field-scale experiment arranged in a complete randomized block design with three N addition treatments including a control (no addition of N), a low N (5 g m-2 year-1), and a medium N (10 g m-2 year-1) was performed in each of the three typical forests, a pine (Pinus massoniana Lamb.) forest (PF), a pine-broadleaf mixed forest (MF) and a mature monsoon evergreen broadleaf forest (MEBF), of the Dinghushan Biosphere Reserve in subtropical China to study the response of soil fauna community to additions of N. Higher NH4+ and NO3- concentrations and a lower soil pH occurred in the medium N treatment of MEBF, whereas the NO3- concentration was the lowest in PF after the additions of N. The response of the density, group abundance and diversity index of soil fauna to addition of N varied with the forest type, and all these variables decreased with increasing N under MEBF but the trend was opposite under PF. The N treatments had no significant effects on these variables under MF. Compared with the control plots, the medium N treatment had significant negative effect on soil fauna under MEBF. The group abundance of soil fauna increased significantly with additions of higher N rates under PF. These results suggested that the response of soil fauna to N deposition varied with the forest type and N deposition rate, and soil N status is one of the important factors affecting the response of soil fauna to N deposition.
基金Under the auspices of National Natural Science Foundation of China (No 40171053)
文摘The Liangshui Natural Reserve in Heilongjiang Province of China was selected as the study area. The authors collected the samples of forest litter (Tilia amurensis, Fraxinus mandshurica, Pinus koraiensis, Acer mono, Betula costata, and mixed litter), soil in humus horizon (0-5cm) and soil horizon (5-20cm), and soil macrofauna (Oli-gochaeta, Geophiloporpha and Juliformia) from 2001 to 2002. The role of soil macrofauna in the material cycle was analyzed through comparing the macro-element contents among various parts of the subsystems and using enrichment index (EI). The results indicate that dynamic changes of various litters are very complicated. The contents of Fe in each kind of litter increase firstly, and then decrease in the study period. The changes of macro-element contents are greater in the broad-leaf litter than in the coniferous litter, and the mixed litter is in the middle level, but the differences among them are not significant. The contents of Mg and Fe in humus are higher than those in soil, but the contents of Ca in soil are higher than that in humus. The dynamic changes of macro-element contents in soil and soil fauna are not consistent with those in litter. The diplopod presented obvious enrichment of Ca and Mg (EI>1), but it does not significantly enrich Fe. Earthworm has a stronger enrichment ability of Fe than diplopod and scolopendra, but EI<1. Soil fauna can make great influences on the material cycle of the subsystems.
基金Project supported by the National Natural Science Foundation of China (No. 30670392)the "100-Talent" Project of the Chinese Academy of Sciences (CAS).
文摘In a field experiment, the populations of major soil fauna groups including earthworms, enchytraeids,arthropods and nematodes were examined in conventional tillage (CT) and no-tillage (NT) red soil ecosystems to evaluate their responses to tillage disturbance. Earthworms, macrry and micro-arthropods were stimulated under NT with earthworms showing the highest population increase by four times, while enchytraeids and nematodes favored CT system, predicting certain adaptability of these animals to plow-disturbed soil environment. On the basis of relative response index it was found that soil fauna was more sensitive to tillage than soil resource base (C and N pools) and microflora. The population structure of soil fauna was also affected by tillage treatments. Analysis on nematode trophic groups showed that bacteria-feeding and plant parasitic nematodes were more abundant in CT soil whereas the proportions of fungivores and omnivorepredators increased in NT soil. Possible reasons for the differentiation in both size and structure of the fauna population were discussed and the ecological significance involved in these changes was emphasized.
基金Under the auspices of State Key Development Program for Basic Research of China (No. 2009CB421103)KeyProgram of National Natural Science Foundation of China (No. 40830535/D0101)Knowledge Innovation Programs of ChineseAcademy of Sciences (No. KZCX2-YW-BR-16, KSCX2-YW-N-46-06)
文摘Litter decomposition is the key process in nutrient recycling and energy flow. The present study examined the impacts of soil fauna on decomposition rates and nutrient fluxes at three succession stages of wetland in the Sanjiang Plain, China using different mesh litterbags. The results show that in each succession stage of wetland, soil fauna can obviously increase litter decomposition rates. The average contribution of whole soil fauna to litter mass loss was 35.35%. The more complex the soil fauna group, the more significant the role of soil fauna. The average loss of three types of litter in the 4mm mesh litterbags was 0.3-4.1 times that in 0.058mm ones. The decomposition function of soil fauna to litter mass changed with the wetland succession. The average contribution of soil fauna to litter loss firstly decreased from 34.96% (Carex lasiocapa) to 32.94% (Carex meyeriana), then increased to 38.16% (Calamagrostics an- gustifolia). The contributions of soil fauna to litter decomposition rates vary according to the litter substrata, soil fauna communities and seasons. Significant effects were respectively found in August and July on C. angustifolia and C. lasiocapa, while in June and August on C. meyeriana. Total carbon (TC), total nitrogen (TN) and total phosphorus (TP) contents and the C/N and C/P ratios of decaying litter can be influenced by soil fauna. At different wetland succession stages, the effects of soil fauna on nutrient elements also differ greatly, which shows the significant difference of influencing element types and degrees. Soil fauna communities strongly influenced the TC and TP concentrations of C. meyeriana litter, and TP content of C. lasiocapa. Our results indicate that soil fauna have important effects on litter decomposition and this influence will vary with the wetland succession and seasonal variation.
基金Under the auspices of National Natural Science Foundation of China(No.41071033,41101049)China Postdoctoral Science Foundation(No.2012M511361)
文摘Microorganisms are nutritious resources for various soil fauna.Although soil fauna grazing affects microorganism composition and decomposition rate,the responses of soil fauna and leaf litter decomposition to added microorganism is little understood.In this study,in the coniferous and broad-leaved mixed forest of Tahe County in the northern Da Hinggan Mountains,China,three sampling sites(each has an area of 10 m2) were selected.The first two sites were sprinkled with 250 times(EM1) and 1000 times(EM2) diluted effective microorganism(EM) preparations evenly,and the third site was sprinkled with the same volume of water as a control site.The responses of soil fauna structure and leaf litter decomposition to EM treatment were conducted during three years.The results revealed that EM treatment resulted in significant increase of soil organic matter.The number of soil fauna in the EM1 and EM2 sites increased by 12.88% and 2.23% compared to the control site,and among them springtails and mites showed the highest increase.However,the groups of soil fauna in the EM1 and EM2 sites decreased by 6 and 9,respectively.And the changes in the diversity and evenness index were relatively complicated.EM treatment slowed the decomposition of broad-leaved litter,but accelerated the decomposition of coniferous litter.However,the decomposition rate of broad-leaved litter was still higher than that of coniferous litter.The results of this study suggested that the added microorganisms could help individual growth of soil fauna,and this method led to a change in the process of leaf litter decomposition.This paper did not analyze the activity of soil microorganisms,thus it is difficult to clearly explain the complex relationships among litter type,soil fauna and soil microorganisms.Further research on this subject is needed.
文摘Objective Faunal health is largely dependent on their soil environment and available litter quality. So the effects of different soil habitats and pesticides on citrate synthase (CS) activity of soil fauna and its population were studied. Methods The soil animals were collected from different pedoecosystems for habitat study. Whereas Vigna radiata based system was selected for pesticidal observations. The field was divided into five equal plots for control and treatment of γ-BHC, quinalphos, carbaryl and cypermethrin. Soil fauna was collected by quadrat method and extracted by Tullgren funnel. Individuals of a species having similar sizes were collected for the estimation of CS activity. They were homogenized and fractions were obtained by differential centrifugation. The activity of CS was assayed spectrophotometrically. Results Citrate synthase (CS) activity of beetle (Rasphytus fregi), woodlouse (Porcellio laevis) and centipede (Scolopendra morsitans) varied significantly with respect to changes in different soil habitats. Though the CS activity of R. fregi, P. laevis, and S. morsitans differed among themselves but the highest activity of CS in these animals was in V. radiata and lowest in A. nilotica based pedoecosystem. The aerobic capacity of centipede was maximum followed by woodlouse and beetle. The treatment of γ-BHC, quinalphos, carbaryl and cypermethrin significantly reduced the CS activity of these animals. γ-BHC showed maximum reduction in CS activity indicating highly toxic effect of organochlorine on aerobic metabolism of soil fauna. However, minimum reduction was observed in response to carbaryl (in beetle) or cypermethrin (in woodlouse/centipede) leading to impairment of aerobic capacity. The differences in pesticide effects might be assigned to the differences in chemical nature of pesticides and their interactions with below-ground fauna. Treatment of γ-BHC and quinalphos reduced the population of Acari, Coleoptera, Collembola, other arthropods as well as total soil fauna. Acari was least affected by γ-BHC and maximally affected (72%) in response to quinalphos. The effect of γ-BHC was fairly similar on Coleoptera, Collembola, other arthropod and total soil fauna suggesting almost similar sensitivity to this pesticide. Likewise, quinalphos was similarly effective on Collemobola and other soil arthropods. Application of carbaryl decreased Acari and Coleoptera population but increased Collembola, other arthropods and total faunal populations. However, application of cypermethrin significantly reduced the population of Acari, Coleoptera, Collembola and total soil fauna and increased the population of other soil arthropods. In both the cases, acarine population was least affected. Conclusion The observations show the habitat-specific variation in aerobic capacity of soil fauna. However, pesticide-dependent loss in population might be due to impairment of aerobic capacity of soil inhabiting animals in desert.
基金supported by the National Natural Science Foundation of China(Grant Number 31370628)the National Science and Technology Support Project of China(Grant Number2011BAC09B05)the Sichuan Provincial Science and Technology Support Project(Grant Number 12ZC0017)
文摘Forest gaps are important in forest dynamics and management, but little is known about how soil fauna influence the degradation of recalcitrant litter components in different-sized forest gaps. This investigation uses litterbags with two different mesh sizes (0.04 and 3 mm) to control the meso- and microfauna entering the bags to quantify the contribution of soil fauna to the degradation of recalcitrant components (including condensed tannins, total phenol, lignin and cellulose) during litter decomposition. The experiment was conducted in seven different forest gap sizes in Pinus massoniana plantations over 1 year. One closed-canopy site (CC) and forest gap sizes of 100, 225, 400, 625, 900, 1225 and 1600 m^2 were created in a P. massoniana plantation in the Sichuan basin of China;the CC was treated as the control. Cinnamomum camphora foliage from local native trees was used in all forest gap experiments. We found the following:(1) Gap size had significant effects on the degradation rates (E) of condensed tannins and lignin and on the contributions of soil fauna;medium-sized gaps also presented high degradation rates. Soil fauna obviously contributed to the degradation of recalcitrant foliar litter components in medium-sized gaps.(2) The highest contribution to degradation (40.98%) was recorded for lignin, and the lowest contribution (0.29%) was recorded for condensed tannins. The results indicate that medium-sized gaps (900 m^2) were conducive to the degradation of recalcitrant litter components by soil fauna.
基金supported by the Shenzhen Strategic Emerging Industrial Development Funds(GCZX20120618100801416)from Shenzhen Municipal People’s Government,China
文摘Cunninghamia lanceolata(Lamb.) Hook. is economically the most important tree species in southern China and has been cultivated in plantations on a large scale. This species is widely used in construction, furniture, utensils and shipbuilding. Soil fertility of C. lanceolata stands affects soil structure, porosity and nutrient availability, which causes changes in fauna activity. During January to February 2008,an ice storm caused extensive damage to C. lanceolata stands.Despite the environmental importance of soil fauna, basic information on the distribution and diversity of soil fauna in C.lanceolata stands after ice storm damage is lacking. To assess the response of soil fauna diversity and distribution to forest gaps following the ice storm, five small gaps(each 30–40 m^2),five large gaps(each 80–100 m^2) and five canopy cover plots were selected within a 2-ha C. lanceolata stand. Soil samples were collected from 0 to 10 cm depth in March 2011 to measure soil fauna diversity and abundance. The abundance and community composition of the soil fauna varied with gap size. In canopy cover sites, the number of individuals was 2.0 and 5.2 times greater than in the small gaps and large gaps.Three taxa(Nematoda, Oribatida and Insecta) of soil invertebrates occurred commonly, and Nematoda dominated the communities in all three habitat types. The Shannon–Wiener diversity index, Margalef diversity index, and Pielou evenness index were high in the small gaps, indicating that they harbored the most species, with the most even distribution, and the highest diversity. Our results indicated that gap size apparently affected abundance and community composition of the soil fauna.
基金Sponsored by National Natural Science Foundation of China(31660152)Youth Program Funded by Guizhou Provincial Department of Forestry([2013]10)Guizhou Science and Technology Fund([2013]2135)
文摘From March 2014 to February 2015, the soil fauna community in the karst cave wetland of Maolan Nature Reserve was investigated. A total of 3,820 soil fauna was obtained, belonging to 31 orders, 11 classes, and 3 phyla. The dominant groups were Araneae, Coleoptera and Hymenoptera, accounting for 48.90% of the total catch. There were 18 common groups and 10 rare groups. The diversity analysis showed that the Banzhai karst cave wetland had the largest soil fauna community diversity index and evenness index and that the Dongsai karst cave wetland had the largest number of groups and individuals. The seasonal variation of the soil fauna in the karst cave wetlands was analyzed: the number of soil fauna individuals showed a downtrend in summer, autumn, spring and winter; there were the highest number of phytophagous soil fauna, followed by predatory soil fauna and saprophagous soil fauna.
文摘The relationship between long-term fertilization and cropland soil fauna was studied at the station’s experiment research network for soil fertility and fertilizers in Loess soil of Shannxi Provincefrom Jul. 2001 to Oct. 2002. Six types of long-term fertilizer were carried out for this study including non-fertilizer (CK), abandonment (ABAND), nitrogenous and phosphors and potassium fertilizers combined (NPK), straw and NPK (SNPK), organic material and NPK (MNPK) and 1.5 times MNPK (1.5MNPK). 72 soil samples were collected and 5 495 species of cropland soil fauna obtained by handsorting and Cobb methods at 4 times, belonging to 6 Phyla, 11 Classes, 22 Orders, 2 Superfamilies, 61 Families and 35 Genera. The result showed that different fertilizer had significantly impacted on the cropland soil fauna (F = 2.24, P<0.007). The number of the cropland soil fauna was related to the soil physicochemical properties caused by long-term fertilization. The result by principal component analysis, focusing on the number of 15 key soil fauna species group’s diversity, evenness of community and the total soil fauna individuals indicated that the effects of SNPK, NPK, MNPK and 1.5MNPK were significantly different from that of the cropland soil fauna, in which, SNPK and NPK had the positive effect on cropland soil fauna, and MNPK and 1.5 MNPK had the negative affect, others could not be explained. By principal component Ⅰ, the synthetic effect of different fertilization on the total soil fauna individuals and the group was most significant, and the effect was little on evenness and diversity. By value of eigenvectors, the maximum one was 9.6248, and the minimum one was -1.0904, that means the 6 types of fertilization did not affect evenly the cropland soil fauna.
基金supported by the Agricultural Science and Technology Independent Innovation Funds of Jiangsu Province(CX(16)1005)the National Key Research and Development Program of China(2017YFD0600700)
文摘The response of soil fauna to the litter decomposition process has received considerable attention,but this effect has not been fully examined in agroforestry systems.A 1-year in situ decomposition experiment was carried out in a pure ginkgo plantation and two ginkgo agroforestry systems using a litterbag method(11 different treatments were tested in three systems).We found that the application of different organic materials(crop residues)produced positive effects on the number of soil fauna in the ginkgo planting systems;the mixture of ginkgo leaves and corn leaves was the best performing treatment.Collembola and Acarina were the predominant groups in the litter bags and were mainly responsible for the differences among the treatments.Litter mixing promoted the abundance,richness,and diversity of soil fauna,and significant differences regarding the Shannon–Wiener index of the soil fauna were observed among the 11 treatments in July.Significantly higher soil MBC(microbial biomass carbon)and MBN(microbial biomass nitrogen)were observed in agroforestry systems than in pure ginkgo plantations.These results suggest that the practice of intercrop residue application plays an important role in enhancing soil ecosystem function in ginkgo agroforestry systems and may ultimately contribute to sustainable intercrop production,soil fertility,and local economic diversity.
基金supported by the National Basic Research Program of China(973 Program,2012CB416904)partially supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Soil fauna decompose litter, whereas land use changes may significantly alter the composition and structure of soil fauna assemblages.However, little is known of the effects of land-use on the contribution of soil fauna to litter decomposition.We studied the impacts of soil fauna on the decomposition of litter from poplar trees under three different land uses(i.e.poplar-crop integrated system, poplar plantation, and cropland), from December2013 to December 2014, in a coastal area of Northern Jiangsu Province.We collected litter samples in litterbags with three mesh sizes(5, 1 and 0.01 mm, respectively) to quantify the contribution of various soil fauna to the decomposition of poplar leaf litter.Litter decomposition rates differed significantly by land use and were highest in the cropland, intermediate in the poplar-crop integrated system, and lowest in the poplar plantation.Soil fauna in the poplar-crop integrated system was characterized by the highest numbers of taxa and individuals, and highest Margalef's diversity, which suggested that agro-forestry ecosystems may support a greater quantity, distribution,and biodiversity of soil fauna than can single-species agriculture or plantation forestry.The individuals and groups of soil fauna in the macro-mesh litterbags were higher than in the meso-mesh litterbags under-the same land use types.The average contribution rate of meso-and micro-fauna to litter decomposition was18.46%, which was higher than the contribution rate of macro-fauna(3.31%).The percentage of remaining litter mass was inversely related to the density of the soil fauna(P < 0.05) in poplar plantations; however, was unrelated in the poplar-crop integrated system and cropland.This may have been the result of anthropogenic interference in poplar-crop integrated systems and croplands.Our study suggested that when land-use change alters vegetation types, it can affect species composition and the structure of soil fauna assemblages, which, in turn, affects litter decomposition.
基金The Special Fund for Forest Scientific Research in the Public Welfare[Grant Nos.201404305 and 200904001]“The Lecture and Study Program for Outstanding Scholars from Home and Abroad”[CAFYBB2011007]funded this research.
文摘Introduction:Wetland soil fauna support material cycling and restoration processes in wetland ecosystems.In our study,we observed variations in wetland soil fauna on the shores of Lake Taihu,China.We examined the relationships between fauna and major environmental factors,and looked at the short-and long-term changes in reed wetlands under restoration and in the natural reed lakeshore.Outcomes:We identified 93 groups of soil fauna in different wetlands and found significant differences in the lakeshore wetlands’soil fauna assemblages,depending on the length of the restoration period.By analyzing the soil fauna community evenness,dominance,number of taxa,and diversity,we found minimal seasonal variation in the soil fauna community diversity and abundance.The abundance of soil fauna in the sites under restoration decreased with depth below the soil surface.The reed restoration was obvious in the succession of the soil fauna groups in the long-term site.Although the restoration had an overall positive long-term effect on the soil fauna communities,there were no obvious short-term changes in the number of individuals.Conclusion:The study explored various potential measures to restore soil fauna in the Lake Taihu wetland and developed a theoretical basis for restoring the lakeshore wetland ecosystem.
基金the National Natural Science Foundation of China(32022056,31800521,32171641,32101509,31922052,and 31800373).
文摘Root and foliar litter inputs are the primary sources of carbon and nutrients for soil fauna and microorganisms,yet we still lack a quantitative assessment to evaluate the effects of root and foliar litter on various groups of soil organisms across terrestrial ecosystems.Here,we compiled 978 paired observations from 68 experimental sites to assess the directions and magnitudes of adding and removing foliar and root litter on the soil faunal density and microbial biomass that was evaluated by phospholipid fatty acids(PLFAs)across forests and grasslands worldwide.We found that litter addition had only a marginal effect on soil faunal density but significantly increased the soil total microbial-,fungal-and bacterial-PLFAs by 13%,14%,and 10%,respectively,across ecosystems,suggesting that the soil microbial community is more sensitive to carbon source addition than soil fauna,particularly in soils with low carbon to nitrogen ratios.In contrast,removing litter significantly decreased the soil faunal density by 17%but had few effects on soil microorganisms.Compared with foliar litter,root litter input had a more positive effect on the development of soil fungal taxa.The effect of both litter addition and removal on soil faunal density and microbial biomass did not differ between humid and arid regions,but a greater influence was observed in grasslands than in forests for soil microbial community.Our results highlight that the increasing litter production under a global greening scenario would stimulate microbial activity in grasslands more than in forests,and this stimulation would be greater for soil microbes than soil fauna.
基金financially supported by the National Natural Science Foundation of China(Nos.32271679,32071631,41907022,31901165)the Natural Science Foundation of Fujian Province(Nos.2020J01138,2020J01186)。
文摘The underlying mechanisms of the relationships between tree species and the soil micro-food web in forest ecosystems remain uncertain,primarily ascribed to an insufficient understanding on how tree functional traits drive soil nematode communities,including in subtropical forests.We investigated the impacts of seven subtropical tree species(evergreen:Pinus massoniana,Mytilaria laosensis,Ilex chinensis,Michelia macclurei;and deciduous:Liquidambar formosana,Quercus acutissima,and Betula luminifera)on the soil nematode communities.We found that the abundance of soil nematodes was not affected by mycorrhizal types,but it was around 83%higher under the deciduous trees than the evergreen trees,indicating the importance of leaf phenology to the abundance of soil nematodes.Nonetheless,both the evergreen and the arbuscular mycorrhizal trees increased soil nematode diversity,resulting from changes in root traits and soil properties.Furthermore,root traits(root C,root N,and root C:N ratio),and soil properties(total C,total N,moisture content,and bulk density)were the best predictors of the community composition of soil nematodes,indicating a key role of resource quality and soil microhabitat in regulating soil nematodes.In contrast,the ectomycorrhizal trees had lower plant parasite and Wasilewska indices,and evenness,whereas the evergreen trees slightly improved the evenness of soil nematodes.This study suggests that tree species affect the soil food web through changes in soil conditions and plant functional traits in subtropical forests.
文摘In the Niger Delta region of Nigeria, oil explorations and exploitations abound, causing environmental pollution with serious consequences on soil ecosystem and its biodiversity. In spite of the relationship between microbes and fauna in soil ecosystem, such that both organisms can metabolize certain range of petroleum hydrocarbon substrates with the fauna influencing the remediation potentials of bacteria, yet soil fauna is still not fully considered in bioremediation. The influence of earthworm;Lumbricus terrestris on the remediating potentials of soil bacteria in petroleum hydrocarbon contaminated soils was investigated. Eighteen pots were filled with 700 g of soil each, with nine treated with mixture of 3 levels crude oil and remediated with earthworm, while the other nine had no earthworm. The total petroleum hydrocarbon (TPH), soil physical, nutrient compositions, and TPH degrading bacteria biodiversity were determined before contamination or commencement of study and thirty days after. The results showed a decrease in TPH concentration of 55.58%, 62.57% and 67.07% in 1 ml, 2 ml and 3 ml crude oil contaminated soil, respectively. Species richness and abundance of bacteria organisms increased with high relative abundance in soils remediated with earthworms, hydrocarbon utilizing bacteria increased from less than 0.1 cfu/g to 0.4 cfu/g, and total heterotrophic bacteria 1.6 cfu/g at the end of the study. Earthworms increased rate of remediation potentials of bacteria, such that within 30 days post remediation treatment, 34.14% of reduced concentration was achieved over soil samples without earthworms at 3 ml, and 25.14% at 2 ml concentration. Reduction in pH levels in remediated soils was between 6.39 to 6.17 and 6.74 to 6.72 in unremediated soils, while moisture content was 6.73% to 6.77% unremediated and 5.85% to 6.62% in earthworm remediated soils. Total organic carbon, nitrates in soils inoculated with earthworms were lower in concentration than those without earthworms. Reverse was the case with potassium, phosphate and phosphorous concentrations which were above those without earthworms. Results indicate statistically, significant difference between reduction in TPH in earthworm remediated soils and unremediated soils, pointing out that earthworm is a good candidate for facilitation of bacteria remediation-petroleum hydrocarbon contamination.
基金supported by Yunnan Province (20080A001)Chinese Academy of Sciences (0902281081,KSCX2-YW-Z-1027)+2 种基金the National Natural Science Foundation of China (31170498)Ministry of Science and Technology of China (2012FY110800)Kunming Institute of Zoology,and the University of East Anglia
文摘A number of basic and applied questions in ecology and environmental management require the characterization of soil and leaf litter faunal diversity. Recent advances in high-throughput sequencing of barcode-gene amplicons ('metabarcoding') have made it possible to survey biodiversity in a robust and efficient way. However, one obstacle to the widespread adoption of this technique is the need to choose amongst many candidates for bioinformatic processing of the raw sequencing data. We compare three candidate pipelines for the processing of 18S small subunit rDNA metabarcode data from solid substrates: (i) USEARCH/CROP, (ii) Denoiser/UCLUST, and (iii) OCTUPUS. The three pipelines produced reassuringly similar and highly correlated assessments of community composition that are dominated by taxa known to characterize the sampled environments. However, OCTUPUS appears to inflate phylogenetic diversity, because of higher sequence noise. We therefore recommend either the USEARCH/CROP or Denoiser/UCLUST pipelines, both of which can be run within the QIIME (Quantitative Insights Into Microbial Ecology) environment.
