Macrofaunal Biomass Research Articles

Effects of increased temperature and altered POC composition on a bathyal macrofaunal community in Cabo Verde, NE Atlantic

Deep-sea ecosystems are particularly important to the cycling of matter and energy in the oceans and therefore in regulating Earth’s climate. The Atlantic Ocean is already experiencing significant abiotic changes, with expected warmer temperatures coupled with decreased particulate organic carbon (POC) export flux. However, there is yet a large gap in our understanding of warming impacts on deep benthic ecosystems and in the organic matter processing by benthic organisms in the seafloor. This study employed an experimental approach to assess the single and cumulative effects of two climate change stressors, temperature and POC quality, on macrofaunal benthic assemblages in the Cabo Verde Basin (CVB, Equatorial Atlantic) bathyal continental slope. Incubation enrichment experiments with 13C and 15N labelled diatoms Phaeodactylum tricornutum simulated climate projections for the next century with a balanced design, studying the effect of either increased temperature (+2°C), reduced POC quality (dialysed labile fraction), or both, against a control treatment. We found that echinoderms and polychaetes rapidly ingested labelled algae at rates between 0.02 and 21.9 µg C m−2 d-1. Given a strong spatial variability in macrofaunal biomass, the carbon and nitrogen incorporation by macrofauna was not affected by a + 2 °C warming, by a decreased organic matter quality, or the combination of both factors. Our study provides valuable insights into the biodiversity, biomass, and ecosystem functioning (C and N uptake rates) of deep-sea benthic ecosystems in the N Atlantic, and stress that potential effects of warmer temperatures and POC quality on carbon and nitrogen incorporation by macrofauna remain uncertain. We highlight the value of these experiments to better understand the effects of climate change on deep-sea ecosystems.

How restoration engineering measures can enhance the ecological value of intertidal flats

Restoration engineering measures, such as managed realignments or building groins, modify the environmental characteristics of coastal intertidal ecosystems. Creating physical modifications that are beneficial to an intertidal system's ecology necessitates an in‐depth understanding of the relationships between the abiotic and biotic components of a given intertidal habitat. In this study, we evaluate how hydrodynamics and sediment characteristics drive the development of the benthic macrofauna community during the first 5 years following engineering measures to enhance benthic macrofauna diversity at three locations. The creation of low‐energy habitats through groins (Knuitershoek and Baalhoek) and a managed realignment dike breach (Perkpolder) led to the accumulation of fine sediments in all three impact sites. Biomass of benthic macrofauna quickly increased between 2016 and 2020, with successional processes being more important in Perkpolder, where the habitat was started completely from scratch due to a managed realignment, than at Knuitershoek or Baalhoek, where habitat conditions were improved by adding groins. In addition, the density of benthos‐eating birds, especially oystercatchers, increased at some of the modified sites. While a low‐energy habitat may harbor more diverse assemblages of benthic macrofauna than a highly dynamic one, the extremely high silt content, which is typical for low‐energy habitats, may slow benthic community development. The observed increase of biomass at our impact sites highlights the value of the interventions, while the delays in the response of the benthic macrofauna community emphasizes the need for extensive monitoring both in time and space and the identification of underlying abiotic–biotic mechanisms.

Variations of the soil macrofauna community and corresponding influencing factors in the newly reclaimed coastal area: A case study in Yangtze Estuary, China

Intensive reclamation activity has reshaped global coastal ecosystems. Soil macrofauna, an effective proxy for ecosystem health, has the potential to predict coastal reclamation ecological impact. Previous studies have primarily focused on the long-term (≥ 30 years) soil macrofaunal succession in reclaimed areas. However, composition of the soil macrofauna and its environmental drivers in newly reclaimed areas (< 30 years) remain uncertain. We selected Hengsha Dongtan in the Yangtze Estuary to conduct the study, and four different regions (reclaimed for 13, 8, 4, and 1 year, respectively) were employed to investigate soil macrofaunal composition and corresponding environmental drivers. The results showed that: (1) Terrestrial species millipedes (Paradoxosomatidae sp.), chinch bugs (Dimorphopterus spinolae), and wolf spiders (Pirata subpiraticus) were dominant. Millipedes, chinch bugs, wolf spiders, ants (Myrmecina sp.), and rove beetles (Stenus melanarius and Paederus fuscipes) were major species contributing to the average dissimilarity among regions. (2) The taxonomic composition of soil macrofauna varied over time after reclamation, which showed that the number of species, density, and biomass of soil macrofauna in region 1 (reclaimed for 13 years) was higher than that in regions 2, 3, and 4 (reclaimed for 8, 4, and 1 year). (3) The functional composition of soil macrofauna varied over time after reclamation. The number of species, density, and biomass of the phytophagous and saprophagous groups increased over time, whereas those of the predatory group decreased gradually. (4) Soil pH and total organic carbon content, together with land use, appeared to be key factors that determine soil macrofaunal composition. Overall, our study illustrates the response of soil macrofauna to changes in environmental factors and land use in newly reclaimed areas. Future studies should expand the range of potential factors and comprehensively analyze the mechanisms that maintain soil macrofaunal diversity in reclaimed areas.

Functional diversity and secondary production of macrofaunal assemblages can provide insights of biodiversity-ecosystem function relationships

BackgroundSemi-enclosed bays are important links in the material cycle and energy flow between terrestrial and marine ecosystems. They are also areas of intense human activities and heavily influenced by such activities as aquaculture, industrial and agricultural wastewater discharge. The rate of biodiversity loss and changes in ecosystems have prompted research into the relationship between species diversity and ecosystem functioning. Studies have shown that application of functional diversity indices is useful for assessing the status of ecosystem functioning. We quantitatively sampled macrofauna in a semi-enclosed bay in four seasons and analyzed the relationship between species, functional diversity and secondary production, biomass and feeding functional groups of macrofauna.ResultsThe annual secondary production was 325.01 kJ m−2 year−1. Detritivorous, carnivorous and planktophagous feeders were the main functional groups of macrofauna. Differences in the spatial–temporal distribution of functional groups were influenced by Ruditapes philippinarum and Hemileucon bidentatus. Functional richness had significant negative correlations with macrofaunal biomass and secondary production. Functional divergence, functional dispersion and Rao's quadratic entropy had highly significant negative correlations with macrofaunal biomass and secondary production.ConclusionThe results showed that high overlap of ecological niches can increase competition for habitat resources, leading to a decline in biomass and secondary production. In addition, aquaculture could promote the use of habitat resources to some extent, while it could increase competition for ecosystem resources (including habitat resources, atmospheric resources, water resources, etc.). Functional diversity is a good indicator for the ecosystem functioning and the competition status for habitat resources, which can provide insights into the current state of ecosystem function.

Decadal changes of macrofauna community in a semi-enclosed Bay of Yueqing in East China Sea

To reveal the long-term variation of macrofauna community in Yueqing Bay, an aquacultural bay famous for its shellfish culturing in the East China Sea, macrofauna samples were collected in three period from 2002 to 2003 and 2006–2007 to 2020–2021. The results show that macrofaunal community structure in this area has changed significantly (ANOSIM, p < 0.01) in nearly two decades with significant decreases in species number, biodiversity index and average biomass. Meanwhile, the taxa composition also changed significantly as the dominance of annelid increased while that of mollusks, echinoderms and vertebrates decreased. As a consequence of the variation of taxa composition and total biomass, macrofauna community showed a tendency of miniaturization as individuals with smaller body size and lower biomass dominated the community. According to the results of CCA analysis, temperature, salinity and dissolved oxygen content were the main environmental factors that restricted the species composition of macrofauna community. Further studies still needed to reveal the main reasons that cause the variation of macrofauna community. Overall, the results of this study suggest that the present status of Yueqing Bay benthic ecosystem is concerning from a macrobenthos perspective, as the biodiversity index and biomass of macrofauna decreased significantly. Effective measures should be taken in urgently to restrain the safety and function of coastal ecosystems.

Macrofauna and Organic Matter in Postagrogenic Sandy Soils at the NW Smolensk Region (Russia)

Natural reforestation on the abandoned arable lands is one of the characteristic processes that triggers the transformation of soils, accompanied by the change in the abundance, biomass, and taxonomic structure of the soil macrofauna. The assessment of the restoration potential of the soil properties and soil macrofauna to the natural state, the duration of this period, the dynamics of soil organic carbon stocks, and the role of macrofauna in this process at different stages of post-agrogenic successions is relevant for prediction of changes in ecosystem components and their role in the storage of organic carbon under various land use scenarios. The work is based on the data on organic carbon reserves, morphological properties of soils, abundance, biomass and taxonomic structure of the soil macrofauna of arable lands, primary forests and 5 stages of pine forest restoration (fallow meadows and pine forests of different ages) at the Smolenskoye Poozerye National Park (Smolensk region). It was revealed that in the soils of the 85–100-year-old pine forests, signs of plowing are preserved in the form of the smooth lower boundary of the humus horizon. At the same time, signs of soil regradation appear already at the meadow stage and are expressed in the formation of a thin humus horizon penetrated by roots, which transforms further at the next stages. In the litter and mineral part of the soil, the carbon stocks change non-monotonically with a maximum at the meadow stage and a minimum in 70–80-year-old forests. By the age of 80, the stock of organic carbon in the mineral part of soils is almost restored to the background values. The composition of soil macrofauna changes drastically during the transition from meadow to forest communities. At the initial stages (in agrocenoses and fallow meadows), the fauna of mineral soil horizons predominates: endogeic earthworms and larvae of lamellar beetles. Further, the fauna of organic horizons is restored, among which there is a high proportion of saprophages – epigeic and epi-endogeic earthworms, which contribute to the differentiation of litter. The biomass of saprophages has a negative correlation with the carbon reserves in the mineral part of forest soils, the thickness and reserves of organic carbon in the litter, and a positive correlation with the share of the easily decomposable litter fraction.

Stages of Restoration of Components of Post-Agrogenic Pine Forest Ecosystems at the National Park “Smolensk Lakeland”

Rural depopulation in Russia was accompanied by the abandonment of arable lands and natural reforestation. The aim of the work was to study soils and phytocenoses of six stages of pine forest restoration on rocks with coarse granulometric composition in the north-west of Smolensk region. The research was carried out at 18 key sites, characterizing 6 stages in triplicates. Under agrocenoses and one-year-old fallow lands we found agrozemes (Arenosols (Aric)) with a thick arable layer and a minimum abundance and biomass of macrofauna, represented mainly by phytophages and saprophages. At the 2nd stage of fallow meadows, grey-humus soils (Arenosols) and sod-podzols postagrogenic (Entic Podzols) were found with unchanged morphological properties in comparison with the first stage. Here, the biomass of macrofauna is maximal due to intensive invasion of open biotopes by insects. Young (up to 30 years old) pine forests grew on similar to the Stage 2 regraded soils. During 10 years of a forest growth, litter and protohumus regrading horizons were formed. In middle-aged (70–80 years old) pine forests on sod-podburs post-agrogenic regraded (Entic Podzols), signs of an eluvial process are manifested. Macrofauna is characterized by a decrease in the biomass of a litter population. In forests older than 80 years, decay of pine stands with the formation of complex spruce forests have begun. In soils, even lower boundary of old-fallow horizon disappears without podzolic horizon formation. Here, the maximum biomass of litter macrofauna is revealed. The final stage is shrubby (lingonberry)-green-moss pine forests older than 90 years growing on podzols (Albic Podzols) with remains of old-fallow horizon. Among macrofauna, litter macrofauna prevail in terms of a biomass, but the biomass is lower than in the previous stage. Due to the different degree of morphological manifestation of the alfegumus process, the fifth and sixth stages can be considered as variants of the development of post-agrogenic soils under pine forests.

城市嵌草式铺装植被和大型土壤动物群落组成特征——以新泰市为例

PDF HTML阅读 XML下载 导出引用 引用提醒 城市嵌草式铺装植被和大型土壤动物群落组成特征——以新泰市为例 DOI: 10.5846/stxb202109232671 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 福建省中青年教师教育科研项目(JAT210346);厦门理工学院科学技术研究项目(YKJ22009R) Community composition of vegetation and soil macrofauna in the urban grass planting pavement: A case study in Xintai City Author: Affiliation: 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:嵌草式铺装近年来广泛应用于城市停车场及道路,研究其群落组成特征对城市生态的综合治理具有重要意义。以新泰市为例,通过现场采样调研分析探讨了嵌草式铺装对植被和土壤动物群落组成和多样性的影响。结果显示,植被调查中共记录草本植物14科22属22种。牛筋草(Eleusine indica)为新泰市嵌草式铺装中植被的优势种。植被的平均密度和生物量分别为(21.87±2.15)株/m2和(4.15±0.45)g/m2。不同站点间植株密度和高度有显著空间差异(P<0.05),生物量和盖度差异不显著。不同站点的植被物种多样性特征也有所差异。大型土壤动物调查共记录7目8科10种,其中蚁科为优势类群。嵌草式铺装中土壤动物的丰度、生物量均显著高于不透水路面(P<0.05)。逐步回归分析表明,嵌草式铺装中植被和土壤动物的丰度和生物量与土壤的容积密度和含水率等理化性质显著相关(P<0.05)。土壤动物丰度与植被盖度、土壤动物生物量与植被生物量间也具有显著相关关系(P<0.05)。结果表明,嵌草式铺装能够有效提高城市生态系统中植被和土壤动物群落的丰度、生物量和多样性,这种影响是直接和间接多种方式的协同作用。未来应结合多种环境因子的监测,在不同时空尺度上系统探究嵌草式铺装带来的生态效应及其高效合理利用途径。 Abstract:Grass planting pavement has been widely used in urban roads, parks, and parking lots in recent years due to its composite structure of plant-soil-permeable filler. Many scholars have extensively studied its ecological and environmental functions in enhancing infiltration, reducing urban surface runoff, purifying water quality, and adjusting the microclimate of the local ecosystem. However, we had little knowledge about its effects on the organism communities and species diversity, even though it is of great significance to the comprehensive management and planning of the urban ecosystem. Therefore, based on field sampling and investigation, we carried out this study to quantitatively analyze the community composition and species diversity of the vegetation and soil macrofauna in the urban grass planting pavement in 9 sites of Xintai City, Shandong Province, and discuss the ecological effects of the grass planting pavement. A total of 22 species of herbaceous plants in 14 families, 22 genera were recorded in the study. With the highest relative abundance and biomass, Eleusine indica was the dominant species of vegetation in the grass planting pavement in Xintai City. The average abundance and biomass of the vegetation in the grass planting pavement was (21.87±2.15) shoots/m2 and (4.15±0.45) g/m2. There were significantly spatial differences in the shoot density (F=2.671, P<0.05) and stem height (F=2.748, P<0.05) among different sampling sites. Nevertheless, the differences in the vegetation biomass and coverage among different sites were not significant (P＞0.05), though significant differences existed in the pairwise comparison between sites by the Least Significant Difference (LSD) analysis. The species diversity of vegetation at different sites also varied significantly, the lowest value appeared in the grass planting pavement of the hospital parking lot. A total of 10 species in 7 orders, 8 families of the soil macrofauna were recorded in the survey. Formicidae was the dominant group of the soil macrofauna communities in the grass-planting pavement transects. Only two species of soil macrofauna were recorded in the porous pavement transect of all sites. The abundance and biomass of the soil macrofauna in grass planting pavement transect were significantly higher than that in porous pavement (P<0.05). The results of stepwise regression analysis showed that the community characteristics of vegetation and soil macrofauna significantly correlated to the soil physiochemical properties, such as bulk density and water content. The biomass (R2=0.810, P<0.05) and coverage (R2=0.819, P<0.001) of the vegetation in the grass planting pavement had the strongest correlations with the biomass and abundance of the soil macrofauna. The study showed that the grass planting pavement could effectively increase the abundance, biomass, and diversity of the vegetation and soil macrofauna communities in the urban ecosystem. This effect is a direct and indirect synergy of multiple factors, such as trampling frequency, soil texture, water content and some other biological factors. On the basis of long-term monitoring, systematic and comprehensive studies should be carried out in combination with environmental factors in the future to systematically explore the ecological effects of the grass planting pavement and provide a scientific basis for the further efficient and reasonable utilization of the grass planting pavement. 参考文献 相似文献 引证文献

Variation in the rates of biomass removal by soil macro-fauna in different land uses at Rashad, South Kordofan, Sudan

One of the main implications of reducing biodiversity is the loss or decline of ecosystem function. We have previously seen in the Rashad location that agricultural practices have a lower effect on ant biodiversity. However, how they affect the environmental services, they provide is unclear. The main objective of this study was to evaluate whether the conversion of native areas into agricultural systems affects the removal of biomass carried out by ants, an important ecosystem function linked to decomposition and predation. We sampled three transects from (the Rashad district). Each sampling plot consisted of a grid of 12 pitfall traps filled with sardine baits (simulating animal organisms) and bananas (as attractive vegetable resources). In addition, grass seeds (Sorghum bicolor) were applied in both natural (Campo, Kubos, and forest) and agricultural settings (soy monoculture, pastures, and organic agriculture). The Results showed that ant&amp;rsquo;s removal was highest in sardine with an average of 87.3g (&amp;sigma; &amp;plusmn; 23.8), followed by banana (average of 70.5g, &amp;sigma; &amp;plusmn; 31.5) and lowest in the seed (mean of 7.8g, &amp;sigma; &amp;plusmn; 7.3) (highest p = 0.017). Only the soy monoculture regions showed the lowest levels of sardine removed, indicating an effect associated with the kind of land use. Because little biomass is eliminated in both natural and agricultural settings, no effect of the seeds bait has been observed. As for the banana bait, the data suggested a redundancy effect with another group of macro-fauna). Our results suggest that there is a redundancy effect with another group of macrofauna. However, macrofauna biomass (excluding ants) does not explain this biomass removal. In addition, it detected no impact of ant species composition on removed biomass. The reduction of sardine and banana biomass was correlated with ant richness, indicating that the effects on ecosystem function depend on the particularities of each evaluated role (such as resource type), the type of land use, and the ant richness in the study area.

Benthic studies adjacent to Sakhalin Island, Russia, 2015 I: benthic biomass and community structure in the nearshore gray whale feeding area

Okhotsk or western gray whales feed in summer along the northeastern coast of Sakhalin Island, Russia, a region with oil and gas extraction facilities. Seismic surveys increased sound levels in the nearshore feeding area in 2015 for part of the summer, potentially displacing whales from preferred foraging habitat or reducing foraging efficiency. Since lost foraging opportunities might lead to vital rate effects on this endangered species, detailed benthic surveys were conducted to characterize benthic community biomass patterns and spatial and temporal differences. Benthic biomass demonstrated strong spatial–temporal interactions indicating that prey biomass differences among locations were dependent on sampling period. Of greatest interest, Amphipoda biomass declined from June to October in the northern and southern portions of the nearshore study area but increased in the middle and Actinopterygii biomass increased in the northern area in mid-summer. Water depth and sediment type were significant covariates with community structure, and water depth strongly covaried with bivalve biomass. Total average prey biomass was ~ 100 g/m2 within the nearshore feeding area with no evidence of reduced biomass among sampling periods or locations, although there were fewer amphipods in the south. Multi-prey investigations provide a stronger basis for inferences than single-prey studies of amphipods when gray whales feed on diverse prey. Benthic community-level variability was moderate to high as would be expected for a shallow-water nearshore area. Overall, spatial and temporal changes in dominant macrofauna biomass reflected small to medium-sized effects that were well within the natural boundaries expected for benthic communities.

Land-use intensification reduces soil macrofauna biomass at the community but not individual level

Land-use intensification and climate change are main threats to the abundance and diversity of soil macrofauna. However, little is known about their biomass in response to these concurrent drivers. Here, we investigated the biomass responses of soil macrofauna along a land-use intensity gradient of five land-use regimes (i.e., from extensively-used grassland to conventional cropland) under two climate scenarios (ambient vs. future). We found that land-use intensification (but not climate change) significantly reduced soil macrofauna biomass at the community rather than individual level. Further, the community structure of soil macrofauna based on total biomass data varied with land-use type (i.e., grasslands vs. croplands). Collectively, our findings suggest that land-use intensification can negatively shift the community biomass patterns of soil macrofauna consistently under both ambient and future climates in agroecosystems.

Insecticide application did not reveal any impact of herbivory on plant roots in boreal forests

The levels of belowground herbivory in natural ecosystems remain practically undetermined, and nothing is known regarding the geographic and/or climatic variations in belowground herbivory. We endeavoured to narrow this knowledge gap by exploring the latitudinal changes in the intensity of background root herbivory in boreal forest ecosystems by conducting a herbivore exclusion experiment in 10 forested sites from 60°N to 69°N in northwestern Russia. We found no statistically significant differences in fine root biomass between diazinon-treated and control plots, nor did the differences show any latitudinal change. From biomass of root-feeding macrofauna we estimated that root herbivory in our sites averages 0.57 %. This low level of root herbivory could not be quantified reliably by herbivore exclusion experiments; therefore, we suggest that macroecological patterns in root herbivory are invoked from simultaneous measurements of the biomasses of fine roots and of root-feeders. More data on the efficiency of conversion of the food ingested by root-feeding invertebrates is needed to increase the accuracy of the suggested method of estimation of root herbivory.

Community Structure of Benthic Macrofauna and the Ecological Quality of Mangrove Wetlands in Hainan, China

Few studies have systematically assessed the ecological status of mangrove wetlands following the stress of anthropogenic activities in China. This study investigated the spatial and seasonal distribution of benthic macroinvertebrate communities and assessed the ecological quality of mangrove habitats on an island scale in Hainan, China (containing the third largest mangrove area of China and the highest mangrove species richness). For the benthic macrofauna community structure, a total of 102 macrobenthic taxa belonging to 50 families were identified, with Crustaceans, Molluscs, Polychaetes, and Oligochaeta having relative abundances of 52.3%, 36.1%, 10.8%, and 0.8%, respectively. Decapoda and Gastropoda dominated the benthic community abundance. Non-metric multidimensional scaling and an analysis of similarities revealed significantly different macroinvertebrate assemblages among the regions during the two seasons. The South mangroves had the lowest macrofauna species numbers, biodiversity, richness, and abundance. The macrofaunal species richness, Shannon index, Margalef index, abundance, and biomass markedly affected by region and season. As indicated by the biotic indices AMBI (AZTI’s Marine Biotic Index) and M-AMBI, more than half of the mangrove habitats on Hainan Island were slightly to heavily disturbed and had poor to moderate ecological quality. Our results recommend long-term monitoring for evaluating the quality status of mangrove wetlands and avoiding extensive land-use conversion of mangroves. Holistic approaches considering ecological characteristics and combining information on both floral and faunal functionality would contribute to the effective management and conservation of mangroves in disturbed areas.

Role of earthworms in soil fertility and its impact on agriculture: A review

Soil fertility is defined as the capacity of a specific kind of soil to function, within natural or managed ecosystem boundaries to sustain plant and animal productivity, maintain or enhance water and air quality, and support human health and habitation. Perhaps no other living organism in the soil is as important as an earthworm in helping to increase soil health. Earthworms are the most commonly occur in the soil. The activities of burrowing and feeding by earthworms have many valuable effects generally on soil quality for crop production. Earthworms increase soil aeration, infiltration, structure, nutrient cycling, water movement, and plant growth. Earthworms are one of the major decomposers of organic matter. They get their nutrition from microorganisms that live on organic matter and in soil material. When they move through the soil eating, earthworms form tubular channels or burrows. These burrows can persist for a long time in the soil. Earthworm burrows increase soil porosity which increases the amount of air and water that get into the soil. Increased porosity also lowers bulk density and increases root development. Earthworm excrement or casts increase soil fertility because it contains nitrogen, phosphorus, potassium, and magnesium. Earthworm casts also contain microorganisms which increase in abundance as organic matter is digested in their intestines. The cycling of nutrients from organic matter and the increase in microorganisms facilitates plant growth. They cast along with binding agents released by earthworms also improve soil structure and increase aggregate stability. The soil biota benefits soil productivity and contributes to the sustainable function of all ecosystems. The cycling of nutrients is a critical function that is essential to life on earth. Earthworms (EWs) are a major component of soil fauna communities in most ecosystems and comprise a large proportion of macrofauna biomass. Their activity is beneficial because it can enhance soil nutrient cycling through the rapid incorporation of detritus into mineral soils. In addition to this mixing effect, mucus production associated with water excretion in earthworm guts also enhances the activity of other beneficial soil microorganisms. This is followed by the production of organic matter. So, in the short term, a more significant effect is the concentration of large quantities of nutrients (N, P, K, and Ca) that are easily assimilable by plants in fresh cast depositions. In addition, earthworms seem to accelerate the mineralization as well as the turnover of soil organic matter. Earthworms are known also to increase nitrogen mineralization, through direct and indirect effects on the microbial community. The increased transfer of organic C and N into soil aggregates indicates the potential for earthworms to facilitate soil organic matter stabilization and accumulation in agricultural systems, and that their influence depends greatly on differences in land management practices.

Effects of topsoil transposition on the taxonomic and functional diversity of macrofauna of highly degraded soil

AbstractTopsoil transposition has been identified as an environmental restoration technique capable of accelerating regeneration in degraded areas. In addition to the seed bank, topsoil contains invertebrates and microorganisms essential in ecological succession. This study evaluated the temporal variation in the macrofauna community structure in an experiment with topsoil transposition. We hypothesized that the morphospecies richness, functional groups and macrofauna biomass would be higher in the plots with topsoil and native vegetation compared with plots with no topsoil. We further hypothesized that the composition of macrofauna community and the proportion of functional groups in the topsoil and the reference plots would become more similar over time. The community was compared between plots that received topsoil, plots that did not receive topsoil and plots in a natural vegetation, over 14 months. The macrofauna biomass and the diversity of functional groups were equivalent in the degraded area and the topsoil. The effect of treatment on richness depended on time, and it was possible to observe higher values of macrofauna richness in the topsoil compared with the degraded area in some months. The compositions of the macrofauna communities in the degraded area and the topsoil showed greater similarity to each other. In contrast, the reference area showed the greatest dissimilarity with the other treatments. In general, the macrofauna community in the topsoil remained more similar to the degraded area. However, in the topsoil plots, we found higher macrofauna richness during rainy months and an increase in predator biomass. In conclusion, the macrofauna community in the topsoil, which has changed over time, presented higher values of morphospecies richness in some months and the increase in predator biomass, indicating an increase in the complexity of the community. Besides, the topsoil can improve biodiversity, but this does not produce the natural communities found at reference sites, in a small‐time scale experiment.

Soil macrofaunal communities develop a habitat-specific trophic structure dependent on the degree of degradation of alpine wetlands

The alpine wetlands in the Qinghai-Tibetan Plateau have degraded in recent decades. However, the response of the soil food web to the degradation is still unclear. Four habitats including a wet meadow (WM), a grassland meadow (GM), a moderately degraded meadow (MDM) and a severely degraded meadow (SDM) (sandy meadows) were selected along the degrees of degradation. The soil macrofaunal biomass and the environmental factors of vegetation and soil were investigated. The soil macrofaunal community biomass increased significantly from WM to MDM and decreased to a very small amount in SDM, with most taxa disappearing. The biomass of the trophic groups of detritivores, herbivores and predators exhibited similar responses to soil macrofaunal communities. The relative biomass of detritivores increased from WM to MDM, but herbivores responded in an opposite manner, resulting in the dominant trophic group and trophic structure varying progressively from WM to GM to MDM. Soil properties but not vegetation determined the changes in trophic groups and trophic structure. The results implied that the higher trophic levels (carnivores or omnivores) responded more sensitively than the lower trophic levels (herbivores) to alpine wetland degradation. Our results also suggested that soil macrofauna have a habitat-specific characteristic trophic structure and can be used as indicators of soil health conditions.

Changes in Biomass and Diversity of Soil Macrofauna along a Climatic Gradient in European Boreal Forests.

Simple SummaryWe used a 1000 km long latitudinal gradient in north-western Russia to study the potential impacts of a changing climate on soil invertebrates visible by a naked eye (insects, spiders, earthworms etc.). We extracted these animals from soil, weighed them and identified them to the species level. We found that the diversity of soil invertebrates decreased towards the north, whereas the latitudinal pattern in biomass depended on the animal’s feeding habit. The biomass of species feeding on live plant roots and fungal mycelia decreased towards the north, whereas the biomass of species feeding on dead plant tissues and live invertebrates showed no significant latitudinal changes. The discovery of this variation in latitudinal biomass patterns suggests that soil invertebrates from different feeding guilds may respond differently to climate change. As a result, the biomass ratio between consumers and their food resources (e.g., herbivores and plants, predators and prey) may change. We poorly understood how this change will affect the future structure and functions of boreal forest ecosystems.Latitudinal gradients allow insights into the factors that shape ecosystem structure and delimit ecosystem processes, particularly climate. We asked whether the biomass and diversity of soil macrofauna in boreal forests change systematically along a latitudinal gradient spanning from 60° N to 69° N. Invertebrates (3697 individuals) were extracted from 400 soil samples (20 × 20 cm, 30 cm depth) collected at ten sites in 2015–2016 and then weighed and identified. We discovered 265 species living in soil and on the soil surface; their average density was 0.486 g d·w·m−2. The species-level diversity decreased from low to high latitudes. The biomass of soil macrofauna showed no latitudinal changes in early summer but decreased towards the north in late summer. This variation among study sites was associated with the decrease in mean annual temperature by ca 5 °C and with variation in fine root biomass. The biomass of herbivores and fungivores decreased towards the north, whereas the biomass of detritivores and predators showed no significant latitudinal changes. This variation in latitudinal biomass patterns among the soil macrofauna feeding guilds suggests that these guilds may respond differently to climate change, with poorly understood consequences for ecosystem structure and functions.

Soil macrofauna abundance, biomass and selected soil properties in the home garden and coffee-based agroforestry systems at Wondo Genet, Ethiopia

Agroforestry practices (AFPs) are typical solutions for low-input agricultural systems. AFPs play critical roles in the improvement of the abundance and biomass of soil invertebrates, which are necessary for long-term improvement of soil properties. The overall objective of the present study was to investigate the spatial and temporal dynamics in macrofauna abundance and biomass in home gardens and coffee-based agroforestry systems and relate it with the dynamics in a range of soil physico-chemical parameters. The two AF systems differed in plant species richness and diversity of life forms. For both sampling seasons, higher number of macrofauna was collected from home garden AF than in the Coffee-based AF plot. Total macrofaunal biomass between the wet and dry seasons was significantly different (p < 0.05) for samples from home garden AF plot. Depth-wise patterns in macrofauna abundance and biomass showed distinct seasonal variation in the two-agroforestry systems. For both AF plots, marked and significant (p < 0.001) seasonal differences were observed in relation to soil moisture, temperature, and pH. On the other hand, dry season samples from the home garden AF plot had significantly (p < 0.001) higher moisture content and soil pH than the coffee-based AF plot. Home garden AF system provides a better belowground environment for enhanced soil macrofauna proliferation and activity reflected in higher biomass & abundance than Coffee-based AF. Accordingly, farmers are encouraged to maintain their farm production and productivity with agroforestry. F0B7 Home garden agroforestry system has diverse plant species composition than coffee based agroforestry system. F0B7 Home garden is better in terms of soil macrofauna abundance and biomass. F0B7 Soil macrofauna biomass and abundance showed seasonal dynamics.

Carbon sources of benthic fauna in temperate lakes across multiple trophic states

Abstract. Previous studies have shown that microbially produced methane can be a dominant carbon source of lacustrine sedimentary macrofauna in eutrophic lakes, most likely through grazing on methane-oxidizing bacteria. Here we investigate the contributions of different carbon sources to macrofaunal biomass across five lakes in central Switzerland that range from oligotrophic to highly eutrophic. Macrofaunal communities change with trophic state, with chironomid larvae dominating oligotrophic and tubificid oligochaetes dominating eutrophic lake sediments. The 13C-isotopic data suggest that the average contribution of methane-derived carbon to the biomass of both macrofaunal groups is similar but consistently remains minor, ranging from only ∼1 % in the oligotrophic lake to at most 12 % in the eutrophic lakes. The remaining biomass can be explained by the assimilation of detritus-derived organic carbon. Low abundances of methane-cycling microorganisms in macrofaunal specimens, burrows, and surrounding sediment based on 16S ribosomal RNA (rRNA) gene sequences and copy numbers of genes involved in anaerobic and aerobic methane cycling (mcrA, pmoA) support the interpretation of isotopic data. Notably, 16S rRNA gene sequences of macrofauna, including macrofaunal guts, are highly divergent from those in tubes or sediments. Many macrofaunal specimens are dominated by a single 16S rRNA phylotype of Fusobacteria, α-, β-, γ-, or ε-Proteobacteria, Bacteroidetes, or Parcubacteria. This raises the question of whether dominant lake macrofauna live in so far uncharacterized relationships with detrital organic-matter-degrading bacterial endosymbionts.

Effects of Sediment Characteristics on Carbon Dioxide Fluxes Based on Interacting Factors in Unvegetated Tidal Flats

The contribution of unvegetated tidal flats to global net primary production is comparable to that of some vegetated coastal habitats. However, compared to carbon flux regulating factors in vegetated habitats, those in unvegetated tidal flats are not well understood, particularly in terms of their cause-effect relationships. Maximum gross primary production (GPPm), net primary production (NPP) and total respiration (TR) during emersion at noon when the irradiance level was at the saturation level for photosynthesis in nine unvegetated tidal flats across the Taiwan Strait in tropical and subtropical regions were determined in winter and summer from 2011 to 2016 to examine the direct and indirect relationships between sediment characteristics and carbon fluxes by using structural equation models (SEM). Most of the GPPm and NPP values were higher in winter than in summer. Conversely, the TR values were higher in summer than in winter. The NPP values at some sites shifted to negative values in summer, indicating the sites were carbon sources. The values of GPPm, TR and NPP for the tidal flats all increased significantly with increasing sediment mud content. The SEM results showed that the sediment mud content directly increased GPPm or indirectly increased GPPm via a compositional shift in benthic microalgae. The sediment mud content also directly increased TR or indirectly increased TR via increased organic matter content. The contribution of benthic microalgal and macrofaunal biomass to TR was relatively minor. This result suggests that primary production was stimulated mainly by the organic matter content rather than by increased microalgal biomass. With the integrated SEM framework, our results showed mechanistic evidence of how sediment mud content acted as a critical factor regulating carbon fluxes in unvegetated tidal flats.