Changes in the species composition and trophic structure of soil macrofauna upon establishment of forest plantations in the Caspian semidesert

The influence of microtopography on the distribution of soil invertebrates in the semidesert and the ways of soil fauna formation in forest plantations established in mesodepressions at the Dzhanybek Research Station, the Northern Caspian Lowland, are considered. The results of earthworm introduction in pedunculate oak plantations performed more than 40 years ago are summarized. The composition of the soil macrofauna and characteristics of forest litter are compared between forest plantations and natural spiraea brushwood.     

Macrofauna assemblage composition and soil moisture interact to affect soil ecosystem functions

Changing climatic conditions and habitat fragmentation are predicted to alter the soil moisture conditions of temperate forests. It is not well understood how the soil macrofauna community will respond to changes in soil moisture, and how changes to species diversity and community composition may affect ecosystem functions, such as litter decomposition and soil fluxes. Moreover, few studies have considered the interactions between the abiotic and biotic factors that regulate soil processes. Here we attempt to disentangle the interactive effects of two of the main factors that regulate soil processes at small scales - moisture and macrofauna assemblage composition. The response of assemblages of three common temperate soil invertebrates (Glomeris marginata Villers, Porcellio scaber Latreille and Philoscia muscorum Scopoli) to two contrasting soil moisture levels was examined in a series of laboratory mesocosm experiments. The contribution of the invertebrates to the leaf litter mass loss of two common temperate tree species of contrasting litter quality (easily decomposing Fraxinus excelsior L. and recalcitrant Quercus robur L.) and to soil CO₂ fluxes were measured. Both moisture conditions and litter type influenced the functioning of the invertebrate assemblages, which was greater in high moisture conditions compared with low moisture conditions and on good quality vs. recalcitrant litter. In high moisture conditions, all macrofauna assemblages functioned at equal rates, whereas in low moisture conditions there were pronounced differences in litter mass loss among the assemblages. This indicates that species identity and assemblage composition are more important when moisture is limited. We suggest that complementarity between macrofauna species may mitigate the reduced functioning of some species, highlighting the importance of maintaining macrofauna species richness.     

Consumption of aquatic subsidies by soil invertebrates in coastal ecosystems

Routes of aquatic allochthonous inputs (aquatic subsidies) to detrital food webs are studied, as is the effect of aquatic subsidies on the functional and taxonomic structure of soil invertebrate communities in coastal ecosystems. The study took place in the coastal zone of an oxbow lake of the Pra River in the Oka Reserve. The results indicate a strong dependence of soil animals in the coastal habitats on aquatic subsidies. Isotopic analysis shows that aquatic resources enter soil food webs not only via predators feeding on flying insects or aquatic prey, but also via saprophages decomposing organic debris of aquatic origin. The contribution of aquatic subsidies to the energy balance of soil invertebrates decreases rapidly with increasing distance from the lake. The fraction of aquatic carbon in tissues of collembolans and saprophages is negligible already a few meters from the water edge. The dependence of predatory invertebrates on aquatic resources can be traced at somewhat greater distance (tens of meters).     

Long‐Term Dynamics of Microbial Biofilm Communities of the River Rhine with Special References to Ciliates

The aim of this study was to quantify and qualify seasonal changes of all important components of a microbial biofilm community. We explored the development of the biofilm community structure on submerged glass slides for 15 months including all organisms from bacteria to macro‐invertebrates. Besides bacteria, heterotrophic flagellates were the most abundant biofilm component followed by ciliates, meiofauna organisms and algae. Most important were sessile choanoflagellates, peritrichous ciliates and some crustaceans. Ciliates and macrofauna were the most important components with regard to the total biovolume. The biofilm architecture was strongly influenced by extracellular structures produced by protozoans and macro‐invertebrates. Alterations within the biofilm community were mainly due to changes in abundances rather than in the composition except for heterotrophic flagellates and macro‐invertebrates. Biofilm organisms were dominated by planktivorous organisms exerting a strong grazing impact on the plankton organisms in this large river. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Importance of predation in regulating density of meio- and macrofauna in seasonal tropical waters

Toward the end of the low water period in two seasonal tropical water bodies, we observed drastic declines in densities of dominant groups of macrofauna (Chironomidae, Oligochaeta and Ostracoda). This, however, was not accompanied by reductions in the densities of meiofauna (Nematoda, small (< 3 mm) Chironomidae and Oligochaeta). The decline of macrofauna was correlated with growing numbers of large, mobile, carnivorous invertebrates (Coleoptera, Heteroptera, Decapoda: Macrobrachium) and small, gape-limited fish, which emigrated from drying habitats and concentrated in places that predation pressure has been directed mainly towards macrofauna. Alternative hypotheses are discussed.     

五大连池药泉山大型土壤动物对旅游踩踏的响应

以黑龙江省五大连池世界地质公园的药泉山为研究对象,按照距离游道的远近分为重度踩踏区,轻度踩踏区和非踩踏区3种踩踏干扰强度,分析大型土壤动物数量,群落组成,多样性对旅游踩踏干扰的响应。研究结果表明不同干扰区之间大型土壤动物类群数量差异显著(P0.001),重度踩踏区显著低于轻度踩踏区和非踩踏区。不同干扰区大型土壤动物个体数差异明显(P0.001),其中轻度踩踏区个体密度最大(68头/m~2),重度踩踏区个体密度最小(10头/m~2)。不同踩踏强度干扰区H'指数差异明显(P0.05),轻度踩踏区及非踩踏区的多样性显著高于严重踩踏区。典型对应分析表明旅游踩踏主要通过改变土壤理化特性而影响大型土壤动物的组成及其多样性,重度踩踏区、轻度踩踏区和非踩踏区对大型土壤动物影响最显著的因子分别为土壤全氮含量,土壤含水率和土壤全磷含量。     

Contribution of paddock trees to the conservation of terrestrial invertebrate biodiversity within grazed native pastures

Abstract: Paddock trees are a common feature in the agricultural landscapes of Australia. Recent studies have demonstrated the value of scattered paddock trees for soil fertility, native pasture plants and arboreal faunas; however, the degree to which scattered paddock trees contribute to the conservation of terrestrial invertebrate biodiversity within grazed landscapes remains unknown. We ask three questions: (i) Is there a difference between the terrestrial invertebrate assemblages found under paddock trees compared with surrounding grazed native pastures? (ii) Can gradients in soil and litter variables from the base of trees explain patterns in invertebrate assemblages? and (iii) Does the presence of scattered paddock trees have implications for the conservation of terrestrial invertebrate biodiversity within grazed native pastures? We used pitfall trapping and extraction from soil cores to sample the invertebrate assemblages under six New England Peppermint trees (Eucalyptus nova‐anglica Deane and Maiden) and compared them with assemblages sampled from the open paddock. Formicidae and Collembola univariate and multivariate data were analysed along with a range of soil and litter variables. We found (i) significant differences in the assemblages of invertebrates under trees compared with surrounding grazed pastures; (ii) that most soil and litter variables revealed gradients away from tree bases and these variables explained significant variation in invertebrate assemblages; and (iii) more native invertebrates and more species of invertebrates were found under trees compared with the surrounding pastures. We discuss the relationships between paddock trees, the ground and soil environments and the invertebrate communities that inhabit these environments, and conclude with a discussion of the future for paddock trees and the biota supported by them.     

Replanting of first‐cycle oil palm results in a second wave of biodiversity loss

相似文献   

Cloud forests of the Orinoco River Basin (Colombia): Variation in vegetation and soil macrofauna composition along the hydrometeorological gradient

Tropical montane cloud forests (TMCF) in the Orinoco River Basin are vulnerable to climate and regional land-use changes. These changes will force TMCF to migrate upwards, affecting biodiversity conservation and water flow regulation. Here, we evaluate how vegetation and soil macrofauna composition vary along the hydrometeorological gradient driven by an increase in fog incidence with elevation. Vegetation data were collected for all individuals with a diameter at breast height (DBH) > 5 cm in four vegetation plots (5 × 50 m; total: 0.1 ha) every 100 m in altitude between 1700 and 2200 m a.s.l. From each plot, we obtained three soil monoliths from the organic layer and three from the mineral horizon, and manually extracted their soil macrofauna. For these groups, we describe: (1) their compositional changes along the hydrometeorological gradient employing ordination analyses techniques and (2) the relation of the composition changes between vegetation and soil macrofauna communities using a symmetrical co-correspondence analysis. Our results show that the vegetation morphospecies composition and soil macrofauna-order composition vary significantly with the hydrometeorological gradient along elevation. The co-correspondence between vegetation and soil macrofauna reveals a shared breakpoint above the 2000 m a.s.l., where fog is more persistent. Furthermore, we identified eight indicator vegetation species and two soil macrofauna orders associated with specific elevations. These results suggest that under a climate-change-driven fog lift, the TMCF of the Orinoco River Basin will be displaced. Moreover, this study provides a baseline to monitor such displacement.     

Diversity of larger consumers enhances interference competition effects on smaller competitors

Competition between large and small species for the same food is common in a number of ecosystems including aquatic ones. How diversity of larger consumers affects the access of smaller competitors to a limiting resource is not well understood. We tested experimentally how species richness (0–3 spp.) of benthic deposit-feeding macrofauna changes meiofaunal ostracods’ incorporation of fresh organic matter from a stable-isotope-labeled cyanobacterial bloom, using fauna from the species-poor Baltic Sea. Presence of macrofauna mostly decreased meiofaunal incorporation of bloom material, depending on the macrofauna species present. As expected, the species identity of macrofauna influenced the incorporation of organic matter by meiofauna. Interestingly, our results show that, in addition, species richness of the macrofauna significantly reduced meiofauna incorporation of freshly settled nitrogen and carbon. With more than one macrofauna species, the reduction was always greater than expected from the single-species treatments. Field data from the Baltic Sea showed a negative correlation between macrofauna diversity and meiofaunal ostracod abundance, as expected from the experimental results. We argue that this is caused by interference competition, due to spatial niche differentiation between macrofauna species reducing the sediment volume in which ostracods can feed undisturbed by larger competitors. Interference from macrofauna significantly reduces organic matter incorporation by meiofauna, indicating that diversity of larger consumers is an important factor controlling the access of smaller competitors to a limiting food resource.     

盐城5 种绿地春季大型土壤动物群落的生物多样性

选取盐城5种城市绿地:杨树林、油菜地、苗圃、公园绿地和草坪,于2011年春季开展了大型土壤动物群落的生物多样性研究。结果显示,密度-类群指数(density-group index,DG)、群落复杂性指数(complexity index,C)与Shannon-Wiener指数(H')等α多样性在苗圃、公园绿地和杨树林中均具有较高水平,在草坪和油菜地的大型土壤动物群落生物多样性水平较低,DG指数与C指数显著线性相关(P0.01,n=5)并对H'有较为一致的校正效果。采用β多样性(Jaccard群落相似性系数)为基础的系统聚类结果认为杨树林、苗圃和公园绿地群落相似,草坪和油菜地群落相似。研究结果认为,大型土壤动物群落的生物多样性与绿地生境特征的复杂程度相关,绿地中树木的分布情况可能是影响大型土壤动物群落生物多样性的重要因素,这可为城市绿地规划设计提供参考。     

Effects of Alpine land‐use changes: Soil macrofauna community revisited

Although soil invertebrates play a decisive role in maintaining ecosystem functioning, little is known about their structural composition in Alpine soils and how their abundances are affected by the currently ongoing land‐use changes. In this study, we re‐assessed the soil macrofauna community structure of managed and abandoned Alpine pastureland, which has already been evaluated 14 years earlier. Our results confirm clear shifts in the community composition after abandonment, in that (1) Chilopoda and Diplopoda were recorded almost exclusively on the abandoned sites, (2) Coleoptera larvae and Diptera larvae were more abundant on the abandoned than on the managed sites, whereas (3) Lumbricidae dominated on the managed sites. By revisiting managed and abandoned sites, we infer community patterns caused by abandonment such as changes in the epigeic earthworm community structure, and we discuss seasonal and sampling effects. Our case study improves the still limited understanding of spatio‐temporal biodiversity patterns of Alpine soil communities.     

Soil microarthropods and macrofauna in monsoon tropical forests of Cat Tien and Bi Dup-Nui Ba National Parks,southern Vietnam

The abundance, biomass, vertical distribution, and taxonomic composition of soil invertebrates (springtails, macrofauna, and termites) were studied in forest formations differing in edaphic and climatic conditions: lowland forests dominated by Lagerstroemia spp. or Dipterocarpus spp. in the Cat Tien National Park and in a mountain pine (Pinus kesiya) forest on the Da Lat Plateau, southern Vietnam. In the lowland forests, springtails had a relatively low density (10000–12000 ind./m²), but their diversity was high (41–43 species in each forest). The density of large soil invertebrates (without ants and termites) reached 500–700 ind./m² at a biomass of approximately 30 g/m² (with earthworms accounting for up to 230 ind./m² and 19–28 g/m²). Among termites, species of the genera Macrotermes and Odontotermes were dominant. Their total biomass in some areas exceeded 15–20 g/m². In the mountain pine forest, the total biomass of soil macrofauna was approximately 11 g/m², the abundance and diversity of springtails were low (7500 ind./m², 28 species), and wood-destroying species of the genera Schedorhinotermes sp. and Coptotermes sp. dominated among termites.     

The effect of topsoil removal in restored heathland on soil fauna, topsoil microstructure, and cellulose decomposition: implications for ecosystem restoration

Communities of soil macrofauna, oribatid mites, and nematodes as well as vegetation and soil chemistry were studied on twelve plots representing three replicates of the following treatments: agricultural meadow, heathland, and heathland restored either by partial or complete topsoil removal 15 years earlier. We also studied the effect of soil macrofauna on decomposition and the microstructure of the soil surface layer with litterbags in combination with the analysis of thin soil sections. The communities of soil macrofauna and oribatid mites significantly differed between agricultural meadows and heathlands. The partial and complete topsoil removal plots were more similar to heathlands with respect to macrofauna and to agricultural meadows with respect to oribatid mites. The density and diversity of soil macrofauna was higher in agricultural meadows than in heathlands; in particular, earthworms, litter transformers, root feeders, and microsaprophags were more abundant on meadows. Heathlands, in contrast, contained a much higher diversity of oribatid mites. The community structure of nematodes did not significantly differ among the treatments. Analysis of thin soil sections revealed a thick organic fermentation layer in heathlands, which was absent in agricultural meadows and only weakly developed in the topsoil removal plots. In agricultural meadows, litterbags and thin soil sections indicated that abundant macrofauna, including endogeic earthworms, were very effective in removing the litter from the soil surface and mixing it into the mineral soil. Possible effects of this soil mixing on restoration success are discussed.     

Herbivore trampling as an alternative pathway for explaining differences in nitrogen mineralization in moist grasslands

Studies addressing the role of large herbivores on nitrogen cycling in grasslands have suggested that the direction of effects depends on soil fertility. Via selection for high quality plant species and input of dung and urine, large herbivores have been shown to speed up nitrogen cycling in fertile grassland soils while slowing down nitrogen cycling in unfertile soils. However, recent studies show that large herbivores can reduce nitrogen mineralization in some temperate fertile soils, but not in others. To explain this, we hypothesize that large herbivores can reduce nitrogen mineralization in loamy or clay soils through soil compaction, but not in sandy soils. Especially under wet conditions, strong compaction in clay soils can lead to periods of soil anoxia, which reduces decomposition of soil organic matter and, hence, N mineralization. In this study, we use a long-term (37-year) field experiment on a salt marsh to investigate the hypothesis that the effect of large herbivores on nitrogen mineralization depends on soil texture. Our results confirm that the presence of large herbivores decreased nitrogen mineralization rate in a clay soil, but not in a sandy soil. By comparing a hand-mown treatment with a herbivore-grazed treatment, we show that these differences can be attributed to herbivore-induced changes in soil physical properties rather than to above-ground biomass removal. On clay soil, we find that large herbivores increase the soil water-filled porosity, induce more negative soil redox potentials, reduce soil macrofauna abundance, and reduce decomposition activity. On sandy soil, we observe no changes in these variables in response to grazing. We conclude that effects of large herbivores on nitrogen mineralization cannot be understood without taking soil texture, soil moisture, and feedbacks through soil macrofauna into account.     

Rates of Decomposition Processes in Mountain Soils of the Sudeten as a Function of Edaphic-Climatic and Biotic Factors

The rate of grass litter decomposition was studied in soils of the Karkonosze Mountains of the Sudeten at different altitudes. Parallel structural-functional investigations of the soil animal population on the example of soil macrofauna were carried out and heavy metals were assayed in the soil at stationary plots to reveal the effects of both natural and anthropogenic factors on the soil biological activity. The recent contamination of soil in the Sudeten by heavy metals and sulfur does not affect the spatial distribution and abundance of the soil-dwelling invertebrates and the decomposition rates. The latter correlated to a high level of soil saprotroph activity. The activity of the decomposition processes depends on the soil content of organic matter, conditions of soil drainage, and the temperature of upper soil horizon.     

The effect of litter type and macrofauna community on litter decomposition and organic matter accumulation in post-mining sites

Field microcosms consisting of mineral soil (spoil substrate) and two types of litter taken either from an unreclaimed site with spontaneously developed vegetation (mostly Salix caprea) or from an alder plantation (a mixture of Alnus glutinosa and A. incana) were exposed in spontaneously developed or reclaimed sites at a post-mining heap near Sokolov (Czech Republic) for one year. The litter types differed remarkably in C:N ratio which was 29 for spontaneous litter and 14 for alder litter. The two microcosm types were either accessible or not accessible to soil macrofauna. The effect of macrofauna exclusion on soil mixing was complex and depended on litter quality and the site that determined soil fauna composition. In reclaimed sites where macrofauna was dominated by saprophags, mainly earthworms, the macrofauna access increased soil mixing. In sites where predators dominated, the macrofauna exclusion probably suppressed fragmentation and mixing activity of the mesofauna.     

川西北冷杉林恢复过程中土壤动物群落动态

为了掌握川西北冷杉林群落恢复过程中土壤动物群落的变化动态,2008年4月对川西北地区的原始冷杉林和50a冷杉林的土壤动物群落进行了调查。共捕获大型土壤动物287个,33科(类);中小型土壤动物4681个,57科(类)。50a冷杉林大型土壤动物群落的类群数和密度显著高于原始冷杉林(P<0.05);中小型土壤动物群落的类群数和密度分别显著低于(P<0.05)和高于原始林(P<0.05)。PCA排序结果表明两个不同年龄段间的大型和中小型土壤动物群落结构均存在明显差异,但大型土壤动物群落间的相似性系数小于中小型土壤动物群落,表明大型土壤动物群落的恢复速度慢于中小型土壤动物群落;且大型和中小型土壤动物群落间的Srenson相似性均低于Morisita-Horn相似性,进一步表明群落物种组成的恢复速度较慢,而优势类群及常见类群的数量恢复较快。50a冷杉林的大型和中小型土壤动物的多样性指数H、丰富度指数D和优势度指数C均高于原始冷杉林,而均匀度指数E则低于原始冷杉林,但仅大型土壤动物的丰富度指数D存在显著差异(P<0.05)。以上研究结果表明,冷杉林的恢复过程可显著提高大型土壤动物群落多样性,且土壤动物群落的组成恢复较慢,而优势类群和常见类群的个体数量恢复较快。     

Artificial light as a disturbance to light‐naïve streams

相似文献