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Drought is expected to increase in temperate regions in the coming decades due to global climate change and will strongly affect nitrogen (N) transformation and balance. However, the underlying mechanisms (soil microenvironment vs. biotic community) of rainfall reduction induced changes in soil N transformation rates, and whether the responses of soil N transformation rates to rainfall reduction vary over time remains poorly understood. In this study, we experimentally examined rainfall reduction effects on soil N transformation rates over two (the second and third experimental years) growing‐seasons in a temperate meadow. We applied four treatments: ambient rainfall, 30%, 50%, and 70% reduction in rainfall. Our findings demonstrated that, 70% rainfall reduction significantly decreased the average net N mineralization and nitrification rates by 68.4% and 72.0%, respectively. Soil nitrous oxide emission was profoundly varied between the experimental years, with it was sensitive no only to changes in annual precipitation amount, but also to seasonal distribution, the highest emissions appeared at the early growing‐season. Moreover, plant diversity, microbial biomass, and soil NO3−‐N content mainly regulated soil N transformation rates in response to rainfall reduction in the greater annual precipitation year; but soil N transformation rates were mainly controlled by soil water content in the less annual precipitation year. We suggest that to accurately project future ecosystem functions and improving the prediction of N cycling responses to changing precipitation patterns, stronger focus should be allocated not only to changes in precipitation amounts, but also to inter‐ and intra‐annual differences in precipitation distribution. Plain Language Summary: The variation in precipitation regimes may have profound impacts on soil N cycling. To understand how the soil N transformation rates respond to different rainfall levels, we used rainout shelters to simulate reduced precipitation amount in a temperate meadow. We examined a suite of soil N transformations responses. Our results showed that soil N transformation rates decreased along the gradient of declining in rainfall amount over the two sampling years, with inter‐ and intra‐annual variation in precipitation distribution also played important roles in determining soil N transformation rates. The high values of each soil N transformation rates were appeared at different periods of the growing‐seasons. We also examined the pathways associated with the responses of soil N transformation rates to rainfall reduction in the two contrasting precipitation years. In summary, we conclude that rainfall reduction led to reductions in soil N transformation rates through a combination of plant, microbial, and soil factors during the greater annual precipitation. Nonetheless, in the less annual precipitation, the key factor determining N transformations was found to be soil water content. These findings offer valuable insights for forecasting interactions within the plant‐microbe‐soil N cycling system under forthcoming precipitation patterns within the context of climate change. Key Points: The high soil N transformation rates corresponded to a certain precipitation range at regional scaleRainfall reduction decreased soil N transformation rates via changing plant, microbial, and soil factors in greater precipitation yearSoil water content was the key factor determining soil N transformation rates, especially in less precipitation year [ABSTRACT FROM AUTHOR]

In high-altitude deserts, the vegetation is spatially structured as a mosaic of patches with vegetation and interpatches of bare soil. Shrub patches create microhabitats that facilitate the persistence of other organisms by ameliorating climate extremes and increasing soil nutrients and moisture. Although this facilitative effect has been studied mainly on shrub understorey plants, the positive influence of desert shrubs may extend to the local arthropod community. In this study, we examined the hypothesis that plant facilitation by the desert shrub species Ephedra multiflora and E. breana positively influences the epigeal arthropod communities of the Andean Puna. We found that arthropod abundance, richness and diversity were all higher on Ephedra shrub microsites relative to paired open microsites. The harsh environmental conditions prevailing in the Puna ecosystems and the protection and resources provided by plants could jointly explain the positive influence of Ephedra shrubs over the arthropod community. The growth of tourism and the boom for lithium, as well as the increasing drought expected for the region under climate change scenarios, strengthens the importance of conserving shrub cover in these ecosystems to sustain biodiversity and ecosystem functioning. Our results are also relevant for restoration projects that consider the whole biological community, where using Ephedra as foundation shrubs to support desert endemics could be a strategy for land restoration. [ABSTRACT FROM AUTHOR]

Introduction: The fugal importance in terrestrial ecosystems is significant. However, our knowledge based on fungal distribution and its diversity in natural communities, especially in semi-arid ecosystems, seems to low. To have proper information on fungal community structure and the impact of environmental factors on the community composition, we assessed fungal diversity accompanied by soil chemical properties. Materials and Methods: Soil sampling was done in two seasons, spring and autumn, from two different sites, which were both cold and warm in a semiarid ecosystem located in Kerman province, Iran. Soil chemical properties were measured according to standard methods. The fungal community was estimated by the next-generation sequencing of the ITS region (ITS1f-ITS2). Results: By Illumina Miseq data analysis, 1542 Operational Taxonomic Units in soil samples were identified. Variation in the fungal community between the two sampling sites may be because of remarkable differences in environmental conditions, such as moisture and soil organic carbon. The dominant phylum was Ascomycota, followed by Basidiomycota. Discussion and Conclusion: Various fungi were identified in this ecosystem. Further studies are necessary to reveal the possible roles of the dominant fungal species inhabiting semiarid soils. [ABSTRACT FROM AUTHOR]

It is commonly accepted that CO2 efflux increases with soil water content in aerated soils and that rewetting after periods of soil drying can result in respiration pulses. It has further been shown that soil pores may become water logged which can impede soil gas exchange. The present study aimed to quantify the carbon response of moss (Polytrichum piliferum) and lichen (Cladonia coniocraea) biocoenoses to different quantities of rain in an artificial catchment, which granted that the starting point of the development of both biocoenoses was the same. To address this aim, we conducted in situ soil moisture and soil respiration measurements, where soil respiration was hypothesised to emerge from a cryptogamic vegetation layer and from mineral soil beneath. We found that higher water‐holding capacity of the moss layer and higher accumulation of organic matter in the upper mineral soil under mosses result in higher amounts of water stored near the surface. As a consequence, evaporation of water as well as pulses of CO2 efflux after moderate rain following a period of drought were higher in the moss biocoenosis, where the upper mineral soil was of key importance. In contrast, the lichen biocoenosis facilitated penetration of rainwater into the deep soil. Superimposing rewetting pulses, near‐saturation of soil pores with water after severe rain resulted in gas exchange inhibition and diminished soil respiration until subsequent aeration in both biocoenoses. [ABSTRACT FROM AUTHOR]

Soil biota, such as root‐associating fungal mutualists and pathogens, influence plant–plant interactions. Yet, the context‐dependency of their effects remains poorly understood, hindering our ability to predict plant invasions. We targeted Centaurea stoebe, an invasive plant which is more successful in arid than mesic North American grasslands. We asked how the abundances of the arbuscular mycorrhizal (AM) fungi and potentially pathogenic fungi are moderated by soil moisture and if shifts in these guilds correspond with C. stoebe growth and competitiveness.We grew C. stoebe plants in pots with every combination of three treatments: soil moisture (wet, dry), soil biota (sterile, live) and competition (none, native grass Bromus marginatus). We measured plant responses and root colonization by AM fungi, identified the relative sequence abundance of AM and potentially pathogenic fungi via guild matches of ITS2 sequences in the database FUNGuild, and examined shifts in AM and potentially pathogenic fungal communities based on the SSU rRNA gene and ITS2, respectively.Soil biota reduced C. stoebe growth in wet but not dry soils, and the presence of the native competitor Bromus marginatus exacerbated these effects. This shift in responsiveness corresponded with relatively fewer AM and more potentially pathogenic fungi in C. stoebe roots grown in wet soils, and vice versa in dry soils. Furthermore, in dry soils, C. stoebe's AM fungal community was strongly dominated by Glomus spp. Conversely, B. marginatus response to soil biota was not affected by soil moisture, and shifts in relative abundance of potentially pathogenic and AM fungi were generally opposite to those observed in C. stoebe.These results suggest that soil biota effects on host plants are species‐specific and depend on soil moisture. Furthermore, native plants can promote pathogens in distantly related invasive neighbours, potentially generating biotic resistance. Thus, plant invasions may be mediated by interactions between soil biota, soil moisture, and identity of native competitor.Predicting invasions as the climate continues to change will require surveys and experiments across relevant landscape‐level gradients of invasion and environmental factors. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Biodiversity is essential for the provision of multiple ecosystem functions simultaneously (ecosystem multifunctionality EMF). Yet, it remains unclear whether and how dominant plant species impact EMF. Here, we aimed at disentangling the direct from indirect above- and belowground pathways by which dominant plant species influence EMF. We evaluated the effects of two dominant plant species (Dasiphora fruticosa, and the toxic perennial plant Ligularia virgaurea) with expected positive and negative impacts on the abiotic environment (soil water content and pH), surrounding biological communities (plant and nematode richness, biomass, and abundance in the vicinity), and on the EMF of alpine meadows, respectively. We found that the two dominant plants enhanced EMF, with a positive effect of L. virgaurea on EMF greater than that of D. fruticosa. We also observed that dominant plants impacted on EMF through changes in soil water content and pH (indirect abiotic effects), but not through changes in biodiversity of surrounding plants and nematodes (indirect biotic pathway). Our study suggests that dominant plants may play an important role in promoting EMF, thus expanding the pervasive mass-ratio hypothesis originally framed for individual functions, and could mitigate the negative impacts of vegetation changes on EMF in the alpine meadows. [ABSTRACT FROM AUTHOR]

Background and aims: A major goal of community ecology focuses on trying to understand how environmental filter on plant functional traits drive plant community assembly. However, slopes positions- mediated soil environmental factors on community-weighted mean (CWM) plant traits in shrub community has not been extensively explored to analyze and distinguish assembly processes. Methods: Here, we surveyed woody shrub plant communities from three slope positions (foot, middle, and upper) in a low hilly area of Guilin, China to assess differences in functional trait CWMs and environmental factors across these positions. We also measured the CWMs of four plant functional traits including specific leaf area, leaf dry matter content, leaf chlorophyll content, and leaf thickness and nine abiotic environmental factors, including soil water content, soil organic content, soil pH, soil total nitrogen, soil total phosphorus, soil total potassium, soil available nitrogen, soil available phosphorus, and soil available potassium. We used ANOVA and Tukey HSD multiple comparisons to assess differences in functional trait CWMs and environmental factors across the three slope positions. We used redundancy analysis (RDA) to compare the relationships between CWMs trait and environmental factors along three slope positions, and also quantified slope position-mediated soil environmental filtering on these traits with a three-step trait-based null model approach. Results: The CWMs of three leaf functional traits and all soil environmental factors except soil pH showed significant differences across the three slope positions. Soil total nitrogen, available nitrogen, available potassium, and soil organic matter were positively correlated with the CWM specific leaf area and leaf chlorophyll content along the first RDA axis and soil total potassium, total phosphorous, and soil water content were positively correlated with the CWM leaf dry matter content along the second RDA axis. Environmental filtering was detected for the CWM specific leaf area, leaf dry matter content, and leaf chlorophyll content but not leaf thickness at all three slope positions. Conclusions: Ultimately, we found that soil environmental factors vary along slope positions and can cause variability in plant functional traits in shrub communities. Deciduous shrub species with high specific leaf area, low leaf dry matter content, and moderate leaf chlorophyll content dominated at the middle slope position, whereas evergreen species with low specific leaf area and high leaf dry matter content dominated in slope positions with infertile soils, steeper slopes, and more extreme soil water contents. Altogether, our null model approach allowed us to detect patterns of environmental filtering, which differed between traits and can be applied in the future to understand community assembly changes in Chinese hilly forest ecosystems. [ABSTRACT FROM AUTHOR]

Ecological restoration is one of the most promising strategies to combat historical wetland losses caused by land use changes. Restored areas are ideal sites to study plant succession and changes in ecosystem functions over time. However, little is known about the influence of restoration on plant succession along environmental stress gradients. Knowing the processes and mechanisms driving the succession over time in contrasting abiotic conditions might provide new insight into the ultimate success of an ecological restoration.Relying on long‐term vegetation monitoring, we studied the community succession of 4 plant communities along a restored waterlogging gradient in North‐East Italy (from high to low soil saturation level): (i) Cladium fens, (ii) low alkaline fens, (iii) Molina wet meadows and (iv) dry meadows. We monitored 23 permanent plots distributed along the gradient, spanning from 1 to 21 years since restoration, and 4 plots as target vegetation (natural habitats). We analysed the changes in plant communities in terms of functional traits, diversity and species composition.We found that exotic and annual species decreased in mature stages of restoration while leaf dry matter content increased over time. Nutrient indicator value and leaf area showed opposite trends at the extreme points of the gradient. Across the successional stages, species richness decreased in Cladium fens and increased in alkaline fens and meadows. Species composition moved toward target vegetation showing contrasting dynamics between different restored habitats.Synthesis and applications. During succession waterlogging stress acts as main abiotic filter, triggering contrasting trajectories of plant communities. This filter seems to be stronger at the extreme points of the gradient generating opposite but faster dynamics than at intermediate conditions. Time and waterlogging promoted a continuous selection of species consistent to target vegetation in terms of richness, functional traits and composition. The evidenced trajectories suggest the need to develop habitat‐specific protocols concerning the selection of restoration site and subsequent management decisions, with particular regard to plant communities at intermediate ecological conditions. [ABSTRACT FROM AUTHOR]

Quantification of soil biological status, through investigation of edaphic communities' composition, constitutes an important factor for the assessment of the grassland ecosystems, including their protection. The structure of soil invertebrate communities was investigated for five grasslands under different chemical and organic treatments, for the first time in Romania. In order to accomplish this task, some structural parameters were quantified: numerical abundance, taxa richness, Shannon diversity index of taxa and equitability. We demonstrated the relationship between five environmental factors (vegetation coverage, soil temperature, soil acidity, soil resistance at penetration, soil moisture content) and the community structures of soil fauna. In total, 17 invertebrate groups were identified with a total numerical abundance of 14,953 individuals. Considering the numerical abundance, the dominant taxa were Acaridae, Collembola, Oribatida and Mesostigmata, the least dominant being Coleoptera, Opiliones and Araneae. In spatial dynamics the investigated plots were characterised specifically by soil invertebrates' communities' structures, highlighted by the varied values of structural parameters: by indicator taxa and by the characteristic average values of environmental parameters. Multivariate statistical analysis revealed that the most important environment parameters influencing the soil taxa were vegetation coverage (especially on Acaridae, Glycyphagidae and Formicoidea) and soil resistance at penetration (Nematoda and Coleoptera). This study constitutes a scientific argument for the usage of soil invertebrate communities as indicators of the ecological conservation status of some fertilised grasslands. [ABSTRACT FROM AUTHOR]

Continuity and discontinuity are fundamental concepts of ecosystem science. In reality, both continuities and discontinuities can exist; lentic and lotic systems can expand and contract as can soil/rock moisture and groundwater systems. Surface water, soil moisture, rock moisture, and groundwater, represent hydrological domains that are interconnected. Under a state of expansion each domain may be characterized by spatial continuity; for instance, a river may be entirely flow connected. However, under a state of contraction, discontinuities may appear, and the river may become fragmented. The rate of expansion and contraction in each domain, that is land‐, lentic‐, and lotic‐scapes, is a function of topography, geology, climate, and biota. In an effort to reconcile older, and sometimes incongruous, concepts of continuity and discontinuity we present a view of water‐connected ecosystems, such as riverscapes and catchments that are nested upon and within the uppermost layer of Earth. This layer is the key interface between the lithosphere, atmosphere, hydrosphere, and biosphere, and is known as the critical zone (CZ). We present the waterscape continuum and define it as the spatially and temporally dynamic water upon and within the CZ. To guide ecosystem research (across the land‐, lentic‐, and lotic‐scapes), we introduce the waterscape continuum template (WCT). We propose the waterscape continuum and the WCT can enhance our understanding of ecosystem processes and mechanisms. This article is categorized under: Science of Water > Hydrological ProcessesWater and Life > Nature of Freshwater Ecosystems [ABSTRACT FROM AUTHOR]

The underground community of soil organisms, known as soil biota, plays a critical role in terrestrial ecosystems. Different ecosystems exhibit varied responses of soil organisms to soil physical and chemical properties (SPCPs). However, our understanding of how soil biota react to different soil depths in naturally established population of salinity tolerant Tamarix ramosissima in desert ecosystems, remains limited. To address this, we employed High-Throughput Illumina HiSeq Sequencing to examine the population dynamics of soil bacteria, fungi, archaea, protists, and metazoa at six different soil depths (0–100 cm) in the naturally occurring T. ramosissima dominant zone within the Taklimakan desert of China. Our observations reveal that the alpha diversity of bacteria, fungi, metazoa, and protists displayed a linear decrease with the increase of soil depth, whereas archaea exhibited an inverse pattern. The beta diversity of soil biota, particularly metazoa, bacteria, and protists, demonstrated noteworthy associations with soil depths through Non-Metric Dimensional Scaling analysis. Among the most abundant classes of soil organisms, we observed Actinobacteria, Sordariomycetes, Halobacteria, Spirotrichea, and Nematoda for bacteria, fungi, archaea, protists, and metazoa, respectively. Additionally, we identified associations between the vertical distribution of dominant biotic communities and SPCPs. Bacterial changes were mainly influenced by total potassium, available phosphorus (AP), and soil water content (SWC), while fungi were impacted by nitrate (NO 3 -) and available potassium (AK). Archaea showed correlations with total carbon (TC) and AK thus suggesting their role in methanogenesis and methane oxidation, protists with AP and SWC, and metazoa with AP and pH. These correlations underscore potential connections to nutrient cycling and the production and consumption of greenhouse gases (GhGs). This insight establishes a solid foundation for devising strategies to mitigate nutrient cycling and GHG emissions in desert soils, thereby playing a pivotal role in the advancement of comprehensive approaches to sustainable desert ecosystem management. • Soil nutrients and diversity of soil biota across different soil depths in Tamarix ramosissima was investigated. • Declining pattern in the alpha diversity of soil biota was recorded with an increase in soil depth except archaea. • The most prevalent classes were Actinobacteria, Sordariomycetes, Halobacteria, Spirotrichea, and Nematoda. • AP and SWC influenced bacteria and protists, while AK affected fungi and archaea and metazoa by AP and pH. • Our findings provide a new perspective on the vertical distribution of soil biota in T. ramosissima in desert ecosystem. [ABSTRACT FROM AUTHOR]

Soil biodiversity constitutes the biological pillars of ecosystem services provided by soils worldwide. Soil life is threatened by intense agricultural management and shifts in climatic conditions as two important global change drivers which are not often jointly studied under field conditions. We addressed the effects of experimental short-term drought over the wheat growing season on soil organisms and ecosystem functions under organic and conventional farming in a Swiss long term trial. Our results suggest that activity and community metrics are suitable indicators for drought stress while microbial communities primarily responded to agricultural practices. Importantly, we found a significant loss of multiple pairwise positive and negative relationships between soil biota and process-related variables in response to conventional farming, but not in response to experimental drought. These results suggest a considerable weakening of the contribution of soil biota to ecosystem functions under long-term conventional agriculture. Independent of the farming system, experimental and seasonal (ambient) drought conditions directly affected soil biota and activity. A higher soil water content during early and intermediate stages of the growing season and a high number of significant relationships between soil biota to ecosystem functions suggest that organic farming provides a buffer against drought effects. [ABSTRACT FROM AUTHOR]

Soil salinity is a serious environmental issue in arid China. Halophytes show extreme salt tolerance and are grow in saline-alkaline environments. There rhizosphere have complex bacterial communities, which mediate a variety of interactions between plants and soil. High-throughput sequencing was used to investigated rhizosphere bacterial community changes under the typical halophyte species in arid China. Three typical halophytes were Leymus chinensis (LC), Puccinellia tenuiflora (PT), Suaeda glauca (SG). The dominant phyla were Proteobacteria, Actinobacteria, Chloroflexi, Gemmatimonadetes, Acidobacteria and Bacteroidetes, Suaeda glauca rhizosphere has stronger enrichment of Nitrospirae and Cyanobacteria. The Ace, Chao and Shannon indices were significantly higher in soils under LC and SG (P<0.05). Functional predictions, based on 16S rRNA gene by PICRUSt, indicated that Energy metabolism, Amino acid metabolism, Carbohydrate metabolism and Fatty acid metabolism are dominant bacterial functions in three halophytes rhizosphere soil. Carbon metabolism, Oxidative phosphorylation, Methane metabolism, Sulfur metabolism and Nitrogen metabolism in SG were significantly higher than that in LC and PT. Regression analysis revealed that rhizosphere soil bacterial community structure is influenced by soil organic matter (SOM) and soil water content (SWC), while soil bacterial community diversity is affected by soil pH. This study contributes to our understanding of the distribution characteristics and metabolic functions under different halophyte rhizosphere bacterial communities, and will provide references for the use of rhizosphere bacteria to regulate the growth of halophytes and ecological restoration of saline soil. [ABSTRACT FROM AUTHOR]

• Investigated community composition of soil bacteria, fungi, archaea, protists & metazoa across diverse soil profiles. • Observed declining alpha diversity of bacteria, archaea, and protists with soil depth, contrasting with fungi and metazoa. • Identified prominent classes like Actinobacteria, Sordariomycetes, Nitrososphaeria, Spirotrichea, and Nematoda. • Bacterial changes linked to TK, fungal dynamics to TN. Archaea influenced by AK, protists by NO 3 and metazoa by SWC. • Article offers new insights into soil biota's vertical distribution and response in K. caspia within desert ecosystem. Soil organisms play a pivotal role in terrestrial ecosystems, sparking growing curiosity about the comprehensive diversity of subterranean biota across large ecological levels. Soil inhabitants' exhibit varied responses to soil physicochemical properties (SPPs) across desert ecosystem. Yet, the knowledge of their population dynamics across different soil depths (SDs) in the indigenous natural dominant zone of Karelinia caspia , a primary desert shrub in China, remains limited. This study employed advanced illumina sequencing to assess soil bacteria, fungi, archaea, protist, and metazoa populations across six distinct SDs (0 to 100 cm) within the K. caspia desert landscape. Our findings indicate a descending alpha diversity pattern in bacteria, archaea, and protists as soil depth increases, contrary to fungi and metazoa, which exhibit the opposite trend. SDs significantly shape soil biota beta diversity, notably impacting bacteria, protists, and fungi, as revealed by Non-Metric Dimensional Scaling. Prominent classes include Actinobacteria, Sordariomycetes, Nitrososphaeria, Spirotrichea, and Nematoda for soil bacteria, fungi, archaea, protists, and metazoa, respectively. Correlation analysis between predominant biotic communities' vertical distribution and SPPs variations revealed total potassium (TK) and pH's pronounced influence on bacteria, while fungi were affected by total nitrogen (TN) and soil water content (SWC). Archaea exhibit sensitivity to SWC, available potassium (AK), and available phosphorus (AP); protists respond to C/N-Ratio, nitrate (NO 3), and total phosphorus (TP); metazoa correlate with SWC, pH, and NO 3. Overall, these findings offer valuable insights regarding population fluctuations of soil biota within naturally established K. caspia across vertical soil strata within China's desert ecosystem. [ABSTRACT FROM AUTHOR]

[Display omitted] • Flow regulation can durably alter the natural trajectories of riparian communities. • Using vegetation resurvey, changes in plant preferences and strategies were tested. • In 40 years, abiotic conditions have become less hygrophilic and more sciaphilic. • In response, communities have become more competitive and less stress-tolerant. • Anthropogenic changes have favored more stable environments and more mature stages. Vegetation resurvey has proven effective in understanding long-term trajectories of plant communities. Combined with information related to ecological preferences and ecological strategies of plants, this framework can provide insight into the dynamics of communities and associated ecological processes over several decades. By comparing old and recent vegetation surveys, we sought to understand how past changes in flow and sediment regimes along a 100-km reach of the Rhône river still influence the structure of riparian plant communities. Specifically, we studied variations in the mean and dispersion values of light, nutrient availability and soil moisture, as well as of competitors, stress tolerators and ruderals, at the community scale over four decades and along connectivity and productivity gradients. Results showed that communities were composed of more hygrophilous and heliophilous species in old surveys and that this decrease in soil moisture and light over time was broadly consistent along environmental gradients. In response to these environmental changes, the ecological strategies of riparian vegetation have evolved into more competitive and less stress-tolerant communities. This was illustrated by the decline of the pioneer species Salix alba , but the increase in several post-pioneer woody species. Given that these changes were observed on almost all the plots studied, irrespective of their position along the connectivity and productivity gradients, our results reflect to some extent an overall evolution of the system towards more mature and closed successional stages. Thus, over a period of 40-years, and probably due to the legacy effects of anthropogenic modifications to flow and sediment regimes that have favored more stable riparian environments, a directional shift of riparian communities towards more advanced successional stages was highlighted. In a context where past and present anthropogenic stressors are accumulating, we infer that these changes in riparian ecosystem properties are probably irreversible and represent a major challenge for restoration. [ABSTRACT FROM AUTHOR]

• Habitat filtering is the dominant mechanism for building plant communities in the Gurbantunggut Desert. • Plant communities of different life types in the same habitat have different construction mechanisms. • The mechanism of community construction on different slopes is mainly influenced by short-lived plants. • Soil factors indirectly influence community phylogenetic diversity by affecting species richness. Analysis of the phylogenetic structure of a community based on the phylogenetic relationships among species in the community can reflect the ecological process of community composition and determine the mechanism of plant community construction. In this study, we analyzed the characteristics of the phylogenetic structure and diversity of plant communities in the Gurbantunggut Desert and their interactions with soil factors and explored the mechanisms of species maintenance in the communities. The results showed that the ecological traits of plants were conserved, habitat filtering was the primary process affecting plant communities, and the diversity of phylogeny was ranked as fixed dunes > semifixed dunes > mobile dunes. At different slope positions within the dune, there is greater phylogenetic diversity at the bottom and lower slope, and habitat filtering dominates community construction, with the dominant role of habitat filtering in the community diminishing as the slope position rises. The phylogenetic diversity of plant communities of different life types is ranked as short-lived plants > small trees and shrubs > annual and perennial herbs. On the bottom and lower slopes, short-lived plants and annual and perennial herbaceous communities are mainly influenced by habitat filtering. Habitat filterability decreased with increasing slope position. On the upper slopes and at the top, competitive exclusion effects between small trees and shrubs dominated. Our analysis shows that soil water content and organic carbon affect phylogenetic diversity mainly by influencing community species richness and that the interaction between soil water content, grain size and plant diversity leads to clustering of species with similar soil preferences, which in turn affects the phylogenetic structure of the community. In addition, the change from habitat filtering to intraspecific competition in plant community construction from the bottom to the top of the slope is mainly influenced by short-lived plant communities, and this type of plant needs to be given priority consideration in the conservation and restoration of desert plant communities. [ABSTRACT FROM AUTHOR]

Climate change is increasingly affecting biotic communities, including soil fauna. Extreme weather events such as the incidence of heavy rainfall or prolonged drought can cause strong fluctuations in soil moisture. In river floodplains such extreme events determine the flooding intensity of the river bank grassland soils, and their communities. The diversity and distribution of many soil fauna groups depends on soil moisture content, so changes in inundation frequency and duration will impact soil fauna communities. We used the natural fluctuations in water levels of large Dutch rivers to investigate the effect of flooding intensity on the composition and traits of Collembola species, a key group of the soil fauna community. At five locations along large rivers in The Netherlands, we sampled Collembola communities at six levels of decreasing elevation and increasing flooding intensity. We identified all Collembola to species level and calculated species richness, composition and abundance values. Moreover, to understand the observed taxonomic changes across elevation we used the traits body size and life form to explain the change in Collembola community composition. Our results show that high flooding intensity favors larger Collembola species in the community. We hypothesize that high soil moisture in frequently flooded soil favors larger Collembola, which tolerate flooding. Life form, i.e. the preferred depth in the soil column, was significantly correlated with flooding intensity. There is an optimum in species richness and abundance at intermediate flooding intensity. These results can help predict the impact of climate change on soil fauna. • Frequently flooded floodplain soil contains larger Collembola (springtail) species. • Flooding does not favor deep-living or surface-dwelling ecological groups. • Species richness has an optimum at intermediate flood frequency. [ABSTRACT FROM AUTHOR]

• The diversity effects were reduced under harsh resource related conditions. • The diversity effects were greater under harsh non-resource related conditions. • Pattern of context-dependence effects of diversity depends on types of stressors. • Management reduces the negative effect of soil water deficit on diversity effects. Mixed-species forests are known to provide enhanced ecosystem functioning when compared with monocultures. The strength of the positive diversity effect is, however, largely dependent on environmental conditions and the human footprint. The specific patterns of context-dependence effects of diversity on productivity and their causal relationships are not well known, especially regarding large-scale natural plant communities. Accordingly, the focus of this study is to evaluate effects of environmental variables on biodiversity-productivity relationships (BPR) in the temperate forest region of North-Eastern China. We used a structural equation modeling and hierarchical Bayesian model to assess individual and interactive effects of human disturbance, environmental factors, and species diversity on productivity. The SEMs showed that the negative interaction effect of human disturbance and mean annual temperature on species diversity was greater than that of human disturbance on species diversity. The positive diversity effects on forest production were severely reduced under stressful soil water conditions due to increased competition for soil water resources. The positive diversity effects were greater under harsh annual mean temperature conditions. The biodiversity effects on productivity were influenced by negative interactive effect of the human footprint and soil water availability. Our results suggest that current management strategies for diversity conservation may be countered by robust negative interactive effects and thus, may be inefficient in temperate forest regions. The variations in the strength of the relationships between tree species diversity and forest productivity are critically dependent on several environmental stressors. Our results highlight the important role of human disturbance in mediating the response of BPR to soil water deficit, and the crucial role of management strategy to prepare for future climatic challenges in our temperate forest region. [ABSTRACT FROM AUTHOR]

Habitat heterogeneity is expected to change community composition and diversity, with large implications for ecosystem processes and function. Understanding the potential mechanisms of habitat heterogeneity affecting community ecological processes is a central issue in biodiversity conservation. In this study, we use a spatial metrics analysis to quantify the spatial pattern of plateau zokor mounds. We integrated soil physicochemical variables and community characteristic data to understand the disturbance effect of plateau zokor mounds on community diversity at a microhabitat scale (400 m2). Results showed that plant species richness increased significantly with increasing disturbance levels. Increases in forb species were largely the reason for the increased plant diversity in the alpine meadow disturbed by plateau zokor mounds. Disturbance caused by the plateau zokor significantly increased the soil macroinvertebrate richness and abundance, with herbivorous taxa playing a key role. Mantel tests and redundancy analysis showed that the composition of plant and soil macroinvertebrate communities are significantly related to soil moisture and soil temperature, and the SEM model revealing soil moisture and soil temperature positive effects on plant and macroinvertebrate richness after plateau zokor disturbance. Furthermore, soil variables (moisture, temperature, and organic carbon) directly affected plant richness, and indirectly affected soil macroinvertebrate communities. Our results suggest that the spatial pattern of plateau zokor mounds facilitate greater biodiversity through increased habitat complexity and heterogeneity. Therefore, it can be regarded as a "key species" in the alpine grassland and researchers should pay more attention to the ecological effects of alpine rodent disturbance on grassland ecosystems. • Spatial metrics analysis can quantify environmental heterogeneity at microhabitat • The spatial pattern of mounds had the biggest effect on herbivorous invertebrate • The soil invertebrate are affected by soil physical properties and plant richness [ABSTRACT FROM AUTHOR]

• Soil nematode richness is relatively low on inshore islands. • Large island maintains high soil nematode abundance and diversity. • Edaphic and climatic-geographical factors drive variations in soil nematode compositions. Factors that influence the composition and diversity of soil nematode communities on oceanic islands are poorly understood. In this study, we evaluated the soil nematode communities and associated biotic and abiotic factors on five oceanic islands in the north of the South China Sea. We detected 38 nematode genera and found that bacterivores and fungivores were the dominant trophic groups, representing 54.2–70.4% and 15.1–35.3%, respectively, of total soil nematode abundance. The abundances of total soil nematodes and of all trophic groups, maturity, structure indices and nematode diversity were positively correlated with island latitude and area, and were negatively correlated with soil total K and annual temperature. In addition, the abundances of total soil nematodes, bacterivores, herbivores and nematode dominance index were positively associated with soil available K. The abundances of total soil nematodes, fungivores, herbivores, predators and omnivores, maturity, structure, Shannon diversity indices were positively related to soil moisture. Variation partitioning analysis showed that the combination of soil properties and climatic-geographical factors explained more of the variation (26.8–61.5%). The results suggest that larger island can maintain greater nematode diversity than smaller islands due to the greater diversity of habitats on larger island. The key climatic-geographical and edaphic factors affecting soil nematode communities were latitude, annual temperature, soil moisture and total K, respectively [ABSTRACT FROM AUTHOR]

• Sex significantly affects water content, NO 3 −, total N and total P of rhizosphere. • Bacteria in bulk and rhizosphere are more strongly affected by sex than fungi. • Higher soil moisture in female rhizosphere promotes N-cycling related bacteria. • More Actinobacteria in rhizosphere contribute to higher N use efficiency of male. Plant-soil microbe interactions are determined by plant characters. Sexual dimorphism in root development, nitrogen (N) assimilation and resource allocation have been studied in different environments. However, how dioecious plants affect soil microbial communities in natural forests, particularly in low precipitation regions, is still poorly known. In this study, natural Populus euphratica forests were investigated in three arid regions. We hypothesized that males and females impose sex-specific impacts on physiochemical traits of soil, microbial communities and N-cycling processes. We discovered only little sex effect on most physiochemical traits, and bacterial and fungal communities in top soil (0–20 cm) in the three studied forests. However, the sex effect was greater in deep soil. Compared with fungi, the structure and composition of bacterial communities were affected more by plant sex in the rhizosphere and bulk soil. Sex indirectly affected N-cycling processes through a negative impact on the soil water content. Expressions of AOA, AOB, nifH , nirS and nirK in the rhizosphere soil were significantly affected by sex, forest site and their interactions. Proteobacteri a, Actinobacteria and Firmicutes in the rhizosphere and bulk soils of P. euphratica males showed more significant effects on ammoxidation, N fixation, denitrification and protease activities when compared to females. The results suggest that sexual differences in shaping bacterial communities and affecting N-cycling processes are greater when the soil becomes drier. Thus, low precipitation causes intense sex differences in the nitrogen uptake and use efficiency. Our study highlights the importance of sexual effects on shaping specific microbial communities and N-cycling processes. [ABSTRACT FROM AUTHOR]