Stairstep cut-slopes, an important slope-protection measure in gully land consolidation projects on the Loess Plateau, facilitate the colonization of well-developed biological soil crusts (BSCs) on their platforms, which helps mitigate slumping risks induced by concentrated upslope flow during rainfall events. However, how the inhibitory effect of BSCs on soil detachment responds to intense overland flow remains unclear, and shifts in BSC community composition may further complicate this response. To elucidate this mechanism, five representative BSC community compositions with near-complete coverage (0–20%, 20–40%, 40–60%, 60–80%, and 80–100% moss coverage, with complementary cyanobacteria cover) and a bare soil control with BSCs removed were collected from typical stairstep cut-slope platforms on the Loess Plateau and subjected to a scouring experiment under six shear stress levels (4.79–21.52 Pa). The results indicated that compared with bare soil, BSCs reduced mean soil detachment capacity (Dc) by 82.87–99.98%. This inhibitory effect leveled off when moss coverage reached about 40%. At the highest moss coverage (80–100%), mean Dc and rill erodibility (Kr) were only 0.96% and 0.12% of those at the lowest coverage (0–20%), while critical shear stress (τc) increased by 22.38%. Dc was more appropriately simulated as a power function of flow shear stress than of stream power. Correlation analyses and partial least squares-structural equation modeling showed that BSCs exerting a dominant and direct reducing effect on Dc and Kr. Moreover, BSCs indirectly raised τc by reducing the erosion susceptibility of the underlying soil, markedly weakening the strong response relationship between soil detachment and intense overland flow. A predictive model of Dc based on flow shear stress, BSC cohesion and soil erodibility performed satisfactory (Nash–Sutcliffe efficiency =0.96). This study provides a scientific basis for ecological protection design of slope-engineering projects and accurate prediction of larger-scale erosion model on the Loess Plateau.

Global aridification threatens dryland ecosystems biodiversity and stability, yet the influence of multidimensional biodiversity on stability across aridity gradients is complex and context-dependent. Here we analyze plant and soil microbial diversity (taxonomic, phylogenetic, functional) across a 3,000-kilometer aridity gradient on the Mongolian Plateau and use multi-year observations from two validation sites. We identify a critical aridity threshold (Aridity ≈ 0.83) where stability mechanisms abruptly shift. Below this threshold (less arid conditions), ecosystem stability is positively linked to plant and fungal taxonomic richness. Above it (more arid conditions), stability correlates with conservative plant traits (lower special leaf area) and lower phylogenetic diversity, reflecting environmental filtering for stress-tolerant species. This transition is driven by a shift from C3 to C4 plant dominance, altering community traits and plant-microbial interactions. While our correlational findings require experimental confirmation, they challenge linear stability models, highlighting the importance of threshold-dependent biodiversity-environment interactions for dryland management. Ecosystem stability shifts at an aridity threshold where in less arid conditions it is linked to plant and fungal richness and in more arid conditions it depends on conservative plant traits and lower phylogenetic diversity, based on sampling across a 3000-km Mongolian Plateau gradient.

Livestock grazing affects ecosystems through vegetation consumption, trampling and dung deposition. However, while numerous studies have examined the combined effects of grazing on plant and soil biota community attributes (CAs) as well as ecosystem multifunctionality and their stability, the independent role of dung deposition has remained unclear. This knowledge gap limits our ability to predict how individual components of grazing shape ecosystem multifunctional stability. By conducting a long-term sheep dung deposition experiment with 9 gradients in Mongolian grasslands, while sheep dung deposition altered plant and soil biota groups, its effect on the CAs and stability of plants (indicated by all 3 CAs and 2 stability of CAs) was significantly greater than that on microorganisms (indicated by only 1 CA and 1 stability of CA) and nematodes (indicated by only 1 CA) along the deposition gradient. Furthermore, both ecosystem multifunctionality (from 0.329 to 0.529, r = 0.771, p < 0.001) and its temporal stability (from 4.018 to 6.965, r = 0.430, p < 0.01) increased with the gradient of increasing sheep dung deposition. More importantly, our piecewise structural equation modeling and linear regression showed that the stability of plant and soil microbial CAs was the primary driver of ecosystem multifunctional stability, with this effect largely attributable to the stability of plant (r = 0.321, p < 0.05) and soil microbial community composition (r = 0.423, p < 0.01) rather than the stability of their diversity (p > 0.05). Our findings reveal that compositional stability represents a critical yet underappreciated dimension of ecosystem stability, which suggests that nutrient input from dung deposition serves as a key stabilizing mechanism in grazing systems. This new perspective emphasizes the importance of maintaining stable community composition to sustain the ecosystem multifunctional stability under anthropogenic nutrient enrichment, with important implications for grassland management and conservation.

Forest-water relationships are increasingly strained by global change, and both planted and natural forests face growing risks of water stress. Thinning has been widely adopted as an important management practice to regulate forest ecohydrological processes. However, whether thinning can effectively alleviate soil water stress across different forest origins remains unclear. Here, we conducted a meta-analysis to quantify the effects of thinning on soil moisture in planted and natural forests. The results show that thinning significantly increased soil moisture by 7.83% overall, and the effect size in natural forests was 1.32 times that in planted forests. Soil-moisture responses to thinning were jointly controlled by multiple factors, including thinning regimes, soil properties, stand structural attributes, and climate. Moderate thinning in planted forests and light thinning in natural forests significantly increased soil moisture and maintained this positive effect over a relatively long period. Thinning enhanced soil moisture in loamy soils across both planted and natural forests, but had no significant positive effect on forest landscapes in sandy soils. The effects of thinning on soil moisture were also stand-age dependent; specifically, soil moisture responses in planted forests transitioned from positive in younger stands to negative in older stands. Relative to natural forests, the effect sizes in planted forests showed stronger sensitivity to climatic gradients (MAT, MAP, and AI). This study highlights differential soil moisture responses to thinning between planted and natural forests, underscoring the need to adopt site-specific approaches to achieve healthy forest-water relationships.

soil detachment is a key variable of soil erosion model, it is strongly influenced on soil physicochemical properties and root characteristics driven by land-use. Therefore, identify the factors that influence soil detachment under different land-use type, and establish a predictive equation is highly important. Four representative land-use types (cropland, grassland, shrubland, woodland), including eight species on the Loess Plateau, were selected, and flume scouring tests were conducted under six shear stresses (4.54–16.06 Pa) to determine soil detachment. The results showed that soil detachment capacity of different species were 0.14–2.78 kg m−2 s−1, among which, Setaria italica var. germanica (Mill.) Schred (SU) and Pinus tabuliformis Carrie (YS) reported greatest and smallest values, respectively. Across various land-use types, cropland exhibited largest soil detachment capacity, increasing by 8.25, 2.03, and 3.22 folds compared with grassland, shrubland, and woodland, respectively. The transformation of land-use types inevitably induces alterations in soil properties and root characteristics, thereby exerting an influence on soil detachment processes. Soil detachment capacity decreased with an increase in soil bulk density, total porosity, water stable aggregate, root length density, and specific root length as power functions. Hydraulic parameters act as driving forces for soil detachment capacity, which increases with overland flow velocity, stream power, shear stress, and unit stream power as power functions. Finally, when soil properties, root characteristics and hydraulic are all considered, soil detachment capacity can be simulated by overland flow velocity (V), water stable aggregate (WSA), and specific root length (SRL) using power functions, with satisfactory model performance (R2 is 0.88, NSE is 0.76). These findings provide a scientific basis for targeted soil erosion control and rational land-use management on the Loess Plateau, offering actionable guidance for prioritizing vegetation restoration and optimizing land-use types in this region.

Abstract The number of co‐occurring global change factors (GCFs) is increasing, yet their combined effects on grassland functioning via plant–soil biotic interactions remain poorly understood, especially under contrasting precipitation contexts. Using a long‐term multifactor experiment in the semi‐arid steppe of Inner Mongolia, we established a gradient in GCF number (0–3) through nitrogen addition, phosphorus addition and soil acidification. By integrating plant diversity with the taxonomic, functional and metabolic dimensions of nematode communities, we evaluated their effects on above‐ground net primary productivity (ANPP) and below‐ground ecosystem multifunctionality (BEMF) and tested whether these relationships were reorganized under contrasting precipitation years. Increasing GCF number consistently reduced plant and nematode diversity, simplified nematode food‐web structure and suppressed nematode metabolic activity. ANPP increased with GCF number only in the wet year, whereas BEMF declined in both years. ANPP was primarily and positively associated with nematode metabolic footprints, whereas BEMF was jointly regulated by plant diversity and nematode metabolic footprints. Importantly, these pathways shifted with precipitation context. In the normal year, plant diversity and nematode metabolic footprints jointly sustained both ANPP and BEMF. In the wet year, a functional divergence emerged: above‐ground processes benefited from nutrient inputs, increasing ANPP, whereas below‐ground processes experienced cumulative stress from multiple GCFs, suppressing nematode metabolic footprints and reducing BEMF. Synthesis and applications . Our findings demonstrate that the number of co‐occurring GCFs is a critical but underappreciated dimension of global change, and its ecological consequences depend strongly on precipitation context. Grassland management should consider cumulative nutrient and acidification pressures, maintain plant diversity and use nematode metabolic footprints as indicators of below‐ground functional change. Incorporating soil faunal functional traits into global change assessment frameworks is therefore essential for understanding and sustaining ecosystem multifunctionality under future environmental change.

Soil parasitic protists influence the health of plants and soil organisms. Yet, the extent to which these interactions impact the stability of terrestrial ecosystems remains largely unquantified. Here, we utilized two independent global-scale biodiversity surveys available online to investigate the relationship between the taxonomic diversity of parasitic protists and satellite-based time series of ecosystem productivity (i.e., normalized difference vegetation index). We found that soil parasitic protist diversity, particularly the diversity of Apicomplexa (common parasites of soil invertebrates), was consistently and positively correlated with ecosystem temporal stability worldwide. Our analyses suggest that Apicomplexa diversity is positively associated with temporal stability of ecosystem productivity by boosting mean productivity, likely through regulating invertebrate plant herbivory and nutrient cycling. Furthermore, the relationships between Apicomplexa diversity and ecosystem temporal stability were strongly mediated by climate, with a stronger correlation found in less productive colder or drier ecosystems. Our findings provide large-scale empirical evidence for the previously undescribed significant statistical relationship between soil parasitic protist diversity and ecosystem stability, highlighting their potential role in explaining the stability of terrestrial ecosystems globally.

The importance of plant root systems in reducing soil erosion is well established; however, existing evaluation approaches based on individual root traits often do not adequately represent the complexity of root-soil interactions. To develop a comprehensive parameter that reflects the effects of plant root systems on soil erosion processes, eight representative herbaceous species from different successional stages were selected from the Chinese Loess Plateau. Root morphology, biomass, mechanical strength, and architectural characteristics were considered, and these parameters were integrated to construct a comprehensive root system parameter using the Amoeba chart method. Relative soil detachment capacity was measured through overland flow scouring experiments under six shear stress levels. The results showed that the comprehensive root system parameter, derived from root surface area density, root mass density, root cohesion, and topology index, ranged from 0.28 to 1.72 among the eight species. The maximum value was observed in Bothriochloa ischaemum (Linn.) Keng, while the minimum values occurred in Artemisia capillaris Thunb. and Astragalus adsurgens Pall. With vegetation succession, the comprehensive root system parameter increased. The mean value for plants with fibrous root systems was 1.41 times that of plants with tap root systems. Relative soil detachment capacity varied significantly among the eight species, ranging from 0.012 to 0.107 kg m-2 s-1, and showed a decreasing trend with vegetation succession. Relative soil detachment capacity was 14% lower in herbaceous plants with fibrous root systems than in those with tap root systems, indicating their stronger ability to reduce soil detachment. The effects of plant root systems on soil erosion differed among species and root types, and these differences were effectively captured by the comprehensive root system parameter. Relative soil detachment capacity decreased exponentially with increasing values of the comprehensive root system parameter. This study demonstrates that integrating multiple root characteristics can improve the prediction of soil erosion for typical grassland species in the studied ecosystems. However, the applicability of the proposed parameter to other vegetation types and ecosystems remains to be tested and will require substantially more data across a wider range of species and environmental conditions.

The partitioning of biodiversity effects into selection and complementarity effects has substantially advanced our understanding of biodiversity–ecosystem functioning relationships. While this framework is well established for plant communities, its extension to soil biota remains underexplored, limiting our understanding of how plant diversity influences ecosystem multifunctionality via belowground pathways. Here, we integrate a three-year monoculture experiment with surveys of naturally assembled plant communities to evaluate how plant diversity shapes soil biotic attributes and ecosystem multifunctionality. Across bacteria, fungi, and nematodes, net diversity effects on soil biota were largely accounted for by complementarity effects, whereas selection effects were generally weak.Notably,selection effects of plant diversity on soil biotic diversity and biomass were associated with ecosystem multifunctionality in contrasting ways, while complementarity effects, particularly those observed for bacterial biomass, were positively related to multifunctionality. Our results indicate that plant diversity is consistently associated with higher ecosystem multifunctionality, a relationship that corresponds strongly with belowground complementarity effects expressed in soil biotic biomass, highlighting the importance of resource partitioning and facilitative interactions in soil communities. We also highlight that these inferences rely on integrating experimental monocultures with observational natural communities and thus represent strong statistical associations rather than direct experimental manipulations of soil biota.

Subsoils store the majority of terrestrial organic carbon, yet the stability of this vast reservoir under climate change remains a critical uncertainty. In this study, we investigated soil profiles across a continental-scale aridity gradient on the Mongolian Plateau to assess the vulnerability of deep soil carbon fractions. Our results reveal that subsoil mineral-associated organic carbon (MAOC), traditionally considered a stable sink, is surprisingly more sensitive to increasing aridity than the labile particulate organic carbon (POC) fraction. Structural equation modeling links this unexpected vulnerability to a fundamental vertical shift in carbon stabilization controls. Unlike topsoils, which are closely linked to abiotic variables, subsoil carbon stability is primarily correlated with microbial community attributes, specifically microbial biomass and fungal diversity. This suggests that subsoil carbon storage is a biotically mediated process highly responsive to environmental stress. We conclude that current conceptual models, which often assume the universal kinetic persistence of MAOC, may critically underestimate the potential for carbon loss from deep dryland soils, posing a risk of positive carbon-climate feedbacks as drylands expand globally.

Vegetation and its community structure are among the key factors influencing soil erosion. Near soil surface characteristics (including canopy cover, litter layer, biological soil crusts, and root systems) can influence soil erosion processes to varying degrees, thereby affecting the estimation of the cover and management factor (C). However, the C factor estimated from near soil surface characteristics remains unclear, largely because current studies have neglected the quantitative relationships and impacts of some near soil surface characteristics on soil erosion processes. Therefore, the Poaceae plant of Bothriochloa ischcemum (Linn.). Keng (BI) and the Asteraceae plant of Artemisia vestita Wall. ex Bess (AG) were planted under 5, 10, 15, 20, 25 and 30 plants m(-2) to investigate the effect of aboveground part, biological soil crusts (BSCs) and plant root system on soil erosion. In total, 24 steel tanks were planted, and two tanks were used as bare soil controls. The artificial simulated rainfalls (60 mm h(-1)) were conducted on a 15 degrees slope, and the sediment yield rate were measured. The results showed that planting density and herbaceous species composition exert significant controls on soil erosion processes by regulating near soil surface characteristics. The C factor decreased significantly with increasing planting density for both species, with maximum C values being 2.79 (BI) and 2.91 (AG) times than minimum values. Generally, the C factor of plant root system has bigger value, and it were 2.33 and 8.84 times aboveground part and BSCs for BI, and were 50.56 and 1.78 times aboveground part and BSCs for AG. Correlation analysis indicated that C was significantly negatively correlated with vegetation coverage (VC), aboveground biomass (AGB), BSCs biomass (BSCs-M), and root collar (RA), and power functions were found between C and VC, AGB, BSCs-M, and RA. Structural equation modeling further revealed that planting density strongly promoted root development, while the strongest direct inhibitory effects on C originated from BSCs and root mechanical reinforcement. Based on these relationships, an empirical C model was developed as a power function of aboveground biomass, BSC biomass, and root collar, and the model shows good performance (R-2 = 0.71, p < 0.01).

A substantial area of abandoned sloping farmland on the Loess Plateau is undergoing natural vegetation succession, which significantly influences runoff and soil loss. However, the responses of soil erosion processes to vegetation and soil property changes driven by natural abandonment remain unclear due to the absence of long-term continuous observations. To address this, an eight-year continuous study was conducted to monitor rainfall, vegetation, soil properties, runoff, and also soil loss across six slope gradients (5°–30°). The first two years (2016 and 2017) represented tilled bare land, while the subsequent six years (2018–2023) represented abandoned land. The results showed that the runoff depth (RD) and soil loss rate (SLR) exhibited a decreasing trend as the duration of abandonment increased. Both RD and SLR initially increased and then decreased with slope gradient, with a critical slope angle identified at 25°. SLR increased linearly with RD from 2016 to 2023, and the slope of their fitted equation was higher before abandonment but fluctuated downward with the increase in abandonment years. The runoff coefficient and SLR significantly decreased with increasing plant density, litter biomass, moss crust cover, saturated hydraulic conductivity, and total porosity (p < 0.05). Additionally, threshold-dependent responses were observed in the relationship between rainfall and runoff. When the comprehensive rainfall index (CRI)—constructed using rainfall depth, duration, and intensity—exceeded 0.23, a significant correlation emerged between rainfall and runoff. Below this threshold, vegetation and soil properties exerted stronger influences, leading to a disordered rainfall–runoff response. Vegetation restoration also complicated the response of soil loss to runoff. A significant relationship between runoff and soil loss was only observed when runoff exceeded 0.46 mm; below this threshold, the relationship remained irregular. These findings from long-term field observations provide a scientific basis for improving soil erosion prediction models and support the development of sustainable and high-quality soil and water conservation measures on the Loess Plateau.

Climate and topography at the zonal scale can significantly influence vegetation and soil properties, which in turn affect the ability of soil to resist raindrops splashing and water erosion. Artificial forests play a key role as ecological barriers on the Loess Plateau. However, the zonal characteristics of soil erosion resistance of Robinia pseudoacacia plantations with the largest planting area in the region and the response mechanism of gradient change of different vegetation zones under mixed management are still unclear. In this study, we selected 13 Robinia pseudoacacia (Rp) pure forest plots, 7 Robinia pseudoacaciaxPinus tabulaeformis mixed forests (RpxPt), 6 Robinia pseudoacacia x Prunus sibirica mixed forests (RpxPs) and 6 Robinia pseudoacacia x Platycladus orientalis Franco mixed forests (RpxPo) mixed forest plots across the steppe, forest-steppe, and forest zones of the Loess Plateau. Based on soil erodibility, we examined zonal characteristics of soil erosion resistance and underlying mechanisms in these plantations. The results show that from the steppe to the forest zone, with the increase of precipitation, the soil erodibility of Rp pure forests and RpxPt mixed forests shows an insignificant decrease and a first decrease followed by an increase, respectively. Compared with pure forest, mixed forest transformation has enhanced soil erosion resistance, especially RpxPo mixed forest in forest-steppe zone. In the correlation analysis, soil erodibility was not directly related to multi-year average precipitation (MAP), but was significantly negatively correlated with altitude, multi-year average temperature (MAT) and litter accumulation. And partial least squares-structural equation modeling indicate that topography indirectly affected soil erodibility by influencing soil nutrients. Climate directly shaped vegetation characteristics, and together, both factors mainly regulated surface soil erodibility indirectly through direct effects on soil nutrients and particle size distribution. This study provides a scientific basis for optimizing forest configurations and ecosystem functions of Robinia pseudoacacia plantations on the Loess Plateau. (c) 2025 International Research and Training Center on Erosion and Sedimentation and China Water and Power Press. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).

Theory and observation suggest that single-dimensional plant attributes and diversity may play a key role in explaining variation in soil biodiversity, but the empirical evidence in this area is still lacking considering multiple functional groups in soil biota. In this study, we explore the associations between plant taxonomic, phylogenetic, and functional diversity and soil biodiversity of multiple functional groups, as well as ecosystem functions in both monoculture and natural grasslands. We identified multidimensional plant attributes that could be categorized into three dimensions related to plant productivity, nutrient levels in leaves and roots, and phylogenetic relationships. We found that multidimensional plant attributes and soil properties commonly explained the biomass, richness and composition of soil biota across multitrophic levels, but this varied with the types of communities and their functional groups in both monoculture and natural grasslands. For example, plant functional traits or phylogeny explained more variation in soil fungi than in soil bacteria. Additionally, some links between multidimensional plant attributes and soil biota and soil functions were similar in both monoculture and natural grasslands, but there were weak effects of soil bacteria in the natural grassland and consistent strong effects of soil fungi in both monoculture and natural grasslands. This study provides experimental evidence supporting the effect of plant taxonomic, phylogenetic, and functional traits on shaping soil biodiversity and functions, which are crucial for understanding how plant-soil interactions may be impacted by ongoing global environmental changes.

Herbaceous plant roots are crucial in combating soil erosion due to their complex network structure and strong mechanical properties. However, current research does not establish an association between root morphological and mechanical characteristics and soil erosion. In this study, we selected eight typical herbaceous plants from the Loess Plateau. 240 undisturbed soil specimens were used to measure the soil resistance (reflected by rill erodibility) under six shear stresses. results showed that rill erodibility ranged from 0.008 to 0.497 m s-1 in the eight grasslands, and the rill erodibility of grasslands was 10-99% lower compared to bare soil. Plants with taproot systems demonstrated higher rill erodibility, a 5.86-fold increase compared to fibrous root systems. Root geometrical, morphological, and mechanical characteristics varied across the eight herbaceous plants, indicating the influences induced by plant roots on soil resistance from diverse perspectives. Rill erodibility decreased exponentially with root mass density, root surface area density, and root length density. Moreover, power functions were found between rill erodibility and root morphological (fractal dimension and topology index) and mechanical (root tensile strength and cohesion) characteristics. Although root geometrical, morphological, and mechanical characteristics can all influence soil resistance, the morphological characteristics exert the greatest impact. The results of the variance partitioning analysis indicate that root geometrical, morphological, and mechanical characteristics explained 98% of the overall variance in soil resistance, and morphological parameters accounted for 53%, followed by mechanical (5%) and geometrical (1%) characteristics. The total effect of root geometrical characteristics on soil resistance was negative effect, and morphological, mechanical characteristics was positive effects. Among these root characteristics, the topology index contributed the most to soil resistance. Lastly, rill erodibility was simulated by surface area density, topology index, and root cohesion. This study provides a mechanistic understanding of how different root characteristics regulate soil resistance, offering a theoretical basis for vegetation selection and root-based strategies to control soil erosion in the Loess Plateau and similar ecologically vulnerable regions.

Litter decomposition is a key process influencing soil carbon and nitrogen mineralization rates (Cmin and Nmin). Although numerous studies have investigated the factors affecting litter decomposition, how litter traits, decomposition time, soil properties, and microbial communities collectively affect Cmin and Nmin across different decomposition stages remains poorly understood. Here, we conducted a microcosm incubation experiment under controlled indoor conditions, using leaf and root litter from four dominant plant species (Cleistogenes squarrosa, Stipa capillata, Leymus chinensis, and Agropyron cristatum) in a typical steppe of Inner Mongolia. We aimed to examine the effects of litter type (leaf vs. root), species richness (1, 2, 4 species), and species identity (11 treatments from 4 dominant species) on soil Cmin and Nmin at different decomposition stages. Our results showed that litter type and decomposition stage had significant interactive effects on both Cmin and Nmin. Species richness showed no significant interaction with decomposition time, whereas the litter identity exhibited a significant interaction with decomposition stage, indicating that species identity was more strongly associated with variation in Cmin and Nmin than species richness. Structural equation modeling revealed distinct predictive relationships: Cmin was most strongly associated with microbial biomass, whereas Nmin was co-associated with litter traits, soil properties, and microbial biomass. As the incubation period progressed, the overarching predictors for both leaf and root litter Cmin and Nmin gradually declined in number and explanatory power. Collectively, these findings suggest that incorporating litter identity and decomposition stage may improve predictions of soil carbon and nitrogen dynamics in grassland ecosystems.

Understanding the mechanisms driving ecosystem stability across trophic levels is essential for sustaining ecosystem services. However, the temporal trajectories of plant and soil microbial stability under combined global change factors, and whether they diverge along grazing-induced environmental gradients, remain poorly resolved. Using an 8-year field experiment in Inner Mongolian grasslands with prior 7-year grazing treatments (light, moderate, heavy), we analyzed the data across five consecutive, moving temporal windows (2012-2015, 2013-2016, 2014-2017, 2015-2018, and 2016-2019) and manipulated water (+30% precipitation) and nitrogen (+10.5 g N m-2 yr-1) addition. Under historically light and moderate grazing, plant stability increased while microbial stability decreased, yet both exhibited similarly unchanged dynamics under heavy grazing. Resource addition reduced both stabilities mainly in light and moderate grazed systems, though effects weakened over time. This reduction occurred through weakened compensatory or statistical-averaging effects within plant and microbial functional groups. Plant stability was primarily driven by statistical-averaging effect among plant functional groups, whereas microbial stability was more strongly predicted by compensatory effect. Notably, statistical-averaging effect in soil microbial groups enhanced plant stability by stimulating plant functional group stability. Trophic asynchrony between plant and microbial groups impaired both stabilities by reducing their respective compensatory or statistical averaging effects. Our findings reveal that plant and microbial stability respond to global changes in trophic-level-specific and context-dependent ways, governed by distinct and temporally shifting biotic mechanisms. This highlights the need to integrate historical land use, plant-soil interactions, and their temporal dynamics for predicting and managing future ecosystem services.

The role of fertilization diversity (the variety of nutrient types added) in modulating the effects of extreme drought on multi-trophic communities and their functions remains a critical unknown in ecology. We conducted a multi-nutrient factorial experiment (control, N, NP, and NPK additions) under simulated extreme drought in an alpine meadow on the Qinghai-Tibetan Plateau. We assessed the responses of soil abiotic properties, plant communities, soil microbial (bacteria and fungi) and nematode communities, and ecosystem multifunctionality (EMF). Our results reveal that fertilization diversity induces a trophic asymmetry in ecosystem responses to drought: increasing fertilization diversity (and total nutrient load) significantly altered the response of the plant community to drought by promoting the competitive dominance of drought-tolerant grasses, which in turn modulated ecosystem function of aboveground net primary productivity. Conversely, fertilization diversity amplified the negative effects of drought on soil bacterial and fungal biomass, likely due to exacerbating microbial carbon limitation. For soil nematodes, fertilization diversity modified the response of community composition to drought and simplified nematode communities. Consequently, despite these compensatory and contrasting responses across trophic levels, fertilization diversity led to a net decline in EMF under drought. This net loss occurred because the positive contributions from the plant pathway were decisively outweighed by the substantial suppression of microbial processes, revealing a fundamental decoupling between above- and below-ground components. Our findings demonstrate that the balance and diversity of nutrient inputs, rather than nitrogen dose alone, is a critical factor modulating ecosystem responses to drought, creating contrasting responses across trophic levels that necessitate a holistic, multi-trophic perspective for effective ecosystem management under global change.

The increase in phosphorus (P) and nitrogen (N) inputs, as well as soil acidification resulting from multiple environmental changes, has profound effects on the attributes of plant and soil biota communities, and on ecosystem functions. However, how these community attributes impact ecosystem multifunctionality (EMF) and its stability under multiple environmental changes remains unclear. By integrating datasets over four consecutive years from an experiment with enrichments of soil acidification and N and P in a semiarid grassland on the Mongolian Plateau, we explored the effects of environmental changes on community attributes (species richness, asynchrony, and compositional temporal stability) of plants and soil biota (bacteria, fungi, and nematodes) and their associations with EMF stability. The attributes of plants and soil biota showed opposite responses to nutrient enrichment under soil acidification and non-acidification conditions. Soil acidification had a more significant effect on the community attributes of plants and soil biota, as well as on the components of EMF stability, than nutrient enrichment. Soil acidification decreased both the mean and stability of EMF, while N enrichment increased the mean of EMF. P did not have a significant effect on the components of EMF stability, but N and P showed positive interactive effects on the mean and stability of EMF. We also found that plant and soil biota richness had a positive effect on EMF, while plant asynchrony and soil biota compositional stability determined EMF stability. The community attributes of plants and soil biota co-regulate the components of EMF stability under multiple environmental changes. These findings highlight the urgent need to protect the biodiversity of plants and soil biota to maintain EMF and its stability, especially for ecosystems undergoing multiple environmental changes.

Soil erodibility serves as a crucial indicator for assessing soil sensitivity to erosion and is a vital parameter in soil erosion prediction models. The mixed transformation of Robinia pseudoacacia L. forests leads to variations in the root morphology of understory vegetation, which subsequently affects soil erodibility. This study focused on five typical mixed forests: Robinia pseudoacacia L. with Prunus sibirica L., Prunus davidiana Franch., Hippophae rhamnoides L., Amorpha fruticosa L., and Pinus tabuliformis Carri & egrave;re. The study analyzed how soil erodibility changed after mixing the Robinia pseudoacacia L. forests, as well as the response mechanisms to root morphology and aggregate stability. Simultaneously, the study has explored an estimation method for soil erodibility in woodland, utilizing parameters of aggregate particle size distribution. The results showed that mixed planting of Robinia pseudoacacia L. with Prunus sibirica L., Prunus davidiana Franch., and Pinus tabuliformis Carri & egrave;re reduced soil erodibility by 1.33 %, 3.72 %, and 3.79 %, respectively. In contrast, mixed planting with Hippophae rhamnoides L. and Amorpha fruticosa L. increased soil erodibility by 6.09 % and 3.63 %. The soil erodibility of ephemeral gullies increased by an average of 7.18 % (5.43-8.37 %) compared to slopes. Changes in root traits and aggregate stability resulting from the mixed planting of Robinia pseudoacacia L. accounted for 93.5 % of the soil erodibility. Aggregate stability was the primary factor influencing soil erodibility, with a standardized path coefficient of -0.865 (p < 0.001). Roots primarily reduced soil erodibility indirectly by enhancing aggregate stability, with a standardized path coefficient of 0.553 (p < 0.01) for the effect of roots on aggregate stability. In the TORRI and EPIC models, estimating soil erodibility based on soil aggregates was feasible on the Loess Plateau (R-2 = 0.26, p < 0.05; R-2 = 0.52, p < 0.001), aligning with the hypothesis of this study. The research findings clarify suitable tree species for mixed afforestation and provide scientific references for optimizing planted forest transformation.