Multiple Global Change Factors Research Articles

Combined Application of Multiple Global Change Factors Negatively Influences Key Soil Processes across an Urban Gradient in Berlin, Germany

Urbanization is a growing phenomenon affecting soils worldwide. Urban centers have been highlighted as hotspots for global change factors due to heightened anthropogenic activity. However, few studies have investigated the multifaceted impacts of global change factors (GCFs) acting in concert with urban soils. Thus, the objective of this study was to add GCFs in different combinations (0, 1, 2, 5, and 8 simultaneously) in three high-urbanity and three low-urbanity soils in Berlin and to evaluate their effects on soil parameters and functions. We hypothesized four potential outcomes of soil process responses to GCF exposure, Site-Specific Resistance, General Susceptibility, Low-Urbanity Resistance, and High-Urbanity Resistance. We provide evidence for the negative impacts of individual and multiple GCF application on litter decomposition, water repellency, and water-stable aggregates. Additionally, we highlight the General Susceptibility of litter decomposition to GCF exposure regardless of urbanity, as well as the Low-Urbanity Resistance of water repellency and High-Urbanity Resistance of water-stable aggregates under increased exposure to GCFs. This study expands on evidence of the growing threat of global change factors in urban settings and highlights some potential consequences regarding soil function.

Shifts in mycorrhizal types of fungi and plants in response to fertilisation, warming and herbivory in a tundra grassland.

Climate warming is severely affecting high-latitude regions. In the Arctic tundra, it may lead to enhanced soil nutrient availability and interact with simultaneous changes in grazing pressure. It is presently unknown how these concurrently occurring global change drivers affect the root-associated fungal communities, particularly mycorrhizal fungi, and whether changes coincide with shifts in plant mycorrhizal types. We investigated changes in root-associated fungal communities and mycorrhizal types of the plant community in a 10-yr factorial experiment with warming, fertilisation and grazing exclusion in a Finnish tundra grassland. The strongest determinant of the root-associated fungal community was fertilisation, which consistently increased potential plant pathogen abundance and had contrasting effects on the different mycorrhizal fungal types, contingent on other treatments. Plant mycorrhizal types went through pronounced shifts, with warming favouring ecto- and ericoid mycorrhiza but not under fertilisation and grazing exclusion. Combination of all treatments resulted in dominance by arbuscular mycorrhizal plants. However, shifts in plant mycorrhizal types vs fungi were mostly but not always aligned in their magnitude and direction. Our results show that our ability to predict shifts in symbiotic and antagonistic fungal communities depend on simultaneous consideration of multiple global change factors that jointly alter plant and fungal communities.

Litter decomposition rate response to multiple global change factors: A meta-analysis

Anthropogenic global change fundamentally impacts ecosystem biogeochemical cycling. Although litter decomposition is a crucial component of carbon (C) cycling, its response to diverse global change factors (GCFs) remains uncertain. In this research, we synthesized 1706 observations from 260 peer-reviewed publications to elucidate the effects of GCFs on litter decomposition rate (k) and the contribution of different variables to them. Overall, nitrogen (N) addition and drought significantly decreased k (−3.3 and −17.7%, respectively), phosphorus (P) addition, warming, and increased precipitation significantly increased k (6.7, 8.2, and 11.6%, respectively), while elevated CO2 had an insignificant effect on k (−0.6%). Combined GCFs had no significant effect on k except for warming*drought, and all combined factors mainly exhibited antagonistic interactions. Further analysis showed that k responses to GCFs were influenced by initial litter quality (C, N, C:N, P, cellulose, lignin, and vegetation types), soil properties (soil organic C, soil total N, soil total P, soil respiration and microbial biomass C), environmental factors (latitude, longitude, annual mean temperature, annual mean precipitation, ecosystem type, and climate type), and experimental methods (experiment type, richness, treatment method, fertilizer form, fertilizer rate, and experimental duration). Initial litter quality predominantly governed the k response to N addition (53.5%), while soil properties were more significant in regulating the P addition response (44.8%). Environmental factors largely determined k responses to warming, drought, and increased precipitation (50.6, 54.7, 46.9%). Moreover, the experimental methodology also played an important role in regulating k responses to GCFs, which explained 8.6, 23.6, 31.1, 23.7, and 29.7% of the variation of the responses of k to N addition, P addition, warming, drought, and increased precipitation. This meta-analysis offers improved global-scale nutrient cycling predictions under climate change and underscores the need for long-term, multi-factor, methodologically standardized experiments to accurately predict the influence of GCFs on litter decomposition.

Number of global change factors alters plant-soil feedbacks via its effect on soil fungal communities

Plants and soil microbes are often challenged by multiple global change factors (GCFs), and their responses to single GCFs may differ from those to multiple GCFs due to synergistic or antagonistic interactions. Therefore, changes in number of GCFs may alter plant-soil feedbacks. We conditioned a soil by growing a plant of Hydrocotyle verticillata in the soil for three months, and then grew a plant of the same species in a sterilized bulk soil inoculated with the live or the sterilized conditioned soil under no, single, two or four GCFs. The strength of plant-soil feedbacks calculated by root biomass was positive in the treatment with four GCFs, but not in any of the other three treatments. The strength of plant-soil feedbacks based on shoot biomass was positive in the treatment with single and four GCFs, but not in the treatments with no or two GCFs. Furthermore, the strength of plant-soil feedbacks was closely related to changes in soil fungal composition mediated by changes in number of GCFs. These results indicate that increasing number of GCFs can alter plant-soil feedbacks via changing fungal legacies that plants leave in the soil. Our results highlight the importance of multiple GCFs in regulating plant-microbial interactions.

Plant community diversity alters the response of ecosystem multifunctionality to multiple global change factors.

Biodiversity is considered important to the mitigation of global change impacts on ecosystem multifunctionality in terrestrial ecosystems. However, potential mechanisms through which biodiversity maintains ecosystem multifunctionality under global change remain unclear. We grew 132 plant communities with two levels of plant diversity, crossed with treatments based on 10 global change factors (nitrogen deposition, soil salinity, drought, plant invasion, simulated grazing, oil pollution, plastics pollution, antibiotics pollution, heavy metal pollution, and pesticide pollution). All global change factors negatively impacted ecosystem multifunctionality, but negative impacts were stronger in high compared with low diversity plant communities. We explored potential mechanisms for this unexpected result, finding that the inhibition of selection effects (i.e., selection for plant species associated with high ecosystem functioning) contributed to sensitivity of ecosystem multifunctionality to global change. Specifically, global change factors decreased the abundance of novel functional plants (i.e., legumes) in high but not low diversity plant communities. The negative impacts of global change on ecosystem multifunctionality were also mediated by increased relative abundance of fungal plant pathogens (identified from metabarcoding of soil samples) and their negative relationship with the abundance of novel functional plants. Taken together, our experiment highlights the importance of protecting high diversity plant communities and legumes, and managing fungal pathogens, to the maintenance of ecosystem multifunctionality in the face of complex global change.

Nitrogen addition regulates the effects of variation in precipitation patterns on plant biomass formation and allocation in a Leymus chinensis grassland of northeast China.

Global warming is predicted to change precipitation amount and reduce precipitation frequency, which may alter grassland primary productivity and biomass allocation, especially when interact with other global change factors, such as nitrogen deposition. The interactive effects of changes in precipitation amount and nitrogen addition on productivity and biomass allocation are extensively studied; however, how these effects may be regulated by the predicted reduction in precipitation frequency remain largely unknown. Using a mesocosm experiment, we investigated responses of primary productivity and biomass allocation to the manipulated changes in precipitation amount (PA: 150mm, 300mm, 450mm), precipitation frequency (PF: medium and low), and nitrogen addition (NA: 0 and 10 g N m-2 yr-1) in a Leymus chinensis grassland. We detected significant effects of the PA, PF and NA treatments on both aboveground biomass (AGB) and belowground biomass (BGB); but the interactive effects were only significant between the PA and NA on AGB. Both AGB and BGB increased with an increment in precipitation amount and nitrogen addition; the reduction in PF decreased AGB, but increased BGB. The reduced PF treatment induced an enhancement in the variation of soil moisture, which subsequently affected photosynthesis and biomass formation. Overall, there were mismatches in the above- and belowground biomass responses to changes in precipitation regime. Our results suggest the predicted changes in precipitation regime, including precipitation amount and frequency, is likely to alter primary productivity and biomass allocation, especially when interact with nitrogen deposition. Therefore, predicting the influence of global changes on grassland structure and functions requires the consideration of interactions among multiple global change factors.

Oligotrophic microbes are recruited to resist multiple global change factors in agricultural subsoils

An increasing number of anthropogenic pressures can have negative effects on biodiversity and ecosystem functioning. However, our understanding of how soil microbial communities and functions in response to multiple global change factors (GCFs) is still incomplete, particularly in less frequently disturbed subsoils. In this study, we examined the impact of different levels of GCFs (0–9) on soil functions and bacterial communities in both topsoils (0–20 cm) and subsoils (20–40 cm) of an agricultural ecosystem, and characterized the intrinsic factors influencing community resistance based on microbial life history strategy. Our experimental results showed a decline in soil multifunctionality, bacterial diversity, and community resistance as the number of GCFs increased, with a more drastic reduction in community resistance of subsoils. Specifically, we observed a significantly positive relationship between the oligotroph/copiotroph ratio and community resistance in subsoils, which was also verified by the negative correlation between 16S rRNA operon (rrn) copy number and community resistance. Structural equation modeling further revealed the direct effects of community resistance in promoting the ecosystem functioning, regardless of top- and subsoils. Therefore, these results suggested that subsoils may recruit more oligotrophic microbes to enhance their originally weaker community resistance under multiple GCFs, which was essential for maintaining sustainable agroecological functions and services. Overall, our study represents a significant advance in linking microbial life history strategy to the resistance of belowground microbial community and functionality.

Independent and combined effects of microplastics pollution and drought on soil bacterial community

Global terrestrial ecosystems are simultaneously threatened by multiple environmental pressures, with microplastics (MPs) pollution and drought possibly being the most pressing, both of which may have unanticipated effects on soil organisms. Here, we investigated the responses of diversity, composition and functions of soil bacterial community to MPs pollution (including two MPs types: polyethylene (PE) and polylactic acid (PLA); two MPs sizes: < 20 μm and <300 μm) and drought in microcosms. We found that only 20 μm PLA MPs significantly decreased soil bacterial diversity by 17.4 % and altered soil bacterial community composition, while PE MPs and 300 μm PLA MPs had no significant effects. The copiotrophic bacteria (i.e., Proteobacteria and Firmicutes) were enriched in the 20 μm PLA MPs pollution soils due to the enhanced dissolved organic carbon contents. Moreover, our results showed that the 20 μm PLA MPs also affected the potential phenotypes and functions of soil bacterial community, increasing the potentially pathogenic, stress-tolerant, containing mobile elements and forming biofilms phenotypes, and promoting membrane transport and signal transduction pathways. These results suggested that the effects of MPs on soil bacterial community varied depending on MPs types and sizes. However, drought significantly increased soil bacterial diversity by 10.3 % and affected soil bacterial community composition in the 20 μm PLA MPs pollution soils. We also found that drought inhibited the levels of potentially pathogenic, containing mobile elements and forming biofilms phenotypes in the 20 μm PLA MPs pollution soils. Taken together, these findings reveal that drought may alleviate the adverse effects of MPs pollution on soil bacterial community, which enhances our understanding of the interactive effects of multiple global change factors on agroecosystem functions.

Climate change reshapes plant trait spectrum to explain biomass dynamics in an old-growth subtropical forest

Climate change leads to novel species interactions and continues to reshuffle ecological communities, which significantly declines carbon accumulation rates in mature forests. Still, little is known about the potential influence of multiple global change factors on long-term biomass dynamics and functional trait combinations. We used temporal demographic records spanning 26 years and extensive databases of functional traits to assess how old-growth subtropical forest biomass dynamics respond to various climatic change scenarios (extreme drought, subsequent drought, warming, elevated CO2 concentrations, and windstorm). We found that the initial severe drought, subsequent drought and windstorm events increased biomass loss due to tree mortality, which exceeded the biomass gain produced by survivors and recruits, ultimately resulting in more negative net biomass balances. These drought and windstorm events caused massive biomass loss due to tree mortality that tended towards acquisition species with high hydraulic efficiency, whereas biomass growth from survivors and recruits tended to consist of acquisition species with high hydraulic safety. Compensatory growth in this natural forest provided good explanation for the increase in biomass growth after drought and windstorm events. Notably, these dominant-species transitions reduced carbon storage and residence time, forming a positive carbon-climate feedback loop. Our findings suggest that climate changes could alter functional strategies and cause shifts in new dominant species, which could greatly reduce ecological functions and carbon gains of old-growth subtropical forests.

Soil nutrient heterogeneity alters productivity and diversity of experimental plant communities under multiple global change factors

Plant communities in nature are often challenged by multiple global change factors (GCFs) and also ubiquitously encountered with soil nutrient heterogeneity. So far, however, we know little about the interactive effect of multiple GCFs and soil nutrient heterogeneity on plant communities. We conducted an outdoor mesocosm experiment in which a plant community was either grown in heterogeneous soils consisting of high‐ and low‐nutrient patches, or in homogeneous soils where the same amount of nutrients was evenly distributed. These plant communities were exposed to none (control), single, or a combination of two or four GCFs (i.e. drought, nitrogen deposition, microplastic and cadmium). Biomass of the plant community exposed to drought and nitrogen deposition were greater in heterogeneous than in homogeneous soils, but evenness of the plant community exposed to microplastics was lower. Increasing the number of GCFs increased community biomass more in heterogeneous than in homogeneous soils, but it generally reduced community evenness, independent of soil nutrient heterogeneity. These contrasting responses were related to changing competitive hierarchies and root foraging responses under different treatments. Our results suggest that soil nutrient heterogeneity can alter community productivity and diversity via changing competitive interactions of the component species, depending on both the identity and the number of GCFs acting on the community. These results have important implications for the maintenance of ecosystem functions and services under rapid and complex ongoing global changes.

Critical role of multidimensional biodiversity in contributing to ecosystem sustainability under global change

The 21st century has seen an acceleration of global change, including climate change, elevated carbon dioxide, nitrogen deposition, and land-use intensification, which poses a significant threat to ecosystem functioning. Nevertheless, studies on the relationship between biodiversity and ecosystem functioning (BEF) have consistently demonstrated that biodiversity enhances ecosystem functioning and its stability, even in variable environmental conditions. These findings potentially indicate the critical role of biodiversity in promoting sustainable provisioning of ecosystem functioning under global change. Our paper provides a comprehensive review of current BEF research and the response of BEF to multiple global change factors. We demonstrate that (1) assessing the effects of biodiversity on ecosystem functioning requires consideration of multiple dimensions of diversity, such as diversity across multiple trophic levels (plants, animals, and microbes), multiple facets (taxonomy, functional traits, and phylogeny), and multiple spatial scales (local, regional, and landscape scales). (2) The interaction of multiple global change factors may lead to a greater reduction in biodiversity and ecosystem functioning than a single global change factor. (3) Multidimensional biodiversity regulates the response of ecosystem functioning to global change factors, indicating that high levels of multidimensional biodiversity can mitigate the negative impacts of global change on ecosystem functioning. Overall, we emphasize that recognizing the importance of multidimensional biodiversity is critical for sustaining ecosystem functioning. Therefore, prioritizing conservation efforts to maintain and enhance all dimensions of biodiversity is essential to address the challenges of future global change.

Stochastic processes in the structure and functioning of soil biodiversity

Ecologists are increasingly recognizing the importance of stochastic processes in generating spatial and temporal variation in biological communities. This variation is very high in soil, which hosts not &amp;lt;¼ of all biodiversity on Earth and is central to how terrestrial ecosystems respond to perturbations. Measurement errors, demographic stochasticity (individual variability in traits such as birth and death rates), and environmental stochasticity (fluctuations in environmental properties) are the three main sources of stochasticity in ecology. Here, we synthesize how these three sources of stochasticity are quantified and incorporated in the study of soil biodiversity, highlighting current limits, possible solutions, and future research needs. We stress the relevance of all these factors to our future understanding of terrestrial ecosystems via plant-soil and soil-climate interactions and feedbacks. In soil, measurement errors are due to the small size, high abundance, and broad distributions of soil organisms, which limit sampling in space and especially over time. We argue that positive autocorrelation is a main characteristic of soil environmental properties, which may have important consequences on the response of soil biota to perturbations. At a local scale, large populations of soil organisms also imply a minor role of demographic stochasticity. Despite demographic stochasticity being a less significant source of variability than environmental stochasticity, we show that demographic stochasticity can be sizeable, but that within soil systems, stochasticity of environmental conditions must be accounted for. Explicit consideration of stochastic processes in soil biodiversity research is essential to our future understanding of the processes that control soil biodiversity. In classical ecology, stochasticity implies probabilistic predictions in terms of population growth, extinction, species coexistence, and community diversity. In soil, stochasticity implies very variable responses to climate change and the soil-climate feedback. Future studies will have to identify the major sources of environmental stochasticity with a particular focus on the interaction between multiple global change factors.

Nitrogen addition and experimental drought simplified arthropod network in temperate grassland

Abstract Biodiversity is threatened by global changes, but related research has focused primarily on species or functional group diversity, neglecting their interaction networks. The latter are particularly sensitive to global changes and essential for biodiversity maintenance. Furthermore, multiple global change factors are typically examined separately, rather than in concert which is more realistic in nature. To explore the responses of arthropod networks to multiple global changes, we conducted a field experiment in temperate grassland in northeast China, in which nitrogen (N) deposition, drought, snowmelt timing and their interactions were manipulated. We constructed and assessed networks of arthropod functional groups, and explored their responses to changes in plant communities and the abiotic environments. Nitrogen addition decreased arthropod network complexity because increased foliar N and simplified plant community strengthened trophic chains along a single pathway, weakening the net effect of other pathways. However, experimental drought decreased network complexity by filtering out plant species and changing micro‐habitats. While delayed snowmelt significantly increased arthropod abundance only in early spring, its interaction with N addition or with drought had various impacts on arthropod functional groups. Our results suggest that the interaction of arthropod consumers with plant species richness and with plant nutrients finally reduced the robustness, connectedness and function of entire species/functional group networks in response to global change factors. In conclusion, species loss and increasing plant nutrient concentrations are key factors simplifying networks under multiple global changes, and such simplification is likely to be strengthened if coupled with changes in micro‐habitats. Our study highlighted that the effects of multiple global change factors should be studied in concert, even though they occur in different seasons, so that their effects on ecological networks can be perceived as a panorama. Read the free Plain Language Summary for this article on the Journal blog.

Soils worldwide suffer from the combined effects of multiple global change factors

Soils worldwide suffer from the combined effects of multiple global change factors

Effects of Multiple Global Change Factors on Symbiotic and Asymbiotic N2 Fixation: Results Based on a Pot Experiment

Biological N2 fixation, a major pathway for new nitrogen (N) input to terrestrial ecosystems, largely determines the dynamics of ecosystem structure and functions under global change. Nevertheless, the responses of N2 fixation to multiple global change factors remain poorly understood. Here, saplings of two N2-fixing plant species, Alnus cremastogyne and Cajanus cajan, were grown at rural and urban sites, respectively, with the latter representing an environment with changes in multiple factors occurring simultaneously. Symbiotic N2 fixation per unit of nodule was significantly higher at the urban site than the rural site for A. cremastogyne, but the rates were comparable between the two sites for C. cajan. The nodule investments were significantly lower at the urban site relative to the rural site for both species. Symbiotic N2 fixation per plant increased by 31.2 times for A. cremastogyne, while that decreased by 88.2% for C. cajan at the urban site compared to the rural site. Asymbiotic N2 fixation rate in soil decreased by 46.2% at the urban site relative to the rural site. The decrease in symbiotic N2 fixation per plant for C. cajan and asymbiotic N2 fixation in soil was probably attributed to higher N deposition under the urban conditions, while the increase in symbiotic N2 fixation per plant for A. cremastogyne was probably related to the higher levels of temperature, atmospheric CO2, and phosphorus deposition at the urban site. The responses of N2 fixation to multiple global change factors and the underlying mechanisms may be divergent either between symbiotic and asymbiotic forms or among N2-fixing plant species. While causative evidence is urgently needed, we argue that these differences should be considered in Earth system models to improve the prediction of N2 fixation under global change.

Rethinking experiments that explore multiple global change factors

Our current capacity to predict the responses of ecosystem functions under global change factors is limited. We propose new and more efficient approaches to experimental design and modeling that utilize interactions between ecosystem functions to improve our understanding of their sensitivity to global change factors.

Nitrification, denitrification, and related functional genes under elevated CO2 : A meta-analysis in terrestrial ecosystems.

Global change may have profound effects on soil nitrogen (N) cycling that can induce positive feedback to climate change through increased nitrous oxide (N2 O) emissions mediated by nitrification and denitrification. We conducted a meta-analysis of the effects of elevated CO2 on nitrification and denitrification based on 879 observations from 58 publications and 46 independent elevated CO2 experiments in terrestrial ecosystems. We investigated the effects of elevated CO2 alone or combined with elevated temperature, increased precipitation, drought, and N addition. We assessed the response to elevated CO2 of gross and potential nitrification, potential denitrification, and abundances of related functional genes (archaeal amoA, bacterial amoA, nirK, nirS, and nosZ). Elevated CO2 increased potential nitrification (+28%) and the abundance of bacterial amoA functional gene (+62%) in cropland ecosystems. Elevated CO2 increased potential denitrification when combined with N addition and higher precipitation (+116%). Elevated CO2 also increased the abundance of nirK (+25%) and nirS (+27%) functional genes in terrestrial ecosystems and of nosZ (+32%) functional gene in cropland ecosystems. The increase in the abundance of nosZ under elevated CO2 was larger at elevated temperature and high N (+62%). Four out of 14 two-way interactions tested between elevated CO2 and elevated temperature, elevated CO2 and increased precipitation, and elevated CO2 and N addition were marginally significant and mostly synergistic. The effects of elevated CO2 on potential nitrification and abundances of bacterial amoA and nirS functional genes increased with mean annual temperature and mean annual precipitation. Our meta-analysis thus suggests that warming and increased precipitation in large areas of the world could reinforce positive responses of nitrification and denitrification to elevated CO2 and urges the need for more investigations in the tropical zone and on interactive effects among multiple global change factors, as we may largely underestimate the effects of global change on soil N2 O emissions.

Number of simultaneously acting global change factors affects composition, diversity and productivity of grassland plant communities

Plant communities experience impacts of increasing numbers of global change factors (e.g., warming, eutrophication, pollution). Consequently, unpredictable global change effects could arise. However, information about multi-factor effects on plant communities is scarce. To test plant-community responses to multiple global change factors (GCFs), we subjected sown and transplanted-seedling communities to increasing numbers (0, 1, 2, 4, 6) of co-acting GCFs, and assessed effects of individual factors and increasing numbers of GCFs on community composition and productivity. GCF number reduced species diversity and evenness of both community types, whereas none of the individual factors alone affected these measures. In contrast, GCF number positively affected the productivity of the transplanted-seedling community. Our findings show that simultaneously acting GCFs can affect plant communities in ways differing from those expected from single factor effects, which may be due to biological effects, sampling effects, or both. Consequently, exploring the multifactorial nature of global change is crucial to better understand ecological impacts of global change.

Nitrogen addition and warming modulate the pathogen impact on plant biomass by shifting intraspecific functional traits and reducing species richness

Abstract Foliar fungal pathogens can substantially reduce plant biomass. This effect can be modulated by environment conditions, such as soil nitrogen availability and air temperature. The ongoing global changes are altering these variables and thus interact with pathogens to influence plant biomass, but experimental test of their interactions is scarce. We conducted a 4‐year field experiment in a Tibetan alpine meadow to examine the interactive effects of nitrogen addition, warming and foliar pathogens (via fungicide application) on plant biomass. We also measured plant functional traits, species richness and abundance to test the possible mechanisms underlying these interactions. Our results showed that foliar fungal pathogens reduced plant community biomass under nitrogen addition, which in turn weakened the positive nitrogen effect on community biomass. Mechanistically, nitrogen addition shifted the plant communities towards fast‐growing traits; this happened predominantly because of changes in within‐species trait values, including an increase in specific leaf area and height. These trait changes resulted in greater suppression of plant biomass by pathogens, likely because of the trade‐offs associated with the allocation of resources to plant growth and defense. Moreover, the reduction in species richness amplified the pathogen effect under nitrogen addition due to the increased density and susceptibility of the most dominant species (i.e. Kobresia capillifolia). Furthermore, warming did not interact with pathogens and nitrogen addition to influence plant community biomass, but their three‐way interaction modified the biomass of K. capillifolia. Specifically, warming enhanced the positive effect of nitrogen addition on the biomass of K. capillifolia in the fungicide, low infection plots, while it weakened the nitrogen effect in the no fungicide, high infection plots. Synthesis. Our results demonstrate how pathogens interact with nitrogen addition and warming to influence the biomass of dominant species and the whole plant community. Our study highlights the importance of considering foliar fungal pathogens when assessing ecosystem responses to multiple global change factors.

The Effects of Multiple Global Change Factors on Soil Nutrients across China: A Meta-Analysis.

The quantification of the effects of global changes on soil nutrients is crucial for the prediction of future terrestrial ecosystem changes. Combined with 100 articles and 1129 observations from all over China, the meta-analysis method was applied to explore the effects of various global change factors on soil nutrients, including precipitation change, nitrogen addition, warming, and carbon dioxide (CO2) concentration rise. Results indicated that among all the individual drivers, soil nutrients are most sensitive to N addition. Significant positive effects of N addition on carbon concentration (+4.6%), nitrogen concentration (+6.1%), organic carbon (+5.0%), and available nitrogen (+74.6%) were observed considering all the land-use types. The results highlighted that the combined and interactive effects of multiple global change factors on soil nutrients were of great significance. The interaction of the two drivers is usually additive, followed by antagonism and synergy. Our findings contribute to better understanding of how soil nutrients will change under future global change.