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Frosts, increasingly prevalent due to climate warming, can offset the carbon storage benefits of an extended growing season, potentially exacerbating climate warming. However, existing research primarily focus on species, with limited evidence on carbon fluxes at the ecosystem scale. Using a manipulative experiment simulating 7-day frosts in a temperate grassland, we find that ongoing frosts, whether in spring or autumn, have limited effects on gross ecosystem productivity, ecosystem respiration, and net ecosystem productivity during the frost measurement periods. However, frosts profoundly impact net ecosystem productivity over the entire growing season outside the frost measurement periods. Specifically, spring frosts significantly increase net ecosystem productivity, autumn frosts marginal decrease it, and the combined effect of both frosts neutralize net ecosystem productivity. The early-year (2018–2020) impacts of frosts on net ecosystem productivity may be driven by plant eco-physiological changes, whereas the late-year impacts (2021–2023) were attributed to shifts in plant community structure. Our findings suggest that frequent frosts in both seasons may not stimulate ecosystem carbon release in temperate grasslands. Understanding these patterns is crucial for predicting carbon balance and developing effective climate-change mitigation strategies in response to the future warmer climate. Frost is typically seen as a threat to plants and is expected to lead to decreased ecosystem carbon uptake due to reduced photosynthesis. However, this research shows that spring frosts can actually enhance ecosystem carbon absorption, while autumn frosts behave as expected, prompting an increase in carbon emissions.

Grazing can affect plant community composition and structure directly by foraging and indirectly by increasing wind erosion and dust storms and subsequently influence ecosystem functioning and ecological services. However, the combined effects of grazing, wind erosion, and dust deposition have not been explored. As part of a 7-year (2010–2016) field manipulative experiment, this study was conducted to examine the impacts of grazing and simulated aeolian processes (wind erosion and dust deposition) on plant community cover and species richness in a temperate steppe on the Mongolian Plateau, China. Grazing decreased total cover by 4.2%, particularly the cover of tall-stature plants (> 20 cm in height), but resulted in 9.1% greater species richness. Wind erosion also reduced total cover by 17.0% primarily via suppressing shortstature plants associated with soil nitrogen loss, but had no effect on species richness. Dust deposition enhanced total cover by 5.7%, but resulted in a 7.3% decrease in species richness by driving some of the short-stature plant species to extinction. Both wind erosion and dust deposition showed additive effects with grazing on vegetation cover and species richness, though no detectable interaction between aeolian processes and grazing could be detected due to our methodological constraints. The changes in gross ecosystem productivity, ecosystem respiration, and net ecosystem productivity under the wind erosion and dust deposition treatments were positively related to aeolian process-induced changes in vegetation cover and species richness, highlighting the important roles of plant community shifts in regulating ecosystem carbon cycling. Our findings suggest that plant traits (for example, canopy height) and soil nutrients may be the key for understanding plant community responses to grassland management and natural hazards.

Global change has the potential to alter soil carbon (C) inputs from above- and below-ground sources, with subsequent influences on soil microbial communities and ecological functions. Using data from a 13-year field experiment in a semi-arid grassland, we investigated the effects of litter manipulations and plant removal on soil microbiomes and ecosystem multifunctionality (EMF). Litter addition did not affect soil microbial α-diversity whereas litter removal reduced bacterial and fungal α-diversity due to decreased C substrate supply and soil moisture. By contrast, plant removal led to larger declines in bacterial and fungal α-diversity, lower microbial network stability and complexity. EMF was enhanced by litter addition but largely reduced by plant removal, primarily attributed to the loss of fungal diversity. Our findings underscore the importance of C inputs in shaping soil microbiomes and highlight the dominant role of plant root-derived C inputs in maintaining ecological functions under global change scenarios.

Understanding how climate change impacts the vertical distribution of soil microbial communities is critical for predicting ecosystem responses to global environmental shifts. Soil microbial communities exhibit strong depth-related stratification, yet the effects of climate change variables, such as altered precipitation and nighttime warming, on these vertical patterns have been inadequately studied. Our research uncovers that altered precipitation disrupts the previously observed relationships between soil depth and microbial diversity, a finding that challenges traditional models of soil microbial ecology. Furthermore, our study provides experimental support for the hunger game hypothesis, highlighting that oligotrophic microbes, characterized by lower ribosomal RNA gene operon ( rrn ) copy numbers, are selectively favored in nutrient-poor subsoils, fostering increased microbial cooperation for resource exchange. By unraveling these complexities in soil microbial communities, our findings offer crucial insights for predicting ecosystem responses to climate change and for developing strategies to mitigate its adverse impacts.

Asymmetrically seasonal warming has been widely observed on the Earth, but great uncertainties remain for its effects on terrestrial carbon (C) cycling. As a part of a 7-year seasonal warming experiment in an old-field grassland in Central China, this study demonstrated that spring and autumn warming reduced soil respiration by 8.3% and 9.8%, respectively. In addition, spring warming decreased soil respiration by 1.0% and 15.9% without and with autumn warming, respectively. Autumn warming suppressed soil respiration by 2.5% and 17.2% without and with spring warming, respectively. Decreased soil respiration in summer under both spring and autumn warming dominated the treatment-induced suppressions in annual mean soil respiration, which could be primarily attributable to the reductions in plant photosynthesis and growth (aboveground net primary productivity). These observations suggest that the asymmetrically seasonal warming may diminish soil C loss and its feedback to climate warming. Our findings highlight the urgent need of incorporating the interactive and legacy effects of seasonal warming into models used in the IPCC reports for the robust projections of future climate change.

Climate warming has profoundly influenced community structure and ecosystem functions in the terrestrial biosphere. However, how asymmetric rising temperatures between daytime and nighttime affect soil microbial communities that predominantly regulate soil carbon (C) release remains unclear. As part of a decade-long warming manipulation experiment in a semi-arid grassland, we aimed to examine the effects of short- and long-term asymmetrically diurnal warming on soil microbial composition. Neither daytime nor nighttime warming affected soil microbial composition in the short term, whereas long-term daytime warming instead of nighttime warming decreased fungal abundance by 6.28% (p < 0.05) and the ratio of fungi to bacteria by 6.76% (p < 0.01), which could be caused by the elevated soil temperature, reduced soil moisture, and increased grass cover. In addition, soil respiration enhanced with the decreasing fungi-to-bacteria ratio, but was not correlated with microbial biomass C during the 10 years, indicating that microbial composition may be more important than biomass in modulating soil respiration. These observations highlight the crucial role of soil microbial composition in regulating grassland C release under long-term climate warming, which facilitates an accurate assessment of climate-C feedback in the terrestrial biosphere.

Background Soil microclimate plays critical roles in influencing terrestrial ecosystem functioning. However, how the impacts of climatic change on microclimate vary with vegetation types remains elusive. Methods Using a 9-year (2014–2022) dataset from a field manipulative experiment conducted on the Mongolian Plateau, this study examined the effects of nighttime warming and changing precipitation on soil microclimate of three temperate steppes (i.e., desert, typical, and meadow steppes) along a precipitation gradient. Results Over the 9 years, nighttime warming increased soil temperature by 0.88, 0.78, and 0.65 °C, decreased precipitation elevated it by 0.63, 0.34, and 0.24 °C, but increased precipitation lowered it by 0.46, 0.84, and 0.90 °C in the desert, typical, and meadow steppes, respectively. Nighttime warming suppressed soil moisture by 0.64% (v/v) in the meadow steppe only. Decreased precipitation reduced soil moisture by 0.84, 0.88, and 1.30%, whereas increased precipitation enhanced it by 0.92, 1.23, and 1.24% in the desert, typical, and meadow steppes, respectively. The response of soil microclimate to the simulated climate change was primarily driven by evaporation, transpiration, and plant cover in the desert and typical steppes, whereas transpiration and plant cover explained those changes in the meadow steppe. Conclusions These findings of the variations of underlying mechanisms of soil microclimate response to climate change with water conditions can improve predictions of ecosystem carbon cycling across diverse grassland ecosystems.

Numerous ecosystem manipulative experiments have been conducted since 1970/80 s to elucidate responses of terrestrial carbon cycling to the changing atmospheric composition (CO2 enrichment and nitrogen deposition) and climate (warming and changing precipitation regimes), which is crucial for model projection and mitigation of future global change effects. Here, we extract data from 2,242 publications that report global change manipulative experiments and build a comprehensive global database with 5,213 pairs of samples for plant production (productivity, biomass, and litter mass) and ecosystem carbon exchange (gross and net ecosystem productivity as well as ecosystem and soil respiration). Information on climate characteristics and vegetation types of experimental sites as well as experimental facilities and manipulation magnitudes subjected to manipulative experiments are also included in this database. This global database can facilitate the estimation of response and sensitivity of key terrestrial carbon-cycling variables under future global change scenarios, and improve the robust projection of global change‒terrestrial carbon feedbacks imposed by Earth System Models.Measurement(s)organic material • plant production • carbon exchangeTechnology Type(s)digital curationFactor Type(s)climate characteristics • vegetation traitsSample Characteristic - Environmentclimate systemSample Characteristic - LocationglobalMachine-accessible metadata file describing the reported data: 10.6084/m9.figshare.12932843

Forest ecosystems contain a substantial terrestrial reservoir of soil organic carbon (SOC). Here, a “Detritus Input and Removal Treatments” experiment was conducted to explore the effects of litter and roots on soil labile, persistent, and total organic C (TOC) pools in the coniferous, broad-leaved, and coniferous-broad-leaved mixed forests (CF, BF, and CBF, respectively) in the subtropical and warm temperate transition zone in Henan province, eastern China. After 2–3 years of detritus manipulations, neither litter addition nor root exclusion affected soil temperature or moisture. In contrast, litter removal increased soil temperature but decreased soil moisture, regardless of forest types. Litter addition marginally decreased labile OC and TOC contents in the BF but not in the CF and CBF. Litter removal reduced labile OC and TOC contents in the CF and BF and persistent OC contents in the CF only. Root exclusion decreased labile OC contents in the CBF only, but reduced persistent OC and TOC contents in the CF and CBF. Structural equation models suggested that litter but not root manipulation altered SOC pools via changing soil temperature and moisture in the BF, whereas the effects of litter and root manipulation on SOC pools were not related to the changes in soil temperature and moisture in the CF and CBF. Our results suggest that the impact of litter and roots on SOC pools depends on forest types, which may indicate differential responses of SOC storage among forests under global change scenarios.

Changing precipitation regimes can profoundly affect plant growth in terrestrial ecosystems, especially in arid and semi-arid regions. However, how changing precipitation, especially extreme precipitation events, alters plant diversity and community composition is still poorly understood. A 3-year field manipulative experiment with seven precipitation treatments, including − 60%, − 40%, − 20%, 0% (as a control), + 20%, + 40%, and + 60% of ambient growing-season precipitation, was conducted in a semi-arid steppe in the Mongolian Plateau. Results showed total plant community cover and forb cover were enhanced with increased precipitation and reduced under decreased precipitation, whereas grass cover was suppressed under the − 60% treatment only. Plant community and grass species richness were reduced by the − 60% treatment only. Moreover, our results demonstrated that total plant community cover was more sensitive to decreased than increased precipitation under normal and extreme precipitation change, and species richness was more sensitive to decreased than increased precipitation under extreme precipitation change. The community composition and low field water holding capacity may drive this asymmetric response. Accumulated changes in community cover may eventually lead to changes in species richness. However, compared to control, Shannon–Weiner index (H) did not respond to any precipitation treatment, and Pielou’s evenness index (E) was reduced under the + 60% treatment across the 3 year, but not in each year. Thus, the findings suggest that plant biodiversity in the semi-arid steppe may have a strong resistance to precipitation pattern changes through adjusting its composition in a short term.