Shifts of growing‐season precipitation peaks decrease soil respiration in a semiarid grassland

Ru, Jingyi; Zhou, Yaqiong; Hui, Dafeng; Zheng, Mengmei; Wan, Shiqiang

doi:10.1111/gcb.13941

Cited by 106 publications

(50 citation statements)

References 57 publications

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“…On average, our results showed that warming, elevated CO 2 , N fertilization, and increased precipitation significantly increased APCP, BPCP, SCP, and Rs, while drought exhibited negative effects on those variables (Figure ). Drought generally impedes plant growth due to the reduction of canopy photosynthesis and nutrient uptake from soil by decreased SM and relative humidity in grassland ecosystems (Davidson & Janssens, ; Knapp & Smith, ; Ru, Zhou, Hui, Zheng, & Wan, ). The decreased canopy photosynthesis induced by drought may also reduce root biomass due to depressed supply of photosynthetic products to roots, resulting in decreased microbial biomass, a smaller SCP, and lower Rs (Knapp & Smith, ; Liu et al, ; van Groenigen et al, ).…”

Section: Discussionmentioning

confidence: 99%

Effects of livestock grazing on grassland carbon storage and release override impacts associated with global climate change

Zhou¹,

Luo²,

Chen³

et al. 2018

Global Change Biology

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Predicting future carbon (C) dynamics in grassland ecosystems requires knowledge of how grazing and global climate change (e.g., warming, elevated CO2, increased precipitation, drought, and N fertilization) interact to influence C storage and release. Here, we synthesized data from 223 grassland studies to quantify the individual and interactive effects of herbivores and climate change on ecosystem C pools and soil respiration (Rs). Our results showed that grazing overrode global climate change factors in regulating grassland C storage and release (i.e., Rs). Specifically, grazing significantly decreased aboveground plant C pool (APCP), belowground plant C pool (BPCP), soil C pool (SCP), and Rs by 19.1%, 6.4%, 3.1%, and 4.6%, respectively, while overall effects of all global climate change factors increased APCP, BPCP, and Rs by 6.5%, 15.3%, and 3.4% but had no significant effect on SCP. However, the combined effects of grazing with global climate change factors also significantly decreased APCP, SCP, and Rs by 4.0%, 4.7%, and 2.7%, respectively but had no effect on BPCP. Most of the interactions between grazing and global climate change factors on APCP, BPCP, SCP, and Rs were additive instead of synergistic or antagonistic. Our findings highlight the dominant effects of grazing on C storage and Rs when compared with the suite of global climate change factors. Therefore, incorporating the dominant effect of herbivore grazing into Earth System Models is necessary to accurately predict climate–grassland feedbacks in the Anthropocene.

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Section: Discussionmentioning

confidence: 99%

Effects of livestock grazing on grassland carbon storage and release override impacts associated with global climate change

Zhou¹,

Luo²,

Chen³

et al. 2018

Global Change Biology

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“…Lower soil water contents in the growing season may impede canopy photosynthesis and then suppress root activity (e.g. water and nutrient uptake, Ru et al, 2018). Decreased transport of assimilated C towards the rhizosphere could also suppress soil microbial biomass F I G U R E 5 Effects of drought on relationships between soil temperature and autotrophic respiration (Ra, A), heterotrophic respiration (Rh, B), and soil respiration (Rs, C), relationships between volumetric soil moisture and Ra (D), Rh (E) and Rs (F).…”

Section: Root Biomass and Microbial Community Regulate The Responsementioning

confidence: 99%

“…Model simulations and field experiments both indicate that drought decreases soil water availability (Ru et al, 2018) and influences Rs by modifying roots and soil microbial communities (Luo & Zhou, 2006).…”

mentioning

confidence: 99%

Soil fungi and fine root biomass mediate drought‐induced reductions in soil respiration

Zhou

Liu

et al. 2020

Functional Ecology

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1. Climate change has increased the frequency and intensity of droughts, with potential impacts on carbon (C) release from soil (i.e. soil respiration, Rs). Although numerous studies have investigated drought-induced changes in Rs, how roots and the soil microbial community regulate responses of Rs to drought remains unclear. 2. We conducted a 4-year field experiment (2014-2017) with three treatments (i.e. 70% rainfall reduction, control and ambient) in a subtropical forest to examine effects of drought on Rs and its components [i.e. autotrophic (Ra) and heterotrophic respiration (Rh)] and explore the mechanisms underlying these effects. 3. Drought significantly decreased Rs by 17% averaged over the 4 years, but it had no significant effect in the first experimental year. The decrease in Rs was mediated by soil fungi and fine root biomass. Fine root biomass was correlated negatively with Ra and Rs under drought, but positively in the control treatment. Furthermore, drought treatments increased physiological stress in the bacterial community. Structural equation model (SEM) analysis suggested that under drought conditions, microclimate affected Rs via its impact on fine root biomass and fungal biomass. 4. Our results highlight the complex interactions between microclimate, roots and soil microbes in regulating Rs under drought in subtropical forest ecosystems. Incorporating these interactions into land surface models may improve predictions of climate change impacts on forest ecosystems. K E Y W O R D S C-climate feedback, CO 2 emission, drought, fine root biomass, fungi community, physiological stress, structural equation model 1 | INTRODUC TI ON Earth system models predict that global hydrological cycles will intensify in the next decades (IPCC, 2013), thereby altering the frequency and intensity of precipitation around the world (IPCC, 2013). Consequently, several regions will experience increased droughts, which threaten the biodiversity and stability of terrestrial ecosystems and alter ecosystem structure and function | 2635 Functional Ecology ZHOU et al.

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“…Our planet has experienced drastic global climate change, with accelerating warming and shifting precipitation regimes, in past decades [1][2][3]. Climate change affects ecosystem services and functions by altering vegetation phenology, plant community composition, and biogeochemical cycles [4][5][6]. For example, semiarid grasslands in East Africa are threatened in the context of increasing climate variability and climate extremes, especially in terms of ecosystem productivity and stability [7].…”

Section: Introductionmentioning

confidence: 99%

Temporal Variability of Precipitation and Biomass of Alpine Grasslands on the Northern Tibetan Plateau

Song

et al. 2019

Remote Sensing

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The timing regimes of precipitation can exert profound impacts on grassland ecosystems. However, it is still unclear how the peak aboveground biomass (AGBpeak) of alpine grasslands responds to the temporal variability of growing season precipitation (GSP) on the northern Tibetan Plateau. Here, the temporal variability of precipitation was defined as the number and intensity of precipitation events as well as the time interval between consecutive precipitation events. We conducted annual field measurements of AGBpeak between 2009 and 2016 at four sites that were representative of alpine meadow, meadow-steppe, alpine steppe, and desert-steppe. Thus, an empirical model was established with the time series of the field-measured AGBpeak and the corresponding enhanced vegetation index (EVI) (R2 = 0.78), which was used to estimate grassland AGBpeak at the regional scale. The relative importance of the three indices of the temporal variability of precipitation, events, intensity, and time interval on grassland AGBpeak was quantified by principal component regression and shown in a red–green–blue (RGB) composition map. The standardized importance values were used to calculate the vegetation sensitivity index to the temporal variability of precipitation (VSIP). Our results showed that the standardized VSIP was larger than 60 for only 15% of alpine grassland pixels and that AGBpeak did not change significantly for more than 60% of alpine grassland pixels over the past decades, which was likely due to the nonsignificant changes in the temporal variability of precipitation in most pixels. However, a U-shaped relationship was found between VSIP and GSP across the four representative grassland types, indicating that the sensitivity of grassland AGBpeak to precipitation was dependent on the types of grassland communities. Moreover, we found that the temporal variability of precipitation explained more of the field-measured AGBpeak variance than did the total amount of precipitation alone at the site scale, which implies that the mechanisms underlying how the temporal variability of precipitation controls the AGBpeak of alpine grasslands should be better understood at the local scale. We hypothesize that alpine grassland plants promptly respond to the temporal variability of precipitation to keep community biomass production more stable over time, but this conclusion should be further tested. Finally, we call for a long-term experimental study that includes multiple natural and anthropogenic factors together, such as warming, nitrogen deposition, and grazing and fencing, to better understand the mechanisms of alpine grassland stability on the Tibetan Plateau.

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Shifts of growing‐season precipitation peaks decrease soil respiration in a semiarid grassland

Cited by 106 publications

References 57 publications

Effects of livestock grazing on grassland carbon storage and release override impacts associated with global climate change

Effects of livestock grazing on grassland carbon storage and release override impacts associated with global climate change

Soil fungi and fine root biomass mediate drought‐induced reductions in soil respiration

Temporal Variability of Precipitation and Biomass of Alpine Grasslands on the Northern Tibetan Plateau

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