Dynamics and Controls of Carbon Use Efficiency across China’s Grasslands

Hou, Guichen; Sun, Jian; Wang, Jinniu

doi:10.15244/pjoes/76912

Cited by 15 publications

(8 citation statements)

References 44 publications

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“…By integrating multiple‐sourced data, this study revealed a phenomenon rarely captured by related studies for the TP, that is, negative and nonlinear responses of the CUEe to warming (Z. Chen et al., 2018; Fu et al., 2016; Hou et al., 2018). It is worth noting that the CUEe declines by a greater magnitude under HW than under LW.…”

Section: Discussionmentioning

confidence: 77%

“…The TP has also undergone a faster rate of climate warming than the Northern Hemisphere average in recent decades, and warming has emerged as a widely studied ecosystem driver (Qiu, 2008; Y. Zhang, Zhu, et al., 2019). Pioneering studies of CUEc on the TP apply remote sensing observations at a regional scale, and the underlying CUEe mechanisms remain elusive (Fu et al., 2016; Hou et al., 2018). Here, by integrating a manipulative experiment using a warming gradient at a site scale, two EC measurements at a landscape scale and ten synthetic warming experiments and four ecosystem process models at a regional scale, we explored the impacts of warming on the CUEe across the alpine grasslands of the TP.…”

Section: Introductionmentioning

confidence: 99%

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Multiple‐scale negative impacts of warming on ecosystem carbon use efficiency across the Tibetan Plateau grasslands

Chen

Zhang

Zhu

et al. 2020

Global Ecol. Biogeogr.

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Aim Ecosystem carbon use efficiency (CUEe) is a core parameter of ecosystem process models, but its relationships with climate are still uncertain, especially for ecosystems with harsh environments. Large inconsistencies in climate impacts on the CUEe have been reported among various spatial scales. The goal of this study was to examine whether warming promotes or restricts the CUEe and whether the CUEe responds to a warming gradient in a linear or nonlinear manner. Location Tibetan Plateau. Time period 2000–2018. Major taxa studied Alpine grassland ecosystem. Methods We integrated multiple‐source data of carbon fluxes and CUEe, including warming experiments at a site scale, eddy covariance observations at a landscape scale and synthesized warming experiments and ecosystem process models at a regional scale. Next, we deployed a statistical model to examine the warming impacts on the CUEe across scales; the effects of biotic and abiotic factors on the CUEe and its components were summarized based on the results of standardized major axis tests and routines, structural equation modelling and nonlinear models. Results This study reported a suppressive warming impact on the CUEe, which followed a nonlinear curve with severe inhibition in the high‐level warming treatment. With a warming threshold of 1.5–2.0°C, CUEe response patterns transitioned from no change to a significant decrease. The restriction effects can be ascribed to the joint adverse and asymmetric effects of warming on CUEe components under multiple‐level warming. Warming‐modified relationships among CUEe components and the nonlinear effects of biotic and abiotic factors led to the nonlinear responses of CUEe to warming. Main conclusions This study revealed suppressive and nonlinear effects of warming on the CUEe, including especially dramatic CUEe decreases with high‐level warming. These findings are critical for optimizing model parameters and improving predictions of the carbon sequestration capacity of alpine grasslands.

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Section: Discussionmentioning

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Multiple‐scale negative impacts of warming on ecosystem carbon use efficiency across the Tibetan Plateau grasslands

Chen

Zhang

Zhu

et al. 2020

Global Ecol. Biogeogr.

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“…Other studies have reported a positive relationship between annual CUE and temperature across biomes (Hou, Sun, & Wang, 2018;Piao et al, 2010). One plausible explanation for the positive relationship between CUE and temperature that has been given is that, although rising temperature is generally accompanied by an extension of the GS and an increase in GEP, the accompanying increase in R a is limited by respiration acclimation over a long-term warming period (Piao et al, 2010).…”

Section: Spring (April To May)mentioning

confidence: 89%

Divergent long‐term trends and interannual variation in ecosystem resource use efficiencies of a southern boreal old black spruce forest 1999–2017

Liu

Black

Jassal

et al. 2019

Global Change Biology

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Long‐term trends in ecosystem resource use efficiencies (RUEs) and their controlling factors are key pieces of information for understanding how an ecosystem responds to climate change. We used continuous eddy covariance and microclimate data over the period 1999–2017 from a 120‐year‐old black spruce stand in central Saskatchewan, Canada, to assess interannual variability, long‐term trends, and key controlling factors of gross ecosystem production (GEP) and the RUEs of carbon (CUE = net primary production [NPP]/GEP), light (LUE = GEP/absorbed photosynthetic radiation [APAR]), and water (WUE = GEP/evapotranspiration [E]). At this site, annual GEP has shown an increasing trend over the 19 years (p < 0.01), which may be attributed to rising atmospheric CO2 concentration. Interannual variability in GEP, aside from its increasing trend, was most strongly related to spring temperatures. Associated with the significant increase in annual GEP were relatively small changes in NPP, APAR, and E, so that annual CUE showed a decreasing trend and annual LUE and WUE showed increasing trends over the 19 years. The long‐term trends in the RUEs were related to the increasing CO2 concentration. Further analysis of detrended RUEs showed that their interannual variation was impacted most strongly by air temperature. Two‐factor linear models combining CO2 concentration and air temperature performed well (R2~0.60) in simulating annual RUEs. LUE and WUE were positively correlated both annually and seasonally, while LUE and CUE were mostly negatively correlated. Our results showed divergent long‐term trends among CUE, LUE, and WUE and highlighted the need to account for the combined effects of climatic controls and the ‘CO2 fertilization effect’ on long‐term variations in RUEs. Since most RUE‐based models rely primarily on one resource limitation, the observed patterns of relative change among the three RUEs may have important implications for RUE‐based modeling of C fluxes.

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“…Soil water is another important environmental condition in altering plant colonization and distribution specially in the arid alpine steppe (Sun et al, 2013;Ma et al, 2017). Soil water conditions can affect soil nutrient supply ability and drive plant succession in alpine steppe (Yang et al, 2013;Hou et al, 2018). For example, low SWC is inhospitable to nitrogen uptake for graminoids which is more nitrophilous (Hou et al, 2018).…”

Section: Habitat Conditions and Root Morphological Traits Determine Pmentioning

confidence: 99%

“…Soil water conditions can affect soil nutrient supply ability and drive plant succession in alpine steppe (Yang et al, 2013;Hou et al, 2018). For example, low SWC is inhospitable to nitrogen uptake for graminoids which is more nitrophilous (Hou et al, 2018). Additionally, even a small variation in SWC may cause a remarkable difference in both seed germination and seedling survival, which consequently affects the individual amount and composition of plant community (Ma et al, 2017).…”

Section: Habitat Conditions and Root Morphological Traits Determine Pmentioning

confidence: 99%

Root Features Determine the Increasing Proportion of Forbs in Response to Degradation in Alpine Steppe, Tibetan Plateau

Zhang¹,

Sun²

2020

Front. Environ. Sci.

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Understanding the response of plant community to degradation is fundamentally important for grassland conservation and management. The objective of this study is to examine the changes in soil properties and plant characteristics along a degradation gradient in alpine steppe, and explore the potential mechanisms that biotic and abiotic controls regulate plant community variations. We chose seven sequent degrees of degradation, and conducted a field survey as well as soil and plant samplings in an alpine steppe in Northern Tibet. The results showed that soil water content (SWC), soil compaction (SCOM), soil total carbon (STC), and total nitrogen (STN) dramatically decreased along the degradation gradient. The species richness, overall aboveground biomass (AGB), and AGB of graminoids were apparently reduced with increasing degradation, while AGB of forbs slightly increased. The increasing degradation levels induced a significant increase in the trade-off value of AGB of forbs, which was negatively associated with SWC, SCOM, STC, STN, and soil available nitrogen. The mean root length of forbs was significantly longer than that of graminoids (P < 0.05). Moreover, the mean root diameter of the top 1/3 part of forbs was remarkably thicker than that of graminoids (P < 0.05). These findings indicate that the degradation-induced cohesionless soils with insufficient water and nutrients together with the divergent root morphological traits of graminoids and forbs determine the plant community structure shift with grassland degradation. This study can improve the understanding of community succession of grassland degradation, and provide guidance for the management of degraded alpine steppe on the Tibetan Plateau.

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Dynamics and Controls of Carbon Use Efficiency across China’s Grasslands

Cited by 15 publications

References 44 publications

Multiple‐scale negative impacts of warming on ecosystem carbon use efficiency across the Tibetan Plateau grasslands

Multiple‐scale negative impacts of warming on ecosystem carbon use efficiency across the Tibetan Plateau grasslands

Divergent long‐term trends and interannual variation in ecosystem resource use efficiencies of a southern boreal old black spruce forest 1999–2017

Root Features Determine the Increasing Proportion of Forbs in Response to Degradation in Alpine Steppe, Tibetan Plateau

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