Ecological responses of Stipa steppe in Inner Mongolia to experimentally increased temperature and precipitation 5: Synthesis and implications

2018 ◽  
Vol 40 (2) ◽  
pp. 167 ◽  
Author(s):  
Guozheng Hu ◽  
Zhiqiang Wan ◽  
Yali Chen ◽  
Luomeng Chao ◽  
Qingzhu Gao ◽  
...  
Keyword(s):  
Climate Change ◽  
Soil Respiration ◽  
Inner Mongolia ◽  
Temporal Dynamics ◽  
Ecosystem Respiration ◽  
Net Ecosystem Exchange ◽  
Community Diversity ◽  
Future Climate Change ◽  
Ecosystem Productivity ◽  
Gross Ecosystem Productivity

A randomised block experiment was conducted to study the response of plant community characteristics (biomass, density and diversity) and ecosystem carbon exchange processes to warming, increased precipitation and their combination on Stipa steppe in Inner Mongolia. Increased precipitation enhanced the effect that warming had in promoting community diversity and biomass. Increased precipitation directly increased net ecosystem exchange and gross ecosystem productivity, although ecosystem respiration and soil respiration also increased. However, warming did not have a significant effect on net ecosystem exchange and gross ecosystem productivity, whereas ecosystem respiration and soil respiration were significantly decreased by warming. All carbon flux processes had a significantly positive correlation with soil moisture. However, the carbon sequestration processes, gross ecosystem productivity and net ecosystem exchange, were significantly negatively correlated with temperature, contrary to carbon emission processes, soil respiration and ecosystem respiration. Results suggest that Stipa steppe may be benefited by future climate change, as the predicted precipitation is increasing with warming in Inner Mongolia. However, it is hard to predict the feedback of Stipa steppe to climate, because of the uncertainty in magnitude and temporal dynamics of climate change. To reveal the mechanism of the observed responses, further studies are suggested in this region on the effects of altered climate variables on plant species interactions, soil organic carbon composition, soil extracellular enzyme activity, microbial biomass and microbial respiration.

Ecological responses of Stipa steppe in Inner Mongolia to experimentally increased temperature and precipitation. 4. Carbon exchange

2018 ◽  
Vol 40 (2) ◽  
pp. 159 ◽  
Author(s):  
Luomeng Chao ◽  
Zhiqiang Wan ◽  
Yulong Yan ◽  
Rui Gu ◽  
Yali Chen ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Air Temperature ◽  
Inner Mongolia ◽  
Ecosystem Respiration ◽  
Block Design ◽  
Net Ecosystem Exchange ◽  
Carbon Exchange ◽  
Ecosystem Productivity ◽  
Temperature And Precipitation ◽  
Gross Ecosystem Productivity

Aspects of carbon exchange were investigated in typical steppe east of Xilinhot city in Inner Mongolia. Four treatments with four replicates were imposed in a randomised block design: Control (C), warming (T), increased precipitation (P) and combined warming and increased precipitation (TP). Increased precipitation significantly increased both ecosystem respiration (ER) and soil respiration (SR) rates. Warming significantly reduced the ER rate but not the SR rate. The combination of increased precipitation and warming produced an intermediate response. The sensitivity of ER and SR to soil temperature and air temperature was assessed by calculating Q10 values: the increase in respiration for a 10°C increase in temperature. Q10 was lowest under T and TP, and highest under P. Both ER and SR all had significantly positive correlation with soil moisture. Increased precipitation increased net ecosystem exchange and gross ecosystem productivity, whereas warming reduced them. The combination of warming and increased precipitation had an intermediate effect. Both net ecosystem exchange and gross ecosystem productivity were positively related to soil moisture and negatively related to soil and air temperature. These findings suggest that predicted climate change in this region, involving both increased precipitation and warmer temperatures, will increase the net ecosystem exchange in the Stipa steppe meaning that the ecosystem will fix more carbon.

scholarly journals Simulation of Carbon Exchange from a Permafrost Peatland in the Great Hing’an Mountains Based on CoupModel

Atmosphere ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 44
Author(s):  
Yue Li ◽  
Zhongmei Wan ◽  
Li Sun
Keyword(s):  
Climate Change ◽  
Carbon Sink ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Net Ecosystem Exchange ◽  
Carbon Accumulation ◽  
Future Climate ◽  
Future Climate Change ◽  
Growing Seasons ◽  
Source Sink

Climate change is accelerating its impact on northern ecosystems. Northern peatlands store a considerable amount of C, but their response to climate change remains highly uncertain. In order to explore the feedback of a peatland in the Great Hing’an Mountains to future climate change, we simulated the response of the overall net ecosystem exchange (NEE), ecosystem respiration (ER), and gross primary production (GPP) during 2020–2100 under three representative concentration pathways (RCP2.6, RCP6.0, and RCP8.5). Under the RCP2.6 and RCP6.0 scenarios, the carbon sink will increase slightly until 2100. Under the RCP8.5 scenario, the carbon sink will follow a trend of gradual decrease after 2053. These results show that when meteorological factors, especially temperature, reach a certain degree, the carbon source/sink of the peatland ecosystem will be converted. In general, although the peatland will remain a carbon sink until the end of the 21st century, carbon sinks will decrease under the influence of climate change. Our results indicate that in the case of future climate warming, with the growing seasons experiencing overall dryer and warmer environments and changes in vegetation communities, peatland NEE, ER, and GPP will increase and lead to the increase in ecosystem carbon accumulation.

Mismatch between the optimal ages for ecosystem productivity and net CO2 sequestration in Norway spruce forests

2021 ◽  
Author(s):  
Junbin Zhao ◽  
Holger Lange ◽  
Helge Meissner
Keyword(s):  
Climate Change ◽  
Primary Production ◽  
Norway Spruce ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Economic Benefits ◽  
Sink Strength ◽  
Climate Change Scenarios ◽  
Ecosystem Productivity ◽  
Spruce Forests

<p>Forests have climate change mitigation potential since they sequester carbon. However, their carbon sink strength might depend on management. As a result of the balance between CO<sub>2</sub> uptake and emission, forest net ecosystem exchange (NEE) reaches optimal values (maximum sink strength) at young stand ages, followed by a gradual NEE decline over many years. Traditionally, this peak of NEE is believed to be concurrent with the peak of primary production (e.g., gross primary production, GPP); however, in theory, this concurrence may potentially vary depending on tree species, site conditions and the patterns of ecosystem respiration (R<sub>eco</sub>). In this study, we used eddy-covariance (EC)-based CO<sub>2</sub> flux measurements from 8 forest sites that are dominated by Norway spruce (Picea abies L.) and built machine learning models to find the optimal age of ecosystem productivity and that of CO<sub>2</sub> sequestration. We found that the net CO<sub>2</sub> uptake of Norway spruce forests peaked at ages of 30-40 yrs. Surprisingly, this NEE peak did not overlap with the peak of GPP, which appeared later at ages of 60-90 yrs. The mismatch between NEE and GPP was a result of the R<sub>eco</sub> increase that lagged behind the GPP increase associated with the tree growth at early age. Moreover, we also found that newly planted Norway spruce stands had a high probability (up to 90%) of being a C source in the first year, while, at an age as young as 5 yrs, they were likely to be a sink already. Further, using common climate change scenarios, our model results suggest that net CO<sub>2</sub> uptake of Norway spruce forests will increase under the future climate with young stands in the high latitude areas being more beneficial. Overall, the results suggest that forest management practices should consider NEE and forest productivity separately and harvests should be performed only after the optimal ages of both the CO<sub>2</sub> sequestration and productivity to gain full ecological and economic benefits.</p>

Grassland dynamics in response to climate change and human activities in Inner Mongolia, China between 1985 and 2009

2013 ◽  
Vol 35 (3) ◽  
pp. 315 ◽  
Author(s):  
S. J. Mu ◽  
Y. Z. Chen ◽  
J. L. Li ◽  
W. M. Ju ◽  
I. O. A. Odeh ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Ecological Restoration ◽  
Human Activities ◽  
Inner Mongolia ◽  
Management Practices ◽  
Net Primary Productivity ◽  
Temporal Dynamics ◽  
Driving Forces ◽  
Landscape Patterns

China’s grassland has been undergoing rapid changes in the recent past owing to increased climate variability and a shift in grassland management strategy driven by a series of ecological restoration projects. This study investigated the spatio-temporal dynamics of Inner Mongolia grassland, the main grassland region in China and part of the Eurasia Steppe, to detect the interactive nature of climate, ecosystems and society. Land-use and landscape patterns for the period from 1985 to 2009 were analysed based on TM- and MODIS-derived land-use data. Net Primary Productivity (NPP) estimated by using the Carnegie-Ames-Stanford Approach model was used to assess the growth status of grassland. Furthermore, the factors related to the dynamics of grassland were analysed from the perspectives of two driving factors, climate change and human activities. The results indicated that higher temperatures and lower precipitation may generally have contributed to grassland desertification, particularly in arid regions. During the period from 1985 to 2000, a higher human population and an increase in livestock numbers were the major driving forces responsible for the consistent decrease in NPP and a relatively fragmented landscape. From 2000 to 2009, the implementation of effective ecological restoration projects has arrested the grassland deterioration in some ecologically fragile regions. However, a rapid growth of livestock numbers has sparked new degradation onnon-degraded or lightly degraded grassland, which was initially neglected by these projects. In spite of some achievement in grassland restoration, China should take further steps to develop sustainable management practices for climate adaptation and economic development to bring lasting benefits.

Amazon forest responses to drought: scaling from individuals to ecosystems.

2020 ◽  
Author(s):  
Scott R. Saleska ◽  
Natalia Restrepo-Coupe ◽  
Fernanda V. Barros ◽  
Paulo R. L. Bittencourt ◽  
Neill Prohaska ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Cycle ◽  
Ecosystem Respiration ◽  
Global Climate ◽  
Forest Composition ◽  
Future Climate Change ◽  
Amazon Forest ◽  
Ecosystem Responses ◽  
Climate Conditions ◽  
Dry Seasons

<p>Scaling from individuals or species to ecosystems is a fundamental challenge of modern ecology and understanding tropical forest response to drought is a key challenge of predicting responses to global climate change.  We here synthesize our developing understanding of these twin challenges by examining individual and ecosystem responses to the 2015 El Niño drought at two sites in the central Amazon of Brazil, near Manaus and Santarem, which span a precipitation gradient from moderate (Manaus) to long (Santarem) dry seasons.  We will focus on how ecosystem water and carbon cycling, measured by eddy flux towers, emerges from individual trait-based responses, including photosynthetic responses of individual leaves, and water cycle responses in terms of stomatal conductance and hydraulic xylem embolism resistance.  We found the Santarem forest (with long dry seasons) responded strongly to drought: sensible heat values significantly increased and evapotranspiration decreased.  Consistent with this, we also observed reductions in photosynthetic activity and ecosystem respiration, showing levels of stress not seen in the nearly two decades since measurements started at this site.  Forests at the Manaus site showed significant, however, less consistent reductions in water and carbon exchange and a more pronounced water deficit.  We report an apparent community level forest composition selecting for assemblies of traits and taxa manifest of higher drought tolerance at Santarem, compared to the Manaus forest (short dry seasons) and other forest sites across Amazonia.  These results suggest that we may be able to use community trait compositions (as selected by past climate conditions) and environmental threshold values (e.g. cumulative rainfall, atmospheric moisture and radiation) as to help forecast ecosystem responses to future climate change.</p>

Is the impact of climate change on desertification predictable?

2020 ◽  
Author(s):  
YaoJie Yue ◽  
Min Li
Keyword(s):  
Climate Change ◽  
Inner Mongolia ◽  
North China ◽  
Evaluation Model ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Arid Areas ◽  
Sandy Land ◽  
Desertification Risk ◽  
Semi Arid

<p>Desertification, as one of the gravest ecological and environmental problems in the world, is affected both by climate change and human activities. As the consequences of global warming, the temperature in global arid and semi-arid areas is expected to increase by 1-3℃ by the end of this century. This change will significantly influence the spatial and temporal pattern of temperature, precipitation and wind speed in global arid and semi-arid areas, and in turn, ultimately impact the processing of desertification. Although current studies point out that future climate change tends to increase the risk of desertification. However, the future global or regional desertification risk under different climate change scenarios hasn’t been quantitively assessed. In this paper, we focused on this question by building a new model to evaluate this risk of desertification under an extreme climate change scenario, i.e. RCP8.5 (Representative Concentration Pathways, RCPs). We selected the northern agro-pastoral ecotone in China as the study area, where is highly sensitive to desertification. Firstly, the risk indicators of desertification were chosen in both natural and anthropic aspects, such as temperature, precipitation, wind speed, evaporation, and population. Secondly, the decision tree C5.0 algorithm of the machine learning technique was used to construct the quantitative evaluation model of land desertification risk based on the database of the 1:100,000 desertification map in China. Thirdly, with the support of the simulated meteorological data by General Circulation Models of HadGEM2-ES, the risk of desertification in the agro-pastoral ecotone in the north China under the RCP 8.5 scenario and SSP3 scenario (Shared Socioeconomic Pathways, SSPs) were predicted. The results show that the overall accuracy of the C5.0-based quantitative evaluation model for desertification risk is up to 83.32%, indicating that the C5.0 can better distinguish the risk of desertification according to the status of desertification impacting factors. Under the influence of future climate change, the agro-pastoral ecotone in northern China was estimated to be dominated by mild desertification risk, covering an area of more than 70%. Severe and moderate desertification risk is mainly distributed in the vicinity of Hulunbuir sandy land in the northeast of Inner Mongolia and the Horqin sandy land in the junction between Inner Mongolia, Jilin and Liaoning provinces. Compared with the datum period, the risk of desertification will decrease under the RCP8.5-SSP3 scenario. However, the desertification risk in Hulunbuir sandy land and that in the northwest of Jilin province will increase. The results of this study provide a scientific basis for developing more effective desertification control strategies to adapt to climate change in the agro-pastoral ecotone in north China. More importantly, it shows that the desertification risk can be predicted under the different climate change scenarios, which will help us to make a better understanding of the potential trend of desertification in the future, especially when the earth is getting warmer.</p>

Net ecosystem exchange of CO2 and ecosystem respiration in two bogs in Estonia along disturbance gradient

2021 ◽  
Author(s):  
Martin Maddison ◽  
Gert Veber ◽  
Ain Kull
Keyword(s):  
Climate Change ◽  
Water Level ◽  
Water Table ◽  
Air Temperature ◽  
Ecosystem Respiration ◽  
Net Ecosystem Exchange ◽  
Growing Period ◽  
Disturbance Gradient ◽  
Study Sites

<p>Northern peatlands are important terrestrial carbon (C) stores, but their ability to sequestrate C is at delicate balance affected by management and also by climate change. The climate change causes less snow pack and warmer winters with faster water table drop in spring and drier summers in most boreal areas. Due to those changes natural peatlands may become C source instead of sink.</p><p>This study presents ecosystem respiration (ER) over five-year period and the annual estimates of net ecosystem exchange (NEE) of CO<sub>2</sub> in Umbusi and Laukasoo in Estonia along disturbance gradient from drained to natural ombrotrophic bog. Both study sites locate next to the active cutaway peatlands. There were four CO<sub>2</sub> flux measurements plots with three measurements points at different distance from the drainage ditch (10, 50, 100 and 200 m in Umbusi; 3, 40, 50, 125 m in Laukasoo) to form a water table depth and soil moisture gradient on both study sites. ER was measured using opaque static chamber throughout of the year in period 2012-2016. A vented and thermostated transparent plastic chamber with removable opaque cover was used for CO<sub>2</sub> exchange measurements. NEE measurements occurred biweekly from April to December in 2015, totally were done 648 measurements. NEE was derived from modelling of ER and gross primary production with temperature, photosynthetically active radiation, water level and days of year (as phenological phase) as driving variables.</p><p>Annual mean NEE at four different distance from the ditch toward undisturbed area in Umbusi and Laukasoo were 0.37, 0.28, 0.15, 0.08 and 0.44, 0.34, 0.04, 0.21 kg C m<sup>-2</sup> y<sup>-1</sup>, respectively. Although mean NEE was positive for all plots on both sites, there were also negative annual NEE values in some points in undisturbed plots (100 and 200 m from the ditch in Umbusi and 50 and 125 m in Laukasoo).</p><p>Average water level at four different distance from the ditch toward undisturbed area in Umbusi and Laukasoo during growing period (from the beginning of May to the end of October) in 2015 were -94, -45, -22, -22 and -124, -33, -21, -22 cm, respectively. Monthly mean air temperature and sum of precipitation were not different from the long-term measurements in studied growing period in 2015 while winter was significantly warmer.</p><p>Modelled ER remained high for cold period because of higher air temperature in 2015. Due to higher respiration rate from non-frozen peat layer in cold season, more CO<sub>2</sub> was released back to atmosphere and annually less C was accumulated. Monthly mean air temperature for cold period was 3.5 ºC warmer than the long-term average.</p>

Response of potential grassland vegetation to historical and future climate change in Inner Mongolia

2021 ◽  
Author(s):  
Liu Xiaoni ◽  
Li Qiang ◽  
Wang Hongxia ◽  
Ren Zhengcao ◽  
He Guoxing ◽  
...  
Keyword(s):  
Climate Change ◽  
Inner Mongolia ◽  
Future Climate ◽  
Future Climate Change ◽  
Grassland Vegetation

scholarly journals Influence of spring and autumn phenological transitions on forest ecosystem productivity

2010 ◽  
Vol 365 (1555) ◽  
pp. 3227-3246 ◽  
Author(s):  
Andrew D. Richardson ◽  
T. Andy Black ◽  
Philippe Ciais ◽  
Nicolas Delbart ◽  
Mark A. Friedl ◽  
...  
Keyword(s):  
Climate Change ◽  
Eddy Covariance ◽  
Boreal Forests ◽  
Ecosystem Respiration ◽  
Ecosystem Productivity ◽  
Important Conclusion ◽  
Gross Ecosystem Photosynthesis ◽  
Eddy Covariance Measurements ◽  
Phenological Shifts ◽  
Carry Over

We use eddy covariance measurements of net ecosystem productivity (NEP) from 21 FLUXNET sites (153 site-years of data) to investigate relationships between phenology and productivity (in terms of both NEP and gross ecosystem photosynthesis, GEP) in temperate and boreal forests. Results are used to evaluate the plausibility of four different conceptual models. Phenological indicators were derived from the eddy covariance time series, and from remote sensing and models. We examine spatial patterns (across sites) and temporal patterns (across years); an important conclusion is that it is likely that neither of these accurately represents how productivity will respond to future phenological shifts resulting from ongoing climate change. In spring and autumn, increased GEP resulting from an ‘extra’ day tends to be offset by concurrent, but smaller, increases in ecosystem respiration, and thus the effect on NEP is still positive. Spring productivity anomalies appear to have carry-over effects that translate to productivity anomalies in the following autumn, but it is not clear that these result directly from phenological anomalies. Finally, the productivity of evergreen needleleaf forests is less sensitive to phenology than is productivity of deciduous broadleaf forests. This has implications for how climate change may drive shifts in competition within mixed-species stands.

scholarly journals Soil respiration of a Moso bamboo forest significantly affected by gross ecosystem productivity and leaf area index in an extreme drought event

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5747 ◽  
Author(s):  
Yuli Liu ◽  
Guomo Zhou ◽  
Huaqiang Du ◽  
Frank Berninger ◽  
Fangjie Mao ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Respiration ◽  
Soil Temperature ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Moso Bamboo ◽  
Drought Event ◽  
Ecosystem Productivity ◽  
Area Index ◽  
Gross Ecosystem Productivity

Moso bamboo has large potential to alleviate global warming through carbon sequestration. Since soil respiration (Rs) is a major source of CO2 emissions, we analyzed the dynamics of soil respiration (Rs) and its relation to environmental factors in a Moso bamboo (Phllostachys heterocycla cv. pubescens) forest to identify the relative importance of biotic and abiotic drivers of respiration. Annual average Rs was 44.07 t CO2 ha−1 a−1. Rs correlated significantly with soil temperature (P < 0.01), which explained 69.7% of the variation in Rs at a diurnal scale. Soil moisture was correlated significantly with Rs on a daily scale except not during winter, indicating it affected Rs. A model including both soil temperature and soil moisture explained 93.6% of seasonal variations in Rs. The relationship between Rs and soil temperature during a day showed a clear hysteresis. Rs was significantly and positively (P < 0.01) related to gross ecosystem productivity and leaf area index, demonstrating the significance of biotic factors as crucial drivers of Rs.

Sign in / Sign up

Export Citation Format

Share Document