Carbon Fluxes and Carbon Sequestration in Grassland Ecosystems of Mongolia

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1 Workshop on Carbon Fluxes & Sequestration in the Ecosystems of Mongolia, 6 th September 2017, UB, Mongolia Carbon Fluxes and Carbon Sequestration in Grassland Ecosystems of Mongolia Qinxue WANG*, Tomohiro OKADERA, Eer DENI National Institute for Environmental Studies, Japan (*wangqx@nies.go.jp) Masataka WATANABE Research and Development Initiative, Chuo University, Japan Ochirbat BATKHISHIG Institute of Geography, Mongolian Academy of Sciences, Mongolia

2 Research Background & Objectives Grassland ecosystems play a critical role in regulating carbon (C) sequestration from atmosphere (Michael A. et al., 2009, FAO). In this study, we try to develop an ecosystem-grazing model to evaluate the spatiotemporal distribution of C sequestration by grassland ecosystems under the influence of both climate change and livestock grazing. Carbon sequestration is the process involved in carbon capture and the long-term storage of atmospheric carbon dioxide (Sedjo, Roger; Sohngen, Brent, 2012) Schematic showing both terrestrial and geological sequestration of carbon dioxide emissions (Source: Carbon_sequestration.jpg)

3 Research Background & Objectives Carbon Cycle & Carbon Sequestration GPP-Gross Primary Production NPP-Net Primary Production NEP-Net Ecosystem Production NBP-Net Biome Production Global terrestrial carbon uptake(adapted from Steffen et al., 1998). Plant (autotrophic) respiration (Ra) releases CO2 to the atmosphere, reducing GPP to NPP and resulting in short-term carbon sequestration. Decomposition of litter and soils (heterotrophic respiration, Rh) further releases CO2 to the atmosphere, reducing NPP to NEP and resulting in medium-term carbon sequestration. Disturbance from both natural and anthropogenic sources (e.g., harvest) leads to further release of CO2 to the atmosphere, which, in turn, leads to long-term carbon sequestration.

4 Case Study Area --- Mongolia Mongolia is a large inland country with a vast territory of 1.56 million km 2 72% of territory is rangeland supporting over 170,000 herder families Major ecosystems: Forest, forest steppe, tundra, meadows, steppe & desert

5 Climate Change in Mongolia Climate change in Mongolia: an obvious tendency of warming up and drying up (Data Source:

6 Carbon Emission in Mongolia Consumption of Coal (1,000 tons) CO2 Emissions from Fossil-Fuel CO2 emissions estimated by the revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories. It was shown that CO2 emissions from fossilfuel burning in Mongolia increased largely since the 1980s. (Data Source: budget/16/data.htm)

7 Atmospheric CO2 Concentration Satellite XCO2 in Mongolia retrievals from GOSAT, JAXA Satellite XCO2 retrievals from GOSAT, JAXA GOSAT -Greenhouse Gases Observing Satellite is a JAXA (Japan Aerospace Exploration Agency) mission within the GCOM (Global Change Observation Mission) program of Japan. The GOSAT mission goals call for the study of the transport mechanisms of greenhouse gases such as carbon dioxide (CO2) and methane (CH4).

8 CO2 Flux of Land Surface Satellite CO2 Fluxes in Mongolia retrievals from GOSAT, JAXA Our duty is to use the GOSAT Satellite to detect the effects of both mitigation and adaptation strategies on GHGs emission reductions or removals

9 Inventory Data Statistic Data Research Methods Natural Impacts Human Impacts Climatic factors Biophysical factors Geochemical factors Socioeconomic factors Met. & Hyd. Radiation (R) Temp. (Ta) Precip. (P) Wind (W) Drought(WDI) Snow etc. Satellite Data of GOSAT, MODIS etc. NDVI LAI FPAR CO2 DEM SOIL Slope(SLP) Director(DIR) Texture(TEX) Organic Matter(SOM) Livestock (LSD) Population (POD) Farming (AGR) Water use (WAT) Mining (MIN) Fire (FIR) Gross Primary Production (GPP) GPP=f (R, Ta, P, WDI, etc) Autotrophic Respiration (RA) RA=f (FPAR, LAI, CO2, etc.) Heterotrophic Respiration (RH) RH=f (SOM, TEX, SLP, etc.) Carbon Loss due to Disturbance (DIS) DIS=f (LSD, AGR, MIN, etc.) C Sequestrated by vegetation NPP=GPP-RA (short-term) C Sequestrated by ecosystems NEP=NPP-RH (medium-term) C Sequestrated by biogeosphere NBP=NEP-DIS (long-term) Diagram of our ecosystem-grazing model to estimate carbon sequestration

10 Input Datasets LAND USE MAP Sources: Mongolia Academy of Sciences

11 Input Datasets Topography & Slope Map Sources: Derived from the 90m DEM dataset, NASA

12 Input Datasets Normalized Difference Vegetation Index (NDVI) Measured by MODerate resolution Imaging Spectroradiometer (MODIS), Terra Satellite, NASA

13 Input Datasets 1970s 1980s 1990s 2000s 2010s The grazing density in Mongolia increased largely in last decades, especially since 2000.

14 CO2 Flux Observations for Validation To validate the model, we have established ground observation systems to monitor CO2 fluxes using eddy covariance method in different grassland ecosystems in Mongolia

15 CO2 Flux Observations for Validation Observed CO2 Absorption and Emission at Nalaikh Site

16 CO2 Flux Observations for Validation Observed CO2 Absorption and Emission at Uvur Zaisan Site

17 CO2 Flux Observations for Validation Observed CO2 Absorption and Emission at Hustai Site

18 CO2 Flux Observations for Validation Monitoring data of CO2 fluxes during by eddy covariance method in a typical grassland ecosystem at Nalaikh site, Mongolia

19 CO2 Flux Observations for Validation Atmospheric CO2 Atmospheric CO2 GPP gc/m 2 RE gc/m 2 GPP gc/m 2 RE gc/m 2 NEP gc/m 2 Soil Soil NEP 88.8 gc/m 2 Nalaikh Site Hustai Site

20 Model Estimation Results

21 Model Estimation Results NPP, Jul 2 nd,2000 NPP, Jul 2 nd,2016 The C sequestration by vegetation (NPP) increased from 2000 to 2016 in Mongolia

22 Model Estimation Results The C sequestration by ecosystems (NEP) also increased from 2000 to 2016, in which by forest steppe and meadow steppe was about 2 times of that by dry steppe, and more than 3 times of that by semi-desert steppe.

23 Model Estimation Results Land Surface Temperature(LST) Water Deficit Index (WDI=1-ET a /ET 0 ) NPP vs. WDI in forest steppe and meadow steppe NPP vs. WDI in dry steppe and semi-desert steppe We found that the water deficit index (WDI) was the most important driving factor for the C sequestration in dry steppe and semi-desert steppe, however, the land surface temperature (LST) was the important factor in forest and meadow steppe.

24 Model Estimation Results CARRYING CAPACITY= f (MET, DEM, LUC, BIOM, SLOPE, WAT, etc.)

25 Conclusions In this study, we have developed an ecosystem-grazing model to evaluate the spatiotemporal distribution of C sequestration by grassland ecosystems under the influence of both climate change and livestock grazing. We found that: the C sequestration by both vegetation (NPP) and ecosystems (NEP) increased from 2000 to 2016; the water deficit index (WDI) was the most important driving factor for the C sequestration in dry steppe and semi-desert steppe, however, the land surface temperature (LST) was the important factor for that in forest and meadow steppe; large areas of grasslands surrounding the capital city, Ulaanbaatar, have seriously degraded due to heavy grazing, although these areas originally have a high capacity of C sequestration; Overall, our results indicate that C sequestration in the most part of grassland are highly sensitive to grazing pressure and precipitation fluctuation. It was concluded that the recovery of degraded grasslands due to overgrazing could contribute to significant C sequestration by well-management of livestock numbers.

26 Acknowledgement This study is supported by a policy contribution-oriented research project of the Environment Research and Technology Development Fund (No. 2E-1203): Vulnerability assessment and Adaptation strategies for Permafrost regions in Mongolia ( ) and Development of Innovative Adaptation System and MRV Method for JCM in Mongolia" ( ) funded by Ministry of the Environment, Government of Japan.