Impacts of climate change on vegetation phenology and net primary productivity in arid Central Asia

2021 ◽  
pp. 149055
Author(s):  
Lizhou Wu ◽  
Xiaofei Ma ◽  
Xin Dou ◽  
Jianting Zhu ◽  
Chengyi Zhao
Keyword(s):  
Climate Change ◽  
Central Asia ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Vegetation Phenology ◽  
Arid Central Asia ◽  
Impacts Of Climate Change

scholarly journals Impacts of climate change on net primary productivity in arid and semiarid regions of China

2015 ◽  
Vol 26 (1) ◽  
pp. 35-47 ◽  
Author(s):  
Hao Wang ◽  
Guohua Liu ◽  
Zongshan Li ◽  
Xin Ye ◽  
Meng Wang ◽  
...  
Keyword(s):  
Climate Change ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Semiarid Regions ◽  
Arid And Semiarid ◽  
Impacts Of Climate Change

scholarly journals Effects of climatic factors on the net primary productivity in the source region of Yangtze River, China

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhe Yuan ◽  
Yongqiang Wang ◽  
Jijun Xu ◽  
Zhiguang Wu
Keyword(s):  
Climate Change ◽  
Primary Productivity ◽  
Yangtze River ◽  
Net Primary Productivity ◽  
Climatic Factors ◽  
Source Region ◽  
Primary Reason ◽  
Vegetation Types ◽  
Temperature And Precipitation ◽  
Increasing Trend

AbstractThe ecosystem of the Source Region of Yangtze River (SRYR) is highly susceptible to climate change. In this study, the spatial–temporal variation of NPP from 2000 to 2014 was analyzed, using outputs of Carnegie–Ames–Stanford Approach model. Then the correlation characteristics of NPP and climatic factors were evaluated. The results indicate that: (1) The average NPP in the SRYR is 100.0 gC/m2 from 2000 to 2014, and it shows an increasing trend from northwest to southeast. The responses of NPP to altitude varied among the regions with the altitude below 3500 m, between 3500 to 4500 m and above 4500 m, which could be attributed to the altitude associated variations of climatic factors and vegetation types; (2) The total NPP of SRYR increased by 0.18 TgC per year in the context of the warmer and wetter climate during 2000–2014. The NPP was significantly and positively correlated with annual temperature and precipitation at interannual time scales. Temperature in February, March, May and September make greater contribution to NPP than that in other months. And precipitation in July played a more crucial role in influencing NPP than that in other months; (3) Climatic factors caused the NPP to increase in most of the SRYR. Impacts of human activities were concentrated mainly in downstream region and is the primary reason for declines in NPP.

Quantitatively assessing the effects of climate change and human activities on ecosystem degradation and restoration in southwest China

2019 ◽  
Vol 41 (4) ◽  
pp. 335
Author(s):  
Z. G. Sun ◽  
J. S. Wu ◽  
F. Liu ◽  
T. Y. Shao ◽  
X. B. Liu ◽  
...  
Keyword(s):  
Climate Change ◽  
Primary Productivity ◽  
Human Activities ◽  
Southwest China ◽  
Net Primary Productivity ◽  
Terrestrial Ecosystems ◽  
Ecosystem Degradation ◽  
Relative Contribution ◽  
Degraded Ecosystem ◽  
Annual Means

Identifying the effects of climate change and human activities on the degradation and restoration of terrestrial ecosystems is essential for sustainable management of these ecosystems. However, our knowledge of methodology on this topic is limited. To assess the relative contribution of climate change and human activities, actual and potential net primary productivity (NPPa and NPPp respectively), and human appropriation of net primary productivity (HANPP) were calculated and applied to the monitoring of forest, grassland, and cropland ecosystems in Yunnan–Guizhou–Sichuan Provinces, southwest China. We determined annual means of 476 g C m–2 year–1 for NPPa, 1314 g C m–2 year–1 for NPPp, and 849 g C m–2 year–1 for HANPP during the period between 2007 and 2016. Furthermore, the area with an increasing NPPa accounted for 75.12% of the total area of the three ecosystems. Similarly, the areas with increasing NPPp and HANPP accounted for 77.60 and 57.58% of the study area respectively. Furthermore, we found that ~57.58% of areas with ecosystem restored was due to climate change, 23.39% due to human activities, and 19.03% due to the combined effects of human activities and climate change. In contrast, climate change and human activities contributed to 19.47 and 76.36%, respectively, of the areas of degraded ecosystem. Only 4.17% of degraded ecosystem could be attributed to the combined influences of climate change and human activities. We conclude that human activities were mainly responsible for ecosystem degradation, whereas climate change benefitted ecosystem restoration in southwest China in the past decade.

scholarly journals Modelling the response of net primary productivity of the Zambezi teak forests to climate change along a rainfall gradient in Zambia

2019 ◽  
Vol 16 (19) ◽  
pp. 3853-3867
Author(s):  
Justine Ngoma ◽  
Maarten C. Braakhekke ◽  
Bart Kruijt ◽  
Eddy Moors ◽  
Iwan Supit ◽  
...  
Keyword(s):  
Climate Change ◽  
21St Century ◽  
Primary Productivity ◽  
General Circulation ◽  
Net Primary Productivity ◽  
Co2 Concentration ◽  
Annual Rainfall ◽  
Rainfall Gradient ◽  
Local Soil ◽  
Parameter Values

Abstract. Understanding climate change effects on forests is important considering the role forests play in mitigating climate change. We studied the effects of changes in temperature, rainfall, atmospheric carbon dioxide (CO2) concentration, solar radiation, and number of wet days (as a measure of rainfall intensity) on net primary productivity (NPP) of the Zambian Zambezi teak forests along a rainfall gradient. Using 1960–1989 as a baseline, we projected changes in NPP for the end of the 21st century (2070–2099). We adapted the parameters of the dynamic vegetation model, LPJ-GUESS, to simulate the growth of Zambian forests at three sites along a moisture gradient receiving annual rainfall of between 700 and more than 1000 mm. The adjusted plant functional type was tested against measured data. We forced the model with contemporary climate data (1960–2005) and with climatic forecasts of an ensemble of five general circulation models (GCMs) following Representative Concentration Pathways (RCPs) RCP4.5 and RCP8.5. We used local soil parameter values to characterize texture and measured local tree parameter values for maximum crown area, wood density, leaf longevity, and allometry. The results simulated with the LPJ-GUESS model improved when we used these newly generated local parameters, indicating that using local parameter values is essential to obtaining reliable simulations at site level. The adapted model setup provided a baseline for assessing the potential effects of climate change on NPP in the studied Zambezi teak forests. Using this adapted model version, NPP was projected to increase by 1.77 % and 0.69 % at the wetter Kabompo and by 0.44 % and 0.10 % at the intermediate Namwala sites under RCP8.5 and RCP4.5 respectively, especially caused by the increased CO2 concentration by the end of the 21st century. However, at the drier Sesheke site, NPP would respectively decrease by 0.01 % and 0.04 % by the end of the 21st century under RCP8.5 and RCP4.5. The projected decreased NPP under RCP8.5 at the Sesheke site results from the reduced rainfall coupled with increasing temperature. We thus demonstrated that differences in the amount of rainfall received in a site per year influence the way in which climate change will affect forest resources. The projected increase in CO2 concentration would thus have more effects on NPP in high rainfall receiving areas, while in arid regions, NPP would be affected more by the changes in rainfall and temperature. CO2 concentrations would therefore be more important in forests that are generally not temperature- or precipitation-limited; however, precipitation will continue to be the limiting factor in the drier sites.

scholarly journals Quantifying the Impacts of Anthropogenic Activities and Climate Variations on Vegetation Productivity Changes in China from 1985 to 2015

2020 ◽  
Vol 12 (7) ◽  
pp. 1113
Author(s):  
Shahid Naeem ◽  
Yongqiang Zhang ◽  
Jing Tian ◽  
Faisal Mueen Qamer ◽  
Aamir Latif ◽  
...  
Keyword(s):  
Climate Change ◽  
Primary Productivity ◽  
Human Activities ◽  
Vegetation Cover ◽  
Net Primary Productivity ◽  
Anthropogenic Activities ◽  
Climate Factors ◽  
Climate Variations ◽  
Base Period ◽  
Increasing Trends

Accurate assessment of vegetation dynamics provides important information for ecosystem management. Anthropogenic activities and climate variations are the major factors that primarily influence vegetation ecosystems. This study investigates the spatiotemporal impacts of climate factors and human activities on vegetation productivity changes in China from 1985 to 2015. Actual net primary productivity (ANPP) is used to reflect vegetation dynamics quantitatively. Climate-induced potential net primary productivity (PNPP) is used as an indicator of climate change, whereas the difference between PNPP and ANPP is considered as an indicator of human activities (HNPP). Overall, 91% of the total vegetation cover area shows declining trends for net primary productivity (NPP), while only 9% shows increasing trends before 2000 (base period). However, after 2000 (restoration period), 78.7% of the total vegetation cover area shows increasing trends, whereas 21.3% of the area shows decreasing trends. Moreover, during the base period, the quantitative contribution of climate change to NPP restoration is 0.21 grams carbon per meter square per year (gC m−2 yr−1) and to degradation is 2.41 gC m−2 yr−1, while during the restoration period, climate change contributes 0.56 and 0.29 gC m−2 yr−1 to NPP restoration and degradation, respectively. Human activities contribute 0.36 and 0.72 gC m−2 yr−1 during the base period, and 0.63 and 0.31 gC m−2 yr−1 during the restoration period to NPP restoration and degradation, respectively. The combined effects of climate and human activities restore 0.65 and 1.11 gC m−2 yr−1, and degrade 2.01 and 0.67 gC m−2 yr−1 during the base and restoration periods, respectively. Climate factors affect vegetation cover more than human activities, while precipitation is found to be more sensitive to NPP change than temperature. Unlike the base period, NPP per unit area increases with an increase in the human footprint pressure during the restoration period. Grassland has more variability than other vegetation classes, and the grassland changes are mainly observed in Tibet, Xinjiang, and Inner Mongolia regions. The results may help policy-makers by providing necessary guidelines for the management of forest, grassland, and agricultural activities.

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