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 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.

Relative effects of climate change and human activities on net primary productivity in Shule River Basin

2019 ◽  
Vol 39 (14) ◽  
Author(s):  
周妍妍 ZHOU Yanyan ◽  
朱敏翔 ZHU Minxiang ◽  
郭晓娟 GUO Xiaojuan ◽  
李凯 LI Kai ◽  
苗俊霞 MIAO Junxia ◽  
...  
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Primary Productivity ◽  
Human Activities ◽  
Net Primary Productivity

scholarly journals Recent responses of grassland net primary productivity to climatic and anthropogenic factors in Kyrgyzstan

2020 ◽  
Author(s):  
Yanwen Wang
Keyword(s):  
Climate Change ◽  
Primary Productivity ◽  
Human Activities ◽  
Net Primary Productivity ◽  
Anthropogenic Activities ◽  
Dominant Factor ◽  
Anthropogenic Factors ◽  
Grassland Degradation ◽  
Contributing Factors ◽  
Spatial And Temporal Patterns

Net primary productivity (NPP) is an essential indicator of ecosystem function and sustainability and plays a vital role in the carbon cycle, especially in arid and semi-arid grassland ecosystems. Quantifying trends in NPP and identifying the contributing factors are important for understanding the relative impacts of climate change and human activities on grassland degradation. We quantified spatial and temporal patterns in potential NPP (NPPP) and actual NPP (NPPA) in Kyrgyzstan from 2000 to 2014 based on the Zhou Guangsheng model and MOD17A3 NPP data, respectively. By calculating the difference between NPPP and NPPA, we inferred human-induced NPP (NPPH) and thereby characterised changes in grassland NPP attributable to anthropogenic activities. We found that over the past two decades, both climatic variation and anthropogenic activities have significantly affected Kyrgyzstan’s grasslands. Grassland NPP decreased overall but patterns varied between provinces. Climate change, in particular changes in precipitation was the dominant factor driving grassland degradation in the north but human pressures also contributed. In the south however, human activities were associated with extensive areas of grassland recovery. The results provide important contextual understanding for supporting policy for grassland maintenance and restoration under climate change and intensifying human pressures.

Assessment of the contribution of climate change and human activities to desertification in Northern Kordofan-Province, Sudan using net primary productivity as an indicator

2016 ◽  
Vol 9 (6) ◽  
pp. 674-683 ◽  
Author(s):  
Abdelrahim Elobeid Jahelnabi ◽  
Jun Zhao ◽  
ChuanHua Li ◽  
Sona Mohammed Fadoul ◽  
YinFang Shi ◽  
...  
Keyword(s):  
Climate Change ◽  
Primary Productivity ◽  
Human Activities ◽  
Net Primary Productivity

scholarly journals Roles of Climate Change and Increasing CO2 in Driving Changes of Net Primary Productivity in China Simulated Using a Dynamic Global Vegetation Model

2019 ◽  
Vol 11 (15) ◽  
pp. 4176 ◽  
Author(s):  
Qing Huang ◽  
Weimin Ju ◽  
Fangyi Zhang ◽  
Qian Zhang
Keyword(s):  
Climate Change ◽  
Interannual Variability ◽  
Primary Productivity ◽  
Southwest China ◽  
Net Primary Productivity ◽  
Terrestrial Ecosystem ◽  
Co2 Concentration ◽  
Series Data ◽  
Geographical Regions ◽  
The Future

Net primary productivity (NPP) is the key component of the terrestrial carbon cycle, and terrestrial NPP trends under increasing CO2 and climate change in the past and future are of great significance in the study of the global carbon budget. Here, the LPJ-DGVM was employed to simulate the magnitude and pattern of China’s terrestrial NPP using long-term series data to understand the response of terrestrial NPP to increasing CO2 concentration and climate change. The results showed that total NPP of China’s terrestrial ecosystem increased from 2.8 to 3.6 Pg C yr−1 over the period of 1961–2016, with an annual average of 3.1 Pg C yr−1. The average NPP showed a gradient decrease from the southeast to northwest. Southwest China and Northwest China, comprising mostly arid and semi-arid regions, exhibited the largest increase rate in total NPP among the six geographical regions of China. Additionally, large interannual variability around the NPP trends was presented, and NPP anomalies in China’s terrestrial ecosystem are strongly associated with the El Niño-Southern Oscillation (ENSO). Southwest China made the largest contribution to the interannual variability of national total NPP. The total NPP of China’s terrestrial ecosystem continuously increased with the concurrent increase in the CO2 concentration and climate change under different scenarios in the future. During the period from 2091 to 2100, the average total NPP under the A2 and RCP85 scenarios would reach 4.9 and 5.1 Pg C yr−1 respectively, higher than 4.2 and 3.9 Pg C yr−1 under the B1 and RCP45 scenarios. Forests, especially temperate forests, make the largest contribution to the future increase in NPP. The increase in CO2 concentration would play a dominant role in driving further NPP increase in China’s terrestrial ecosystems, and climate change may slightly attenuate the fertilization effect of CO2 on NPP.

Relative contribution of climate change and human activities to vegetation degradation and restoration in North Xinjiang, China

2017 ◽  
Vol 39 (3) ◽  
pp. 289 ◽  
Author(s):  
Hongfei Yang ◽  
Liang Yao ◽  
Youbao Wang ◽  
Jianlong Li
Keyword(s):  
Climate Change ◽  
Human Activities ◽  
Net Primary Productivity ◽  
Degradation Process ◽  
Vegetation Restoration ◽  
Dominant Factor ◽  
Positive Role ◽  
Vegetation Degradation ◽  
Relative Contribution ◽  
North Xinjiang

Climate change and human activities are the two primary driving factors in the vegetation degradation process, and the assessment of their relative roles in vegetation degradation is important to understand the driving mechanisms of vegetation degradation. In this study, net primary productivity (NPP) was selected as an indicator to distinguish the relative roles of climate change and human activities in vegetation degradation and restoration from 2001 to 2010 in North Xinjiang, China. The potential NPP and the human appropriation of NPP were served as the indicator of the effects of climate change and human activities in vegetation degradation and restoration. The results showed that human activities were the dominant factor that induced vegetation degradation, accounts for 55% (153 720 km2) of the total degradation, whereas 25% (69 336 km2) of the total degradation resulted from climate change; the combination of human activities and climate change was the cause in 20% (55 429 km2) of the total degradation. In contrast, 61% (66 927 km2) of the total vegetation restoration was dominated by human activities and 29% (31 553 km2) was caused by climate change; the areas of vegetation restoration caused by the combination of human activities and climate change were 10 551 km2 (10%). The relative roles of the two factors possessed great spatial heterogeneity in five vegetation types. Climate dominated degradation expansion and human activities dominated vegetation restoration in forest. Both the degradation and restoration were dominated by human activities in grassland. In desert, degradation was dominated by human activities and vegetation restoration by climate. In cropland and crop/natural vegetation mosaic, degradation was dominated by both human activities and climate change and restoration was dominated by human activities. These results demonstrated that human activities played a demonstrably positive role in vegetation restoration, and ecological restoration projects were effective on mitigating vegetation degradation and also promoting restoration in the southern areas of North Xinjiang.

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