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.

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.

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.

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

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

The effects of climate factors and human activities on net primary productivity in Xinjiang

2020 ◽  
Vol 64 (5) ◽  
pp. 765-777 ◽  
Author(s):  
Yelin Jiang ◽  
Jing Guo ◽  
Qing Peng ◽  
Yanlong Guan ◽  
Yang Zhang ◽  
...  
Keyword(s):  
Primary Productivity ◽  
Human Activities ◽  
Net Primary Productivity ◽  
Climate Factors

scholarly journals Disentangling Climatic Factors and Human Activities in Governing the Old and New Forest Productivity

2021 ◽  
Vol 13 (18) ◽  
pp. 3746
Author(s):  
Shanshan Chen ◽  
Zhaofei Wen ◽  
Maohua Ma ◽  
Shengjun Wu
Keyword(s):  
Climate Change ◽  
Human Activities ◽  
Forest Restoration ◽  
Net Primary Productivity ◽  
Climatic Factors ◽  
Yangtze River Basin ◽  
Forest Degradation ◽  
Stand Age ◽  
Climate Factors ◽  
Research Period

Forest ecosystem plays a vital role in the global carbon cycle and maintaining climate stability. However, how net primary productivity (NPP) dynamics of different stand ages of forest respond to climatic change and residual (being other climate factors or human activities) still remain unclear. In this study, firstly, forests are divided into two categories based on their stand age: forests appeared before appeared before the research period (Fold), and forests appeared during the research period (Fnew). Secondly, we improved a quantitative method of basic partial derivatives to disentangle the relative contributions of climatic factors, other climate factors, and human activities to the NPP of Fold and Fnew. Then, different scenarios were simulated to identify the dominant drivers for forest restoration and degradation. In this study, we hypothesized the residual of Fold was other climate factors rather than human activities. Our results revealed that from 2000 to 2019, Fold and Fnew of NPP in Yangtze River Basin showed a significant increment trend and precipitation was the major positive contributor among all of the climatic factors. We found that, in Fold, climate change and other climate factors contributed 9.77% and 28.33%, respectively, in explaining NPP. This finding unsupported our initial hypothesis and implied that residuals should be human activities for Fold. Furthermore, we found that human activities dominate either restoration or degradation of Fnew. This result may be due to the attenuated human disturbances and strengthened forest management, such as ecological policies, forest tending, closing the land for reforestation, etc. Therefore, based on disentangling the two types of factors, we concluded that human activities govern the forest change, and imply that the environment-friendly forest managements may favorite to improving the forest NPP against the impacts of climate change. Thus, effective measures and policies are suggested implement in controlling forest degradation in facing climate change.

scholarly journals Grassland Dynamics and the Driving Factors Based on Net Primary Productivity in Qinghai Province, China

2019 ◽  
Vol 8 (2) ◽  
pp. 73
Author(s):  
Xiaoxu Wei ◽  
Changzhen Yan ◽  
Wei Wei
Keyword(s):  
Climate Change ◽  
Primary Productivity ◽  
Human Activities ◽  
Net Primary Productivity ◽  
Alpine Meadow ◽  
The Tibetan Plateau ◽  
Temperate Steppe ◽  
Qinghai Province ◽  
Alpine Steppe ◽  
Increase Rate

Qinghai province is an important part of the Tibetan Plateau, and is characterized by extremely fragile ecosystems. In the last few decades, grasslands in this province have been influenced profoundly by climate change, as well as human activities. Here, we use the Carnegie-Ames-Stanford Approach (CASA) model to assess the dynamics of temperate steppe, alpine steppe, temperate meadow, alpine meadow, sparse grassland and herbaceous wetland via actual net primary productivity (NPPa). Our findings showed that: (1) From 2001 to 2016, the average NPPa in Qinghai province showed a fluctuation presented a generally increasing trend. The mean value of NPPa was 114.27 g C m−2 year−1, and the increase rate was 0.47 g C cm−2 year−1. (2) There were NPPa increase rate discrepancies among the six typical grassland biomes. Herbaceous wetland had the highest change rate, closely followed by alpine steppe, temperate steppe, alpine meadow, temperate meadow and sparse grassland. (3) The largest area of restoration mainly impacted by climate change reached 47.08% of the total grassland area, with human activities accounting for 21.74%. By contrast, the deteriorated area induced by human activities accounted for 9.78% of the total grassland. (4) Temperature may have been a greater factor than precipitation in driving grassland change during the study period. Decreasing grazing intensity and implementing effective protection measures were favorable to grassland restoration.

scholarly journals Climate changes during the past 31 years and their contribution to the changes in the productivity of rangeland vegetation in the Inner Mongolian typical steppe

2014 ◽  
Vol 36 (6) ◽  
pp. 519 ◽  
Author(s):  
Xinhong Wu ◽  
Peng Li ◽  
Chao Jiang ◽  
Pengtao Liu ◽  
Jing He ◽  
...  
Keyword(s):  
Climate Change ◽  
Primary Productivity ◽  
Aboveground Biomass ◽  
Human Activities ◽  
Net Primary Productivity ◽  
Annual Production ◽  
Typical Steppe ◽  
The Past ◽  
Grassland Production ◽  
The Impact

The objectives of this study were to explore the impact of climate change and human activities on the annual production of aboveground biomass of vegetation during the past 31 years at a county scale in the typical steppe region of Inner Mongolia. The changes in three banners in the region (Abag Banner, Xilinhaote City, and Xiwuzhumuqin Banner) were analysed. The changes in the annual potential grassland production (net primary productivity) and in the annual production of vegetation, as the sum of aboveground biomass and consumption by livestock, were estimated for each year. A comparison of the changing rates in net primary productivity and aboveground biomass of vegetation over the 31 years was used to distinguish the effects of climate change on grassland production from human activities. The results showed that the climate had become warmer and drier during the past 31 years and thus net primary productivity and annual production of vegetation decreased significantly. Climate change was a major factor for these decreases, while human activities were a minor factor in the decrease of grassland production in Xuwuzhumuqi Banner. The importance of human activities in reducing this decrease in grassland production during the last 31 years is in accordance with the changes in grassland-use policy that has encouraged destocking for grassland restoration in recent years.

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