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

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

The Rangeland Journal ◽

10.1071/rj18111 ◽

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.

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

10.31219/osf.io/3q6h8 ◽

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.

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The effects of ENSO, climate change and human activities on the water level of Lake Toba, Indonesia: a critical literature review

Geoscience Letters ◽

10.1186/s40562-021-00191-x ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Hendri Irwandi ◽

Mohammad Syamsu Rosid ◽

Terry Mart

Keyword(s):

Climate Change ◽

Water Level ◽

Human Activities ◽

Southern Oscillation ◽

Climatic Conditions ◽

Water Levels ◽

Dominant Factor ◽

Climate Projections ◽

Continuous Increase ◽

The Future

AbstractThis research quantitatively and qualitatively analyzes the factors responsible for the water level variations in Lake Toba, North Sumatra Province, Indonesia. According to several studies carried out from 1993 to 2020, changes in the water level were associated with climate variability, climate change, and human activities. Furthermore, these studies stated that reduced rainfall during the rainy season due to the El Niño Southern Oscillation (ENSO) and the continuous increase in the maximum and average temperatures were some of the effects of climate change in the Lake Toba catchment area. Additionally, human interventions such as industrial activities, population growth, and damage to the surrounding environment of the Lake Toba watershed had significant impacts in terms of decreasing the water level. However, these studies were unable to determine the factor that had the most significant effect, although studies on other lakes worldwide have shown these factors are the main causes of fluctuations or decreases in water levels. A simulation study of Lake Toba's water balance showed the possibility of having a water surplus until the mid-twenty-first century. The input discharge was predicted to be greater than the output; therefore, Lake Toba could be optimized without affecting the future water level. However, the climate projections depicted a different situation, with scenarios predicting the possibility of extreme climate anomalies, demonstrating drier climatic conditions in the future. This review concludes that it is necessary to conduct an in-depth, comprehensive, and systematic study to identify the most dominant factor among the three that is causing the decrease in the Lake Toba water level and to describe the future projected water level.

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Explicitly Identifying the Desertification Change in CMREC Area Based on Multisource Remote Data

Remote Sensing ◽

10.3390/rs12193170 ◽

2020 ◽

Vol 12 (19) ◽

pp. 3170

Author(s):

Zemeng Fan ◽

Saibo Li ◽

Haiyan Fang

Keyword(s):

Climate Change ◽

Human Activities ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Net Primary Productivity ◽

Regression Tree ◽

Google Earth ◽

Classification And Regression Tree ◽

Support Vector ◽

Driving Mechanisms

Explicitly identifying the desertification changes and causes has been a hot issue of eco-environment sustainable development in the China–Mongolia–Russia Economic Corridor (CMREC) area. In this paper, the desertification change patterns between 2000 and 2015 were identified by operating the classification and regression tree (CART) method with multisource remote sensing datasets on Google Earth Engine (GEE), which has the higher overall accuracy (85%) than three other methods, namely support vector machine (SVM), random forest (RF) and Albedo-normalized difference vegetation index (NDVI) models. A contribution index of climate change and human activities on desertification was introduced to quantitatively explicate the driving mechanisms of desertification change based on the temporal datasets and net primary productivity (NPP). The results show that the area of slight desertification land had increased from 719,700 km2 to 948,000 km2 between 2000 and 2015. The area of severe desertification land decreased from 82,400 km2 to 71,200 km2. The area of desertification increased by 9.68%, in which 69.68% was mainly caused by human activities. Climate change and human activities accounted for 68.8% and 27.36%, respectively, in the area of desertification restoration. In general, the degree of desertification showed a decreasing trend, and climate change was the major driving factor in the CMREC area between 2000 and 2015.

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Spatio-temporal pattern of net primary productivity in Hengduan Mountains area, China: impacts of climate change and human activities

Chinese Geographical Science ◽

10.1007/s11769-017-0895-5 ◽

2017 ◽

Vol 27 (6) ◽

pp. 948-962 ◽

Cited By ~ 9

Author(s):

Tiantian Chen ◽

Li Peng ◽

Shaoquan Liu ◽

Qiang Wang

Keyword(s):

Climate Change ◽

Primary Productivity ◽

Human Activities ◽

Temporal Pattern ◽

Net Primary Productivity ◽

Hengduan Mountains ◽

Spatio Temporal ◽

Impacts Of Climate Change

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

Remote Sensing ◽

10.3390/rs12071113 ◽

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

The Rangeland Journal ◽

10.1071/rj12042 ◽

2013 ◽

Vol 35 (3) ◽

pp. 315 ◽

Cited By ~ 31

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.

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

Acta Ecologica Sinica ◽

10.5846/stxb201809141984 ◽

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

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Impact of Climate Change and Human Activities on Streamflow Variations Based on the Budyko Framework

Water ◽

10.3390/w11102001 ◽

2019 ◽

Vol 11 (10) ◽

pp. 2001 ◽

Cited By ~ 3

Author(s):

Lee ◽

Yeh

Keyword(s):

Climate Change ◽

Time Series ◽

Human Activities ◽

Potential Evapotranspiration ◽

Land Use Changes ◽

Dominant Factor ◽

Climate Factors ◽

The Sustainable Development ◽

Precipitation Changes ◽

Northern Taiwan

In recent years, the influence of climate change and human activity on the global environment have become a concern. It is essential to better understand the hydrologic environment to evaluate water availability and related issues. In this study, we perform a trend and breakpoint analysis on streamflow time series in the Lanyang, Keelung, Dahan, Fengshan, Youluo and Shangping River Basins in northern Taiwan. Furthermore, we apply the Budyko–Fu equation and the Budyko–Mezentsev–Choudhury–Yang equation to evaluate the elasticity of streamflow with respect to climate factors and the catchment characteristics parameter. We discuss the sensitivity of streamflow to climate factors (precipitation and potential evapotranspiration), as well as sensitivity to human activities such as land use changes. We detected breakpoints in the streamflow time series for the Lanyang and Keelung rivers in in 1993 and 1990, respectively. The streamflow of Lanyang River increased by 32.50% during the variation period (1993–2017), with 109.00% of the variation caused by non-climate factors. The Keelung River’s streamflow was reduced by 18.11% during the variation period (1990–2017), and the dominant factor was climate change, accounting for 71.53% of the reduction. Sensitivity analysis showed that precipitation changes were the most sensitive factor of streamflow variation. For every 1% increase in precipitation, the streamflow would increase by 1.05% to 1.37%. These results could serve as a reference for the sustainable development of water resources and territorial policies in northern Taiwan.

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