scholarly journals Spatial and Temporal Differences in Alpine Meadow, Alpine Steppe and All Vegetation of the Qinghai-Tibetan Plateau and Their Responses to Climate Change

2021 ◽  
Vol 13 (4) ◽  
pp. 669
Author(s):  
Hanchen Duan ◽  
Xian Xue ◽  
Tao Wang ◽  
Wenping Kang ◽  
Jie Liao ◽  
...  
Keyword(s):  
Climate Change ◽  
Alpine Meadow ◽  
Global Climate ◽  
Growing Season ◽  
Tibet Plateau ◽  
Vegetation Types ◽  
Analysis Method ◽  
Alpine Steppe ◽  
Qinghai Tibet Plateau ◽  
Variation Trends

Alpine meadow and alpine steppe are the two most widely distributed nonzonal vegetation types in the Qinghai-Tibet Plateau. In the context of global climate change, the differences in spatial-temporal variation trends and their responses to climate change are discussed. It is of great significance to reveal the response of the Qinghai-Tibet Plateau to global climate change and the construction of ecological security barriers. This study takes alpine meadow, alpine steppe and the overall vegetation of the Qinghai-Tibet Plateau as the research objects. The normalized difference vegetation index (NDVI) data and meteorological data were used as the data sources between 2000 and 2018. By using the mean value method, threshold method, trend analysis method and correlation analysis method, the spatial and temporal variation trends in the alpine meadow, alpine steppe and the overall vegetation of the Qinghai-Tibet Plateau were compared and analyzed, and their differences in the responses to climate change were discussed. The results showed the following: (1) The growing season length of alpine meadow was 145~289 d, while that of alpine steppe and the overall vegetation of the Qinghai-Tibet Plateau was 161~273 d, and their growing season lengths were significantly shorter than that of alpine meadow. (2) The annual variation trends of the growing season NDVI for the alpine meadow, alpine steppe and the overall vegetation of the Qinghai-Tibet Plateau increased obviously, but their fluctuation range and change rate were significantly different. (3) The overall vegetation improvement in the Qinghai-Tibet Plateau was primarily dominated by alpine steppe and alpine meadow, while the degradation was primarily dominated by alpine meadow. (4) The responses between the growing season NDVI and climatic factors in the alpine meadow, alpine steppe and the overall vegetation of the Qinghai-Tibet Plateau had great spatial heterogeneity in the Qinghai-Tibet Plateau. These findings provide evidence towards understanding the characteristics of the different vegetation types in the Qinghai-Tibet Plateau and their spatial differences in response to climate change.

scholarly journals Quantitative Assessment of the Impact of Physical and Anthropogenic Factors on Vegetation Spatial-Temporal Variation in Northern Tibet

2019 ◽  
Vol 11 (10) ◽  
pp. 1183 ◽  
Author(s):  
Qinwei Ran ◽  
Yanbin Hao ◽  
Anquan Xia ◽  
Wenjun Liu ◽  
Ronghai Hu ◽  
...  
Keyword(s):  
Population Density ◽  
Alpine Meadow ◽  
Tibet Plateau ◽  
Anthropogenic Factors ◽  
Physical Factors ◽  
Northern Tibet ◽  
Alpine Steppe ◽  
Key Factor ◽  
Qinghai Tibet Plateau ◽  
Vegetation Variation

The alpine grassland on the Qinghai-Tibet Plateau covers an area of about 1/3 of China’s total grassland area and plays a crucial role in regulating grassland ecological functions. Both environmental changes and irrational use of the grassland can result in severe grassland degradation in some areas of the Qinghai-Tibet Plateau. However, the magnitude and patterns of the physical and anthropogenic factors in driving grassland variation over northern Tibet remain debatable, and the interactive influences among those factors are still unclear. In this study, we employed a geographical detector model to quantify the primary and interactive impacts of both the physical factors (precipitation, temperature, sunshine duration, soil type, elevation, slope, and aspect) and the anthropogenic factors (population density, road density, residential density, grazing density, per capita GDP, and land use type) on vegetation variation from 2000 to 2015 in northern Tibet. Our results show that the vegetation index in northern Tibet significantly decreased from 2000 to 2015. Overall, the stability of vegetation types was sorted as follows: the alpine scrub > the alpine steppe > the alpine meadow. The physical factors, rather than the anthropogenic factors, have been the primary driving factors for vegetation dynamics in northern Tibet. Specifically, meteorological factors best explained the alpine meadow and alpine steppe variation. Precipitation was the key factor that influenced the alpine meadow variation, whereas temperature was the key factor that contributed to the alpine steppe variation. The anthropogenic factors, such as population density, grazing density and per capita GDP, influenced the alpine scrub variation most. The influence of population density is highly similar to that of grazing density, which may provide convenient access to simplify the study of the anthropogenic activities in the Tibet plateau. The interactions between the driving factors had larger effects on vegetation than any single factor. In the alpine meadow, the interaction between precipitation and temperature can explain 44.6% of the vegetation variation. In the alpine scrub, the interaction between temperature and GDP was the highest, accounting for 27.5% of vegetation variation. For the alpine steppe, the interaction between soil type and population density can explain 29.4% of the vegetation variation. The highest value of vegetation degradation occurred in the range of 448–469 mm rainfall in the alpine meadow, 0.61–1.23 people/km2 in the alpine scrub and –0.83–0.15 °C in the alpine steppe, respectively. These findings could contribute to a better understanding of degradation prevention and sustainable development of the alpine grassland ecosystem in northern Tibet.

Changes in vegetation composition and plant diversity with rangeland degradation in the alpine region of Qinghai-Tibet Plateau

2015 ◽  
Vol 37 (1) ◽  
pp. 107 ◽  
Author(s):  
Lin Tang ◽  
Shikui Dong ◽  
Ruth Sherman ◽  
Shiliang Liu ◽  
Quanru Liu ◽  
...  
Keyword(s):  
Plant Diversity ◽  
Large Scale ◽  
Alpine Meadow ◽  
Vegetation Indices ◽  
Desert Ecosystem ◽  
Tibet Plateau ◽  
Vegetation Composition ◽  
Rangeland Degradation ◽  
Alpine Steppe ◽  
Qinghai Tibet Plateau

The changes in vegetation composition and plant diversity of three different alpine ecosystems: alpine meadow, alpine steppe and alpine desert, impacted by different levels of degradation (healthy, lightly degraded and moderately degraded) were examined across a large-scale transect on the Qinghai-Tibet Plateau. The alpine meadow was dominated by sedges, the alpine steppe was dominated by grasses and the alpine desert was dominated by shrubs. The alpine meadow had the highest species diversity, whereas the alpine steppe had the lowest and tended to be dominated by a few species. Forbs were the dominant and most diverse functional group in the alpine meadow and the alpine steppe, which was different from the alpine desert. The importance values of the dominant species and levels of diversity measured by various vegetation indices were only slightly different in the degraded sites as compared with the non-degraded alpine meadow and steppe, whereas the alpine desert showed large changes in the composition and diversity of the plant community in response to degradation. In conclusion, the plant composition of the alpine meadow and alpine steppe ecosystems was more stable and appeared more resistant to disturbance than that of the alpine desert ecosystem.

scholarly journals Disaster Chain Analysis of Avalanche and Landslide and the River Blocking Dam of the Yarlung Zangbo River in Milin County of Tibet on 17 and 29 October 2018

2019 ◽  
Vol 16 (23) ◽  
pp. 4707 ◽  
Author(s):  
Huicong Jia ◽  
Fang Chen ◽  
Donghua Pan
Keyword(s):  
Climate Change ◽  
Global Climate ◽  
Tibet Plateau ◽  
Sequence Of Events ◽  
Chain Analysis ◽  
Flow Formation ◽  
Yarlung Zangbo River ◽  
Disaster Chain ◽  
Secondary Disasters ◽  
Qinghai Tibet Plateau

As a “starting zone” and “amplifier” of global climate change, the Qinghai–Tibet Plateau is very responsive to climate change. The global temperature rise has led directly to an acceleration of glacial melting in the plateau and various glacier avalanche disasters have frequently occurred. The landslide caused by glacier avalanches will damage the surrounding environment, causing secondary disasters and a disaster chain effect. Take the disaster chain of the Yarlung Zangbo River at Milin County in Tibet on 17 and 29 October 2018 as an example; a formation mechanical model was proposed. The evolution mechanism for the chain of events is as follows: glacial melt → loose moraine deposit → migration along the steep erosion groove resulting in glacier clastic deposition then debris flow → formation of the dam plug to block the river → the dammed lake. This sequence of events is of great significance for understanding the developmental trends for future avalanches, landslides, and river blocking dam disasters, and for disaster prevention planning and mitigation in the Qinghai–Tibet Plateau.

scholarly journals Actual Evapotranspiration in Suli Alpine Meadow in Northeastern Edge of Qinghai-Tibet Plateau, China

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Jin-kui Wu ◽  
Shi-qiang Zhang ◽  
Hao Wu ◽  
Shi-wei Liu ◽  
Yu Qin ◽  
...  
Keyword(s):  
Energy Balance ◽  
Alpine Meadow ◽  
Bowen Ratio ◽  
Growing Season ◽  
High Elevation ◽  
Actual Evapotranspiration ◽  
Tibet Plateau ◽  
Evapotranspiration Estimation ◽  
Qinghai Tibet Plateau ◽  
Ratio Energy

Actual evapotranspiration was observed by using eddy covariance (EC) technique, calculated by micrometeorological method the Bowen ratio energy balance (BREB) and measured by micro-lysimeter (ML) in the Suli alpine meadow which located in the northeastern edge of Qinghai-Tibet Plateau noted for its high elevation and cold environment during the growing season in 2011. Results showed that the energy balance ratio for half-hour data was 0.74. Without consideration of uncertainty, the evapotranspiration values estimated by BREB, ML, and EC were 270.6 mm, 238.9 mm, and 236.1 mm, respectively. Significant correlation existed between the evapotranspiration results by the three methods. Uncertainties of the evapotranspiration estimation by BREB, ML, and EC were 19.6 mm, 15.6 mm, and 15.1 mm, respectively. Deduced by facts on the natural and vegetation conditions, the value of evapotranspiration should be equal to that of precipitation, that is, about 252 mm. From this point, the evapotranspiration values estimated by the three methods were within a reliable range. The EC method has larger advantage and wider scope for the estimation of evapotranspiration in alpine meadow area.

scholarly journals The Impact of Climate Change on the Surface Albedo over the Qinghai-Tibet Plateau

2021 ◽  
Vol 13 (12) ◽  
pp. 2336
Author(s):  
Chaonan Chen ◽  
Li Tian ◽  
Lianqi Zhu ◽  
Yuanke Zhou
Keyword(s):  
Climate Change ◽  
Solar Radiation ◽  
Land Surface ◽  
Meteorological Data ◽  
Growing Season ◽  
High Elevation ◽  
Tibet Plateau ◽  
Decrease Rate ◽  
The Impact ◽  
Qinghai Tibet Plateau

Albedo is a characterization of the Earth’s surface ability to reflect solar radiation, and control the amount of solar radiation absorbed by the land surface. Within the context of global warming, the temporal and spatial changes of the albedo and its response to climate factors remain unclear. Based on MCD43A3 (V005) albedo and meteorological data (i.e., temperature and precipitation), we analyzed the spatiotemporal variations of albedo (2000–2016) and its responses to climate change during the growing season on the Qinghai-Tibet Plateau (QTP). The results indicated an overall downward trend in the annual albedo during the growing season, the decrease rate was 0.25%/decade, and the monthly albedo showed a similar trend, especially in May, when the decrease rate was 0.53%/decade. The changes also showed regional variations, such as for the annual albedo, the areas with significant decrease and increase in albedo were 181.52 × 103 km2 (13.10%) and 48.82 × 103 km2 (3.52%), respectively, and the intensity of albedo changes in low-elevation areas was more pronounced than in high-elevation areas. In addition, the annual albedo-temperature/precipitation relationships clearly differed at different elevations. The albedo below 2000 m and at 5000–6000 m was mainly negatively correlated with temperature, while at 2000–4000 m it was mainly negatively correlated with precipitation. The contemporaneous temperature could negatively impact the monthly albedo in significant ways at the beginning of the growing season (May and June), whereas in the middle of the growing season (July and August), the albedo was mainly negatively correlated with precipitation, and at the end of the growing season (September), the albedo showed a weak correlation with temperature/precipitation.

scholarly journals Socio-Environmental Dynamics of Alpine Grasslands, Steppes and Meadows of the Qinghai–Tibetan Plateau, China: A Commentary

2020 ◽  
Vol 10 (18) ◽  
pp. 6488 ◽  
Author(s):  
Haiying Feng ◽  
Victor R. Squires
Keyword(s):  
Alpine Meadow ◽  
Tibet Plateau ◽  
South East Asia ◽  
Alpine Grasslands ◽  
Growing Seasons ◽  
Alpine Steppe ◽  
Tibetan Sheep ◽  
Low Humidity ◽  
Bactrian Camels ◽  
Qinghai Tibet Plateau

Alpine grasslands are a common feature on the extensive (2.6 million km2) Qinghai–Tibet plateau in western and southwestern China. These grasslands are characterized by their ability to thrive at high altitudes and in areas with short growing seasons and low humidity. Alpine steppe and alpine meadow are the principal plant Formations supporting a rich species mix of grass and forb species, many of them endemic. Alpine grasslands are the mainstay of pastoralism where yaks and hardy Tibetan sheep and Bactrian camels are the favored livestock in the cold arid region. It is not only their importance to local semi nomadic herders, but their role as headwaters of nine major rivers that provide water to more than one billion people in China and in neighboring countries in south and south-east Asia and beyond. Grasslands in this region were heavily utilized in recent decades and are facing accelerated land degradation. Government and herder responses, although quite different, are being implemented as climate change and the transition to the market economy proceeds apace. Problems and prospects for alpine grasslands and the management regimes being imposed (including sedentarization, resettlement and global warming are briefly discussed.

scholarly journals Effects of rodent-induced land degradation on ecosytem carbon fluxes in alpine meadow in the Qinghai–Tibet Plateau, China

2014 ◽  
Vol 6 (2) ◽  
pp. 3003-3023 ◽  
Author(s):  
F. Peng ◽  
Y. Quangang ◽  
X. Xue ◽  
J. Guo ◽  
T. Wang
Keyword(s):  
Soil Respiration ◽  
Land Degradation ◽  
Alpine Meadow ◽  
Net Ecosystem Exchange ◽  
Growing Season ◽  
Tibet Plateau ◽  
Organic C ◽  
Soil C ◽  
Significant Difference ◽  
Qinghai Tibet Plateau

Abstract. Land degradation induced by rodent activities is extensively occurred in alpine meadow ecosystem in the Qinghai–Tibet Plateau that would affect the ecosystem carbon (C) balance. We conducted a field experiment with six levels of land degradation (D1–D6, degradation aggravates from D1 to D6) to investigate the effects of land degradation on ecosystem C fluxes. Soil respiration (Rs), net ecosystem exchange (NEE), ecosystem respiration (ER) and gross ecosystem production (GEP) were measured from June to September 2012. Soil respiration, ER, GEP and above-ground biomass (AGB) was significantly higher in slightly degraded (D3 and D6) than in severely degraded land (D1, D2, D4 and D5). Positive averages of NEE in the growing season indicate that alpine meadow ecosystem is a weak C sink during the growing season. Net ecosystem exchange had no significant difference among different degraded levels, but the average NEE in slightly degraded group was 33.6% higher than in severely degraded group. Soil respiration, ER and NEE were positively correlated with AGB whereas soil organic C, labile soil C, total nitrogen (N) and inorganic nitrogen were associated with root biomass (RB). Our results highlight the decline of vegetation C storage of alpine meadow ecosystem with increasing number of rodent holes and suggest the control of AGB on ecosystem C fluxes, and the control of RB on soil C and N with development of land degradation.

scholarly journals Distinguishing Stoichiometric Homeostasis of Soil Microbial Biomass in Alpine Grassland Ecosystems: Evidence From 5,000 km Belt Transect Across Qinghai–Tibet Plateau

2021 ◽  
Vol 12 ◽  
Author(s):  
Jihui Fan ◽  
Tianyuan Liu ◽  
Ying Liao ◽  
Yiying Li ◽  
Yan Yan ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
Alpine Meadow ◽  
Alpine Grassland ◽  
Tibet Plateau ◽  
Trade Off ◽  
Soil C ◽  
Soil Microbial ◽  
Alpine Steppe ◽  
Qinghai Tibet Plateau

The biogeographic characteristics of soil microbial biomass stoichiometry homeostasis and also its mechanisms are commonly thought to be key factors for the survival strategies and resource utilization of soil microbes under extreme habitat. In this work, we conducted a 5,000-km transect filed survey in alpine grassland across Qinghai–Tibet Plateau in 2015 to measure soil microbial biomass carbon (MBC) and nitrogen (MBN) across alpine steppe and meadow. Based on the differences of climate and soil conditions between alpine steppe and meadow, the variation coefficient was calculated to investigate the homeostatic degree of MBC to MBN. Furthermore, the “trade-off” model was utilized to deeply distinguish the homeostasis degree of MBC/MBN between alpine steppe and meadow, and the regression analysis was used to explore the variability of trade-off in response to environmental factors in the alpine grassland. The results showed that the coefficient of variation (CV) of MBC/MBN in alpine meadow (CV = 0.4) was lower than alpine steppe (CV = 0.7). According to the trade-off model, microbial turnover activity of soil N relative to soil C increased rapidly and then decreased slightly with soil organic carbon (SOC), soil total nitrogen (STN), and soil water content across alpine meadow. Nevertheless, in alpine steppe, SOC/STN had a positive effect on microbial turnover of soil N. These results suggested that water, heat, and soil nutrients availability were the key factors affecting the C:N stoichiometry homeostasis of soil microbial biomass in Qinghai–Tibet Plateau (QTP)’s alpine grassland. Since the difference of survival strategy of the trade-off demands between soil C and N resulting in different patterns and mechanism, the stoichiometry homeostasis of soil microbial biomass was more stable in alpine meadow than in alpine steppe.

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