Vegetation Changes in the Permafrost Regions of the Qinghai-Tibetan Plateau from 1982-2012: Different Responses Related to Geographical Locations and Vegetation Types in High-Altitude Areas

Wang, Zhiwei; Wang, Qian; Wu, Xiaodong; Zhao, Lin; Yue, Guozhen; Zhang, Nan; Wang, Puchang; Yi, Shuai; Zou, Defu; Qin, Yu; Wu, Tonghua; Shi, Jianzong

doi:10.1371/journal.pone.0169732

Cited by 7 publications

(5 citation statements)

References 28 publications

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“…We found that the breakpoints of TP temperature during 1982-2013 at different time scales largely occurred between 1994 and 1998 (Figures 2-6). This result is not only closer to direct NDVI segmentation investigation on the TP [52], but it is also closer to the artificial breakpoint of 2000 years in some investigations of TP NDVI response analysis [39,46]. Nevertheless, our results strongly imply that the artificial abrupt points later than 2000 may bring greater bias in TP NDVI response analysis.…”

Section: Discussionsupporting

confidence: 87%

Annual and Seasonal Trends of Vegetation Responses and Feedback to Temperature on the Tibetan Plateau since the 1980s

Wang

Darvishzadeh

et al. 2023

Remote Sensing

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The vegetation–temperature relationship is crucial in understanding land–atmosphere interactions on the Tibetan Plateau. Although many studies have investigated the connections between vegetation and climate variables in this region using remote sensing technology, there remain notable gaps in our understanding of vegetation–temperature interactions over different timescales. Here, we combined site-level air temperature observations, information from the global inventory modeling and mapping studies (GIMMS) dataset, and moderate-resolution imaging spectroradiometer (MODIS) products to analyze the spatial and temporal patterns of air temperature, vegetation, and land surface temperature (LST) on the Tibetan Plateau at annual and seasonal scales. We achieved these spatiotemporal patterns by using Sen’s slope, sequential Mann–Kendall tests, and partial correlation analysis. The timescale differences of vegetation-induced LST were subsequently discussed. Our results demonstrate that a breakpoint of air temperature change occurred on the Tibetan Plateau during 1994–1998, dividing the study period (1982–2013) into two phases. A more significant greening response of NDVI occurred in the spring and autumn with earlier breakpoints and a more sensitive NDVI response occurred in recent warming phase. Both MODIS and GIMMS data showed a common increase in the normalized difference vegetation index (NDVI) on the Tibetan Plateau for all timescales, while the former had a larger greening area since 2000. The most prominent trends in NDVI and LST were identified in spring and autumn, respectively, and the largest areas of significant variation in NDVI and LST mostly occurred in winter and autumn, respectively. The partial correlation analysis revealed a significant negative impact of NDVI on LST during the annual scale and autumn, and it had a significant positive impact during spring. Our findings improve the general understanding of vegetation–climate relationships at annual and seasonal scales.

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Section: Discussionsupporting

confidence: 87%

Annual and Seasonal Trends of Vegetation Responses and Feedback to Temperature on the Tibetan Plateau since the 1980s

Wang

Darvishzadeh

et al. 2023

Remote Sensing

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“…An increasing number of studies, which have benefitted greatly from the accumulation of more than a decade of satellite observations, have focused on photosynthetic metabolism over the TP (Lehnert et al, ). The central issues, which have been investigated widely in prior studies, are the changes that are actually occurring and the mechanisms underlying these changes (Shen, Piao, Cong, et al, ; Wang et al, ). However, our current understanding is quite limited in the following aspects.…”

Section: Introductionmentioning

confidence: 99%

Multisatellite Analyses of Spatiotemporal Variability in Photosynthetic Activity Over the Tibetan Plateau

Wang

Liú

et al. 2019

JGR Biogeosciences

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Ecosystems on the Tibetan Plateau are particularly sensitive to climate change. Significant advances have been made toward understanding the effects of climate change on the vegetation productivity of the plateau by using satellite observations, but a comprehensive study including various satellite measurements has yet to be presented. Here, we analyze the spatiotemporal variability in Tibetan vegetation productivity using a variety of proxies, including the Normalized Difference Vegetation Index, Enhanced Vegetation Index, Near‐Infrared Reflectance of vegetation, and Solar‐Induced chlorophyll Fluorescence. First, in terms of productivity responses to seasonal climate variation, Near‐Infrared Reflectance of vegetation‐ and Solar‐Induced chlorophyll Fluorescence‐based growing season length had better correlation with eddy covariance site measurements and was ~50 days shorter than those of the other proxies. Second, all proxies, except the Normalized Difference Vegetation Index derived from Système Probatoire d'Observation de la Terre, displayed a dipole‐like trend pattern, similar to the observed north‐south dipole pattern of precipitation change. This result is explained by the finding that moisture is a dominant driver controlling the interannual variation in productivity. Third, we analyzed the long‐term responses of vegetation productivity to the precipitation regime and found four distinct productivity regimes, desert steppe, alpine steppe, meadow, and shrub/forests, indicating that Tibetan productivity varies with precipitation in a nonlinear way. The result offers insights into how Tibetan vegetation will respond to future climate change. Our results provide a multisatellite perspective on the impacts of climate change on spatiotemporal variation in productivity and suggest an urgent need to improve Tibetan productivity simulation.

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“…Islands of permafrost and seasonally frozen soil are mainly distributed in the LRHR and YERHR (Mao et al, 2016). The lower altitude, the warmer and more humid climate, and higher vegetation cover lead to higher SWC and ST in the southeast areas than those in the northwest (Cuo et al, 2015; Wang, Wang, et al, 2017). Moreover, the existence of permafrost restricts the water and heat exchange between the atmosphere and the ground, making them both relatively low (Chang et al, 2018).…”

Section: Discussionmentioning

confidence: 99%

Soil bulk density and altitude are primary drivers of soil water content and soil temperature in the Three Rivers Headwaters Region, China

Qiao

Feng

et al. 2023

Soil Use and Management

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Soil water content (SWC) and soil temperature (ST) are important indicators of environmental change in permafrost regions. In this study, we conducted soil sampling at 89 locations in the Three Rivers Headwaters Region (TRHR) to investigate the individual and synergistic effects of environmental factors on SWC and ST. We used multivariable regression and random forest modelling to analyse the data. The results show that SWC and ST were higher in the southeast TRHR than in the northwest and higher in surface layers than deeper soil layers. The most important factors affecting SWC in the 0–20 cm and 20–40 cm soil layers were soil bulk density and precipitation, while bulk density was the most important factor in the 40–60 cm layer, and soil bulk density and steppe vegetation were the most important factors in the 60–80 cm layer. For ST, altitude, temperature and slope gradient were the drivers in the 0–20 cm surface layer, while altitude and temperature were the most critical drivers in the 20–40 cm, 40–60 cm and 60–80 cm layers. Overall, bulk density and altitude were the key environmental factors influencing SWC and ST values, respectively. The outcomes of this study provide valuable insights into the environmental factors that impact the SWC and ST in permafrost regions, which can guide decision‐making processes for sustainable soil management in the context of climate change.

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Vegetation Changes in the Permafrost Regions of the Qinghai-Tibetan Plateau from 1982-2012: Different Responses Related to Geographical Locations and Vegetation Types in High-Altitude Areas

Cited by 7 publications

References 28 publications

Annual and Seasonal Trends of Vegetation Responses and Feedback to Temperature on the Tibetan Plateau since the 1980s

Annual and Seasonal Trends of Vegetation Responses and Feedback to Temperature on the Tibetan Plateau since the 1980s

Multisatellite Analyses of Spatiotemporal Variability in Photosynthetic Activity Over the Tibetan Plateau

Soil bulk density and altitude are primary drivers of soil water content and soil temperature in the Three Rivers Headwaters Region, China

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