The role of permafrost and soil water in distribution of alpine grassland and its NDVI dynamics on the Qinghai-Tibetan Plateau

Abstract Soil temperature and soil water are two important factors controlling vegetation growth. Climate warming and associated permafrost degradation might change these soil conditions and affect alpine grassland on the Qinghai-Tibetan Plateau. However, our current understanding of the role of soil temperature and water at the plateau scale is inadequate. In this study, we used plateau scale soil water content, frozen soil type, vegetation index and land surface temperature datasets to investigate the spatial distribution, limiting factors of vegetation growth and normalized difference vegetation index (NDVI) changing trends in two major alpine grasslands, alpine meadow and alpine steppe, in relation to soil temperature and soil water conditions. Our results showed that: 1) alpine meadow is mainly distributed in seasonal frozen soil areas (55.90% of alpine meadow) with a soil water content between 0.15 and 0.25 m3/m3 and alpine steppe is mainly found in seasonal frozen and sub-stable permafrost areas (69.38% of alpine steppe) with a soil water content between 0.05 and 0.20 m3/m3; 2) at the plateau scale, there were 35.6% (more in colder regions) of alpine meadow pixels and 33.6% (more in wetter regions) of alpine steppe pixels having increase NDVI changing trends during 1982–2012, respectively; and the values having decrease NDVI changing trends are 7.3% and 9.7%, respectively; and 3) the vegetation growth of alpine meadow is mainly limited by soil temperature, while that of alpine steppe is limited by both soil temperature and soil water. We also find the limiting factors of temperature or water can only explain

[1]  Yu Qin,et al.  Responses of alpine grassland on Qinghai–Tibetan plateau to climate warming and permafrost degradation: a modeling perspective , 2014 .

[2]  Philippe Ciais,et al.  Growing season extension and its impact on terrestrial carbon cycle in the Northern Hemisphere over the past 2 decades , 2007 .

[3]  G. Ren,et al.  Inconsistencies of precipitation in the eastern and central Tibetan Plateau between surface adjusted data and reanalysis , 2012, Theoretical and Applied Climatology.

[4]  P. Ciais,et al.  Impacts of climate and CO2 changes on the vegetation growth and carbon balance of Qinghai-Tibetan grasslands over the past five decades , 2012 .

[5]  Yongjian Ding,et al.  Effects of gravel on soil and vegetation properties of alpine grassland on the Qinghai-Tibetan plateau , 2015 .

[6]  Han Sun,et al.  Study of normalized difference vegetation index variation and its correlation with climate factors in the three-river-source region , 2011, Int. J. Appl. Earth Obs. Geoinformation.

[7]  Xiao-dong Liu,et al.  Climatic warming in the Tibetan Plateau during recent decades , 2000 .

[8]  Howard E. Epstein,et al.  Recent changes in phenology over the northern high latitudes detected from multi-satellite data , 2011 .

[9]  G. Cheng,et al.  Responses of permafrost to climate change and their environmental significance, Qinghai‐Tibet Plateau , 2007 .

[10]  S. Piao,et al.  Variations in Vegetation Net Primary Production in the Qinghai-Xizang Plateau, China, from 1982 to 1999 , 2006 .

[11]  J. Qin,et al.  Validation of a dual-pass microwave land data assimilation system for estimating surface soil moisture in semiarid regions. , 2009 .

[12]  Martha C. Anderson,et al.  Use of NDVI and Land Surface Temperature for Drought Assessment: Merits and Limitations , 2010 .

[13]  Jian Sun,et al.  On the Variation of NDVI with the Principal Climatic Elements in the Tibetan Plateau , 2013, Remote. Sens..

[14]  Linking thaw depth with soil moisture and plant community composition: effects of permafrost degradation on alpine ecosystems on the Qinghai-Tibet Plateau , 2013, Plant and Soil.

[15]  Yanhong Tang,et al.  Alpine grassland degradation and its control in the source region of the Yangtze and Yellow Rivers, China , 2005 .

[16]  B. Poulter,et al.  Detection and attribution of vegetation greening trend in China over the last 30 years , 2015, Global change biology.

[17]  Yanhong Tang,et al.  High positive correlation between soil temperature and NDVI from 1982 to 2006 in alpine meadow of the Three-River Source Region on the Qinghai-Tibetan Plateau , 2011, Int. J. Appl. Earth Obs. Geoinformation.

[18]  Jinzhong Min,et al.  Comparison of multiple datasets with gridded precipitation observations over the Tibetan Plateau , 2015, Climate Dynamics.

[19]  S. Seneviratne,et al.  Investigating soil moisture-climate interactions in a changing climate: A review , 2010 .

[20]  Yanhong Tang,et al.  Altitude and temperature dependence of change in the spring vegetation green-up date from 1982 to 2006 in the Qinghai-Xizang Plateau , 2011 .

[21]  Qingbai Wu,et al.  Changes in active layer thickness over the Qinghai‐Tibetan Plateau from 1995 to 2007 , 2010 .

[22]  C. Tucker,et al.  Increased plant growth in the northern high latitudes from 1981 to 1991 , 1997, Nature.

[23]  Shen Zhenxi,et al.  Causes and Restoration of Degraded Alpine Grassland in Northern Tibet , 2013 .

[24]  Mingjun Ding,et al.  Spatiotemporal variation in alpine grassland phenology in the Qinghai-Tibetan Plateau from 1999 to 2009 , 2013 .

[25]  Yu Qin,et al.  Effects of permafrost degradation on alpine grassland in a semi-arid basin on the Qinghai–Tibetan Plateau , 2011 .

[26]  Na Li,et al.  Responses of typical grasslands in a semi-arid basin on the Qinghai-Tibetan Plateau to climate change and disturbances , 2014, Environmental Earth Sciences.

[27]  Volker C. Radeloff,et al.  Regime shift on the roof of the world: alpine meadows converting to shrublands in the southern Himalayas. , 2013 .

[28]  Nicholas C. Coops,et al.  Changes in vegetation photosynthetic activity trends across the Asia-Pacific region over the last three decades , 2014 .

[29]  J. Klein,et al.  Growing Season Length and Soil Moisture Interactively Constrain High Elevation Aboveground Net Primary Production , 2011, Ecosystems.

[30]  S. Piao,et al.  Interannual variations of monthly and seasonal normalized difference vegetation index (NDVI) in China from 1982 to 1999 , 2003 .

[31]  C. Tucker,et al.  Higher northern latitude normalized difference vegetation index and growing season trends from 1982 to 1999 , 2001, International journal of biometeorology.

[32]  Xinquan Zhao,et al.  Effects of warming and grazing on soil N availability, species composition, and ANPP in an alpine meadow. , 2012, Ecology.

[33]  Zhang Yong-qiang,et al.  Characterizing the dynamics of soil organic carbon in grasslands on the Qinghai-Tibetan Plateau , 2007 .

[34]  Jianping Huang,et al.  Accelerated dryland expansion under climate change , 2016 .

[35]  C. Tucker,et al.  Higher Northern Latitude NDVI and Growing Season Trends from 1982 to 1999 , 2001 .

[36]  Guodong Cheng,et al.  Permafrost and groundwater on the Qinghai-Tibet Plateau and in northeast China , 2013, Hydrogeology Journal.

[37]  Lazhu,et al.  A MULTISCALE SOIL MOISTURE AND FREEZE-THAW MONITORING NETWORK ON THE THIRD POLE , 2013 .

[38]  J. Tao,et al.  The impact of climate change and anthropogenic activities on alpine grassland over the Qinghai-Tibet Plateau , 2014 .

[39]  Z. Jiping,et al.  Vegetation variation of mid-subtropical forest based on MODIS NDVI data — A case study of Jinggangshan City, Jiangxi Province , 2014 .

[40]  Thomas Scholten,et al.  Pedogenesis, permafrost, and soil moisture as controlling factors for soil nitrogen and carbon contents across the Tibetan Plateau , 2009 .

[41]  Yaoming Ma,et al.  Auto-calibration System Developed to Assimilate AMSR-E Data into a Land Surface Model for Estimating Soil Moisture and the Surface Energy Budget( Coordinated Enhanced Observing Period(CEOP)) , 2007 .

[42]  Shi-chang Kang,et al.  Decreasing wind speed and weakening latitudinal surface pressure gradients in the Tibetan Plateau , 2010 .

[43]  Xingliang Xu,et al.  Effects of permafrost degradation on ecosystems , 2010 .

[44]  Jinwei Dong,et al.  Green-up dates in the Tibetan Plateau have continuously advanced from 1982 to 2011 , 2013, Proceedings of the National Academy of Sciences.

[45]  Yanhong Tang,et al.  Influences of temperature and precipitation before the growing season on spring phenology in grasslands of the central and eastern Qinghai-Tibetan Plateau , 2011 .

[46]  Y. Sheng,et al.  Effect of permafrost degradation on hydrological processes in typical basins with various permafrost coverage in Western China , 2011 .

[47]  A. McGuire,et al.  Representing the effects of alpine grassland vegetation cover on the simulation of soil thermal dynamics by ecosystem models applied to the Qinghai‐Tibetan Plateau , 2013 .

[48]  R. Harris.  Rangeland degradation on the Qinghai-Tibetan plateau: A review of the evidence of its magnitude and causes , 2010 .

[49]  Wu,et al.  Spatiotemporal variability of permafrost degradation on the Qinghai-Tibet Plateau , 2011 .

[50]  Philippe Ciais,et al.  Evidence for a weakening relationship between interannual temperature variability and northern vegetation activity , 2014, Nature Communications.

[51]  Y. Sheng,et al.  Responses of Alpine Grassland to Climate Warming and Permafrost Thawing in Two Basins with Different Precipitation Regimes on the Qinghai-Tibetan Plateaus , 2015 .

[52]  Yaoming Ma,et al.  The Tibetan plateau observatory of plateau scale soil moisture and soil temperature, Tibet - Obs, for quantifying uncertainties in coarse resolution satellite and model products , 2011 .

[53]  Shilong Piao,et al.  Increasing altitudinal gradient of spring vegetation phenology during the last decade on the Qinghai–Tibetan Plateau , 2014 .

[54]  Cheng Guodong,et al.  Eco-environmental changes and causative analysis in the source regions of the Yangtze and Yellow Rivers, China , 2000 .

[55]  Wang Yibo,et al.  Effects of permafrost thawing on vegetation and soil carbon pool losses on the Qinghai–Tibet Plateau, China , 2008 .

[56]  Edwin W. Pak,et al.  An extended AVHRR 8‐km NDVI dataset compatible with MODIS and SPOT vegetation NDVI data , 2005 .

[57]  P. Ciais,et al.  Evaporative cooling over the Tibetan Plateau induced by vegetation growth , 2015, Proceedings of the National Academy of Sciences.

[58]  Matthew A. Williamson,et al.  Complex responses of spring vegetation growth to climate in a moisture-limited alpine meadow , 2016, Scientific Reports.

[59]  Qingbai Wu,et al.  Thermal hazards zonation and permafrost change over the Qinghai–Tibet Plateau , 2012, Natural Hazards.

[60]  Jun Qin,et al.  Recent climate changes over the Tibetan Plateau and their impacts on energy and water cycle: A review , 2014 .

[61]  Xiaobo Qin,et al.  Climate change and its impacts on vegetation distribution and net primary productivity of the alpine ecosystem in the Qinghai-Tibetan Plateau. , 2016, The Science of the total environment.

[62]  Qingbai Wu,et al.  Permafrost temperatures and thickness on the Qinghai-Tibet Plateau , 2010 .

[63]  Liqiang Ji,et al.  Carbon dynamics of terrestrial ecosystems on the Tibetan Plateau during the 20th century: an analysis with a process-based biogeochemical model , 2010 .

[64]  Jiansheng Wu,et al.  Trend analysis of vegetation dynamics in Qinghai–Tibet Plateau using Hurst Exponent , 2012 .

[65]  Jiyuan Liu,et al.  Assessment of effects of climate change and grazing activity on grassland yield in the Three Rivers Headwaters Region of Qinghai–Tibet Plateau, China , 2010, Environmental monitoring and assessment.