Response of rangeland vegetation to snow cover dynamics in Nepal Trans Himalaya
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Response of rangeland vegetation to snow cover dynamics in Nepal Trans Himalaya Keshav Prasad Paudel & Peter Andersen
Received: 25 March 2011 / Accepted: 28 July 2012 / Published online: 25 August 2012 # Springer Science+Business Media B.V. 2012
Abstract Global climate change is expected to result in greater variation in snow cover and subsequent impacts on land surface hydrology and vegetation production in the high Trans Himalayan region (THR). This paper examines how the changes in timing and duration of snow cover affect the spatio-temporal pattern of rangeland phenology and production in the region. Moderate Resolution Imaging Spectrometer (MODIS) 16-day normalized difference vegetation index (NDVI) data from 2000 to 2009 and concurrent snow cover, precipitation and temperature data were analyzed. In contrast to numerous studies which have suggested that an earlier start of the season and an extension of the length of the growing season in mid and higher latitude areas due to global warming, this study shows a delay in the beginning of the growing season and the peak time of production, and a decline in the length of growing season in the drier part of THR following a decline and a delay in snow cover. Soil moisture in the beginning of the growing season and consequent rangeland vegetation production in drier areas of the THR was found to be strongly dependent upon the timing and duration of snow cover. However, in the wetter part of the THR, an earlier start of season, a delay in end of season and hence a longer growing season was observed, which could be attributed to warming in winter and early spring and cooling in summer and late spring and changes in timing of snow melt. The study shows a linear positive relationship between rangeland vegetation production and snow cover in the drier parts of THR, a quadratic relationship near to permanent snow line, and a negative linear relationship in wetter highlands. These findings suggest that, while temperature is important, changes in snow cover and precipitation pattern play more important roles in snow-fed, drier regions for rangeland vegetation dynamics.
Electronic supplementary material The online version of this article (doi:10.1007/s10584-012-0562-x) contains supplementary material, which is available to authorized users.
K. P. Paudel (*) : P. Andersen Department of Geography, University of Bergen, Fosswinkelsgate 6, N-5007 Bergen, Norway e-mail: [email protected]
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Climatic Change (2013) 117:149–162
1 Introduction The cryosphere of the Hindu Kush Himalaya is considered to be a critical region that will experience significant alterations under the current projections of climate change. Studies show the region has one of the highest warming rates (0.21±0.08 °C per decade for the period 1979–2007) over the last decades (Gautam et al. 2010). As a result, the entire Himalayan region is reportedly having the highest rate of glacial retreat in the world (Dyurgerov and Meier 2005) and especially the central Hindu Kush Himalayan region is reported t
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