Poster, Himalayan Karakorum Tibet Workshop & International Symposium on Tibetan Plateau 2013, Tübingen: 22.10.2013 - 24.10.2013
Abstract:
The Cyperaceae Kobresia pygmaea (Kp) forms one of the earth’s largest alpine ecosystems on the Tibetan Plateau (TP). It grows between 3000 to 5960 m a.s.l. and is especially adapted to grazing pressure, growing 2-6 cm tall while building up a stable turf layer from roots which protects soil from erosion. To investigate the impact of human induced land use change on Kp pastures, especially plant communities, soil carbon stocks and turnover and energy & matter exchange at the border between atmosphere-ecosystem, grazing exclosure sites have been installed in different altitudes on the TP. Experiments 3300-3600 m a.s.l showed differences in vegetation composition and soil carbon stocks/turnover on 7 year grazing exclosures. Overall fodder quality and C-storage within was soil reduced, suggesting that exclusion of grazing livestock might not be the best choice for management of Kp meadows. In 2010 and 2012 multidisciplinary experiments were conducted within the centre of the major distribution of Kp in 4400 m a.s.l.. C turnover within the plant-soil-atmosphere continuum was observed by combining NEE measurements (Eddy-Covariance method) with and relative C- fluxes (13C Labelling). Additionally Chamber based flux measurements over different surface types, which make up the heterogeneity of the pastures were conducted. The derived knowledge will be used to setup and validate land surface models which can resolve the special characteristics of this ecosystem.