Authors: Hongwei Wan Yongfei Bai Philipp Schönbach Martin Gierus Friedhelm Taube
Publish Date: 2010/11/24
Volume: 340, Issue: 1-2, Pages: 215-226
Abstract
Under the aim of searching for a more sustainable grazing management system a mixed management system grazing and haymaking alternate annually was proposed and tested against traditional management system used consistently either for grazing or haymaking in the semiarid grassland of Inner Mongolia with a field manipulation experiment The responses of aboveground biomass to the two grazing management systems were examined across different levels of organization ie species plant functional group and community and in five consecutive years from 2005 to 2009 The effects of the two systems on seed production potential of four dominant species Leymus chinensis Stipa grandis Agropyron cristatum Cleistogenes squarrosa were also investigated Our results demonstrate that in the traditional system aboveground biomass production across all the levels of organization was reduced by grazing In mixed system however no significantly negative relationship between the biomass response and stocking rate was detected at all organization levels Precipitation fluctuation had strong influence on biomass responses and compared to the traditional system the slope of the biomassprecipitation relationship tends to be higher in the mixed system This effect might be attributed to the more positive response of L chinensis and A cristatum to increase in precipitation In the traditional system both the ratio and the density of reproductive tillers of the grazing subplots were significantly reduced compared to the haymaking or ungrazed control plots In the mixed system there was no significant difference between the haymaking subplots and the ungrazed control plots regardless of the grazing pressures imposed on the haymaking subplots in the previous growing season Our findings suggest that the mixed system mitigates the sheep grazinginduced species shift and it tends to be more responsive to increasing precipitation as compared to the traditional system Therefore replacement of the traditional grazing strategy with the mixed system could provide an important contribution to sustainable landuse of the Inner Mongolia grasslandsWe acknowledge the Deutsche Forschungsgemeinschaft DFG for funding the research group 536 MAGIM Matter fluxes of grasslands in Inner Mongolia as influenced by stocking rate project This research was supported by the National Natural Science Foundation of China 30825008 and 30770370 We also appreciate the Inner Mongolia Grassland Ecosystem Research Station IMGERS of the Chinese Academy of Sciences for providing lab and field facilities accommodation and precious long term climatic dataset
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