Abstract

HU, FL et al. Effects of grazing on plant species diversity and carbon partitioning in semiarid rangelands of northeastern China. Phyton (B. Aires) [online]. 2015, vol.84, n.1, pp.209-221. ISSN 1851-5657.

Grasslands are one of the most widespread landscapes worldwide, covering approximately one-fifth of the world's land surface, where grazing is a common practice. How carbon storage responds to grazing in steppes remains poorly understood. We quantified the effects of grazing on community composition and species diversity, and carbon storage in two typical grasslands of northeastern China, one in Horqin and the other one in Hulunbeier. In both grasslands, grazing did not infuence plant species diversity. However, it substantially decreased aboveground carbon by 31% and 54% in Horqin and Hulunbeier, respectively. Fenced and grazing treatments showed a similar belowground carbon at both locations. The predominant carbon pool in the study grassland ecosystem was found in the upper 100 cm soil depth, from 98.2 to 99.1% of the total carbon storage. There were no significant effects of grazing on soil carbon neither in the whole profile nor in the uppermost 20 cm soil depth in the two study grasslands. Studies on the efects of varying rangeland management, such as region disparity and grazing systems, may have important consequences on species diversity and carbon partitioning, and thus on rangeland stability and ecosystem functioning.

Keywords : Species diversity; Carbon allocation; Carbon stock; Optimal partitioning; Community heterogeneity; Soil depth.

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