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Increases in temperature and grazing intensity are believed to promote the relative abundance of C4 plants in grassland communities in Inner Mongolia. However, there is a lack of understanding as to which factor is the primary driver at the household scale. The relative abundance of C4 plants in grassland communities within 32 households was monitored over a 5-year period (2008-12) in the typical steppe region of Inner Mongolia. The relationships between the mean annual temperature, grazing intensity and their combinations on the patterns of the relative abundance of C4 plants across the land managed by these households were analysed. The results showed that (1) the herbage mass of the typical steppe grassland was mainly composed of C3 plants (87%); (2) the C4 plants were more sensitive to, and can be used as indicators of, environmental changes. These C4 species included Cleistogenes squarrosa (Trin.) Keng, Chenopodium glaucum Linn. and Salsola collina Pall.; (3) both increasing temperature and grazing intensity promoted the relative abundance of C4 plants. Grazing intensity was the primary driver of the change in relative abundance of C4 plants in this region. Not only did grazing change the micro-environment of the grasslands, but also the C3 species were preferentially grazed by the livestock. Comparison of the results with previous studies on the temporal variation in the abundance of C4 plants suggests that the relative importance of grazing and climatic factors depends on the spatial scales of the studies, with climate being of greater importance at the regional rather than the household scale.