Effects of grazing intensities on functional traits of Cleistogenes squarrosa in a typical grassland of Inner Mongolia, China.

Abstract

We examined the response of 11 functional traits of Cleistogenes squarrosa, including plant height and clump width, to the grazing of different intensity (no grazing; twice grazing in May and July; five grazing in the whole growing season). After five-year treatments, the number of reproductive branches, plant height, stem quality, specific leaf area and total leaf area were significantly reduced. Such reduction was significantly increased with the increases of grazing intensity. Under the treatments of grazing in May and July, the declines of each index were 61.7%, 21.5%, 33.3%, 21.6% and 26.7%, respectively; and the declines in the treatment of whole growing season grazing were 75.7%, 24.7%, 46.7%, 28.5% and 43.7%, respectively. The number of vegetative branches, number of leaf, total leaf area, stem quality, total leaf quality and clump width of the C. squarrosa had a synergistic relationship with aboveground biomass of the whole clump under different grazing intensities. The number of vegetative branches was significantly positively correlated with stem quality and total leaf quality. C. squarrosa had a dwarf-dense branching strategy to avoid grazing. The reduction of grazing intensity would be conducive to maintaining the stability of functional traits.