Summer grazing by three livestock species at moderate intensity enhances primary productivity and drives community divergence in a semi‐arid steppe

Abstract

Aims:The general effects of grazing by large herbivores on plant species composition and productivity are well known. Meanwhile, how different livestock species affect community structure is not fully understood. In northern China, livestock species composition is changing rapidly and hence, it is imperative to understand the resulting effects on grassland productivity and composition.Location: Xilingol, Inner Mongolia, China. Methods:We studied how grazing by three major livestock species affects typical steppe dominated by Leymus chinensis, Stipa grandis, Cleistogenes squarrosa and Carex korshinskyi, in a 4-year field experiment using a random block-design with four treatments (sheep, goat, cattle, no grazing), under summer grazing at moderate intensity.We calculated above-ground net primary productivity (ANPP) and a selectivity index (SI) based on biomass to quantify livestock forage preferences.Result: We found that (i) sheep preferred Leymus chinensis and mixed subordinate species, cattle preferred Stipa grandis, and goat preferred Carex korshinskyi and Cleistogenes squarrosa. (ii) Consistent with these preferences, sheep increased the relative biomass of Stipa grandis, but reduced that of Carex korshinskyi; cattle reduced the relative biomass of Stipa grandis and Carex korshinskyi but increased that of mixed subordinate species; and goats reduced the relative biomass of Cleistogenes squarrosa and Carex korshinskyi but increased that of mixed subordinate species. (iii) Overall, grazing significantly increased ANPP, mainly due to an increase in ANPP of Leymus chinensis and subordinate species, at the cost of Stipa grandis.Conclusions: Summer grazing by different livestock species at moderate intensity can increase ANPP, while livestock forage preferences can drive divergent changes in species composition. Our results also imply that livestock composition can be used as a mean to manage vegetation dynamics.

Grazing season regulates plant community structure and production by altering plant litter mass in a typical steppe

“…Precipitation in the usually dry early stage of the plant growing season promotes plant growth and biomass more than in the late stage (Hossain & Beierkuhnlein, 2018). The increase in plant AGB over the three‐year period in the studied grassland is driven by the precipitation, not by the additive effects of management over the period, as revealed by a partial correlation analysis of AGB with precipitation and “year” (representing the vegetation succession or additive effects) for the same experimental grassland (Li et al, 2022). The effects of precipitation on community attributes differ for the grassland in different grazing seasons (Table 1).…”

Difference in determinants and changing patterns of plant community composition with and without grazing across semi-arid and arid regions in Mongolian steppe

“…The copyright holder for this this version posted December 24, 2022. ; https://doi.org/10.1101/2022.12.24.521851 doi: bioRxiv preprint Grassland vegetation is widely used for livestock grazing to support secondary production in drylands. Numerous studies have revealed the impact of livestock grazing on plant community composition mediated by selective herbivory, depending on the livestock species (Díaz et al, 2007;Li et al, 2022;Sasaki et al, 2008a). The grazing impacts on plant species richness and community composition differed according to changes in water availability among the sites.…”