Different deterministic versus stochastic drivers for the composition and structure of a temperate grassland community

Abstract It is a central goal of current community ecology to explore the pattern and mechanism of community response to anthropogenic disturbances. Most researches focus on the response of community composition, which is based on the presence/absence or relative abundances of different species. However, the response of species-identity-independent community structure, such as the rank-abundance distribution, remains relatively understudied. We conducted a ten-year nitrogen addition experiment in a temperate steppe, with nine nitrogen rates under fencing (un-mowed) or mowing conditions. Mowing and nitrogen addition significantly altered both the composition and structure of plant communities. While the relative importance of stochastic change in community composition under mowing was not significantly different from that under fencing, the relative importance of stochastic change in community structure under mowing was significantly larger than that under fencing. Overall, our results demonstrated that mowing led to different drivers for the community composition and structure, meaning that mowing promoted the stochastic allocation of material and energy in primary producers in the grassland ecosystem.