Title: Stocking rate affects plant community structure and reproductive strategies of a desirable and an undesirable grass species in an alpine steppe, Qilian Mountains, China
Authors: Yarong Guo, Xiong Z. He, Fujiang Hou*, Jizhou Ren
Journal: The Rangeland Journal (农林科学4区，IF2019= 1.019)
Abstract: Grazing effects on species reproduction are a fundamental issue of grassland management. The present study investigated plant density and dry weight changes at community and spe-cies level, and the reproductive strategies of the dominant desirable Stipa purpurea and the undesirable Achnatherum inebrians grass species in response to the stocking rate in an alpine steppe with a 10-year grazing history. Results showed complex patterns of plant community and reproductive strategy. Overall plant density increased with increasing stocking rate and dry weight was significantly higher at light and high stocking rates. Plant density and dry weight of A. inebrians peaked at moderate stocking rates. Higher stocking rate had little impact on S. purpurea density but significantly reduced its dry weight. Both species dis-played linearly increasing/decreasing or unimodal/bimodal reproductive effort in response to increased stocking rate. The discrepancies in plant reproductive characteristics between S. purpurea and A. inebrians indicated that: (1) light and moderate grazing may promote an adaption strategy of reproduction by desirable species, which may then contribute to their maintenance in grasslands, and (2) undesirable species presence did not lead to the replace-ment of desirable species in the grasslands. Therefore, light and moderate stocking rates are recommended to maintain the grasslands and to increase the reproductive outputs of desirable species.