Maintenance of dominant populations in heavily grazed grassland: Inference from a Stipa breviflora seed germination experiment

PeerJ

article

Wenting Liu¹  Zhijun Wei²  Xiaoxia Yang¹ 

[1] Qinghai University, Qinghai Academy of Animal and Veterinary Sciences;Key Laboratory of Grassland Resources, Ministry of Education P.R. of China, Huhhot, P.R. China, College of Grassland, Resources and Environment, Inner Mongolia Agricultural University

关键词: Seed phenotypic characteristics;    Awn;    Germination rate;    Ecological strategy;    Population adaptation;   

DOI  :  10.7717/peerj.6654

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

An understanding of population adaptation and maintenance mechanisms under interference from large herbivores is lacking and is a major focus of ecological research. In the Eurasian steppe, which has been subjected to continuous interference from domesticated ungulates throughout history and shows increased grazing, it is particularly urgent to analyze the ecological adaptation strategies of widely distributed Stipa plants. In this study, Stipa breviflora in a group of desert steppes in the Mongolian Plateau was selected to study the potential mechanism underlying the maintenance of dominant populations under the continuous interference of heavy grazing from the new perspective of seed germination rate. Laboratory experimental results showed that the values of the phenotypic traits of S. breviflora seeds were lower under a heavy grazing treatment than under a non-grazing treatment, but the seed germination rate did not decrease. The awns of non-grazed seeds significantly affected the seed germination rate, while those of heavily grazed seeds did not. Field observations showed that grazing does not significantly affect the population density of S. breviflora at different growth stages except in extremely wet and dry years. Our study suggests that under heavy grazing, S. breviflora uses an “opportunistic” ecological strategy to ensure population maintenance by increasing the seed germination rate and reducing dispersal via changes in associated seed phenotypic traits.

【 授权许可】

CC BY