Different responses of plant N and P resorption to overgrazing in three dominant species in a typical steppe of Inner Mongolia, China

PeerJ

article

Zhen Wang¹  Saheed Olaide Jimoh¹  Xiliang Li¹  Baoming Ji³  Paul C. Struik⁴  Shixian Sun¹  Ji Lei¹  Yong Ding¹  Yong Zhang¹ 

[1] Institute of Grassland Research, Chinese Academy of Agricultural Sciences;Sustainable Environment Food and Agriculture Initiative;College of Forestry, Beijing Forestry University;Department of Plant Sciences, Wageningen University

关键词: Livestock;    Nutrient cycling;    Leaf N concentration;    Leaf P concentration;    Nutrient resorption efficiency;   

DOI  :  10.7717/peerj.9915

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Nutrient resorption from senesced leaves is an important mechanism for nutrient conservation in plants. However, little is known about the effect of grazing on plant nutrient resorption from senesced leaves, especially in semiarid ecosystems. Here, we evaluated the effects of grazing on N and P resorption in the three most dominant grass species in a typical steppe in northern China. We identified the key pathways of grazing-induced effects on N and P resorption efficiency. Grazing increased N and P concentrations in the green leaves of Leymus chinensis and Stipa grandis but not in Cleistogenes squarossa. Both L. chinensis and S. grandis exhibited an increasing trend of leaf N resorption, whereas C. squarrosa recorded a decline in both leaf N and P resorption efficiency under grazing. Structural equation models showed that grazing is the primary driver of the changes in N resorption efficiency of the three dominant grass species. For L. chinensis, the P concentration in green and senesced leaves increased the P resorption efficiency, whereas the senesced leaf P concentration played an important role in the P resorption efficiency of C. squarrosa. Grazing directly drove the change in P resorption efficiency of S. grandis. Our results suggest that large variations in nutrient resorption patterns among plant species depend on leaf nutritional status and nutrient-use strategies under overgrazing, and indicate that overgrazing may have indirect effects on plant-mediated nutrient cycling via inducing shifts in the dominance of the three plant species.

【 授权许可】

CC BY