The influence of enclosure on the ecological niche and interspecific associations of dominant plant species in temperate grasslands of the Kuizu Mountains in Tibe

Abstract

Abstract [Objective] In order to reveal the effects of non-grazing restriction on ecological niches and interspecific associations of the herbaceous species in the dominant plant communities in the temperate grasslands of the Kuizu Mountains in Linzhou County, Tibet, and to provide theoretical basis for the protection of plant diversity in the temperate grasslands in the Tibetan Plateau and for scientific management of the grasslands. [Methods] The “Levins” method, variance ratio method (Vr), Chi-square test, association coefficient (Ac), and Ochiai (Oi) index were used to analyze eight major plant species in the dominant plant communities in the temperate grasslands of the Kuizu Mountains in Tibet. [Results] (1) Non-grazing treatments increased the niche width and niche overlap of grass sedge (Tripogon bromoides), alpine tarragon (Carex parvula), whitegrass (Pennisetum flaccidum ), and silky needle fescue (Stipa capillacea). (2) The enclosure community in the study area showed an overall negative association (Vr =0.43), and the free-grazing community showed an overall positive association (Vr =1.21). According to the Chi square test, 67.9% and 53.6% of the 28 species pairs composed of 8 dominant species displayed negative association under the non-grazing and free grazing treatments, respectively. The association coefficient showed that 50% and 42.9% of species pairs were negatively linked under the non-grazing and free grazing treatments, respectively. The non-grazing treatments increased the Oi values of the main species, including Tripogon bromoides, Carex parvula, Pennisetum flaccidum , and Stipa capillacea. [Conclusion] Based on the interspecific association analysis, non-grazing treatments strengthened inter-species competition within the dominant plant communities in the temperate grasslands in the Kuizu Mountains, and the inter-species relationships become closer with unstable community structures

Keywords

• non-grazing
• kuizu mountains
• ecological niche
• interspecific association