Impacts Of Grazing On Arbuscular Mycorrhizal Fungi Diversity In A Meadow Steppe

Arbuscular mycorrhizal (AM) is mutualistic symbiont between arbuscular mycorrhizaefungi (AMF) and plant root in soil, which is a primary component in ecosystem. As one of theimportant grassland management, grzaing can influence plant diversity directly and AMFindirectly. We conducted this study on the Songnen grassland, with two plant diversity levels(high and low) and four grazing treatments (cattle grazing, sheep grazing, mixed grazing withby sheep and cattle, no grazing) to examine the impacts of grazing patterns on AMF diversity,and the interactions between diversity of plants and AMF, and explore response of AMFdiversity to grazing. The main results and conclusions are present as the followings:(1) Form soil sample, three genus (Glomus, Acaulospora and Archaeospora) and26species were identified. Glomus in the dominate fungi in the natural Songnen grassland that is69.2%of the total fungi, which Acaulospora is a secondary species that is15.4%of the totalfungi, and Acaulospora is a companion species.(2) Large herbivore grazing influenced AMF diversity significantly. For forbs, grazingdecreased richness of AMF spore, but increased Shannon-Weiner and evenness, and plantdiversity did not influenced the effects of grazing on AMF diversity. For grasses, grazing hadsimilar impacts on AMF. At the scale of plant community, the effects of grazing on AMFdiversity varied with plant diversity. At low level of plant diversity, sheep grazing and mixedgrazing increased AMF diversity, while at high level plant diversity, cattle grazing and mixedgrazing increased AMF diversity. For forbs, grasses and plant community, grazing of largeherbivore and plant diversity had significant interactive effects on AMF abundance.(3) Inspection rate of AMF differed among plant diversity and grazing patterns. At highand low plant diversity levels, cattle grazing and mixed grazing increased total inspection ofAMF and arbuscular inspection, while sheep grazing had no significant impacts. Thisdemonstrated that grazing treatments with cattle (cattle grazing and mixed grazing) promotedcolonization of AMF in plant root and formation of arbuscular. For vesicle, effects of grazingvaried with change in plant diversity. At low level of plant diversity, grazing had inhibition onvesicle number, while at high level of plant diversity, grazing had positive effects.In summary, grazing decreased richness of AMF spores in forbs and grasses, andincreased Shannon-Weiner and evenness, while impacts of grazing on AMF diversity wereinfluenced by plant diversity. Cattle grazing and mixed grazing increased inspection of AMFand arbuscular, and effects of grazing on vesicle number varied with plant diversity. This study clarified impacts of grazing and plant diversity on AMF, which improved ourunderstanding of the effects of grazing on ecosystem structure and function, and gave ascientific guide to grassland management.