Effects of grassland utilization on soil nematode community structure and metabolic footprint
In August 2021,soil nematodes were collected from mowed,free-grazed,and fenced(control)plots of Stipa baicalensis meadow grassland to investigate the effects of different grassland utilization on the structural characteristics and metabolic footprints of soil nematode communities.A total of 15632 soil nematodes belonging to 55 genera were captured in this study,and the dominant genera were Cervidellus,Tylencholaimus,and Filenchus,which accounted for 7.05％,7.14％,and 6.18％of the total captures,respectively.The total nematode abundance was significantly lower in free-grazing habitats compared to fenced habitats.In terms of functional groups,the relative abundance of phytophagous nematodes(33.84％～37.45％)and c-p 2groups(38.78％～47.58％)was the largest in all three habitats,and both of them increased significantly in mowed and free-grazing habitats.Concerning diversity and ecological indices,the Maturity index(MI)and Enrichment index(EI)of free-grazing habitats decreased significantly,and the basal index(BI)increased significantly.This indicates that the diversity and stability of nematode communities decreased in free-grazing habitats,and the food web increased in resistance to disturbance.The Structural index(SI)of mowing habitats increased significantly,indicating that the connectivity of food webs in mowing habitats increased,and the food chain was lengthened.The Nematode channel ratio(NCR)is＞0.5and the Wasilewska index(WI)is＞1under different grassland utilization modes,indicating that the microbial nematodes were the main bearers of the soil mineralization pathway in the meadow grassland,and the bacterial pathway dominates the decomposition of organic matter.Concerning metabolic footprints,both mowing and free-grazing habitats decreased the compound metabolic footprint(TNf)and functional metabolic footprint of nematodes,and the food webs were in a structured state.In contrast,fenced habitats significantly increased the overall activity and carbon flow of nematode communities,and the food webs were in a more stable metabolic equilibrium state.The below-ground biomass(BGB),the number of plant individuals(P-N),and available potassium(AK)were the main environmental factors affecting the development of nematode communities under different grassland utilization.In conclusion,the soil nematode community structure varied significantly among different grassland utilization modes,and the changes of environmental factors in different habitats were the main factors driving the changes of soil nematode community.
万方数据
维普
