Co-recovery of soil macrofauna and basic fertility under ecological restoration in karst areas

ObjectiveIndicating functions of soil macrofauna during restoration of karst vegetation were revealed to provide scientific basis for further understanding the mechanism of soil science process of karst ecological restoration and building the technical system of ecological restoration.MethodIn the method of space-for-time substitution,a series of plantation plots with planting age gradients(2,4,8,12 years)were selected,which were numbered F-2a(2-year-old plantation),F-4a(4-year-old plantation),F-8a(8-year-old plantation)and F-12a(12-year-old plantation),and response characteristics of macrofauna community on the soil surface(0-10 cm)to the ecological restoration of plantation and their relationship with basic soil fertility were investigated and analyzed by taking samples of natural growth rocky desertifica-tion as control(CK).ResultSoil basic fertility indicators,including soil porosity,moisture,total organic carbon,solu-ble organic carbon,total nitrogen,available nitrogen and microbial biomass carbon contents gradually increased with the extension of karst ecological restoration years,and their average annual recovery rates were 1.18%,0.63%,0.48 g/kg,33.92 mg/kg,0.05 g/kg,2.77 mg/kg and 62.08 mg/kg respectively.A total of 7621 soil macrofaunas were collected from 5 sample plots and classified as 13 groups,among which,Gastropoda,Coleoptera and Hymenoptera were dominant groups.Soil macrofauna number for all the groups especially Lepisoptera,Geophilidae and Diptera in rare groups(except for Coleoptera and Hemiptera)grew following the extension of eco-restoration years. Soil macrofaunal species number (12-13 species),richness index(SR,1.51-1.63),Shannon-Wiener index(H′,1.91-2.02)and evenness index(J′,0.77-0.81) in the plantation plots were significantly higher than those in CK plot(P<0.05,the same below). Total number of soil macrofauna increased significantly after karst ecological restoration,and was extremely positively correlated(P<0.01) with the main soil fertility indicators.According to redundancy analysis,the number of soil macrofauna such as Lepisop-tera,Hymenoptera,Gastropods,Formicidae,Orthoptera and Araneae showed strong positive correlation with fertility in-dicators such as soil porosity and microbial carbon content.ConclusionThe results indicate that,soil macrofauna com-munity structure had certain synergistic effects with the restoration of soil basic fertility under karst ecological restoration, and it also shows that soil macrofauna community indicators plays an important role as bio-indication on soil ecosystem restoration in karst areas.