The Characteristics Of Soil Fauna Communities And The Division Of Functional Groups In Different Altitudinal Gradients Of Picea Schrenkiana In Western Tianshan Mountains

Picea schrenkiana is the dominant species of forest community in Western Tianshan Nature Reserve.Its climate conditions and soil fauna community structure vary significantly along altitude.Soil fauna are an important part of forest ecosystem.They play an important role in soil food web.They are the key link to determine soil food web and energy flow path.They play an important role in maintaining the stability of forest soil ecosystem,promoting material circulation and energy flow.In view of this,this paper studies the soil fauna community characteristics and functional group division in different altitude gradients in Western Tianshan nature reserve,provides an important theoretical basis for the management and control of local forest resources,and promotes the research of P.schrenkiana forest ecosystem and the protection of its biodiversity in Western Tianshan Mountain.In order to study the structural characteristics of soil fauna community and the division of functional groups in different altitude gradients of P.schrenkiana,soil fauna under P.schrenkiana and the roots,stems and leaves of P.schrenkiana in different altitude gradients(altitude: 1414 m,1595m,1724 m,1868m)in West Tianshan Nature Reserve were selected in spring(May),summer(July)and autumn(September)of 2021.The structure,seasonal dynamics and functional group division of soil fauna community in different altitude gradients of P.schrenkiana were analyzed,and RDA(Redundancy analysis)ranking was used to analyze the correlation between soil fauna community and soil environmental factors.The conclusions are as follows:(1)A total of 15505 soil fauna were captured in this survey,belonging to 42 families,23 orders,8 classes,3 phyla.Among them,there are 427 macro-fauna belong to 24 families,16 orders,7 classes,3 phyla.The three dominant groups(60.89%)were Geophilidae,Lumbricidae and Coleoptera Larvae.There were 12 common groups(35.83%),most of which are Formicidae,Carabidae,Labiduridae,Staphylinidae,Lithobiidae,Glomeridae and Araneida.There are 12 rare groups(3.28%),most of which are Coccinellidae,Tenebrionidae,Scarabaeidae and Armadillidae.there are 15078 meso-micro fauna belong to 32 families,18 orders,6 classes,3 phyla.The two dominant groups(62.10%)were Oribatida and Aphididae.There were 9 common groups(35.83%),which are Diptera Larvae,Gamasida,Actinedida,Hypogastruridae,Onychiuridae,Paronellidae,Tomoceridae,Isotomidae and Enchytraeidae.There are 29 rare groups(4.62%),most of which are Sminthuridae,Staphylinidae and Thripidae.(2)From the horizontal direction,the average density of macro-fauna in the four plots(altitude)was the highest in spring,and the average density of macro-fauna decreases significantly in summer and autumn.The average density of meso-micro fauna was the highest in autumn.The average density of meso-micro fauna in plot-IV(altitude: 1868m)was the highest in spring,summer and autumn compared with other plots.From the vertical direction,the distribution of macro-fauna in litter layer and 0-15 cm soil layer is irregular.The meso-micro fauna were mainly distributed in litter layer and 0-5cm soil layer in spring and summer.The average density of meso-micro fauna in 5-10 cm and 10-15 cm soil layer in autumn was higher than that in spring and summer.Among the four plots,in spring,the diversity index(H’)and evenness index(J)of plot-II(altitude: 1595m)were the highest,and the richness index(D)and dominance index were the lowest(C).In summer,the diversity index(H’),richness index(D)and evenness index(J)of plot-IV(altitude: 1868m)were the highest,and the dominance index was the lowest(C).In autumn,the diversity index(H’)and evenness index(J)of plot-III(altitude: 1595m)were the highest,and the richness index(D)and dominance index were the lowest(C).(3)According to the feeding habits of soil fauna,the soil fauna captured in the four plots(altitude)are divided into four functional groups: phytophagy,detritivores,predacity and omnivorous.There are 14 phytophagous soil fauna(Aphididae,Diptera Larvae,Coleoptera Larvae,Curculionidae,Elateridae etc.).There are 19 detritivorous soil fauna(Oribatida,Actinedida,Isotomidae etc.)There are 10 predatory soil fauna(Geophilidae,Lithobiidae,Carabidae,Araneida,Phalangida etc.)and 7 omnivorous soil fauna(Labiduridae,Culicidae,Thripidae etc.).The main functional groups of soil fauna in the four plots were detritivores.(4)According to the results of RDA ranking,the effects of environmental factors on soil fauna community are as follows: readily available potassium > readily available phosphorus >total nitrogen > total phosphorus > organic matter > ammoniacal nitrogen > total potassium >nitrate nitrogen > p H.Readily available potassium,readily available phosphorus,total nitrogen,total phosphorus,organic matter,ammoniacal nitrogen,total potassium and nitrate nitrogen were important environmental factors affecting the distribution of soil fauna communities in the different altitudes(P<0.01).