A Study On Diversity Of Soil Oribatid Mites In Lesser Khingan Forest Nature Reserves

The oribatid mite is one of the most important soil animals and a relatively large proportion in soil fauna.As one of the important decomposers in the soil,it is of great significance to maintain soil ecosystem and material cycling.The Objective of this study is to provide a scientific basis of understanding the characteristics of community structure,diversity and the influence of stand factors,site condition on the diversity of oribatid mites of different forest types such as Birch forest,Pinus koraiensis forest,Larch plantation,Mongolica oak forest,Spruce and Fir forest,mixed forest of Bir-Larch and coniferous and broad-leaved mixed forest in the three National Nature Reserves,Wuyilin,Hongxing,Youhao,in Lesser Khingan.In August and September 2016,In order to reveal the distribution mechanism of the soil oribatid mites and provide basis for protecting the species,we performed site-specific sampling surveys.The main results are as follows:(1)A total of 53,815 soil oribatid mites were captured from different forest types in Lesser Khingan forest nature reserves,belonging to 22 families,28 genera and 36 species,of which 27 species were identified to species level,7 were identified to the genus level,and 2 species were identified to the family level.The number of individuals in Lar is the highest,while in CBLMF is the lowest;the number of species in the Bir and SFMF are 36 species,and the lowest in BLMF are 28 species.(2)The dominant species in Lesser Khingan forest nature reserves were not obvious,only A.curta?E.ovata?H.minutissima?P.altera?L.neerlandica were subdominant,accounting for 25.66%;P.longisetosus?L.borealis and Allodamaeus sp.were rare,accounting for 2.76%.(3)The MGP-analysis I and MGP-analysis II of groups of different types indicated that the soil oribatid mites of Lesser Khingan nature reserves belonged to O-type,but it is obvious the M-groups is more than G-groups and P-groups.(4)In different forest types,the diversity index(H')showed that: Bir>Lar>PK>SFMF>MO>CBLMF >BLMF.The richness index(M)showed that: Bir>SFMF>PK>Lar> MO>CBLMF>BLMF.The evenness index(E)showed that:Bir = PK= Lar>SFMF>MO>CBLMF>BLMF.The dominance index(W)showed that: MO>CBLMF> Bir>SFMF>PK>BLMF> Lar.(5)According to Jaccard's similarity analysis,the community composition of soil oribatid mites among different forest types has a high similarity.(6)The combined effects of relative abundance and coverage of herbaceous plants of stand conditions has a significant effect on the composition of oribatid mites.With the increase of thickness,the change of litter thickness has more obvious effects on the diversity of oribatid mites.When it reaches 1.5cm-2cm,the composition of species diversity is the most obvious.The change of slope direction and gradient of site conditions has a more significant effect on the species diversity.(7)From the indicator species analysis of oribatid mites in different forest types,N.borussicus is more indicative.In PK,H.rufulus and T.japonicus have a strong indication.In Lar,Anderemaeus sp.,N.nana,Perlohmannia sp.,S.latipes are the highest indicative value,which was significantly higher than other species.In MO,P.peltifer,P.longisetosus,and M.monocornis are strongly indicative.In SFMF,H.peltifer,Damaeus sp.,Damaeidae sp.and Oppiella sp.are strongly indicative.In BLMF,only H.minutissima,Nothrus sp.and Allodamaeus sp.showed strong indication.In CBLMF,Phthiracarus sp.is highly indicative.