Community Composition And Ecological Distribution Of Soil Collembola From Typical Farmland Ecosystems In The Changbai Mountains

Soil Collembola is one of the three dominant groups of meso-micro soil fauna,and important consumer and decomposer in the underground ecosystem,and played an important role in the physical and chemical properties of cultivated soil and soil quality,such as the function of evaluating soil quality,and improving soil fertility and improving soil physical and chemical nature.In addition,soil Collembola was very sensitive to the changes of soil environment.Once the soil environment changed,the community composition,ecological distribution,and diversity of soil Collembola will change soon.Soil Collembola can be used as an indicator of soil environmental changes.It is one of the good environmental indicator organisms.To investigate the community composition,ecological distribution and seasonal dynamics of soil Collembola from typical farmland ecosystems in the Changbai Mountains,three habitats were selected,namely basalt platform,granite low-mountains and granite hills from the Changbai Mountains.Soil Collembola was collected from each habitat in spring(mid-May),summer(mid-July),and autumn(mid-September)of 2015.The composition and ecological distribution of the soil Collembola community were studied.The results of the study were as follows:(1)We obtained 881 collembolan individuals in the three habitats,belonging to10 families,16 genera,and 22 species.There are three dominant species of soil Collembola,Protaphorura sp.1,Proisotoma sp.1,and Proisotoma sp.2,accounting for 56.04%.There were 11 common species,accounting for 41.59%.Dominant species and common species together constituted the main body of soil Collembola in the typical farmland ecosystem of Changbai Mountain,accounting for 97.63%.There are 8 rare species,accounting for 2.37%.(2)The horizontal distribution of soil Collembola varied due to different habitats.On the whole,the individual density of soil Collembola in each habitat was represented by granite low-mountain(2 206.67 ind/m~2)>granite hills(1 906.67ind/m~2)>basalt platform(1 760 ind/m~2).The species numbers displayed only minor differences in all habitats.The species numbers was the highest in the granite hills(18species),followed by the basalt platform(17 species),and the granite low-mountains(13 species).There were still seasonal differences in the individual density and species number of soil Collembola.However,soil Collembola was determined to be the highest in autumn in all of the habitats.The densities and species number of the soil Collembola in the granite low-mountain and granite hills displayed an increasing trend after first reducing.Meanwhile,the densities and species number of the soil Collembola in the basalt platform showed a trend of increasing along with the change of seasons.(3)The individual density and species number of soil Collembola differed among the habitat with sampling season and soil layer.The individual density and the species numbers of soil Collembola showed the same dynamic trend in basalt platform and granite low-mountain,exhibited a significant upward trend,with a clear surface collection,mainly concentrated in the 0-5 cm layer,while varied among the two habitats.The vertical decline law of the individual density of soil Collembola on the basalt platform was more intense,showing a rapid change trend;while relatively gentle,showing a gradual trend in the granite low-mountain.The vertical distribution of soil Collembola in granite hills differs significantly from those in basalt platforms and granite low-mountain.The individual density and species number of soil Collembola in the granite hills were mainly concentrated in the 5-10 cm layer,while the individual density of soil Collembola in 0-5 cm layer was least.There are features that migrate downward and gather at relatively stable levels.(4)Habitat differences and sampling seasonal changes had a certain impact on the characteristics of soil Collembola diversity.Although there were differences in the diversity of soil Collembola in different habitats,Shannon-Wiener index,Pielou index and Margalef index of soil Collembola in all three habitats reached the maximum in autumn.The diversity index and richness index of soil Collembola showed an increasing trend of seasonal variation on the basalt platform.Meanwhile,the diversity and richness of the soil Collembola in the granite low-mountain and granite hills displayed an increasing trend after first reducing.(5)There are certain environmental gradients in all habitats.Among them,the seasonal variation of soil environmental factors in granite low-mountain and granite hills was small,while the soil environmental factors in the basalt platform vary greatly between seasons.Different soil environmental factors had different effects on the soil Collembola,and different groups of soil Collembola showed a mutually reinforcing relationship.In this study,Habitats and seasonal variations had significant effects on community composition and ecological distribution of soil Collembola.