The Responses Of Soil Collembolans' Distribution Pattern To Environmental Changes In The Forests Of Changbai Mountains

Collembolans(springtails)are a group of small-sized wingless Hexapoda and characterized by the abdominal ventral tube and the furca,and have very large amounts and great varieties of individual taxa in the terrestrial ecosystem.At the same time,Collembola,nematode and mites constitute the main component of soil fauna,which play a crucial role in soil formation,improving soil characteristics,keeping soil fertility,promoting soil matter cycle,maintaining energy conversion and repairing soil environment.In addition to these,Collembolan is an important consumer and special decomposer in the terrestrial ecosystem.Owning to narrow geographic scope of activities and weak ability of migration,it is known that Collembola can sensitively respond to changes of soil environment.Consequently,Collembolans can serve as the biological indicators.In this study,samples of soil Collembolan were collected from nine forests types of Basaltplatform,Granite-lowsmontains and Granite-hills,to quantify the distribution patterns of soil Collembolans' communities and responses to forests environmental factors in the Changbai Mountains.ANOVA,Cluster analysis(UPGMA),Regression analysis.Multiple factor analysis,Structural equation model and Redundancy analysis were used to determine the taxation composition,distribution patterns and diversity of soil Collembolans.At the same time,we explored the factors affecting distribution patterns of soil Collembolans,and response of soil Collembolans to forest degradation in the Changbai Mountains.The main results were summarized as follows:(1)In this study,thirty species belonging to 26 genera,12 families,and 3 orders of soil Collembolans were collected from the Basalt-platform,Granite-lowsmontains and Granite-hills of Changbai Mountains.Among these landforms,twenty-nine species were collected in the Basaltplatform;twenty-four species were collected in the Granite-lowsmontains;twenty-six species were collected in the Granite-hills.Bourletiella sp.1were the unique taxa in the Basalt-platform,and Friesea sp.1 was found only in the Granite-lowsmontains.None unique taxa were observed in the Granite-hills.(2)Distribution patterns of soil Collembolan taxa were determined to display some differences among the Basalt-platform,Granite-lowsmontains and Granite-hills.The abundance and richness of soil Collembolans in the Basalt-platform was determined to be greater that in the other landforms.The lowest abundance was observed in the Granite-lowsmontains,and the richness in the Granite-hills was lower than that in the other landforms.Major dissimilarities existed in soil Collembolans' communities of Basalt-platform during the autumn,and other communities displayed a relatively greater similarity between each other.Anywhere,the abundance of soil Collembolans was much greater during the autumn,and much lower during the summer.The seasonal variation of soil Collembolans' diversity was different among the Basalt-platform,Granite-lowsmontains and Granite-hills.The abundance and richness of soil Collembolans were found to tended to gather on the surface of the soil.The abundance and richness of soil Collembolans were affected by lands,and seasons,depth of soil and the interaction of each other.(3)The abundance of soil Collembolans displayed significantly positive correlations with soil moisture,total N,total P,available N and Mn,whereas significantly negative correlations were found between the abundance and available K,Ca and Mg.At the same time,unimodal models were observed between the richness of soil Collembolans and total N,Ca.The richness had significantly significant linear correlations with soil temperature,soil moisture,total N,Total P,available N,Mg and Mn.The available nutrients were found to be most significantly linked to soil Collembolan communities(RV = 0.527;p = 0.001).In contrast,the correlation coefficient between total nutrients and soil Collembolans was determined to be RV = 0.507,p = 0.001.Additionally,soil temperature and moisture were significantly linked to soil Collembolan communities(RV = 0.432;p = 0.007).Furthermore,the correlation coefficient of minerals to soil Collembolan communities was found to be the lowest(RV = 0.399;p = 0.055).The available nutrients and soil temperature and moisture presented positive effects on soil Collembolans,whereas effects of available were more obvious.Additionally,soil total nutrients affected soil Collembolans in negative ways.Onychiuridae(Bionychiurus,Micronychiurus and Protaphorura)displayed significantly positive responses to the soil total N,yet they negatively responded to soil temperature and moisture significantly.Isotomidae(Isotomiella,Parisotoma and Folsomia)positively responded to total P and Mn.Additionally,Tomoceridae(Tomocerina and Tomocerus)displayed significantly negative responses to the total P and Mn.(4)Distribution patterns of soil Collembolan communities varied in the different levels of forest degradation,and soil Collembolan tended to gather in 0-5 cm soil layers at the the forests with higher forest levels.Tomocerus,Proisotoma,and Ceratophysella tended to distribute in the forest with lower forest degradation levels,and this indicated they responded positively to vegetation restoration.However,Folsomia and Parisotoma preferred to live in the forest with higher degradation levels,and this indicated they had a higher tolerance to environmental changes.In addition,Onychiuridae did not display obvious responses to the forest degradation process.