The Effect Of Soil Fauna On Forest Litter Decomposition And Soil Formation Of Maolan Karst Area

The decomposition of forest plays an important role litter in the organic matter storage and nutrient cycling of forest ecosystems.The effects of soil faunas on the litter decomposition were different in the scale of space and time due to the variance factors of climatic conditions,litter properties etc.The studys on the decomposition of litterfalls with different regions and different types of litter can help us to analysis the effect and relationships between soil faunas and litter decomposition,which has a vital practice significance for the improving of productivity and biodiversity conservation of forest ecosysterm.The forest of Maolan karst is a epibitic karst forest in the same subtropical latitudes of the world,which are centralized,original and stable,relatively.The region is the largest area with a primary forest in the karst area and are representative and typical simoutaneously.However,there are few reports of soil faunas on the litter decomposition in this typical karst regions.In order to quantify the effect of different soil fauna types in the forest litter decomposition process in Maolan karst forest.Two typical evergreen tree species litter of Cyclobalanopsis glauca(CD)and Kmeria septentrionalis Dandy(KD)were selected to conduct a field decomposition experiment using three different apertures(5 mm,2 mm and 0.03 mm)mesh size litterbags in a virgin forest of Maolan karst area.The study was aimed to explore the effect mechanism of soil faunas in the litter decomposition and biology soil formation process of Maolan karst area,which can provide a scientific basis for the matainance of surface nutrients,improving of productivity and ecological restoration of karst forest ecosysterm.The main conclusions were as follows:(1)A total number of 4203 individuals of soil faunas,which belongs to 3 species,11 classes,25 orders,were collected from the forest litter of Maolan karst area in this experimentt.The dominant orders in the soil fauna community were Collembola and Acari,which accounted for 37.62% and 45.78%,respectively,accounting for 83.39% of the total.The abundance and abundance of soil fauna in different litters increased with the decomposition time.There was no significant difference in abundance,abundance,and diversity of soil faunas which indicated that soil fauna diversity was not affected by the types of litter.There was no significant difference in soil fauna diversity between the 5 mm and 2 mm mesh size litterbags.This may be due to the existing of multiple soil meso-and microfaunas in the sample plots which were located in subtropical primeval forests that have generated a functional redundancy between the two groups of soil macrofauna and mesofauna.(2)The three types of litter annual decomposition rate in the different mesh size litterbags were as follows,5 mm > 2 mm > 0.03 mm,the range were 1.23~1.35 g/year,0.66~0.01 g/year,0.53~0.66 g/year,respectively.The half-life period of litter were 0.48~0.59 year,0.73~0.98 year and 0.97~1.20 year,while the turnover time of litter were 2.18~2.46 year,3.01~4.47 year and 4.44~5.52 year.During the early decomposition process of the litter,soil faunas have significantly promoted the loss of litter mass in the Maolan karst region.In the 12-month decomposition process,the contribution rate of soil fauna to the literr mass loss was 42.0%~45.9%.Different types of soil faunas have different effects on the mass loss of the three types litter.The maximum effect of macrofauna on the litter decomposition process were found in the mixed litter(CG+KD),while soil meso-and microfauna have the greatest effect on the decomposition of litter KD.The difference with litter properties were the main factors that contribute to the differences of soil fauna effects of on the litter decomposition processs.(3)Soil faunas had facilitated or inhabited the release of element N,P,K,Ca in the three different little decomposition process in the early decomprocess process of Maolan karst forest litter.Soil faunas had promoted the release of elemtent Mn,while soil faunas had less effect on the litter decomposition of C and Mg elemtents in the decomposition process.Soil faunas had a relative significant effect on the decomposition of the Kmeria septentrionalis Dandy(KD)litter for its higher quality(with lower C/N ratio).The relationships between the variation of the elements and litter mass loss rate were relatively complicated in the litter decomposition.The facilitated effect of soil faunas on the release of some elements in the litter decomposition process have promoted the transportation and input of litter to the soil,and would accelerate the matter circulation of the forest ecosysterm.It has illustrated that the soil faunas had a positive effect in the biology soil formation process of the Maolan karst forest ecosysterm.