A Study On The Diversity Of Large Soil Anmials In Different Fencing Duration Of Degraded Typical Grassland In Inner Mongolia

The compositions of large soil animals and epigeic arthropod in different plots,A plot(enclosed in 1983),B plot(enclosed in 1996)and C plot(unenclosed)of degraded typical grassland in Inner Mongolia were investigated in this study.The main methods are hand detection and trap method.The diversity,temporal dynamics and the relationship with soil physical and chemical properties were analyzed,and the influence of enclosing duration on large soil animals was discussed.The results of study showed that as follows:(1)A total of 2378 individuals of large soil animals were collected,belonging to 2 phyla,5 classes,8 orders,34 families,a total of 47 kinds.There were differences in the community structure of large soil animals in the sample plots with different fencing years.(2)The community diversity of large soil animals was significantly restored,but there was no linear relationship between the restoration effect and the enclosing duration.The number of individuals,species abundance,diversity index,evenness index and density groups were higher in 1996 than in 1983.(3)The vertical community composition of large soil animals in three plots was different,but all characterized by apparent aggregation.(4)The diversity of large soil animals community varied with the season,and the highest values of individual number,species richness,diversity index and evenness index all appeared in July.(5)The physical and chemical properties of soil were different in three plots,and the affection of the physical and chemical properties on various groups was different.The main influencing factors were water content and organic matter.(6)The total of 14732 arthropods were collected in three plots,belonging to 2 classes,9 orders and 81 kinds.Formicidae and Carabidae adult were the dominant groups.There were differences in the structure of arthropod community in different fenced plots.The diversity index showed that the plot enclosed in 1983 with the most number of individuals,the plot enclosed in 1996 with the most richness,the plot enclosed in 1996 with the highest diversity index,the plot enclosed in 1983 with the highest evenness index.The diversity index varied with the season.(7)Different plots with the different functional groups the Plot enclosed in 1996 with the most number of individuals of phytophagy and saprophagous,while the plot enclosed in 1983 with the most omnivorous and carnivorous.The richness of groups phytophagy,saprophagous,omnivorous was the same in the plot enclosed in 1983 and the plot enclosed in 1996,and the plot enclosed in 1996 with the most carnivorous.