Effects Of Dung Types On The Dynamics Of The Dung-arthropod Community In The Livestock Dung In Inner Mongolia Typical Steppe

Grazing is an important use of the typical grassland in Inner Mongolia,and cattle and horses are the main livestock.The decomposition of livestock dung pads is not only an important way of the material cycle in the grassland ecosystem,but also the important food sources and suitable habitat,and there is a significant support to the diversity of arthropods in grassland.From June 2016 to September2017,using the method of artificial deposition on the grassland,we investigated dynamic features of the composition,diversity and functional groups of the dung arthropod community in horse and cattle dung,and the changes of physicochemical properties of the dung in a typical steppe of Inner Mongolia.The results can accumulation the information for in-depth understanding of the decomposition mechanism of livestock dung,and providing the basis for the scientific management in the typical steppe of Inner Mongolia.The main results are as follows:1.A total of 3141 and 60 groups of dung arthropods were captured in horse dung,and 2780 and 66 groups of dung arthropods in cattle dung.2.In fresh horse dung pads,the dominant groups of dung arthropod community were Aphodiidae adult and Staphylinidae adult.the dominant species of dung beetle community was Aphodius branesiki,and respectively was Staphylinidae adult and Onthophagus gibbulus in fresh cattle dung.3.Endocoprids were mainly colonization fresh horse dung pads,but paracoprids were mainly colonization cattle dung pads.4.Shannon-Wiener index?H???Pielou evenness index?J??Simpson dominance index?D?and Margalef richness index(D_Ma)of the dung arthropod community in the cattle dung pads were higher than that of in horse dung pads,but the difference is not significant.5.The dung arthropods that colonization dry livestock dung pads mainly were mites,springtails,and small beetles.Laelapidae was the dominant group in dry horse dung,and Cheyletidae in cattle dung.6.As the time of deposition extended,pH,water content,total N,total P,water-soluble organic matter and organic matter of the residual dung pads had the trends of decreasing.The decreasing rates of all the above indexes of the residual cattle dung were slower than that of horse dung.The decomposition rate of horse dung was higher than that of cattle dung.The results suggested that,because the features of more undigested plant fiber,lower water content,faster water losing,easy fragmented,etc.,the horse dung suitable temporary habitat for the dung arthropods represented by endocoprids.And the higher decomposition rate make the nutrients in it faster return to the grassland soil.Also,caused by slow water loss and not easy fragmented,cattle dung pads provided feeding and activity habitats for the dung arthropods represented by paracoprids,and stronger supports for dung arthropod diversity.But,the slower decomposition rate can cause the local accumulation of the nutrients in residual dung pads in grassland.