Division Of Ecological Functional Groups Of Dung Beetles And Their Secondary Dispersal To Seeds In The Dung Of Grazing Livestock

As an important spring and autumn pasture,the Seriphidium semidesert bears the pressure of grazing in two seasons.Dung beetles,as an important decomposer in the grassland ecosystem,play a key role in the energy flow and material circulation of the grassland.The decomposition of feces by dung beetles promotes the nutrient cycle of the grassland ecosystem,and at the same time,the use of dung by dung beetles can secondly spread the seeds mixed in the dung to various places.It is of great significance for maintaining the balance of grassland ecosystem and restoring degraded grassland vegetation.Objective: Aim to start with the small-scale transmission event of the secondary dispersal of dung beetles from plant seeds,based on the investigation of dung beetle species diversity and the division of functional groups,to clarify the secondary dispersal effects of dung beetles on seeds,which can greatly enrich grazing ecology,Insect ecology,grassland plant population ecology research content.Finally,the impact of the second propagation of dung beetle seeds on the grassland will provide a theoretical basis for the grazing management of the Seriphidium semidesert grassland and the restoration of degraded vegetation.Methods: The combined method of collecting samples from field experiments and hand-picking and accounting in indoor laboratories obtained dung beetle samples to analyze the species diversity characteristics,and the behavior of dung beetles was determined through continuous recording and observation in the field.In spring,beads of different sizes were mixed with dung for seed simulants test.In autumn,the dung treated by dung beetles and the underlying soil were brought back to the laboratory for seed germination test.Results:1)A total of 14797 dung-eating insects were captured,belonging to 19 species and 3 families,in which there were 10 species of the family Aphodiidae,8 species of the family Scarabaeidae,1 species of the family Geotrupidae.The diversity analysis demonstrated that the Species richness index were highest in June,the largest number of individuals occurs in October.The relationship between the analysis system constructed by molecular systematics and the classification method of morphology are basically the same.The classification of dung beetle ecological functional groups is basically the same as the classification method of the analysis system relationship constructed by molecular systematics.2)The observation of the behavior of dung beetles entering the feces in June and October showed that there were many types of dung beetles in June,and the food resources were abundant,so they could get enough food in the feces before leaving.The number of dung beetles in the feces reached a peak for 8 hours.There is a large number of dung beetles in October.Stool is a scarce resource.When the nutrients in the dung can’t maintain feeding or lay eggs,the dung beetles will leave on their own.The number of dung beetles in the dung for 4 hours reaches the peak;in June,the species abundance is high.Temperature and humidity did not show a significant correlation with the number of dung beetles.The species of dung beetles in October are relatively single and large in number,and environmental factors have a relatively pure impact on them.The dung beetles show the characteristics of hot and dry.3)The distribution of dung beetles to the seeds in the feces is positively correlated with the size of the seeds.About 80% of the seed simulants are buried in the range of 20 cm horizontally and 0-10 cm deep.20% of the seed simulants were buried below 10 cm by the insects or moved outside the horizontal range of20 cm.As the size of the simulant increases,the proportion of embedded simulants gradually decreases.The results of the seed germination test showed that the dung beetles would spread the seeds in the feces a second time,and the seed density of the soil seed bank at different horizontal distances was 10-20cm>0-10cm> 20-30 cm.Conclusion: The clarification of the species diversity characteristics of the dung beetle in the desert of the Seriphidium semidesert elucidates the spatial and temporal law of the secondary transmission of seeds in the feces under different treatment modes,as well as the impact of the small scale of secondary transmission on the species diversity and landscape diversity of grassland plants.