Effects Of Invasion Of Xanthium Italicum Moretti On Soil Fauna Diversity In Yili Valley

Xanthium italiana Moretti is an annual malignant invasive weed of Xanthium genus in the asteraceae family.It has strong reproductive ability and adaptability and can grow in different habitats.The invasion and mass propagation of Xanthium italicum Moretti has seriously affected the development of crops,cash crops and fauna husbandry,and brought serious harm to the ecosystem and biodiversity of the invaded areas.Soil fauna is an important component of soil ecosystem and an important participant in soil material cycling.Soil fauna plays an important role in soil ecosystem by accelerating the decomposition rate of fauna and plant debris,changing soil physical and chemical properties and fertility,promoting energy flow,and producing soil nutrients.Therefore,this paper studied the soil fauna community characteristics and functional groups in the plots with different invasion degrees of Xanthium italicum Moretti,providing important theoretical basis for the prevention and control of Xanthium italicum Moretti invasion.In order to study the community structure and functional group characteristics of soil fauna in different invasion levels of Xanthium italicum Moretti,four invasive habitats(non-invasive,mildly invasive,moderately invasive,and severely invasive)of Xanthium Italiana in Yili Valley were selected in the spring(May)and summer(July)of 2022.Soil fauna among the roots of Xanthium italicum Moretti were selected as the research objects.The structure and functional group characteristics of soil fauna community were analyzed,and the correlation between soil fauna community and soil environmental factors was explored.The conclusion is as follows:(1)A total of 1190 soil fauna belonging to 34 classes,1 phyla,3 classes,14 orders and 30 families were captured in the four invasion degree plots of Xanthium italiana Moretti.The dominant groups included Actinedida,Gamasida,Formicidae and Isotomidae,accounting for78.91% of the total captured population.The common groups included Oribatida,Paronellidae,Coleoptera Larvae,Curculionidae and Staphylinida,and the number of individuals accounted for 15.21% of the total captured numbers.The rare groups include Hypogastruridae,Tomoceridae,Sminthuridae,Pseudachortidae,Chalcidoidea,Psychodidae,Psocidae,Mycetophilidae,Tipulidae,Aphididae,Thripidae,Scolopendrellidae,Scarabaeidae,Bibionidae,Araneida,Acridiidae,Diptera Larvae,Lepidoptera Larvae,Coreidae,Pentatomidae,Carabidae,Cicindelidae,Tenebrionidae,Cicadellidae and Cicadellidae.The number of individuals accounted for 5.88% of the captured total.A total of 18 families of macro-fauna were captured,with 203 dominant species belonging to Formicidae,accounting for 70.44% of the total.The common groups included 7 families including Staphylinidae,Tenebrionidae,Cicindelidae,Araneida and Coleoptera Larvae,and the number of individuals accounted for 23.15% of the total number captured.The rare groups included 10 families,including Mycetophilidae,Aphididae,Chrysomelidae,Cicadellidae,Pentatomidae,Lepidoptera Larvae and Diptera Larvae,accounting for 6.40% of the total number of captured larvae.A total of 987 meso-micro fauna were captured in 27 families.The dominant groups included Gamasida,Actinedida and Isotomidae,accounting for 79.84% of the total captured population.The common groups included the larvae of Oribatida,Paronellidae and Coleoptera Larvae,and the individual number accounted for 1.50% of the total number of captured larvae.The rare groups included22 families,including Hypogastruridae,Tomoceridae and Mycetophilidae,accounting for5.37% of the total number of captured larvae.(2)In terms of horizontal distribution,the average density of macro-fauna in the four Xanthium italicum Moretti invasion sites in summer was higher than that in spring,while the average density of meso-micro fauna was on the contrary.In the four Xanthium italicum Moretti invasion sites in summer,the average density of meso-micro fauna was lower than that in spring.The average density of meso-micro fauna was the highest in the heavily invaded sites of Xanthium italicum Moretti Italiana in spring.The number of soil macrofauna groups in the moderately and severely invaded sites was higher than that in other sites,the number of meso-micro fauna groups in the moderately and severely invaded sites was higher than that in other sites,and the number of medium bear soil fauna groups was higher than that of large soil fauna.In terms of vertical distribution,soil fauna are mainly distributed in the surface layer,which has "surface aggregation".The upper soil has sufficient nutrients and loose soil,which is the suitable condition for the survival of soil fauna.In the four invasion degree plots of Xanthium italicum Moretti,the richness index of macrofauna was the highest and the dominance index was the lowest in the uninvaded and moderately invaded plots of Xanthium italicum Moretti.The richness index was the highest and the diversity index was the lowest in the Xanthium italicum Moretti mildly invaded plots in Italy.The richness index was the highest and the evenness index was the lowest in the Xanthium italicum Moretti heavy plots in Italy.The richness index of meso-micro fauna was the highest and the dominance index was the lowest in the uninvaded,lightly invaded and heavily invaded plots of Xanthium italicum Moretti in Italy.The richness index was the highest and evenness index was the lowest in the moderately invaded sites of Xanthium italicum Moretti Italiana.There was no significant difference in soil fauna diversity at all invasion levels.The diversity of macrofauna was contrary to that of microfauna which were more sensitive to environmental changes during different invasion of Xanthium italicum Moretti italiana.(3)According to feeding habits,soil fauna were divided into four functional groups:saprovorous,herbivorous,omnivorous and predatory.The saprovorous functional groups were composed of 10 soil fauna,such as Oribatida,Gamasida and Isotomidae.The main groups in the four sites with different invasion levels of Xanthium italicum Moretti Italiana were Actinedida.The phytophagous functional groups were composed of 12 soil fauna,including Coleoptera Larvae,Curculionidae and Aphididae.In the four sites with different invasion degrees of Xanthium italicum Moretti Italiana,the main groups were Coleoptera Larvae.The omnivorous functional groups were composed of five soil fauna,including Formicidae,Scarabaeidae and Mycetophilidae.The main groups in the four sites with different invasion degrees were Formicidae.The predatory functional groups were composed of seven soil fauna,including Araneida,Staphylinidae and Cicindelidae.The main groups in the four sites with different invasion levels of Xanthium italicum Moretti were Staphylinidae.In the four Xanthium italicum Moretti invasion plots,the Staphylinidae functional groups were higher than other functional groups.(4)The correlation analysis between soil fauna and environmental factors showed that soil organic matter,total nitrogen,total phosphorus,nitrate nitrogen,available phosphorus,available potassium and p H of environmental factors were the important indicators affecting soil fauna groups in different invasion degrees of Xanthium italicum Moretti,samples,and soil fauna had a positive response to soil environmental factors.