| Caragana konshinski is one of the most important afforestation species in the Reaumuria soongo-rica shrub land of Urat desert steppe in Inner Mongolia.Its unique morphological and physiological adaptation characteristics play an important role in the restoration and protection of degraded ecosys-tems.Soil fanual,as the most abundant biological group with the most species,not only play an im-portant role in biodiversity conservation and the maintenance of fragile ecosystems,but also play an important role in the process of material circulation,energy flow and information transmission in the desert steppe ecosystem.Therefore,it is an important ecological problem to study the effect of planting C.korshinskii shrub on soil fanual diversity and its ecological effect in R.soongorica shrub land.We selected C.microphylla and R.soongorica shrub vegetation as the study objects,and takes the bare land as the control.In the spring,summer and autumn of 2018 and 2019 respectively,the community com-position and diversity distribution characteristics of ground-active arthropods and soil meso-micro fau-nal in the micro environment inside and outside the shrub were investigated.Combined with the physi-cal and chemical properties of soil,the key environmental factors affecting the distribution of soil faunal in the R.soongorica shrub land were determined,and the the community composition and spa-tial-temporal distribution diversity of soil faunal community in the R.soongorica shrub land were clari-fied.The main results were as follows:(1)In R.soongorica shrub land,the surface herbaceous vegetation mainly includes Stipa Glareosa and Allium polyrhizum,accounting for 46.83%and 34.79%of the total individuals,respectively.Through the analysis of soil physical and chemical properties,it was found that soil moisture content and soil pH were affected by both micro environment changes and seasonal changes;while soil conduc-tivity was mainly affected by micro environment changes,which showed that R.soongorica shrub was significantly higher than C.microphylla shrub and bare land(P<0.05).The main content of soil were silt and fine sand,in which the silt content of soil was in bare land>R.soongorica shrub>C.microphylla shrub.While the fine sand content was in C.microphylla shrub and R.soongorica shrub significantly higher than that in bare land(P<0.05).The soil fractal dimension was found to range from 2.68 and 2.73,and the soil fractal dimension value showed as bare land>R.soongorica shrub>C.microphylla shrub.Further analysis of the correlation between soil fractal dimension and soil particle size distribution showed that soil fractal dimension had a logarithmic positive correlation with clay content(P<0.01),a linear positive correlation with silt content(P<0.01),a linear negative correlation with fine sand and medium sand content(P<0.01),and no significant correlation with coarse sand content(P>0.05).(2)There were 118 individuals of soil meso-micro faunal captured during the investigation,be-longing to 14 groups.Among them,the dominant groups were Pygmatidae,Tydeidae and Isotomidae,accounting for 22.88%,12.71%and 16.95%of the total individual numbers,respectively.There were 9 common groups,accounting for 45.76%of the individual numbers.There were 2 rare groups,account-ing for 1.69%of the total individual numbers.The community composition of soil meso-micro faunal was quite different in R.soongorica shrub,C.microphylla shrub and bare microhabitats.For example,Enocaligonellidae only survived under the R.soongorica shrub,and Bdellidae only survived under the C.microphylla shrub.C.microphylla shrub could significantly promote the increase of individual num-ber and Shannon Wiener index of soil meso-micro faunal(P<0.05).With the change of seasons,the community composition of soil meso-micro faunal was also different.Among them,the number of in-dividuals of the dominant groups was spring>autumn>summer,while that of the common groups weas summer>autumn>spring.There were significant differences in the number of individuals and groups of soil meso-micro faunal with seasonal changes(P<0.05),which were significantly higher in summer than in spring or autumn.Pearson correlation analysis showed that soil moisture content,soil pH,soil clay and medium sand content were the main influencing factors of individual number distribu-tion of soil meso-micro faunal in desert shrub.(3)There were 560 individuals of ground-active arthropods captured during the investigation,be-longing to 23 families and 10 orders.Among them,the dominant group was Tenebrionidae and Formi-cidae,accounting for 41.07%and 22.14%of the total individual numbers,respectively.There were 10 common groups,accounting for 32.68%of the total individual numbers.There were 11 rare groups,accounting for 4.11%of the total individual numbers.The community composition of ground-active arthropods is quite different in R.soongorica shrub,C.microphylla shrub and bare microhabitats.For example,Lycosidae and Clubionidae only survived under the C.microphylla shrub,and Aphodiidae and Neobisiidae only survived in bare microhabitats.There was no significant difference in the number of individuals,groups,Shannon Wiener index,Simpson dominance index and Pielou evenness index among R.soongorica shrub,C.microphylla shrub and bare land(P>0.05).With the change of seasons,the community composition of ground-active arthropods was also different.Among them,the number of individuals of dominant groups was autumn>summer>spring,and that of common groups and rare groups was spring>summer>autumn.The number of individuals,groups,Shannon Wiener index,Simpson dominance index and richness index of ground-active arthropods were significantly higher in summer than in spring or autumn(P<0.05),while Pielou evenness index was significantly higher in spring than in autumn(P<0.05).The results of RDA correlation analysis showed that soil moisture content,soil pH,fine sand and medium sand content were the main factors affecting the distribution of ground-active arthropods population in desert shrub.The results concluded that the C.microphylla shrub planted in R.soongorica shrub forest of Urat desert steppe could effectively promote the recovery of individual number and diversity of soil me-so-micro faunal.However it had little effect on the individual number,groups and diversity distribution of ground-active arthropods,indicating that planted C.korshinskii shrub has limitations on the recovery of ground-active arthropod diversity.On the other hand,the arid and barren desert soil environment may also limit the development of ground-active arthropods.With the change of seasons,the commu-nity composition and distribution patterns of soil meso-micro faunal and ground-active arthropods were quite different,and the influence of different types of environmental factors on the individual number distribution of soil faunal was different,which reflects the obvious seasonal rhythm of soil faunal in R.soongorica shrub land in this area. |
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