Ground arthropod assemblages shaped by ant nests and shrub microhabitats in Gobi Desert ecosystems

Abstract

Shrubs and ant nests enrich food resources, improve soil conditions, and provide refuge in desert ecosystems, thereby influencing the distribution and diversity of ground arthropods. This study investigated the diversity of macro- and microarthropods in two shrub species (Reaumuria songarica and Nitraria sphaerocarpa), as well as in the microhabitats of Messor desertus ant nest and bare ground using pitfall traps. The vegetation and soil factors of the four microhabitats were measured. The key results were as follows: (1) macroarthropod abundance and taxa richness were higher in the two shrub species and ant nest microhabitats compared to bare ground, with abundance in the shrub species surpassing that in the ant nests; (2) microarthropod abundance was higher in ant nests than in the two shrub species and bare ground, but diversity and evenness indices were comparatively lower; (3) dominant taxa exhibited microhabitat-specific distribution patterns. Cicadellidae and Trombidiidae were more associated with shrubs, while Entomobryoidae showed a marked preference for ant nests; and (4) variations in soil conditions driven by shrubs and ant nests had great effects on ground arthropod assemblages. Soil organic carbon explained 6.1 % of the variation in macroarthropod community, while total nitrogen and pH explained 9.5 % of the variation in microarthropod community. In conclusion, M. desertus ant nests and shrubs in the Gobi Desert greatly affected macro- and microarthropod assemblages by improving the soil conditions, and ant nests exhibited a stronger assembly effect on microarthropods (particularly the Entomobryidae) than the shrubs.