Haloxylon ammodendron plantations: enhancing multi-trophic arthropod diversity and soil multifunctionality in arid...

The conversion of natural desert vegetation to artificial sand-fixing vegetation significantly impacts the diversity of ground arthropods across various trophic levels. Consequently, this change modifies the structure and function of arthropod-dominated soil food webs, thereby influencing soil multifunctionality. In this study, we set up a vegetation gradient in the desert-oasis ecotone of Zhangye Oasis, Hexi Corridor, spanning from natural desert vegetation (mobile and fixed sandy dunes) to artificial fixed sandy vegetation (5-, 10-, 20- and 30- year-old Haloxylon ammodendron plantations). Our objective was to examine the relationship between multi-trophic arthropod diversity (MAD) and soil multifunctionality (SMF). SMF was higher in mobile sandy dunes (MSD) than in fixed sandy dunes (FSD). SMF in H. ammodendron plantations (HAs) was also higher than in both MSD and FSD. Furthermore, SMF in H. ammodendron plantations initially increased with plantation age, peaking at 20 years, and subsequently decreased. The established H. ammodendron plantations positively impacted predatory and herbivorous macro-arthropods, while negatively affecting omnivorous macro-arthropods. Additionally, these plantations positively affected predatory mites, oribatid mites, and springtails. However, a declining trend was observed for these three micro-arthropod taxa in HA30 (H. ammodendron plantations of 30 year-old). The co-occurrence network of arthropods reveals that, compared to MSD and FSD, the arthropod network complexity was more pronounced in HAs, peaking in HA20 (H. ammodendron plantations of 20 year-old). Structural equations results showed that multi-trophic abundance and shrub significantly enhanced the SMF, and soil salinity declined the SMF. In conclusion, the establishment of H. ammodendron plantations boost the multi-trophic abundance and community complexity of ground arthropods, thereby enhancing soil multifunctionality.