Impact of Eremosparton songoricum on the diversity of adjacent herbaceousplant communities and its relationship with soil factors

Leguminous plants are an important source of nitrogen supply in desert ecosystems. This study aimed to clarify the impact of desert leguminous plants on the species diversity of adjacent herb communities and their relationship with soil factors. The dominant leguminous plant Eremosparton songoricum in the Gurbantünggüt Desert and its adjacent herbaceous plant communities were taken as the research object. The characteristics of community and species diversity were analyzed using a field survey, and six diversity indices from the community co existing with herbaceous plants (LH) and herbaceous plants only (NH) were compared in detail. Further, redundancy analysis (RDA) was used to explore the relationship between species diversity and soil factors. The results showed that: (1) In the NH community, there are a total of eight families, 11 genera, and 11 species of plants, with Compositae having the most plant species. In the LH community, there are a total of four families, six genera, and six species of plants, among which the Chenopodiaceae family has the most plant species. (2) The diversity index H, D, R of the NH community was significantly higher than that of LH community, and the dominance index C showed the opposite characteristics (P < 0.05). This indicated that the species richness of the NH community was relatively high. However, the species distribution was relatively poor, and the species dominance in the LH community was more prominent. (3) In the vertical direction, soil organic carbon (SOC), soil organic matter (SOM), and the total nitrogen (TN) of different communities gradually decreased with the increase in soil depth, showing prominent “surface aggregation” characteristics. In the same soil layer, the LH community was significantly higher than in the NH community (P < 0.05). (4) Redundancy analysis showed that the main soil factors that significantly affected species diversity of NH and LH communities were soil nitrate nitrogen (NO₃⁻- N) and total phosphorus (TP), respectively. In conclusion, Eremosparton songoricum have a certain impact on the species diversity and environmental factors of adjacent herb communities. The herb species richness in the community with Eremosparton songoricum is low, but the community has more suitable soil structure, higher fertility, and community dominance.