Classification and ordination of a plant community in a desert wetland and its relationship with soil environmental factors

The existence and disappearance of desert wetlands can be considered as the indicators of sustainability in vegetation recovery. The spatial distribution characteristics of plant communities and their relationship with soil environmental factors were described in the desert wetland ecosystem. This can provide a scientific basis for establishing a diversified vegetation restoration model based on the characteristics of different habitats. In this study, the Haba Lake wetland ecosystem in Ningxia was selected as the research object. Based on vegetation and soil data from 152 survey sites with 1 km × 1 km resolution, multiple regression tree and redundant analysis were used to explore the spatial distribution characteristics of different plant community types and their response to soil factors in a 12 km² area. The results were as follows: 1) the plant community was divided into four types: Stipa breviflora + Lespedeza bicolor, Agropyron mongolicum + Leymus secalinus + Astragalus melilotoides, Sophora alopecuroide + Artemisia scoparia, and Splendid achnatherum + Slenderbranch Kalidium. 2) The main factors affecting the spatial distribution of these four plant communities included soil clay and fine sand contents, altitude, soil salt content, and pH. 3) With the decrease in soil clay content, the degree of soil coarsening increased, and the plant community changed from Stipa breviflora + Lespedeza bicolor to Agropyron mongolicum + Leymus secalinus + Astragalus melilotoides; owing to the decrease in altitude, the plant community changed from Stipa breviflora + Lespedeza bicolor to Splendid achnatherum + Slenderbranch kalidium. Conclusion: Across the watershed land to the low beach wetland, the spatial variations in the landscape vegetation system in the desert wetland can be described as follows: spatial differentiation of xerophytic zonal plant communities depends on soil texture, whereas secondary differentiation of zonal to crypzonal plant communities is based on altitude and salinity.