Characteristics of soil seed bank in typical shrub communities of the Luoshan Mountains, Ningxia and their relationships with soil physical and chemical properties.

We explored the characteristics of soil seed banks and their relationship with soil physicochemical pro-perties across six typical shrub communities in the Ningxia Luoshan National Nature Reserve, including <i>Buddleja alternifolia</i>, <i>Caragana korshinskii</i>, <i>Ostryopsis davidiana</i>, <i>Convolvulus tragacanthoides</i>, <i>Cotoneaster soongoricus</i>, and <i>Prunus mongolica</i>. We stratified soil sampling by field vegetation surveys and laboratory germination experiments. The results showed that a total of 43 plant species were found in the soil seed banks of the six communities, belonging to 35 genera and 17 families. Asteraceae, Poaceae, and Fabaceae were dominant families, accounting for 58.1% of the total number of species. In terms of life form, perennial herbs occupied absolute dominant position, with <i>Cyperus rotundus</i> as the most common one. The soil seed bank density ranged from 1033 to 7000 seeds·m^-2, and the density decreased significantly with the increase of soil layers. More than 70% of the seeds were concentrated in the 0-10 cm soil layer. The Shannon diversity index, Pielou evenness index, and Margalef richness index of the soil seed banks in the <i>O. davidiana</i> community were all higher than those of the other communities, while the <i>C. tragacanthoides</i> community had the lowest values of these indices. Soil pH of each community was alkaline. There were significant differences in soil moisture, total nitrogen, available potassium, and available phosphorus contents among different communities. Soil moisture of the <i>C. soongoricus</i> community was significantly higher than that of the other communities, followed by the <i>O. davidiana</i> community, and that of the <i>C. tragacanthoides</i> and <i>C. korshinskii</i> communities was the lowest. The species diversity indices of soil seed bank were significantly positively correlated with soil available phosphorus and moisture content, and negatively correlated with soil pH. In conclusion, the soil physical and chemical properties did not change the surface aggregated characteristics of the vertical distribution of seed bank. The horizontal distribution pattern was driven by the heterogeneity of soil available phosphorus, water content, total nitrogen, and pH. Soil seed bank was scarce in shrubs, resulting in a big challenge in vegetation restoration. We suggested focus on the weak areas of the soil seed bank, regulate key factors, and implement precise ecological restoration in the future.