Quantitative dynamics and influencing factors of the seedling occurrence of the most common plants in Seriphidium desert grassland

This study aims to understand the occurrence types and quantitative dynamics of dominant plant seedlings in Seriphidium desert grassland. We studied the effects of the key factors (soil, aspect, and climate) on seedling number and distribution in 50 sample sites of Seriphidium desert grassland. The results showed that the weight of plant litter was significantly negatively correlated with the total number of seedlings (P < 0.05), while soil organic matter, faeces, and soil compaction were significantly positively correlated with the total number of seedlings (P < 0.01). The correlation between soil pH and the total number of seedlings was not found to be significant (P > 0.05). We divided the seedlings into three types depending on soil environmental factors. Two of the seedling types are sensitive to the amount of plant litter, faecal matter, and organic matter in the soil, while the other type is sensitive to soil compactness and pH level. In addition, the slope aspect and the time of year were found to significantly influence the seedling quantity, and the number of seedlings in different slope directions was also found to change dramatically with the season. The seedlings showed explosive growth in spring, owing to the suitable temperatures and abundant precipitation, but their numbers gradually decreased as spring became summer and temperatures increased. However, the seedlings of Seriphidium transiliense, Ceratocephalus orthoceras, and Alyssum desertorum had a second growth and germination stage in autumn owing to improving meteorological conditions, and a second growth peak in late autumn and early winter. In addition, we conducted regression analysis on average climate conditions and the number of seedlings. The results showed that average monthly precipitation levels and temperature are the main factors influencing seedling dynamics.