Effects of Microhabitat on Seedling Recruitment of the Pioneer Shrub Pyracantha fortuneana in Subtropical Rocky Outcrop‐Rich Areas: Implications for Degraded Karst Shrubland Restoration

Human activities have led to widespread bedrock exposure and vegetation degradation in subtropical karst ecosystems. In these degraded landscapes, the effects of fragmented rock‐soil microhabitats on species regeneration remain poorly understood, particularly in terms of their influence on seedling recruitment. We hypothesized that variations in rocky microhabitats impact seedling establishment by modifying hydrothermal micro‐conditions, thereby shaping recruitment outcomes. This study aims to evaluate the impact of heterogeneous microhabitats on seedling recruitment of the pioneer and dominant shrub Pyracantha fortuneana, and to provide insights for a more effective restoration strategy in rocky outcrop‐rich sites. We conducted year‐long monitoring to quantify each recruitment stage—seed germination, seedling emergence, survival, and seedling growth—across four typical microhabitats: rocky gully (RG), rocky pits (RP), earth flatland (EF), and bare land (BL), through seed burial and sowing trials. Additionally, soil temperature and moisture, air temperature and humidity, and photosynthetically active radiation were monitored during recruitment stages. Results show that no significant differences were detected in final germination across the four microhabitats, whereas RG and EF exhibited significantly higher survival rates and lower seedling biomass compared to BL. This indicated that post‐emergence, rather than seed germination, was significantly influenced by heterogeneous microhabitat. Seedling emergence and survival were positively regulated by patch soil moisture, whereas seedling growth was negatively impacted by soil moisture and positively influenced by temperature. This finding highlights the importance of integrating microsite selection and post‐emergence hydrothermal regulation interventions in shrubland management, especially in the early stages of seed‐based restoration.