Drivers of natural regeneration seedling dynamics in a Larix gmelinii var. principis-rupprechtii artificial forest

Seedling dynamics are crucial for forest regeneration and species coexistence. Understanding the factors influencing seedling survival rate provides insights into improving natural regeneration. This study evaluated the effects of biotic and habitat factors on Larix gmelinii var. principis-rupprechtii seedling survival rate over 2 years on Guandi Mountain, North China, using a generalized linear mixed-effects model. Our results did not provide strong evidence of negative density dependence at the community level during the seedling stage. For seedlings < 2 cm in diameter and < 8 years old, survival rate was primarily influenced by conspecific seedling density. As seedlings grew, the impact of biotic factors declined, whereas soil and light conditions became more important. Elevation strongly affected seedlings < 0.3 m in height. With increasing height, biotic factors became more influential, and conspecific seedling density positively impacted survival rate. Seedling regeneration was found to be increasing on Guandi Mountain, with no evidence of seed limitation. Biotic and habitat factors influenced survival rate, but conspecific seedling density negatively affected survival rate at all levels except for seedlings < 0.3 m in height. Overall, negative density dependence was negligible in the early-seedling stage. In conclusion, although habitat heterogeneity and density effects shape seedling survival rate, density effect plays a more critical role in L. gmelinii var. principis-rupprechtii forest regeneration.