关键词: 垫状植物, 山生福禄草, 出苗率, 埋藏深度, 环境因子, 气候变化

Abstract: Aims As representative ecosystem engineers in alpine subnival ecosystems, cushion plants play a crucial role in maintaining the structure and diversity of plant communities in these regions. Therefore, The dynamic changes (e.g., population decline) in cushion plant populations way directly affect the long-term maintenance of ecosystem functions in alpine subnival zones. However, how the key stages in the dynamics of cushion plant populations—specifically seed emergence and seedling growth—respond to environmental factors is underexplored. Methods This study investigated the effects of different temperatures and seed burial depths on seed emergence rates and seedling growth of the alpine cushion plant Arenaria oreophila, using seeds collected from multiple natural populations under controlled laboratory incubation. Important findings The results indicate that higher temperatures (above 10 °C) accelerate seed germination and seedling emergence, thereby increasing over seedling emergence rates. However, seed burial depth limits seedling emergence rates; when burial depth exceeds 2 cm, seedling emergence rates significantly decrease, or seeds even fail to emerge, regardless of temperature conditions. Low temperatures (below 5 °C) severely inhibit seed emergence and seedling growth. Seedlings grown at higher temperatures exhibit significantly greater heights and biomass accumulation efficiency, with higher fresh and dry weights compared to those grown at lower temperatures. An optimal burial depth of 1 cm further supports biomass accumulation. However, excessively high temperatures pose a significant risk of seedling mortality. We suggest that excessively high temperatures (above 20 °C) and deep burial depths (greater than 2 cm) are detrimental to seedling emergence and growth of Arenaria oreophila. Optimal conditions for seedling emergence and growth are moderate temperatures (10-15 °C) and shallower burial depths (less than 1 cm). Additionally, there may be population-level differences in environmental adaptability among seeds from different populations. This study further suggests that under global climate warming, the field populations of cushion A. oreophila may face numerous uncertain risks: the large, loose-grained soil substrate of subnival zones makes seeds susceptible to becoming buried too deeply, complicating subsequent seedling emergence, and while increased temperatures (due to climate warming) may promote seedling growth, they also substantially increase seedling mortality risk. Both of these two processes may inhibit the potential regeneration process of the populations of cushion A. oreophila.

Key words: cushion plant, Arenaria oreophila, seedling emergence, burial depth, environmental factor, climate change