Fan Baoli, Gao Pengfei, Tian Tingting, Jiang Jinhua, Ding Nana, Wan Yongkuan, Ma Miaojun, Sun Kun
College of Life Science Northwest Normal University Lanzhou China.
Key Laboratory of Eco-Functional Polymer Materials of the Ministry of Education Lanzhou China.
Ecol Evol. 2024 Dec 22;14(12):e70684. doi: 10.1002/ece3.70684. eCollection 2024 Dec.
Shrub encroachment can alter the structure and function of grassland ecosystems, leading to their degradation. Therefore, population regeneration dynamics after shrub encroachment on the influence of grassland should not be ignored. , as a pioneer species, has significantly encroached with large areas on the Qinghai-Tibetan Plateau (QTP) due to climate change and over-grazing. However, few studies have focused on the dynamics of population regeneration following successful encroachment. Therefore, we studied natural population in the alpine grasslands, investigating population regeneration pattern, seed, bud production and storage, and limitation imposed by microhabitats (soil, light and feeding). Our aim was to explore population regeneration strategies and identify key limiting factors for population regeneration after successful encroachment. Our findings revealed several key points: (i) entered the alpine grassland by relying on seeds, it would seize resources by low-cost clonal reproduction, then increase sexual reproduction to improve genetic diversity. (ii) The production and storage of seeds and buds was sufficient, seed vigor was high, seed emergence rate was higher due to mechanical restriction of hard seed coat was weakened by the water transport channels in the palisade layer, and formation of seedlings was less restricted. (iii) population regeneration was mainly limited by microhabitats light and feeding. However, light and feeding significantly affected seedlings photosynthesis and carbon storage, their interaction significantly reduced the seedlings survival, and further restricted population regeneration. The results can provide theoretical basis for the restoration and management of alpine grassland degradation caused by shrub encroachment.
灌丛入侵会改变草原生态系统的结构和功能，导致其退化。因此，灌丛入侵后草原种群更新动态及其影响不容忽视。作为先锋物种，由于气候变化和过度放牧，已在青藏高原大面积显著入侵。然而，很少有研究关注成功入侵后种群更新的动态。因此，我们研究了高寒草原中的自然种群，调查了种群更新模式、种子、芽的产生和储存，以及微生境（土壤、光照和采食）所造成的限制。我们的目的是探索种群更新策略，并确定成功入侵后种群更新的关键限制因素。我们的研究结果揭示了几个要点：（i）通过种子进入高寒草原后，它会通过低成本的克隆繁殖抢占资源，然后增加有性繁殖以提高遗传多样性。（ii）种子和芽的产生与储存充足，种子活力高，由于栅栏层中的水分运输通道削弱了硬种皮的机械限制，种子出苗率较高，幼苗形成受限制较小。（iii）种群更新主要受微生境光照和采食的限制。然而，光照和采食显著影响幼苗光合作用和碳储存，它们的相互作用显著降低了幼苗存活率，进一步限制了种群更新。研究结果可为灌丛入侵导致的高寒草原退化的恢复和管理提供理论依据。
