科尔沁草地沙化裸斑通过有性繁殖进行植被自然恢复的更新制约

Seed availability and microsite habitat have been considered as the two potential limiting factor for plant population recruitment and vegetation restoration via sexual recruitment. Understanding the effects of these two limitations on vegetation restoration of bare patches in desertified grassland not only promotes the theoretical development of sexual recruitment, but also provides basis for implementing effective ecosystem maintenance and vegetation restoration on degraded grassland. In view of this, this program will select the bare patches with different size and shape in Horqin grassland of Inner Mongolia as the study object. By investigating the pattern of seed rain input and retain and soil seed bank, monitoring seed germination dynamics and seedling establishment pattern, and discussing the mechanisms of seed properties vs. microsite conditions in regulating seed dispersal, retain, germination and seedling establishment, this program aims at exploring the scale-dependent effect of seed and microsite limitation in the vegetation restoration of bare patches, quantifying the threshold of vegetation restoration in bare patches via sexual recruitment, and elucidating the role of seed and bare patches properties and their correlation in regulating seed and microsite limitation. This program is useful for exploring the recruitment limitation of vegetation restoration via sexual recruitment, enriching the theoretical development of sexual recruitment, and providing guidance for grassland maintenance and restoration in semi-arid grasslands.

种群借助有性繁殖自然更新存在种子制约和生境制约两个潜在制约，探讨这两个制约对植被自然恢复的影响，既可推动植物有性繁殖理论发展，又与草地生态系统维持与退化草地恢复密切相关。鉴于此，本项目拟以内蒙古科尔沁草地沙化裸斑为研究对象，通过野外调查种子雨输入与停留格局、土壤种子库格局，定点监测种子萌发动态、幼苗定植格局，分析种子属性和裸斑属性在传播、停留、萌发、定植过程中的作用机制，探讨种子制约和生境制约在草地沙化裸斑植被自然恢复过程中的尺度依赖，量化草地沙化裸斑通过有性繁殖进行植被自然恢复的面积阈值，阐明种子属性和裸斑属性在调控种子制约和生境制约中的作用机制及二者之间的相互关联，揭示科尔沁草地沙化裸斑借助有性繁殖进行植被自然恢复的更新制约，丰富植物有性繁殖理论，为半干旱沙区植被恢复与退化生态系统重建提供科学依据。

种群借助有性繁殖自然更新存在种子制约和生境制约两个潜在制约，探讨这两个制约对植 被自然恢复的影响，既可推动植物有性繁殖理论发展，又与草地生态系统维持与退化草地恢复密切相关。本项目以内蒙古科尔沁草地沙化裸斑为研究对象，选取了24个草地沙化裸斑，通过大量的野外调查取样工作，结合实验室分析工作和数据整合分析，探讨了种子制约和生境制约在草地沙化裸斑植被自然恢复过程中的尺度依赖，揭示了科尔沁草地沙化裸斑借助有性繁殖进行植被自然恢复的潜力。研究结果表明：1）草地沙化裸斑的土壤种子库不足以为自然恢复提供充足的种源，草地沙化裸斑植被恢复需要外部种源添加；2）土壤种子库密度和物种丰富度均与草地沙化裸斑面积相关性较低，不能通过草地沙化裸斑面积为沙化草地植被恢复预测土壤种子库的密度和物种丰富度；3）裸斑面积影响植被和土壤种子库与环境因子的相关性，不同面积的草地沙化裸斑植被恢复应采用不同的方法。因此，本项目对于了解草地沙化裸斑植被自然恢复能力具有重要意义，同时也为半干旱沙区植被恢复与退化生态系统重建提供科学依据。