调控物种种内和种间相互作用对混播草地生产力和多样性的影响

Strengthening ecosystem functioning in mixture grassland largely depends on productivity increasing and biodiversity sustaining. One way for controlling productivity and diversity of mixed seeding grassland is by making use of species interactions. Species interactions, biodiversity maintenance and grassland production are all influenced by the structure and characters of species patch pattern. Spatial pattern of species patch at seeding can affect species interactions and further more promote grassland ecosystem functions and services. Currently there is less work about manipulating species patch sizes in building highly productive grassland and influencing grassland benefit. This study tries to use conspecific patch sizes at seeding involved with mixture sowing to manipulate species pattern in grassland, so as to investigate its effects and mechanism on inter- vs. intraspecific interactions, diversity, grassland productivity and ecosystem functions. The results of this study would help to reveal the variability and process of species interactions relationships and the mechanism of regulating diversity- productivity relationships, to optimize the method for the improvement and reconstruction of establishing grassland and ecosystem functions, to provide theoretical bases about scientific grassland management, as well as to maximize these effects during grassland reconstruction efforts.

混播草地生态系统服务功能的增强有赖于草地生产力的提高和植物种多样性的维持。草地植物种的相互作用关系是调控草地生产力和多样性的主要因素之一。斑块化分布格局能够改变混播草地物种的种间和种内相互作用关系，对多样性保育和生产力产生影响，进而提高草地生态系统的服务功能。能否通过调控混播草地中物种斑块分布格局以建立高产优质草地仍需深入解析。本项目拟研究物种的斑块化分布格局和多样性组合对物种内和种间相互作用、生物多样性、生产力和两者关系以及生态系统功能过程的影响，深入探索其对草地植被的影响机理和作用机制。该研究结果有助于揭示物种内和物种间相互作用过程和变化规律以及生产力-多样性关系的调控机制，优化草地改良补播建植方法和生态系统的服务功能，为科学的草地补播提供理论基础，也为优质高效草地的建植和合理利用提供新的研究方法和理论指导。

草地植物种的相互作用关系是调控草地生产力、多样性和外来种入侵，影响混播草地生态系统个服务功能的主要因素之一。斑块化分布格局能够改变混播草地物种的种间和种内相互作用关系，对多样性保育和生产力以及抵抗入侵能力产生影响，进而提高草地生态系统的服务功能。本项目研究豆科-禾本科混播草地物种的斑块化分布格局和多样性组合对物种内和种间相互作用、生物多样性、生产力和两者关系以及生态系统功能过程的影响，深入探索其对草地植被的影响机理和作用机制。连续三年的生长实验探究种间竞争作用、物种多样性、生产力和物种入侵能力对4个斑块面积大小梯度（正方形斑块边长为0, 1.0, 0.5, 或0.25 m，0代表无斑块化的传统混播方式）的混播草地的响应，结果定量论证了1、物种在不同斑块梯度下生态位和相对适宜度差异显著，达到稳定共存；2、群落生产力、超产效应和稳定性随斑块面积减小、物种多样性增加而增加，物种多样性最大时，斑块化种植草地因促进多样性-生产力的正相关关系而远优于传统混播；3、非播种的入侵种随斑块面积减少而减少，指征人工草地建植中有效的杂草控制方式。斑块面积越小，物种间较高的邻居效应强度作用下的生态位和相对适宜度差异越高，0.25m边长大小斑块的结构化豆-禾混播种植达到物种种内和种间竞争的平衡，群落生产力、稳定性和抗入侵能力均达到最高，优于传统的混播方式。这样的结构化种植能够实现物种的最适共存，改进草地生产力和稳定性。