基于家畜放牧调控下物种多样性与生态系统可持续性关系的研究

Persistence is one important aspect of ecosystem stability. It addresses the loss of the resources that the ecosystem provides. Plant diversity plays a great part in maintaining the stability of grassland ecosystem. However, the relationship between plant diversity and persistence remains almost completely unstudied. Under the situation of herbivore grazing, revealing the mechanisms of the diversity-persistence interaction is of great importance to understand the ecosystem function in grassland of China. Using sheep as a regulatory factor, we will analyze herbivore foraging selectivity, richness and evenness of plant diversity, persistence of plant communities and the relationship among the three aspects. Our aim is to explain the interaction between foraging selectivity of herbivore and plant diversity, and how this affects plant community's persistence. This study not only makes a great sense in understanding plant community structure, ecosystem processes and function, but also has the practical value in maintaining the stability of grazing grassland system, rationally utilizing grassland resources, and making effective grazing management policies.

可持续性是生态系统稳定性的重要方面，它强调生态系统所提供资源的损失情况。植物多样性在维护草地生态系统稳定性方面起了重要作用。但草地植物多样性与可持续性的关系目前还不明确，特别是在放牧利用下，揭示两者的互作机制对维持我国草地生态系统功能有重要意义。本项目以草食动物绵羊为调控因素，以动物的采食行为、植物多样性(丰富度和均匀度)、植物群落的可持续性以及三者之间的互作关系为主要研究内容，从动物采食策略的角度，分析动物食性选择与植物多样性的互作机制，以及多样性与群落可持续性的内在关系，进而阐明放牧调控植物多样和群落可持续性关系的作用机制。本研究不仅对于进一步深入理解植物群落结构、生态过程与功能以及动植物间、物种多样性与群落生态功能之间的互作关系具有重要的理论价值，并且对于实现草地生态系统的科学管理与持续发展具有实际指导意义。

沙质草地植物群落生产力和多样性的可持续性是衡量沙质草地生态系统功能恢复的重要指标之一。而植物群落的可持续性与物种多样性密切相关。放牧是调节沙质草地植物多样性的重要手段。本项目以科尔沁沙质草地植物群落为研究对象，以绵羊为放牧调控动物，综合分析了动物采食行为—物种多样性—群落可持续性的相互关系和互作机制。研究结果表明：短期放牧虽然没有显著影响沙质草地植物地上生产力和多样性，但显著地降低了植被的盖度。动物通过选择性采食行为，大量的消耗了杂类草和禾本科植物，从而调节了植物生产力和多样性与群落可持续性的互作关系。此外，动物对植物生产力和多样性的影响显著依赖于植物群落初始生产力和多样性状况。放牧调控下，群落生产力可持续性与草地植物多样性显著正相关，而植物多样性可持续性与多样性呈显著负相关。因此，草地植物多样性在抵抗放牧干扰、维持系统稳定性方面具有重要作用。