高寒草甸植物优势种在群落构建中的作用：以施肥响应为例

局域尺度上物种如何共存是群落生态学研究的核心论题。最新研究预测群落内处于不同地位的物种可能受不同作用的调控。但是由于量化指标的短缺等技术难题，我们依然不清楚确定性和随机作用如何交互影响群落内不同地位的物种及生物多样性的变化。基于申请者近期提出的量化物种综合竞争能力的指标—空间资源利用量（SRU），本项目拟在青藏高原高寒草甸长期施肥实验中，通过控制优势种的SRU（如对照（减少0%）、部分移除（减少50%）、全部移除（减少100%）），检验：1）施肥介导的环境筛选作用对优势种的影响是否更加明显；2）其他常见种的相对多度（适合度）是否主要取决于优势种对光和土壤营养等资源的利用；3） 稀有种的丧失是否取决于随机漂变影响而非环境筛选或种间作用。通过对上述问题的探究，本项目拟阐明确定性作用和随机性作用如何协同调控群落生物多样性的维持和变化，该研究将对高寒草甸植被恢复和可持续发展具有理论指导意义。

Understanding how species coexist at a local scale is the core topic in community ecology. Recent studies predict that different species in a community may be regulated by different processes. However, due to technical problems such as the lack of quantitative indicators, it is still unclear how deterministic and random effects regulate diversity dynamics in real communities. Based on the comprehensive indicator of quantifying species resource utilization ability proposed by applicant (Space Resource Utilization; SRU), we conduct an experiment to artificially control the SRU of the dominant species (e.g., control (0% reduction), partial removal (50% reduction), and total removal (100% reduction)) on the basis of a long-term fertilization experiment in Tibetan alpine meadows. We aim to test: (1) whether fertilization mediated abiotic environmental filtering has a more significant effect on dominant species; (2) whether the relative abundance (fitness) of other common species mainly depends on the utilization of light and soil nutrients by the dominant species; (3) Whether the loss of rare species is due to random drift rather than environmental filtering or interspecific interactions. Through the exploration of the above issues, this project aims to clarify how deterministic and stochastic effects co-regulate the maintenance and change of community biodiversity. This study will have theoretical guiding significance for the vegetation restoration and sustainable development of alpine meadow on the Qinghai-Tibet Plateau.