青海湖流域针茅草原物候对放牧的响应机制研究

Study on the response of vegetation phenology help us understanding of the modeling land-surface exchange, evaluating climate-phenology relationships, has become the hottest research point in global change and been widely used to solve various environmental problems. However, the response mechanism of many vegetation phenology dynamic is still not clear, especially there are few studies on phenological response mechanism of alpine grassland under grazing disturbance. This study selected alpine grassland in Qinghai Lake watershed as the research object, mainly analyzes the response mechanism of alpine grassland phenology to grazing using remote sensing model inversion and field monitoring, the main research: ①Phenological characteristics of alpine grassland changes under different grazing intensity and season; ②The relationship between different grazing intensity, season and vegetation characteristics, soil physicochemical properties of grassland ecosystem; ③The relationship between different vegetation characteristics, soil physicochemical properties of grassland ecosystem and phenology under grazing disturbance; ④We elaborate on phenology of alpine grassland to grazing response mechanism basis on the above conclusions and establish "phenology - community characteristics/soil properties - grazing" Response Mechanism Model. Scientific clarify response mechanism of alpine grassland phenology to grazing not only provide a scientific basis for rational grazing in Qinghai Lake watershed, but also provide theoretical support for ecological management and protection projects under national implementation in Qinghai Lake watershed.

进行植被物候响应机制研究有助于理解陆面交换模型，准确评估“物候 — 气候”的关系，已经成为全球变化研究的热点问题，并被广泛应用到解决多种生态环境问题中。然而，许多植被物候动态变化的响应机制仍不明确，尤其是高寒草地物候对放牧的响应机制研究尚少。本项目通过野外定点观测、遥感提取相结合的方法对青海湖流域内不同放牧干扰下针茅草原物候的响应机制进行分析，主要研究：①不同放牧强度、季节轮牧下针茅草原物候变化特征；②不同的放牧强度、季节轮牧与针茅草原植物群落特征、土壤理化性质的关系；③针茅草原植物群落特征、土壤理化性质与物候的关系；④在综合以上研究结论的基础上，阐述针茅草原物候对放牧的响应机制，建立“物候 — 植物群落特征、土壤理化性质 — 放牧”响应机制模型。科学的阐明针茅草原物候对放牧的响应机制不仅为青海湖流域合理的放牧提供科学依据，更利于国家实施的青海湖流域生态治理与保护工程提供理论支持。

进行植被物候响应机制研究有助于理解陆面交换模型，准确评估“物候-气候”的关系，已经成为全球变化研究的热点问题，并被广泛应用到解决多种生态环境问题中。然而，许多植被物候动态变化的响应机制仍不明确，尤其是高寒草地物候对放牧的响应机制研究尚少。本项目通过野外定点观测、遥感提取相结合的方法对青海湖流域内不同放牧干扰下针茅草原物候的响应机制进行分析，主要研究：①不同放牧强度、季节轮牧下针茅草原物候变化特征；②不同的放牧强度、季节轮牧与针茅草原植物群落特征、土壤理化性质的关系；③针茅草原植物群落特征、土壤理化性质与物候的关系；④在综合以上研究结论的基础上，阐述针茅草原物候对放牧的响应机制，建立“物候—植物群落特征、土壤理化性质—放牧”响应机制模型。通过研究表明，冬季不同的放牧强度会通过改变地表枯落物、土壤水热条件和速效磷、速效钾改变植被返青期，枯黄期变化并不明显。不合理的放牧强度会导致植被演替，改变植被返青期、枯黄期和生长季。不同的放牧干扰季节明显改变植被物候期，秋季放牧对高寒草地的干扰造成枯黄期延迟尤其明显。科学的阐明针茅草原物候对放牧的响应机制不仅为青海湖流域合理的放牧提供科学依据，更利于国家实施的青海湖流域生态治理与保护工程提供理论支持