黄河源区高寒草地时空变化分异特征及其影响机制研究

Over the past few decades, alpine grassland in the Qinghai-Tibet Plateau has undergone significant changes under the dual influence of human activities and climate change. Due to the lack of observational data, the temporal and spatial variation of alpine grassland and its influencing mechanism still have some uncertainties. Relying on 417 ecological observation sites that can be matched with the spatial scales of MODIS remote sensing pixels in the source region of the Yellow River, taking the UAV aerial survey as the main survey method, the project takes the most direct parameter of alpine grassland degradation (vegetation coverage and patch) as evaluation index to study the spatial and temporal variation characteristics of alpine grassland and its influencing mechanism. First, by analyzing the differences of spectral features of different ground objects in aerial photography, the optimal algorithm for simulating vegetation and bare ground information is constructed to obtain high-precision field monitoring data. Then, the remote sensing data and aerial photography data are used to retrieve the ecological parameters of alpine grassland in different years to quantitatively evaluate the spatial and temporal variation of alpine grassland. Finally, based on the monitoring data of natural environment such as soil moisture, soil heat and soil nutrients, combined with disturbance information such as grazing and rodent activities, the mechanism of the spatial and temporal variation of alpine grassland is clarified. The implementation of this project can not only provide data support for the construction of the Three Rivers National Park, but also provide an important basis for the sustainable development of alpine grassland.

过去几十年，在人类活动与气候变化的双重影响下，青藏高原地区的高寒草地发生了显著变化。受限于观测资料的不足，高寒草地的时空变化特征及其影响机制还存在一定的不确定性。本项目依托417个布设在黄河源区能与MODIS遥感像元空间尺度匹配的生态观测样地，以无人机定点定位航拍为主要调查手段，以高寒草地退化最直观的参数（植被覆盖度与斑块）为评价指标，对高寒草地时空变化分异特征及其影响机制进行研究。通过分析航拍影像中不同地物的光谱特征差异，构建数值方程模拟植被与裸地信息提取的最佳算法，获取高精度野外监测数据；利用遥感数据与航拍数据反演不同年份高寒草地生态参数，定量评估高寒草地时空变化分异特征；同时基于土壤水热、养分等自然环境监测数据，结合放牧、啮齿动物活动等外界扰动信息，阐明高寒草地时空变化分异特征的影响机制。本项目的实施不仅可为三江源国家公园建设提供数据支撑，还可为高寒草地可持续发展提供重要依据。

过去几十年，在人类活动与气候变化的双重影响下，青藏高原地区的高寒草地发生了显著变化。受限于观测资料的不足，高寒草地的时空变化特征及其影响机制还存在一定的不确定性。本项目依托417个布设在黄河源区能与MODIS遥感像元空间尺度匹配的生态观测样地，以无人机定点定位航拍为主要调查手段，以高寒草地退化最直观的参数（植被覆盖度与斑块）为评价指标，对高寒草地时空变化分异特征及其影响机制进行研究。通过分析航拍影像中不同地物的光谱特征差异，构建数值方程模拟植被与裸地信息提取的最佳算法，获取高精度野外监测数据；利用遥感数据与航拍数据反演不同年份高寒草地生态参数，定量评估高寒草地时空变化分异特征；同时基于土壤水热、养分等自然环境监测数据，结合放牧、啮齿动物活动等外界扰动信息，阐明高寒草地时空变化分异特征的影响机制。通过本项目的研究，定量评估了空天地协同观测的误差来源与改进措施，优化了植被覆盖度反演方法，生成了黄河源区高精度的植被覆盖度数据集，定量评估了高寒草地时空变化分异特征，阐明了高寒草地时空变化分异特征的影响机制，本研究结果不仅可为三江源国家公园建设提供数据支撑，还可为高寒草地可持续发展提供重要依据。