陇东地区是黄土高原重要的生态过渡带和生态脆弱区,植被覆盖指数(NDVI)变化对区域生态安全具有重要影响。基于2000—2024年长序列NDVI、气候与土地利用等数据,采用Theil-Sen趋势分析、Hurst指数等方法研究陇东地区NDVI的时空演变特征及...陇东地区是黄土高原重要的生态过渡带和生态脆弱区,植被覆盖指数(NDVI)变化对区域生态安全具有重要影响。基于2000—2024年长序列NDVI、气候与土地利用等数据,采用Theil-Sen趋势分析、Hurst指数等方法研究陇东地区NDVI的时空演变特征及其对气候变化及人类活动的响应。结果表明:①陇东地区NDVI呈东南高、西北低的空间分布格局,NDVI显著改善区域面积占总面积的54.74%,Hurst指数为0.35~0.65,表明未来植被改善趋势持续性偏弱;②人类活动是NDVI变化的主导驱动力,主要受退耕还林还草(2248.11 km 2耕地转草地)和城市化(城市化率增幅35.14%)双向影响;③86.6750%的区域受气候-人类活动的共同作用形成了人类活动驱动为主、气候变化基础支撑为辅的空间分布格局。陇东地区NDVI虽显著改善,但其变化主要受人类活动驱动与快速干预使生态系统未来持续性偏弱,存在“绿化后退化”的潜在风险。展开更多
弄清碳收支变化是促进区域可持续发展的重要方面。研究结合光合能力模型(Photosynthetic Capacity Model,PCM)和呼吸遥感模型(Remote Sensing Model for Ecosystem respiration,Re-RSM)提出了一个完全基于遥感数据的陆地碳收支动态评估...弄清碳收支变化是促进区域可持续发展的重要方面。研究结合光合能力模型(Photosynthetic Capacity Model,PCM)和呼吸遥感模型(Remote Sensing Model for Ecosystem respiration,Re-RSM)提出了一个完全基于遥感数据的陆地碳收支动态评估模型(Remote Sensing Land Carbon Budget Dynamic Assessment Model,RS-CBM),引入中国三北地区(东北、华北和西北地区)7种植被类型(玉米农田、针阔混交林、落叶针叶林、高寒草地、灌丛草甸、荒漠草原和芦苇湿地)的多年碳通量观测数据对RS-CBM模型进行参数化和验证,并应用此模型定量评估了2001—2020年三北地区植被NEE的时空特征与规律。结果表明,RS-CBM模型的模型精度高达0.75,均方根误差为0.07 mol·m^(-2)·d^(-1),RS-CBM模型的NEE模拟值与通量观测值具有较好的一致性,在不同植被类型的生长季旺盛期均出现较明显的碳吸收峰值,但存在不同程度的峰值低估现象。2001—2020年三北地区的NEE变化呈波动上升趋势,年平均值为82.01 g·m^(-2)·a^(-1),年平均增长量为5.843 g·m^(-2)·a^(-1),总体表现为碳汇。三北地区NEE在空间上呈现南高北低,东高西低的空间分异性。综上,RS-CBM模型能较好地模拟出三北地区碳收支变化和空间分布,具有在区域尺度模拟NEE时空变化的潜力。展开更多
The invasion of exotic plants is a severe problem due to its tremendous damage and impact. The management and assessments of exotic plants are very important. The effective assessments include:①the properties related...The invasion of exotic plants is a severe problem due to its tremendous damage and impact. The management and assessments of exotic plants are very important. The effective assessments include:①the properties related to establishment of exotic plant.② the factors which influence the spread of exotic plants;③ the impacts of exotic species. When evaluating exotic species, the three aspects should be integrated to assess exotic plants. Every guideline of assessment plays different role in assessment of different exotic species. At the same time, it is becoming increasingly important to predict which species will invade an area alien to them and to estimate what harm they can do. Three ways of predicting invasions of exotic species,should be conducted. Models may help us to evaluate the influence of exotic species. Managing exotic plants, especially the exthose with large distribution area, requires a coordinated strategy based on cooperation among all departments, which include forestry, agriculture, fishery, all land managers and so on. This strategy emphasizes on cooperation, education, and science, and is based on integrated management techniques. The management is divided into three steps. The first step is to effectively prevent new invasion, the second step is to control and eliminate exotic plants, in which mechanical methods, chemical means, and biocontrol technologies are used. Sometimes, the three ways are integrated in order to obtain better results. The third step is to effectively restore native vegetation and prevent reinvasion.展开更多
文摘陇东地区是黄土高原重要的生态过渡带和生态脆弱区,植被覆盖指数(NDVI)变化对区域生态安全具有重要影响。基于2000—2024年长序列NDVI、气候与土地利用等数据,采用Theil-Sen趋势分析、Hurst指数等方法研究陇东地区NDVI的时空演变特征及其对气候变化及人类活动的响应。结果表明:①陇东地区NDVI呈东南高、西北低的空间分布格局,NDVI显著改善区域面积占总面积的54.74%,Hurst指数为0.35~0.65,表明未来植被改善趋势持续性偏弱;②人类活动是NDVI变化的主导驱动力,主要受退耕还林还草(2248.11 km 2耕地转草地)和城市化(城市化率增幅35.14%)双向影响;③86.6750%的区域受气候-人类活动的共同作用形成了人类活动驱动为主、气候变化基础支撑为辅的空间分布格局。陇东地区NDVI虽显著改善,但其变化主要受人类活动驱动与快速干预使生态系统未来持续性偏弱,存在“绿化后退化”的潜在风险。
文摘The invasion of exotic plants is a severe problem due to its tremendous damage and impact. The management and assessments of exotic plants are very important. The effective assessments include:①the properties related to establishment of exotic plant.② the factors which influence the spread of exotic plants;③ the impacts of exotic species. When evaluating exotic species, the three aspects should be integrated to assess exotic plants. Every guideline of assessment plays different role in assessment of different exotic species. At the same time, it is becoming increasingly important to predict which species will invade an area alien to them and to estimate what harm they can do. Three ways of predicting invasions of exotic species,should be conducted. Models may help us to evaluate the influence of exotic species. Managing exotic plants, especially the exthose with large distribution area, requires a coordinated strategy based on cooperation among all departments, which include forestry, agriculture, fishery, all land managers and so on. This strategy emphasizes on cooperation, education, and science, and is based on integrated management techniques. The management is divided into three steps. The first step is to effectively prevent new invasion, the second step is to control and eliminate exotic plants, in which mechanical methods, chemical means, and biocontrol technologies are used. Sometimes, the three ways are integrated in order to obtain better results. The third step is to effectively restore native vegetation and prevent reinvasion.
