植被在地球碳循环和气候变化中扮演着重要角色,了解植被及其动态变化对人们应对气候变化和开展生物多样性保护工作具有重要意义。本文以叶面积指数(Leaf Area Index,LAI)作为表征植被绿度的指标,采用Theil-Sen Median趋势分析和Mann-Ken...植被在地球碳循环和气候变化中扮演着重要角色,了解植被及其动态变化对人们应对气候变化和开展生物多样性保护工作具有重要意义。本文以叶面积指数(Leaf Area Index,LAI)作为表征植被绿度的指标,采用Theil-Sen Median趋势分析和Mann-Kendall检验来研究植被绿度的变化趋势特征,并对我国2000−2021年植被绿度(不含港澳台地区数据,下同)时空变化特征进行了分析。结果表明:①我国植被绿度平均值总体呈现出增加趋势,尤其是胡焕庸线东南区域以“显著增加”为主,反映出该地区的生态环境显著改善。然而,青藏高原等生态脆弱区的部分区域仍面临退化问题。②不同生态系统类型中,森林和农田植被绿度表现最为突出,分别有82.18%和75.47%的区域绿度“显著增加”,灌丛的植被绿度增幅为66.06%,但部分区域变化有限;草地生态系统面临较大挑战,17.54%的区域绿度下降,需加强草地的精细化管理和生态修复。③在重点区域分析中,内蒙古自治区对全国植被绿度增长贡献度最高(12.9%),与四川省、黑龙江省等4个省份共同贡献了39.1%的全国植被绿度增长。黄河流域和长江经济带的植被绿度“显著增加”,占比超过70%,而青藏高原局部区域植被绿度呈现“显著减少”或“轻微减少”的占比超过15%。这表明我国实施的生态修复政策成效显著,为生物多样性保护提供了良好支持,但仍需加强部分区域生态系统的精细化管理和保护以巩固生态系统功能和栖息地稳定性。展开更多
人类活动导致全球氮沉降急剧增加,氮沉降促进了陆地生态系统的碳汇。本文利用来自CMIP6模型的数据,将1pctCO2与1pctCO2Ndep气候情景进行比较,来量化氮沉降对植被以及水文特征的影响。结果显示,氮沉降增加导致植被变绿,间接影响水文特征...人类活动导致全球氮沉降急剧增加,氮沉降促进了陆地生态系统的碳汇。本文利用来自CMIP6模型的数据,将1pctCO2与1pctCO2Ndep气候情景进行比较,来量化氮沉降对植被以及水文特征的影响。结果显示,氮沉降增加导致植被变绿,间接影响水文特征。结构方程模型表明,氮沉降增加通过促进植被生长来增加植被蒸腾。植被通过冠层截留作用直接减少降水量,以及通过提高蒸腾间接增加降水。植被变绿对径流的影响则因地区的干旱程度而异。植被冠层截留的降水也能通过蒸发补充土壤水分。这些发现提高了我们对陆地生态系统水文特征对氮沉降响应的理解,并为评估氮沉降对植被以及水文特征的影响提供了新的见解。Human activities have resulted in a significant upsurge in global nitrogen deposition, and such nitrogen deposition has facilitated the carbon sink of terrestrial ecosystems. This study utilizes data from CMIP6 models to compare the 1pctCO2 and 1pctCO2Ndep climate scenarios, aiming to quantify the effects of nitrogen deposition on vegetation and hydrological characteristics. The findings suggest that elevated nitrogen deposition leads to enhanced vegetation greenness, which subsequently affects hydrological properties. Structural equation modeling reveals that enhanced nitrogen deposition fosters vegetation growth, thereby increasing vegetation transpiration. Vegetation directly reduces precipitation through canopy interception and indirectly increases it by enhancing transpiration. The influence of enhanced vegetation greenness on runoff is contingent upon regional aridity levels. Moreover, precipitation that is intercepted by the vegetation canopy has the potential to replenish soil moisture via the process of evaporation. These findings contribute to a deeper understanding of the responses of terrestrial ecosystem hydrological characteristics to nitrogen deposition and offer new insights for evaluating the impacts of nitrogen deposition on vegetation and hydrological characteristics.展开更多
文摘植被在地球碳循环和气候变化中扮演着重要角色,了解植被及其动态变化对人们应对气候变化和开展生物多样性保护工作具有重要意义。本文以叶面积指数(Leaf Area Index,LAI)作为表征植被绿度的指标,采用Theil-Sen Median趋势分析和Mann-Kendall检验来研究植被绿度的变化趋势特征,并对我国2000−2021年植被绿度(不含港澳台地区数据,下同)时空变化特征进行了分析。结果表明:①我国植被绿度平均值总体呈现出增加趋势,尤其是胡焕庸线东南区域以“显著增加”为主,反映出该地区的生态环境显著改善。然而,青藏高原等生态脆弱区的部分区域仍面临退化问题。②不同生态系统类型中,森林和农田植被绿度表现最为突出,分别有82.18%和75.47%的区域绿度“显著增加”,灌丛的植被绿度增幅为66.06%,但部分区域变化有限;草地生态系统面临较大挑战,17.54%的区域绿度下降,需加强草地的精细化管理和生态修复。③在重点区域分析中,内蒙古自治区对全国植被绿度增长贡献度最高(12.9%),与四川省、黑龙江省等4个省份共同贡献了39.1%的全国植被绿度增长。黄河流域和长江经济带的植被绿度“显著增加”,占比超过70%,而青藏高原局部区域植被绿度呈现“显著减少”或“轻微减少”的占比超过15%。这表明我国实施的生态修复政策成效显著,为生物多样性保护提供了良好支持,但仍需加强部分区域生态系统的精细化管理和保护以巩固生态系统功能和栖息地稳定性。
文摘人类活动导致全球氮沉降急剧增加,氮沉降促进了陆地生态系统的碳汇。本文利用来自CMIP6模型的数据,将1pctCO2与1pctCO2Ndep气候情景进行比较,来量化氮沉降对植被以及水文特征的影响。结果显示,氮沉降增加导致植被变绿,间接影响水文特征。结构方程模型表明,氮沉降增加通过促进植被生长来增加植被蒸腾。植被通过冠层截留作用直接减少降水量,以及通过提高蒸腾间接增加降水。植被变绿对径流的影响则因地区的干旱程度而异。植被冠层截留的降水也能通过蒸发补充土壤水分。这些发现提高了我们对陆地生态系统水文特征对氮沉降响应的理解,并为评估氮沉降对植被以及水文特征的影响提供了新的见解。Human activities have resulted in a significant upsurge in global nitrogen deposition, and such nitrogen deposition has facilitated the carbon sink of terrestrial ecosystems. This study utilizes data from CMIP6 models to compare the 1pctCO2 and 1pctCO2Ndep climate scenarios, aiming to quantify the effects of nitrogen deposition on vegetation and hydrological characteristics. The findings suggest that elevated nitrogen deposition leads to enhanced vegetation greenness, which subsequently affects hydrological properties. Structural equation modeling reveals that enhanced nitrogen deposition fosters vegetation growth, thereby increasing vegetation transpiration. Vegetation directly reduces precipitation through canopy interception and indirectly increases it by enhancing transpiration. The influence of enhanced vegetation greenness on runoff is contingent upon regional aridity levels. Moreover, precipitation that is intercepted by the vegetation canopy has the potential to replenish soil moisture via the process of evaporation. These findings contribute to a deeper understanding of the responses of terrestrial ecosystem hydrological characteristics to nitrogen deposition and offer new insights for evaluating the impacts of nitrogen deposition on vegetation and hydrological characteristics.
