氮沉降对植被和水文特征的影响

The Impact of Nitrogen Deposition on Vegetation and Hydrological Characteristics

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.