Subjects: Geosciences >> Geography submitted time 2023-03-13 Cooperative journals: 《干旱区研究》
Abstract： The accurate estimation of grassland net primary productivity (NPP) is crucial to understanding the carbon cycle of grassland ecosystems and their adaption to climate change. Based on 1788 grassland biomass data and 19 environmental factors (climate, vegetation, soil, and topographic factors), we simulated the spatiotemporal dynamics of grassland NPP in the Loess Plateau from 2002 to 2020 using the random forest (RF) model. The future trends of grassland NPP under four future climate scenarios of shared socioeconomic pathways were estimated. Results showed that (1) the RF model had a good accuracy, which indicated that RF can be used to estimate grassland NPP in the Loess Plateau; (2) grassland NPP in the Loess Plateau exhibited a“high in southeastern and low in northwestern”pattern, with a mean value of 276.55 g C·m−2·a−1. The highest grassland NPP was observed in Guanzhong Plain of Shaanxi; (3) the grassland NPP in the Loess Plateau showed an overall increasing trend during 2002-2020. Regions experiencing an increase in grassland NPP accounted for 55.01% of the total land area, which is mainly located in Guanzhong Plain, western Gansu, and northern Shanxi; (4) under the wetter and warmer climate, grassland NPP in the Loess Plateau will continually increase by the end of this century. Grassland NPP will increase the most under the SSP585 scenario and the least under the SSP126 scenario. RF can be used to simulate the temporal and spatial trends of grassland NPP in the Loess Plateau. The results provide data support for the protection and sustainable development of grassland ecosystem in the Loess Plateau.
Subjects: Environmental Sciences, Resource Sciences >> Other Disciplines of Environmental Sciences, Resource Sciences submitted time 2021-03-02 Cooperative journals: 《干旱区研究》
Abstract：区域碳储量是生态系统功能的重要度量指标，探索土地改造对区域碳储量变化的影响，对于协调区域生态建设和生态产业发展具有重要意义。基于InVEST模型和地理信息系统技术，研究了陕西省延安南部麻塔流域1999—2016年土地结构改造过程中区域碳储量变化，并探讨坡度、坡向、坡位对碳储量空间分布的影响。结果表明：麻塔流域18 a的土地改造使得区域碳储量增加1688.36 Mg（碳密度增加6.92 Mg·hm2），总固碳功能提升约7.63%。森林、草地和果园土地类型面积的增加是植被转换后流域景观碳储量提升的主要贡献者。碳储量增加的空间位置主要分布在半阴坡、中上坡位以及坡度10°~30°。本研究认为林草植被建设和经济果林建设两者都有利于增强麻塔流域景观固碳能力。麻塔流域土地转换模式能够协调区域生态建设和生态产业的发展，在黄土丘陵区具有较好的推广价值。
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