新疆草地净初级生产力(NPP)空间分布格局及其对气候变化的响应

分析植被物候与净初级生产力对气候变化的响应一直是研究全球变化的核心内容之一。新疆草地生态系统极为脆弱,对气候和环境变化的影响十分敏感,在新疆地区开展草地物候和净初级生产力及其对气候变化的响应有着独特的意义。基于遥感数据和野外台站实测数据,利用CASA模型模拟了新疆草地植被净初级生产力(NPP),阐述了2001—2014年新疆地区草地的NPP的空间格局及与气象因子的关系。(1)通过实测生物量精度检验表明,CASA模型基本可以反映新疆地区草地植被NPP。(2)2001—2014年新疆草地NPP平均值为102.49 gC m^-2 a^-1。不同草地类型的NPPA存在明显差异。其中,山地草甸平均NPP最高,达到252.37 gC m^-2 a^-1;温性草甸草原次之,为204.93 gC m^-2 a^-1。高寒荒漠和温性荒漠的平均NPP最低,分别为43.94 gC m^-2 a^-1,53.11 gC m^-2 ...

Spatial distribution pattern of NPP of Xinjiang grassland and its response to climatic changes

Analysis of vegetative net primary productivity (NPP) in response to climate change has been one of the core issues of global change studies. The grassland ecosystem in Xinjiang is extremely fragile and sensitive to climate and environmental changes. Hence, it is particularly important to investigate grassland net primary productivity and its response to climate change in Xinjiang. This study simulates the NPP of Xinjiang grassland vegetation with the CASA model based on remote sensing data and measured data from field stations and describes the relationship between spatial patterns of the NPP on the Xinjiang grassland and meteorological factors from 2001 to 2014.(1) Through accuracy verification with the measured biomass data, it was shown that the CASA model can basically reflect the NPP of Xinjiang grassland vegetation.(2) The average value of the NPP of the Xinjiang grassland from 2001 to 2014 was 102.49 gC m^-2a^-1. There are significant differences in NPP among different grassland types. The NPP of mountain meadows is the highest, reaching 252.57 gC m^-2a^-1, followed by that of the temperate meadow grasslands, with 204.93 gC m^-2a^-1. The NPP of alpine desert and temperate grassland desert is the lowest, at 43.94 gC m^-2a^-1 and 53.11 gC m^-2a^-1, respectively. (3) The spatial distribution pattern of the NPP of Xinjiang grassland vegetation has the following characteristics: the NPP of the mountain grassland is higher than that of the basin grassland, and the NPP of the grassland in northern Xinjiang is higher than that of the grassland in southern Xinjiang.(4) Rainfall can promote an increase in the NPP of Xinjiang grasslands. In particular, in grasslands with less precipitation but higher temperatures, such as temperate desert grasslands, temperate grassland deserts, temperate deserts, and lowland meadows, annual precipitation and summer and autumn precipitation have a significant impact on grassland NPP. However, the temperature has little influence on the NPP of the Xinjiang grassland. By analyzing the spatial patterns of the grassland in Xinjiang, the response of grassland NPP to climate change was studied in order to provide a decision-making basis for the rational planning of grassland production and utilization, the healthy development of grassland ecosystems and the response to climate change.