| 黄土高原植被净初级生产力时空变化及其影响因素 |
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| 引用本文： | 谢宝妮,秦占飞,王洋,常庆瑞.黄土高原植被净初级生产力时空变化及其影响因素[J].农业工程学报,2014,30(11):244-253. |
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| 作者姓名： | 谢宝妮 秦占飞 王洋 常庆瑞 |
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| 作者单位： | 西北农林科技大学资源环境学院，杨凌 712100;西北农林科技大学资源环境学院，杨凌 712100;西北农林科技大学资源环境学院，杨凌 712100;西北农林科技大学资源环境学院，杨凌 712100 |
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| 基金项目： | 863计划（2013AA102401-2）；博士点基金（20120204110013）；国家自然科学基金（30872073） |
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| 摘 要： | 为了探明黄土高原地区植被生产力变化的驱动机制,该文基于MODIS传感器获得的MOD17A3数据,分析了黄土高原2000-2010年间植被净初级生产力(net primary productivity,NPP)的时空变化及其主要影响因素,并借助多元统计分析方法对引起NPP变化的自然和人为因素进行量化分析。结果表明:黄土高原植被总NPP从2000年的119 Tg(以C计)增加到2010年的144 Tg(以C计),年增速4.57 g/(m2·a)(P0.05)(以C计)。黄土高原约91%的区域NPP呈增加趋势,37%的区域增加趋势显著,主要分布在陕西、青海大部分地区、甘肃南部及宁南山区。整个黄土高原近11 a间NPP变化受自然和人为因素共同影响,其中退耕还林还草累计面积、帕尔默干旱指数(palmer drought severity index,PDSI)、耕地面积和人口数量是影响NPP变化的主要因素。退耕还林还草累计面积占四者总贡献率的43%,PDSI占40%,耕地面积和人口数量分别占13%和4%。对区域而言,由退耕还林还草工程引起的土地利用覆被变化是退耕区(陕北、甘肃东南部等)NPP增加的主要因素,而近年来干旱情况的缓解(PDSI呈上升趋势)则是青海、内蒙古等地NPP增加的主要因素。该研究对于黄土高原各区域生态资源管理,以及生态系统的建设具有一定的指导和借鉴意义。
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| 关 键 词： | 植被 生态系统 土地利用 净初级生产力 MODIS 黄土高原 时空变化 影响因素 |
| 收稿时间： | 1/2/2014 12:00:00 AM |
| 修稿时间： | 2014/4/15 0:00:00 |
Spatial and temporal variation in terrestrial net primary productivity on Chinese Loess Plateau and its influential factors |
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| Xie Baoni,Qin Zhanfei,Wang Yang and Chang Qingrui.Spatial and temporal variation in terrestrial net primary productivity on Chinese Loess Plateau and its influential factors[J].Transactions of the Chinese Society of Agricultural Engineering,2014,30(11):244-253. |
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| Authors: | Xie Baoni Qin Zhanfei Wang Yang and Chang Qingrui |
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| Institution: | College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China;College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China;College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China;College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China |
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| Abstract: | Abstract: Monitoring dynamics of vegetation productivity and its influential factors are important for understanding the mechanisms of carbon cycling in terrestrial ecosystems. This study investigated the variation in vegetation net primary productivity (NPP) and its major influential factors on the Chinese Loess Plateau during 2000-2010. The remotely sensed time-series data MOD17A3 for vegetation collected by a MODIS sensor was analyzed for NPP changes. The climate factors (temperature, precipitation and solar radiation), palmer drought severity index (PDSI) and land use in the year of 2000-2010 were used to explore the effects of natural factors and human activities on NPP change. Linear least square regression was employed to estimate the trends of NPP in each grid point. The correlation between NPP change and various environmental factors was identified with Pearson coefficient. It was demonstrated that changes in NPP were related to factors such as climate, PDSI, crop area, crop yield and area of accumulative vegetation restoration. With multiple regression analysis, the contribution of human and natural forces to NPP shifts was evaluated separately for the whole Loess Plateau and several hot-spot cities within this region, respectively. The results showed that the NPP on the Loess Plateau was between 100-400 g C/(m2?a), and the average annual NPP during the 11 years was 238 g C/(m2?a). The NPP on the Loess Plateau increased by a rate of 4.57 g C/(m2?a) during the past 11 years. The total annual NPP increased from 119 Tg C in year 2000 to 144 Tg C in 2010. About 91% of the study area showed an increasing NPP trend but only 37% of the study area had a significant (P<0.05) increase in NPP including most areas of Shaanxi and Qinghai, southern Gansu and Ningxia. The increase of NPP varied with vegetation types. It was highest in shrub land (5.25 g C/(m2?a)) and crop land (5.26 g C/(m2?a)) but lowest in wet land (1.40 g C/(m2?a)). The areas with significant (P<0.05) increase in crop and grasses were mainly due to the vegetation restoration scheme. But, the areas with the increase of forest coverage appeared to be the smallest. Across the whole Loess Plateau, both natural and human factors were responsible for changes in NPP during the 11 years. However, accumulated area of farmland returned to forest or grassland, PDSI, farmland area and population tended to be dominant influential factors with the standard regression coefficients between NPP and these factors of 0.634, 0.587, 0.187 and 0.062, respectively. The relative contributions of these four factors were 43%, 40%, 13% and 4%, respectively. Land use change resulted from the central government program of Grain for Green may be the reason for the NPP increase in the regions with vegetation restoration (e.g. northern Shaanxi, southwestern Gansu). The relief of drought events (increased PDSI) during last 11 years might be a reason for the rise of NPP in Qinghai and Inner Mongolia. This study could provide valuable information for regional ecological resources management and ecosystem reconstruction on the Chinese Loess Plateau. |
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| Keywords: | vegetation ecosystems land use net primary productivity (NPP) MODIS Chinese Loess Plateau temporal and spatial variation influential factors |
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