基于光能利用率模型的内蒙古天然草原植被净初级生产力动态监测与气候因子的响应

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乌尼图, 刘桂香, 杨勇, 宋向阳, 白海花. 基于光能利用率模型的内蒙古天然草原植被净初级生产力动态监测与气候因子的响应. 草业学报, 2020,29(11): 1-10
WU Ni-tu, LIU Gui-xiang, YANG Yong, SONG Xiang-yang, BAI Hai-hua. Dynamic monitoring of net primary productivity and its response to climate factors in native grassland in Inner Mongolia using a light-use efficiency model. Acta Prataculturae Sinica,2020,29(11): 1-10 复制到剪切板

Doi:10.11686/cyxb2019543
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基于光能利用率模型的内蒙古天然草原植被净初级生产力动态监测与气候因子的响应

乌尼图^1,², 刘桂香^1,^*, 杨勇³, 宋向阳³, 白海花¹

1.中国农业科学院草原研究所,内蒙古呼和浩特010010

2.中国农业科学院研究生院,北京100081

3.内蒙古自治区草原勘察规划院,内蒙古呼和浩特010051

*通信作者. E-mail: liugx804@163.com

作者简介:乌尼图(1988-),男,蒙古族,内蒙古锡林浩特人,在读博士。E-mail: unteecaas@outlook.com

收稿日期: 2019-12-10

基金项目:中国农业科学院草原研究所科技创新工程“中蒙俄草原火灾联合监测防控研究”项目和内蒙古自治区科技计划项目(2060399-273)资助

摘要

利用光能利用率模型和MODIS数据对内蒙古天然草原2000-2018年植被生长期草原净初级生产力进行连续动态监测,并在像元尺度利用最小二乘法分析了近20年植被净初级生产力(NPP)时空变化规律。结果表明:近20年中,内蒙古天然草原NPP在空间上呈由西向东递增分布规律,年均NPP为198.04 g C·m^-2·a^-1,潜在草地退化面积16.22万km²,其中重度、较重度面积分别为0.20万和1.11万km²,主要分布于人类活动密集区域,如矿区、建设用地及周边;在草地类型上,温性草原、温性草甸草原、温性荒漠以及温性荒漠草原潜在退化面积分别为5.22万、1.40万、4.04万和2.21万km²。通过分析NPP与气候因子的相关性表明:近20年,内蒙古草原NPP与降水具有显著相关性,与温度无相关性;温性草甸草原NPP对降水的响应最敏感,温性荒漠草原其次,温性草原对降水响应最低。研究还根据上述结果,围绕草地生态保护提出了建议。

关键词: 光能利用率模型; MODIS; 草地净初级生产力; 气候因子

Dynamic monitoring of net primary productivity and its response to climate factors in native grassland in Inner Mongolia using a light-use efficiency model

WU Ni-tu^1,², LIU Gui-xiang^1,^*, YANG Yong³, SONG Xiang-yang³, BAI Hai-hua¹

1. Grassland Research Institute, Chinese Academy of Agricultural Sciences, Hohhot 010010, China

2. Graduate School of Chinese Academy of Agricultural Sciences, Beijing 100081, China

3. Grassland Investigation and Planning Institute of Inner Mongolia, Hohhot 010051, China

*Corresponding author. E-mail: liugx804@163.com

Abstract

Based on a light-use efficiency model and MODIS data, the net primary productivity (NPP) of grassland during the growing seasons from 2000 to 2018 in native grassland in Inner Mongolia was continuously estimated, and the spatial-temporal change trend of NPP over the past 20 years was also analyzed using a least square method at pixel scale to determine the degree of grassland degradation. It was found that NPP increased from west to east across Inner Mongolia, with an annual average of 198.04 g C·m^-2·yr^-1. An area of potential grassland degradation of 162200 km² was identified. The areas of severely and heavily degraded grassland identified were 2000 and 11100 km², respectively. The latter were mainly distributed in areas with intensive human activities, such as mining areas, or construction land and its surrounding areas. In terms of grassland types, the potentially degraded areas of temperate steppe, temperate meadow, temperate desert and temperate desert-steppe were 52200, 14000, 40400 and 22100 km² respectively. Through analyzing the correlation between NPP and climate factors in the last two decades, it was found that NPP is significantly correlated with precipitation, but has no correlation with temperature. The response of NPP to precipitation was the most sensitive in temperate meadow, that of temperate desert steppe was the second, and that of temperate steppe was the lowest. Based on the above results, this paper puts forward some suggestions for grassland ecological protection.

Keyword: light-use efficiency model; MODIS; net primary productivity of grassland; climate factors

文章图片

草地是陆地最大的生态系统之一, 不仅是承载人类活动重要的“ 场所” , 而且具有很高的生态服务价值^[1]。据联合国粮农组织(Food and Agriculture Organization of the United Nations, FAO)最新统计表明, 世界草地面积约为0.35亿km², 占世界陆地面积的26%, 占世界农业总面积的70%, 是发展畜牧业经济的载体^[2]。近些年, 受过度开发利用以及气候变化的影响, 草地减产、草地退化现象日益严重, 成为制约经济可持续发展, 威胁区域生态安全的主要障碍^[3]。我国草地面积约为393万km², 约占国土面积的40%, 天然牧草种类达5000多种, 位居世界第一位, 但受人类活动和气候的影响, 我国近90%的天然草原出现了不同程度的退化^{[1, 3]}。

植被净初级生产力(net primary productivity, NPP)是植被通过光合作用所同化的有机物量中扣除自养呼吸后的剩余部分^[4]。NPP作为地表碳循环的重要组成部分, 不仅直接反映了植被群落在自然环境条件下的生产能力, 而且还是判定生态系统健康状况的重要指标^[5]。自20世纪60年代以来, 遥感技术的发展为宏观尺度草地生产力监测提供了技术支撑, 尤其自多光谱影像问世以来, 国内外学者围绕植被光学遥感开展了大量研究, 发展了大量可实施的NPP估算模型方法^{[6, 7]}。早期的模型主要利用植被指数结合实测数据进行NPP的修正和模拟^[8], 近年来则将生态系统碳循环过程与遥感技术结合, 建立碳通量过程的遥感模型, 具代表性的有GLO-PEM^[9]、VPM^[10]、EC-LUE^[11]和CASA^[12]等, 由于这类模型具有模拟生态过程、易获取基础参数等优势, 被广泛应用于植被NPP的计算中。但在区域尺度应用上述模型还需在关键参数上进行修正, 以确保模型精度^[8]。针对我国植被特点, 国内一批学者^{[13, 14, 15]}通过构建基于光能利用率的NPP估算模型, 取得了较好的模拟精度。

内蒙古草原是我国北方天然草原的重要组成部分, 在宏观尺度下研究草地NPP的空间变化规律, 以及NPP与水热条件的响应规律对于合理利用草地资源具有重要意义。近年来, 大批学者针对内蒙古草地NPP开展了遥感监测研究^{[16, 17, 18, 19, 20]}, 从不同侧面增强了对内蒙古草原生态的了解, 也为本研究开展大尺度草地遥感监测提供了宝贵经验。本研究在学习和借鉴上述研究方法的基础上, 利用MODIS作为数据源, 以朱文泉等^[14]构建的光能利用率模型作为NPP估测模型, 在1 km× 1 km栅格像元尺度分析内蒙古天然草原植被NPP在近20年的时空变化规律, 并结合气象数据分析草地NPP对水热供给的响应关系, 为草原生态修复以及区域生态规划提供科学依据。

1 材料与方法

1.1 研究区概况

内蒙古自治区地处中国北部边疆(E 97° 12'-126° 04', N 37° 24'-53° 23'), 东西直线跨度达2400 km, 土地面积118.3万km², 其中天然草原面积达78.6万km², 占自治区总面积的66.4%^[21]。内蒙古地形条件复杂, 平均海拔900~1300 m, 主要由内蒙古高平原、鄂尔多斯高平原、大兴安岭山地、阴山山地、贺兰山山地、河套平原等地貌单元构成。内蒙古属干旱大陆性气候, 年均气温由东北向西南递升, 由低温区年均-3~-5 ℃上升至高温区年均8~9 ℃, 具有冬季寒冷, 夏季温热, 有效积温多等特点; 年降水量自东南向西北递减, 由大兴安岭山地年降水450 mm递减至贺兰山以西年降水150~250 mm, 具有冬春少雨雪, 夏季多雨, 降水变率大, 保证率低等特点; 全区年太阳总辐射在0.50~0.70 MJ· cm^-2, 由东向西递增, 年日照时数在2600~3400 h, 自东北向西南递增^{[17, 18, 21]}。内蒙古土壤类型主要以草原土为主, 自东向西依次分布黑土带-黑钙土带-栗钙土带-棕钙土带-漠钙土带-灰棕钙土带^[21]。根据第一次全国草地资源普查和《中国草地分类原则与分类系统》, 内蒙古天然草原可划分为温性草甸草原类、温性草原类、温性荒漠草原类、温性草原化荒漠类、温性荒漠类、低地草甸类、山地草甸类和沼泽类8个大类、21个亚类以及476个草地型^[21](图1)。

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	图1 研究区概况Fig.1 Map of study area

1.2 数据来源与处理

本研究数据资料包括遥感数据、气象数据、样地实测数据和地图界限数据。由于研究区属于干旱与半干旱地区, 草地植被生长期主要集中于4月初-9月底, 因此, 遥感影像选取2000-2018年4-9月MOD13A3, 数据来源于美国地质勘探局数据共享中心(http://www.usgs.gov); 气象数据选取2000-2018年4-9月内蒙古及周边8个省区市94个气象站点月均温、月降水以及全国677个气象站点月日照数据, 来源于中国气象数据网(http://data.cma.cn); 样地实测数据为研究区固定监测点历年监测数据; 研究区地图界限数据来源于全国地理信息资源目录服务系统中《1:100万全国基础地理数据库》(http://www.webmap.cn)。遥感数据的投影、拼接、裁剪和格式转化等预处理工作在ENVI和ArcGIS上进行, 气象数据在ANUSPLIN上进行插值, NPP利用朱文泉等^[14]开发的光能利用率模型插件进行估算。

1.3 草地净初级生产力计算

朱文泉等^{[14, 15]}根据中国植被实测数据, 在已有模型基础上, 修正了各植被类型最大光能利用率, 构建了新的光能利用率模型, 该模型具有符合中国植被实际情况、模型因子获取简单、可操作性强等特点, 具有较高的应用价值。本研究基于朱文泉等^[14]构建的光能利用率模型估算草地净初级生产力, 公式如下:

NPP(x, t)=APAR(x, t)× ε (x, t)

APAR(x, t)=SOL(x, t)× FPAR(x, t)× 0.5

ε (x, t)=T_ε₁ (x, t)× T_ε₂ (x, t)× W_ε (x, t)× ε _max

式中:APAR(absorbed photosynthetic active radiation)为植被光合有效辐射; ε 为光能利用率; SOL(solar radiation)为太阳总辐射, 由气象数据插值获得; FPAR(fraction of photosynthetically active radiation)为植被冠层对入射APAR的吸收比, 可通过归一化植被指数(normalized difference vegetation index, NDVI)和比值植被指数(simple ratio index, SR)的线性关系获得; 0.5为植被所吸收的太阳有效辐射分量占SOL的比例系数; T_ε (x, t)和W_ε (x, t)分别为温度因子和水胁迫因子, 均由气象数据插值获得。

FPAR计算公示如下:

FPAR= $\frac{[NDVI (x, t) - NDV I_{\min}] (FPA R_{\max} - FPA R_{\min})}{(NDV I_{\max} - NDV I_{\min}) + FPA R_{\min}}$

FPAR= $\frac{[SR (x, t) - S R_{\min}] (FPA R_{\max} - FPA R_{\min})}{(S R_{\max} - S R_{\min}) + FPA R_{\min}}$

内蒙古草原NDVI、SR的最大值和最小值由2000-2018年MODIS-NDVI平均值和草地类型界限数据裁剪并统计得出(表1)。

表1 内蒙古各草地类型NDVI、SR指数最大值和最小值 Table 1 Maximum and minimum values of NDVI and SR of each grassland type in Inner Mongolia

1.4 模型验证

选取研究区2017年8月固定监测点(均匀分布于研究区各草地类型)实测产量数据对模型估算NPP值进行验证。由于实测产量数据单位是干物质重量, 在转换成以碳为单位重量时需乘以0.45的系数^[22]。

1.5 NPP变化趋势

采用基于最小二乘法的一元线性公式对研究区NPP数据集进行趋势分析, 公式如下:

TREND= $\frac{n \times \sum_{i = 1} i \times NP P_{i} - (\sum_{i = 1} i) (\sum_{i = 1} NP P_{i})}{n \times \sum_{i = 1} i^{2} - {(\sum_{i = 1} i)}^{2}}$

式中:TREND代表趋势大小, 若TREND> 0, 则表示NPP增加, 且数值越大, NPP增加越大; TREND< 0, 表示NPP下降, 且数值越小, NPP下降越快。i代表第几年度(1代表2000年, 2代表2001年, …, 19代表2018年), NPP_i表示第i年的NPP值。

为直观体现草地生产力退化程度, 将研究区NPP下降趋势栅格像元(TREND< 0)结合土地利用现状数据和实地调查资料, 制定了包括重度、较重度、中度、轻度4个级别的退化分级标准(表2)。

表2 内蒙古草地生产力退化程度分级 Table 2 Grassland degradation level in Inner Mongolia

1.6 NPP与气候因子的相关分析

本研究基于像元尺度研究近20年内蒙古草地NPP与气候因子(年均温度和年降水)的相关性。为消除NPP与气候因子间的潜在控制变量的影响, 本研究采用偏相关分析法, 公式如下:

$r_{XY \cdot Z} = \frac{r_{XY} - r_{XZ} \times r_{YZ}}{\sqrt[]{(1 - {r_{XZ}}^{2})} \sqrt[]{(1 - {r_{YZ}}^{2})}}$

式中:r_XY_·_Z为以Z为控制变量的变量X与变量Y的偏相关系数; r_XY、r_XZ、r_YZ分别为变量X与Y、X与Z、Y与Z之间的相关系数。由于草地NPP、年降水和年均温度都是连续型数据, 本研究采用皮尔森相关系数来反映各变量之间的相关系数, 公式如下:

$r_{XY} = \frac{\sum_{i = 1} (x_{i} - \overset{̅}{x}) (y_{i} - \overset{̅}{y})}{\sqrt[]{\sum_{i = 1} (x_{i} {- \overset{̅}{x})}^{2}} \sqrt[]{\sum_{i = 1} (y_{i} {- \overset{̅}{y})}^{2}}}$

式中:r_XY为变量X与Y间的皮尔森相关系数; x_i为变量X观测值, y_i为变量Y观测值, $\overset{̅}{x}$ 为变量X多年观测平均值, $\overset{̅}{y}$ 为变量Y多年观测平均值。

2 结果与分析

2.1 模型精度分析

通过NPP模拟值与NPP实测值的相关分析表明, 模拟值与实测值之间的相关性达到显著水平(P< 0.05, n=786)(图2), 可以认为, 基于MODIS数据和光能利用率模型的研究区草地植被NPP估算符合研究要求精度。

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	图2 研究区NPP模拟值与实测值线性回归分析Fig.2 Linear regression analysis of simulated and measured values of NPP in the study area

2.2 草原植被NPP空间分布规律

2000-2018年内蒙古天然草地NPP在空间上呈由西向东递增分布规律(图3), 年均NPP为198.04 g C· m^-2· a^-1, 其中内蒙古东部大兴安岭山地段森林、杂类草地片区年均NPP呈最高, 均值高于350 g C· m^-2· a^-1; 呼伦贝尔东部丘陵平原线叶菊(Filifolium sibiricum)、贝加尔针茅(Stipa baicalensis)草地片区以及乌珠穆沁丘陵平原贝加尔针茅、羊草(Leymus chinensis)、杂类草地片区年均NPP其次, 均值在300~350 g C· m^-2· a^-1; 锡林郭勒中部高平原大针茅(Stipa grandis)、隐子草(Cleistogenes squarrosa)、冷蒿(Artemisia frigida)草地片区以及通辽市南部草地年均NPP在200~300 g C· m^-2· a^-1。随着经度的西移, 在大尺度上内蒙古中西部草地NPP均值在100~250 g C· m^-2· a^-1; 西部干旱荒漠区, 草地NPP年均值在50 g C· m^-2· a^-1以下, 尤其在阿拉善极干旱荒漠地区, 草地NPP年均值不到10 g C· m^-2· a^-1。

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	图3 近20年内蒙古天然草地NPP空间分布规律Fig.3 Spatial distribution of NPP in Inner Mongolia native grassland in recent 20 years

在草地类型上, 近20年山地草甸和低地草甸年均NPP较高, 分别达410.48和441.56 g C· m^-2· a^-1; 温性草甸、温性草原、温性荒漠草原类年均NPP分别为416.84、257.00、140.68 g C· m^-2· a^-1; 温性草原化荒漠、温性荒漠年均NPP分别为92.76和31.28 g C· m^-2· a^-1。

2.3 草原植被NPP时间变化规律

在1 km× 1 km像元尺度对研究区草原植被NPP变化趋势分析发现, 自2000年以来, 潜在退化草地总面积为16.22万km², 约占全区总草地面积的20%, 分布于全区草地大部, 在呼伦贝尔草原东部、锡林郭勒草原大部以及阿拉善西部分布较为集中(图4)。其中全区重度退化草原面积约为0.20万km², 较重度退化面积1.11万km², 中度退化面积为3.45万km², 轻度退化面积为11.46万km²; 研究区近20年草地生产力恢复面积为16.96万km², 约占全区总草地面积的21%, 主要分布于鄂尔多斯市大部、锡林郭勒中东部及呼伦贝尔草原西部; 近20年来NPP变化基本趋于稳定的草地面积为40.88万km², 分布于全区大部。

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	图4 近20年内蒙古天然草原NPP变化趋势Fig.4 The variation trend of NPP in Inner Mongolia native grassland in recent 20 years

从草地类型上来看, 在近20年中, 内蒙古温性草原、温性草甸草原、温性荒漠以及温性荒漠草原潜在退化面积分别为5.22万、1.40万、4.04万和2.21万km², 草地生产力恢复面积分别为8.16万、3.51万、0.15万和1.59万km²(图5)。

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图5 近20年内蒙古主要草地类型潜在草地退化面积和草地NPP恢复面积
A: 温性草原 Temperate steppe; B:温性草甸草原 Temperate meadow; C: 温性荒漠 Temperate desert; D: 温性荒漠草原 Temperate desert-steppe; E: 全区草地 Grassland of Inner Mongolia.Fig.5 Potential grassland degradation area and restoration area of main grassland types in Inner Mongolia in recent 20 years

2.4 草原植被NPP对气候因子的响应

水热是植被赖以生存的必要条件, 水热供给不足会导致植被长势的下降以及植被种群退化^[23]。通过研究区2000-2018年草地NPP栅格数据集与同期年均温度和年降水栅格数据集的偏相关分析得出, NPP与年降水相关系数明显高于NPP与年均温度相关系数, 且以正相关为主, 数值在0.3~0.8; NPP与年均温度相关系数则在不同草地类型、不同空间分布上明显不同(图6)。

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	图6 近20年内蒙古天然草原NPP与降水(A)和温度(B)的响应关系Fig.6 Response of NPP and precipitation (A) and temperature (B) in Inner Mongolia native grassland in recent 20 years

由于相关系数是由样本数据计算出来的, 要得到研究区草地NPP与气候因子是否显著相关, 则需要对相关系数进行统计检验。分别对草地NPP与年降水、年均温度的相关性进行置信度95%的t检验(零假设:r₀=0, 即NPP与气候因子不相关)得出(图7), 在置信度为95%的置信区间, 研究区绝大多数草地NPP与年降水具有显著相关性(P< 0.05, n=19), 但在呼伦贝尔低地草甸草原类、锡林郭勒中部温性草原类、鄂尔多斯温性草原类以及阿拉善温性荒漠类等个别像元斑块草地NPP与年降水不具有相关性; 在草地NPP与年均温度方面, 除锡林郭勒西部温性荒漠草原类型NPP与年均温度具有显著负相关外(P< 0.05, n=19), 其余均无相关性。

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	图7 近20年内蒙古天然草原NPP与降水(A)、温度(B)的相关性检验Fig.7 Correlation test of NPP with precipitation (A) and temperature (B) in Inner Mongolia native grassland in recent 20 years

通过提取2000-2018年研究区草地NPP与降水相关性在草地类型上的分布面积可知, 近20年内蒙古温性草甸草原NPP与降水的相关性最高, 即对降水的响应最敏感, 在置信度为95%和99%的置信区间, 显著相关面积占该类型总面积的83.21%和48.74%, 温性荒漠草原类型其次, 达81.14%和40.96%, 温性草原类型对降水的响应最低, 达73.41%和33.77%(表3)。

表3 近20年内蒙古各草地类型NPP与降水的相关性面积 Table 3 The correlation area between NPP and precipitation of grassland types in Inner Mongolia in recent 20 years (× 10⁴ km²)

3 讨论

植被NPP对于反映植被群落功能完整性, 评价生态系统健康具有重要意义, 被众多学者喻为研究植被生态的“ 黄金指标” 。本研究在借鉴李刚等^[4]、朱文泉等^[14]的NPP估算模型的基础上, 针对内蒙古天然草原特点, 对各草地类型NDVI、SR最大值和最小值进行了修正, 使模型更加准确的模拟研究区草地NPP。结果也表明, NPP模拟值与实测值线性相关性达到显著性水平(P< 0.05)。同时, 对比其他研究结果, 虽然研究时段和研究范围有所不同, 但大多数基于光能利用率模型计算的内蒙古草地NPP均值在(290± 55) g C· m^-2· a^-1, 例如, 穆少杰等^[16]利用改进的CASA模型模拟的2001-2010年内蒙古草地NPP均值为281.3 g C· m^-2· a^-1; 杨晗等^[17]利用改进的CASA模型模拟的2001-2016年内蒙古草地NPP均值为343.46 g C· m^-2· a^-1; 朱文泉等^[20]利用光能利用率模型计算的2002年内蒙古草地NPP为259.9 g C· m^-2· a^-1。同样, 本研究在不考虑荒漠类型的内蒙古草地NPP均值为293.22 g C· m^-2· a^-1, 数值上与其他研究出入较小, 可以认为修正后的模型可以较好地反映研究区草地NPP空间分布规律。

本研究通过内蒙古草地NPP与气候因子的偏相关分析表明, 近20年草地NPP与水分条件的相关性要远高于NPP与温度的相关性, 温度对NPP的作用主要来源于水分的“ 桥梁作用” , 通过偏相关可消除。通过相关性检验可知, 除个别地区外, 内蒙古大部分草地NPP与年降水具有显著相关性, 而与年均温度无显著性相关性。表明在1 km× 1 km像元尺度, 水分条件越好, 其对应草地产量越高, 因此在水分条件的限制作用下, 在大尺度上形成了内蒙古天然草地NPP由西向东递增的分布规律。在草地类型上, 温性草甸草原NPP对降水的响应最为敏感, 温性荒漠草原其次, 温性草原则最低。内蒙古温性草甸草原集中分布于大兴安岭山地及其岭西、岭东的高平原、低山丘陵地上, 年降水充沛, 导致牧草抗旱性普遍较差, 长势易受降水影响, 对水分的依赖性较强。温性荒漠草原类型主要以旱生、多年生丛生禾草为建群种, 但在多雨年份, 一年生夏雨型植被, 如狗尾草(Setaria viridis)、冠芒草(Nneapogon borealis)、猪毛菜(Salsola collina)等很容易形成优势层片, 对提高草地群落产量具有积极作用, 在干旱年份, 又由于得不到充足的水分而影响整体群落产量, 所以温性荒漠草原因一年生草种对降水的响应较为敏感。导致温性草原对降水响应较低的原因很可能与人类活动有关。内蒙古温性草原面积大, 分布广, 承载人类活动集中, 是发展畜牧业的主要物质来源地。自2000年以来, 过度放牧, 能源开发利用等现象频繁, 导致在雨水充沛年份, 牧草年均NPP受人类活动影响得不到有效递增, 使得NPP与降水相关性降低。由草地NPP与温度的相关性分析结果可知, 内蒙古中部温性荒漠草原以及部分温性草原产量与温度呈显著负相关性, 这与温性荒漠草原植被水热特点有关外, 还可能与插值栅格数据的自身误差有关, 有待于今后进一步研究分析。

在像元尺度提取研究区天然草地NPP近20年的变化趋势发现, 内蒙古天然草地退化趋势严峻, 约占全区总草地面积的20%, 其中重度、较重度退化草地斑块在呼伦贝尔市和锡林郭勒盟分布较为密集。自2000年以来, 地方政府以能源发展为导向, 开发建立了一批规模以上矿产企业, 这无疑对当地生态环境带来一定影响。通过进一步分析发现, 退化趋势值较高的像元主要出现在矿区及周边, 而且这些像元周边一定范围内的像元也具有不同程度的退化趋势值, 表明开采是短时间导致草地退化的主要因素之一。此外, 在实施草原生态保护补助奖励政策之前, 超载过牧等不合理利用现象严重, 不少地方载畜量长期高于牧草理论载畜量, 导致草地大面积退化和沙化^{[24, 25, 26]}。通过结合草地NPP与降水的响应关系发现, 局部地区草地与降水具有较低相关性, 尤其是锡林郭勒中部温性草原区以及西南部温性荒漠草原NPP与降水呈显著不相关, 即在水热条件良好的情况下, 草地NPP具有下降趋势, 表明近20年来受人类活动影响, 草地退化趋势明显。因此, 严禁草地非法征用和开采行为, 制定科学合理的载蓄率, 严禁超载过牧和无序打草, 继续实施草原生态保护补助奖励政策是保护草地生态, 坚持可持续发展的重要措施。

4 结论

本研究基于光能利用率模型结合MODIS数据, 在像元尺度分析了2000-2018年内蒙古天然草原NPP变化趋势及与降水和温度的响应规律, 得出了如下结论:1)内蒙古天然草原在空间上呈由西向东递增分布规律, 年均NPP为198.04 g C· m^-2· a^-1; 2)内蒙古草地退化趋势严峻, 潜在退化草地总面积为16.22万km², 约占全区总草地面积的1/5, 同时草地生产力恢复面积为16.96万km², 约占全区总草地面积的21%。3)人类活动, 尤其是开采利用是短时间导致草地退化的主要因素, 应严禁草地非法征用和开采行为。4)近20年, 总体上内蒙古草原NPP与降水具有显著相关性, 与温度无相关性。5)近20年, 内蒙古温性草甸草原NPP对降水的响应最敏感, 温性荒漠草原其次, 温性草原类型由于受人类活动影响对降水响应最低。

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2011

0.0

. 2011, 28(4):549-560

Review on grassland ecosystem health

草地生态系统健康研究述评

Ye X , Zhou H K , Zhao X Q

叶鑫, 周华坤, 赵新全

This study reviewed the progresses, problems and future fields in the grassland ecosystem health, emphasizing on indicator system and its establishment methods. This study compared structural function indicator system and integrated indicator system, and pointed out the characteristics of ten establishment methods and its application. And then this study put forward some advice for indicator selection, weight assignment of indicator, and criterion. This study suggested that different methods were used to evaluate the same grassland ecosystem, which benefited the comparison and rectification deviation, and more comprehensive and interdisciplinary evaluation would be core of future field of grassland ecosystem health evaluation based on nature, economy, society, and human health.

阐述了草地生态系统健康的研究进展、存在问题和发展趋势，重点介绍了评价的指标体系和方法，包括结构功能指标体系法、综合指标体系及10多种方法的特点和适用情况。同时对于指标的筛选、权重的确定、标准的划分等难重点问题给出了建议。提出了用多种方法来评价同一研究对象来进行比较和矫正的观点，并强调形成集自然、经济、社会、人类健康为一体的综合性交叉的新型研究领域将是未来发展的趋势。

... ,而且具有很高的生态服务价值^[1] ...

... 我国草地面积约为393万km²,约占国土面积的40%,天然牧草种类达5000多种,位居世界第一位,但受人类活动和气候的影响,我国近90%的天然草原出现了不同程度的退化^[1,3] ...

0.0

... 35亿km²,占世界陆地面积的26%,占世界农业总面积的70%,是发展畜牧业经济的载体^[2] ...

2011

0.0

. 2011, 19(5):865-871

Research progress of grassland degraded succession and diagnosis

草地退化演替过程及诊断研究进展

Liu H L , Lu W H , Chen C

刘洪来, 鲁为华, 陈超

1. College of Animal Science, Guizhou University, Guiyang, Guizhou Province 550025, China; 2. College of Animal Science, Shihezi University, Shihezi, Xinjiang 830003, China

Different degree degradation of grassland ecosystem has been found under the stress of population increasing and impact of modern agricultural and industrial demands.The degradation of grassland ecosystem includes qualitative and quantitative changes in grassland composition,structure,process and function.They are the foundation and precondition of ecological restoration for the understanding of degraded grassland concept,driving forces,process and diagnosis of degradation degree.A series questions about grassland degradation was discussed systematically in this paper by summarizing former studies,and a conceptual model of grassland degradation was made."Natural grassland ecosystem" characterized by mild disturbance from human beings or nature was suggested to be "Model Grassland Ecosystem" for degradation research from an ecological point of view.Diagnostic approaches of grassland degradation were summarized as biological approach,habitat approach,function/service approach.The available diagnostic methods and their indices(system) related to grassland degradation degree were analyzed;and integral critical point during diagnosis of degradation degrees and the restoration precautions of degraded grassland were discussed.

随着人口的不断增加和现代工农业文明的冲击,草地生态系统出现不同程度的退化,导致草地生态系统组成、结构、过程和功能等方面发生量和质的变化;对草地退化的系统理解是进行草地恢复与重建的基础与前提。本文综述了草地退化的内涵、驱动力、退化过程与特点,以及草地生态系统退化程度诊断等一系列问题,绘制了描述草地退化程度的概念模型;建议从生态学角度研究草地退化程度诊断时选择相应的气候顶级系统或受干扰程度较轻的"自然生态系统";从草地经营学角度研究草地退化程度诊断时选择适度放牧草地作为参照系统。归纳了退化草地生态系统诊断的生物途径、生境途径和功能服务途径;分析了草地退化程度诊断的方法与可选择的指标体系,并对草地退化程度诊断及草地恢复中应注意的事项进行了讨论。

... 近些年,受过度开发利用以及气候变化的影响,草地减产、草地退化现象日益严重,成为制约经济可持续发展,威胁区域生态安全的主要障碍^[3] ...

2007

0.0

. 2007, 26(12):2100-2106

Application of improved CASA model in productivity evaluation of grassland in Inner Mongolia

改进CASA模型在内蒙古草地生产力估算中的应用

Li G , Xin X P , Wang D L

李刚, 辛晓平, 王道龙

... 植被净初级生产力(net primary productivity, NPP)是植被通过光合作用所同化的有机物量中扣除自养呼吸后的剩余部分^[4] ...

... 本研究在借鉴李刚等^[4]、朱文泉等^[14]的NPP估算模型的基础上,针对内蒙古天然草原特点,对各草地类型NDVI、SR最大值和最小值进行了修正,使模型更加准确的模拟研究区草地NPP ...

2015

0.0

. 2015, 34(8):2344-2352

Simulation of net primary productivity by a satellite data-driven improved CASA model in Xilingol grassland

基于改进的CASA模型模拟锡林郭勒草原植被净初级生产力

Yang Y , Li L H , Wang B L

杨勇, 李兰花, 王保林

( 1 College of Ecology and Environmental Science, Inner Mongolia Agricultural University, Huhhot 010019, China;  2 Inner Mongolia Institute of Grassland Survey and Planning, Huhhot 010051, China)

We improved the parameters of the maximum solar energy utilization efficiency and water stress coefficient algorithm of the original CASA model. The improved CASA model was verified by simulating the net primary productivity (NPP) of Xilingol grassland in 2010. Our results show that the improved CASA model could estimate small scale vegetation NPP in Inner Mongolia grassland, with significant correlation between simulated NPP and observed data ( R 2 =0.829,  P -2 ·a -1 . NPP was considerably different among different regions. For example, NPP was up to 411.11 g C·m -2 ·a -1  in Ujimqin grassland and 158.87 g C·m -2 ·a -1  in Erenhot City grassland. Consistent to the trend of regional water and heat variation, NPP of Xilingol grassland decreased from east to west. There were two peaks in the temporal pattern of NPP due to lag effect of precipitation. NPP in 2010 varied among different grassland types and was mostly in the range of 250-350 g C·m -2 ·a -1 , in which the NPP of meadow steppes was the highest, followed by typical steppes, while NPP of desert steppes was the lowest.

本研究在原来CASA模型的基础上，对模型参数最大光能利用率和水分胁迫系数的算法进行了改进，利用改进后的CASA模型模拟了2010年内蒙古锡林郭勒盟草原植被净初级生产力（NPP），并用地面实测样方数据对改进后的模型进行精度验证。结果表明：改进的CASA模型可应用于内蒙古草原小尺度植被NPP的估测，模拟NPP值与地面实测值之间的相关性达到显著水平（ R 2 =0.829， P -2 ·a -1 ，不同地区年均NPP相差较大，东北部东乌珠穆沁旗草原NPP高达411.11 g C·m -2 ·a -1 ，而西北部的二连浩特市草原NPP仅为158.87 g C·m -2 ·a -1 ；整体上，锡林郭勒盟草原的NPP由东向西逐步递减，这与该区域水热条件限制基本一致；由于降水量的时滞效应，该年度内NPP出现两次峰值；2010年锡林郭勒境内草原NPP集中分布在250～350 g C·m -2 ·a -1 ，草甸草原的NPP最大，典型草原次之，荒漠草原最小。

... NPP作为地表碳循环的重要组成部分,不仅直接反映了植被群落在自然环境条件下的生产能力,而且还是判定生态系统健康状况的重要指标^[5] ...

2010

0.0

. 2010, 29(4):471-477 DOI:10.11820/dlkxjz.2010.04.012

A review on researching scale effect of net primary productivity based on remote sensing

应用遥感技术模拟净初级生产力的尺度效应研究进展

Wei Y X , Wang L W

卫亚星, 王莉雯

1. Center for Marine Economic and Sustainable Development, Liaoning Normal University, Dalian 116029, China. 2. College of Urban and Environmental Science, Liaoning Normal University, Dalian 116029, China

Remote sensing is often used to simulate net primary productivity (NPP) of vegetation on the surface land. It has become an important direction of simulating NPP. With the rapid development of data process capability of remote sensing technology and physiology-ecology research based on remote sensing observations , dynamic quantitative observations of large scale ecosystem pattern and process have become possible. Multi-source satellite sensors have sent abundant multi-scale earth observing data, and images level system with various resolutions has been made. Therefore, simulating NPP derived from quantitative remote sensing has multi-scale problems. When remote sensing data of various resolutions are input in the NPP model as parameters, the simulated NPP values as outputs of the NPP model will be obviously different. In order to improve the precision of simulating NPP, the effect of simulated NPP results from remote sensing data derived at different resolutions should be fully studied, and that is the scale effects of the NPP model. In the paper, study examples of scale effect of remote sensing are discussed. Research cases of monitoring NPP distribution variation using multi-resolution remote sensing data and recent research progresses of scale effect of simulating NPP are also presented. In addition, future trend of researching scale effect of NPP by remote sensing is also discussed in detail.

采用遥感技术估算地表植被净初级生产力(NPP),已经成为模拟NPP的主要发展方向.遥感技术以及数据处理能力的迅速发展和基于遥感观测生理生态理论研究的进展使大尺度生态系统格局和过程的定量、动态观测成为可能.多种卫星传感器提供了丰富的多尺度对地观测数据,从而形成了不同空间分辨率的影像数据层次体系,使得从定量遥感出发的NPP估算必然存在多尺度的问题.NPP遥感估算模型以不同分辨率的遥感数据(代表不同的研究尺度)作为输入参数时,得到的NPP模拟值差异明显.为了提高NPP的估算精度,需要充分认识不同分辨率的遥感数据对NPP估算结果的影响差异,即NPP的尺度效应问题.本文介绍了遥感尺度效应研究进展,多分辨率遥感数据监测NPP变化的多尺度研究进展,以及NPP估算尺度效应问题的研究进展.并分析了应用遥感技术研究NPP尺度效应的发展趋势.

... 自20世纪60年代以来,遥感技术的发展为宏观尺度草地生产力监测提供了技术支撑,尤其自多光谱影像问世以来,国内外学者围绕植被光学遥感开展了大量研究,发展了大量可实施的NPP估算模型方法^[6,7] ...

2008

0.0

. 2008, 24(1):208-212

Estimation of Chinese grassland productivity using remote sensing

基于遥感的中国草地生产力初步计算

Chen S R , Wang S X , Zhou Y

陈世荣, 王世新, 周艺

It is important to study grassland productivity for evaluating the food supply of the grassland ecosystem. Based on a 1 km Chinese land cover product and a 1 km Chinese vegetation NPP product of the year 2001 using MODIS data, the authors use several grassland productivity evaluating models to calculate some Chinese grassland productivity indexes of the year 2001. The results indicate that in 2001, Chinese dry grass yield is about 144 million tons, theoretic stock carrying capability is about 108 million sheep units, potential food supply ability is about 3089.2 thousand tons of sheep meat. The method for calculating grassland productivity using remote sensing has good mechanism and timeliness, can achieve yearly grassland productivity indexes of large area in short time, and the results match the actual distribution of Chinese grassland productivity well.

草地生产力研究对于评估草地生态系统食物供给具有重要意义。在基于MODIS的2001年1 km中国陆地生态系统土地覆盖类型产品和植被净初级生产力(NPP)产品，运用各种草地生产力计算模型，初步计算了当年中国各草地生产力指标。计算得到：2001年，中国草地生态系统产干草1.44亿t，理论载畜量为1.08亿个羊单位，潜在食物供给为羊肉308.92万t。结果表明，基于遥感的草地生产力计算方法机理性较强，现势性好，可在较短时间内获取大范围年度草地生产力指标，其计算结果较为符合中国草地生产力的实际分布情况。

2013

0.0

... 早期的模型主要利用植被指数结合实测数据进行NPP的修正和模拟^[8],近年来则将生态系统碳循环过程与遥感技术结合,建立碳通量过程的遥感模型,具代表性的有GLO-PEM^[9]、VPM^[10]、EC-LUE^[11]和CASA^[12]等,由于这类模型具有模拟生态过程、易获取基础参数等优势,被广泛应用于植被NPP的计算中 ...

... 但在区域尺度应用上述模型还需在关键参数上进行修正,以确保模型精度^[8] ...

1995

0.0

2005

0.0

2007

0.0

1993

0.0

2015

0.0

. 2015, 35(4):1079-1085 DOI:10.5846/stxb201305030909

Comprehensive estimation model of grassland NPP based on MODIS in China

基于MODIS的中国草地NPP综合估算模型

Sun C M , Sun Z G , Liu T

孙成明, 孙政国, 刘涛

Grassland ecosystem is one of the most widely distributed types in the terrestrial ecosystems. Estimating carbon storage in grassland ecosystem has been a central focus of global change researches. In order to estimate the grassland net primary productivity (NPP) quickly and reliably, based on the field survey data and the remote sensing image data of the same period, the comprehensive estimation model of grassland NPP in China was developed by using normalized difference vegetation index (NDVI) and climate data. According to the basic principles of grassland genetic and the relationship between the single factor and the NPP, through statistical analysis, the model structural factors were put forward, and then integrated together. The comprehensive model included two sub models of leaf area index (LAI) and photosynthetic accumulation (PA), and it was NPP= LAI×PA. The remote sensing data NDVI was used as a driving factor for constructing LAI sub model and it was LAI=ln(5.79×NDVI+5.91)/(2.73-2.46×NDVI). The climate data such as temperature, precipitation, and radiation were used as driving factors to construct PA sub model. In the PA sub model, there was a logarithmic relationship between the grassland NPP and mean monthly temperature, and the correlation coefficient r =0.4382 ( P n =95). There was a linear positive correlation between the grassland NPP and monthly rainfall, and the correlation coefficient r =0.6626 ( P n =95). There was an exponential relationship between the grassland NPP and radiation, and the correlation coefficient r =-0.7047 ( P n =95). So PA sub model was described as PA=ln(2+ T /18.1)×Sqrt( W /89.3)×110/Exp( R /603-0.8), where T was mean monthly temperature, W was monthly rainfall, and R was monthly radiation. The model was validated by independent measured data which was not used for constructing the model. There was a good correlation between the simulated and observed NPP values, and the R 2 was 0.8519 ( P 2 and 0.358, respectively. The small values of RMSE and RRMSE indicated that the model was reliable. The average relative error between the simulated and measured values was only 1.97%, and the model can accurately predict NPP. So it was feasible to estimate grassland NPP in China by using this model, and this model provided a new method for estimating of grassland NPP in China.

草地生态系统是陆地生态系统分布最广的生态系统类型之一,其碳储量的估算在全球变化中的作用越来越受到重视。为了快速、便捷地实现中国草地净初级生产力(NPP)的估算,在获取野外调查资料与同期遥感影像数据的基础上,利用归一化植被指数(NDVI)以及气候数据,构建了草地NPP综合估算模型。模型包括叶面积指数(LAI)和光合累积量(PA)两个子模型,其中LAI子模型利用了遥感数据NDVI,PA子模型利用了温度、降水和辐射等气候数据。通过建模以外独立的实测数据的验证,模拟值与实测值之间有很好的相关性, R 2 为0.8519,相关性达到极显著水平。RMSE和RRMSE均较小,表明模型的模拟结果比较可靠。同时模拟值与实测值之间的平均相对误差仅为1.97%,模拟结果的准确度较高,因此利用上述模型估算中国草地NPP是可行的。以上结果为中国草地NPP估算提供了新的方法。

... 针对我国植被特点,国内一批学者^[13,14,15]通过构建基于光能利用率的NPP估算模型,取得了较好的模拟精度 ...

2007

0.0

. 2007, 31(3):413-424

Estimation of net primary productivity of Chinese terrestrial vegetation based on remote sensing

中国陆地植被净初级生产力遥感估算

Zhu W Q , Pan Y Z , Zhang J S

朱文泉, 潘耀忠, 张锦水

Key Laboratory of Environmental Change and Natural Disaster of Ministry of Education, College of Resources Science and Technology, Beijing Normal University, Beijing 100875, China

Aims Net primary productivity ( NPP ) is a key component of the terrestrial carbon cycle. Model simulation is commonly used to estimate regional and global NPP given difficulties to directly measure NPP at such spatial scales. A number of NPP models have been developed in recent years as research issues related to food security and biotic response to climatic warming have become more compelling. However, large uncertainties still exist because of the complexity of ecosystems and difficulties in determining some key model parameters. Methods We developed an estimation model of NPP based on geographic information system (GIS) and remote sensing (RS) technology. The vegetation types and their classification accuracy are simultaneously introduced to the computation of some key vegetation parameters, such as the maximum value of normalized difference vegetation index (NDVI) for different vegetation types. This can remove some noise from the remote sensing data and the statistical errors of vegetation classification. It also provides a basis for the sensitivity analysis of NPP on the classification accuracy. The maximum light use efficiency ( LUE ) for some typical vegetation types in China is simulated using a modified least squares function based on NOAA/AVHRR remote sensing data and field-observed NPP data. The simulated values of LUE are greater than the value used in the CASA model and less than the values simulated with the BIOME-BGC model. The computation of the water restriction factor is driven with ground meteorological data and remote sensing data, and complex soil parameters are avoided. Results are compared with other studies and models. Important findings The simulated mean NPP in Chinese terrestrial vegetation from 1989-1993 is 3.12 Pg C (1 Pg=10 15 g). The simulated NPP is close to the observed NPP , and the total mean relative error is 4.5%for 690 NPP observation stationsdistributed in the whole country. This illustrates the utility of the model for the estimation of terrestrial primary production over regional scales.

该文在综合分析已有光能利用率模型的基础上，构建了一个净初级生产力( NPP )遥感估算模型，该模型体现了3方面的特色：1)将植被覆盖分类引入模型，并考虑植被覆盖分类精度对 NPP 估算的影响，由它们共同决定不同植被覆盖类型的归一化植被指数( NDVI )最大值；2)根据误差最小的原则，利用中国的 NPP 实测数据，模拟出各植被类型的最大光能利用率，使之更符合中国的实际情况；3)根据区域蒸散模型来模拟水分胁迫因子，与土壤水分子模型相比，这在一定程度上对有关参数实行了简化，使其实际的可操作性得到加强。模拟结果表明，1989～1993年中国陆地植被 NPP 平均值为3.12 Pg C (1 Pg=10 15 g)， NPP 模拟值与观测值比较接近，690个实测点的平均相对误差为4.5%；进一步与其它模型模拟结果以及前人研究结果的比较表明，该文所构建的 NPP 遥感估算模型具有一定的可靠性，说明在区域及全球尺度上，利用地理信息系统技术将遥感数据和各种观测数据集成在一起，并对 NPP 模型进行参数校正，基本上可以实现全球范围不同生态系统 NPP 的动态监测。

... 针对我国植被特点,国内一批学者^[13,14,15]通过构建基于光能利用率的NPP估算模型,取得了较好的模拟精度 ...

... 本研究在学习和借鉴上述研究方法的基础上,利用MODIS作为数据源,以朱文泉等^[14]构建的光能利用率模型作为NPP估测模型,在1 km#cod#x000D7 ...

... 遥感数据的投影、拼接、裁剪和格式转化等预处理工作在ENVI和ArcGIS上进行,气象数据在ANUSPLIN上进行插值,NPP利用朱文泉等^[14]开发的光能利用率模型插件进行估算 ...

... 3 草地净初级生产力计算朱文泉等^[14,15]根据中国植被实测数据,在已有模型基础上,修正了各植被类型最大光能利用率,构建了新的光能利用率模型,该模型具有符合中国植被实际情况、模型因子获取简单、可操作性强等特点,具有较高的应用价值 ...

... 本研究基于朱文泉等^[14]构建的光能利用率模型估算草地净初级生产力,公式如下: ...

2005

0.0

... 针对我国植被特点,国内一批学者^[13,14,15]通过构建基于光能利用率的NPP估算模型,取得了较好的模拟精度 ...

2013

0.0

. 2013, 22(3):6-15 DOI:10.11686/cyxb20130302

Spatio-temporal variation analysis of grassland net primary productivity and its relationship with climate over the past 10 years in Inner Mongolia

内蒙古草地生态系统近10年NPP时空变化及其与气候的关系

Mu S J , Li J L , Yang H F

穆少杰, 李建龙, 杨红飞

植被净初级生产力（ｎｅｔｐｒｉｍａｒｙｐｒｏｄｕｃｔｉｖｉｔｙ，ＮＰＰ）及其对气候变化的响应研究是全球变化的核心内容之一。通过改进的光能利用率模型（ＣＡＳＡ模型），利用ＭＯＤＩＳＮＤＶＩ数据、土地覆盖分类数据、气象数据等，逐像元模拟２００１－２０１０年内蒙古草地生态系统ＮＰＰ的时空变化，分析其对气候因子变化的响应关系。结果表明，１）２００１－２０１０年内蒙古草地多年平均ＮＰＰ为２８１．３ｇＣ／（ｍ２ ·ａ），空间分布呈由西南向东北递增的趋势，草甸草原、典型草原和荒漠草原平均ＮＰＰ分别为４３１．８，２８８．７和１２３．５ｇＣ／（ｍ２ ·ａ）；２）２００１－２０１０年间内蒙古草地ＮＰＰ总体上呈上升趋势。ＮＰＰ上升趋势最明显的草地主要分布在毛乌素沙地、浑善达克沙地、科尔沁沙地、呼伦贝尔盟和大兴安岭南麓地区，而下降趋势最明显的草地主要分布在阴山山脉和锡林郭勒盟中部的典型草原区；３）总体而言，降水量是内蒙古草地净初级生产力的主要影响因素。草甸草原ＮＰＰ与降水量、温度的关系均很密切，而且与温度的相关性更强；典型草原和荒漠草原ＮＰＰ则主要受降水量控制，其中荒漠草原ＮＰＰ与降水量的关系更密切。

... 近年来,大批学者针对内蒙古草地NPP开展了遥感监测研究^{[16,17,18,19,20]},从不同侧面增强了对内蒙古草原生态的了解,也为本研究开展大尺度草地遥感监测提供了宝贵经验 ...

... a^-1,例如,穆少杰等^[16]利用改进的CASA模型模拟的2001-2010年内蒙古草地NPP均值为281 ...

2019

0.0

... cm^-2,由东向西递增,年日照时数在2600~3400 h,自东北向西南递增^[17,18,21] ...

... 杨晗等^[17]利用改进的CASA模型模拟的2001-2016年内蒙古草地NPP均值为343 ...

2016

0.0

. 2016, 71(1):21-34 DOI:10.11821/dlxb201601002

Spatial-temporal features of carbon source-sink and its relationship with climate factors in Inner Mongolia grassland ecosystem

内蒙古草地生态系统碳源/汇时空格局及其与气候因子的关系

Dai E F , Huang Y , Wu Z

戴尔阜, 黄宇, 吴卓

1. Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China 2. Key Laboratory of Land Surface Pattern and Simulation, CAS, Beijing 100101, China 3. School of Planning, Faculty of Environment, University of Waterloo, Waterloo ON N2L 3G1, Canada 4. University of Chinese Academy of Sciences, Beijing 100049, China

In this paper, field sampling data, remote sensing data, and ground meteorological observation data were used to estimate the net primary productivity (NPP) in the grassland ecosystem in Inner Mongolia from 2001 to 2012 based on a light use efficiency model. The spatiotemporal distribution of the NEP in the Inner Mongolia grassland ecosystem was then analyzed by estimation of the NPP and soil respiration from 2001 to 2012. This paper also investigated the response of the NPP and NEP to main climatic variables on the spatial and temporal scales from 2001 to 2012. Results showed that most of the grassland area in Inner Mongolia has functioned as a carbon sink since 2001 and that the annual carbon sequestration rate amounts to 0.046 Pg C·yr -1 . The total net carbon sink of the Inner Mongolia grassland ecosystem over the 12-year period reached 0.557 Pg C. The carbon sink area accounted for 60.28% of the total grassland area and sequestered 0.692 Pg C, whereas the C source area accounted for 39.72% of the total grassland area and released 0.135 Pg C. The NPP and NEP of the Inner Mongolia grassland ecosystem have more significant correlations with precipitation than with temperature, and the Inner Mongolia grassland ecosystem has great potential for carbon sequestration.

草地净生态系统生产力(NEP)能够表征草地生态系统的固碳能力,直接定性定量地描述草地生态系统的碳源/汇性质和大小.因此,研究区域尺度草地生态系统NEP具有重要的实践意义.基于卫星遥感资料,地面气象观测资料及实地采样数据,结合光能利用率模型估算了2001-2012年内蒙古草地生态系统净初级生产力(NPP).同时,应用土壤呼吸模型估算了逐月平均土壤呼吸量(Rs),进而估算内蒙古草地净生态系统生产力(NEP).研究揭示了2001-2012年内蒙古草地生态系统NPP,NEP年际变化规律,气候因子的年际变化规律,以及草地NPP,NEP与主要气候因子的关系.结果表明:2001年以来,内蒙古草地生态系统整体发挥碳汇效应,净碳汇总量达到0.55 Pg C,年均固碳率约为0.046 Pg C/a;研究区大部分草地NPP,NEP与降水均呈正相关关系,与温度相关性不显著,内蒙古草地生态系统仍有巨大的固碳潜力.

... cm^-2,由东向西递增,年日照时数在2600~3400 h,自东北向西南递增^[17,18,21] ...

2008

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2005

0.0

. 2005, 9(3):300-307 DOI:10.11834/jrs.20050344

Estimating net primary productivity of terrestrial vegetation based on remote sensing: A case study in Inner Mongolia, China

基于GIS和RS的区域陆地植被NPP估算#cod#x02014;#cod#x02014;以中国内蒙古为例

Zhu W Q , Pan Y Z , Long Z H

朱文泉, 潘耀忠, 龙中华

According to recent studies that there are important differences in maximum light utiliazion efficiency(εmax)\namong vegetation types,an estimation model of net primary productivity (NPP),based on geographic information system\n(GIS)and remote sensing (RS)technology,is presented.This model has two significant characteristics;(1)NPPcan be\nestimated just using ground meteorological data and remote sensing data.It is relatively easier to acquire data and its ap-\nplication can be enhanced.(2)Afterthe validationwith observed data and the comparisonwith otherNPPmodels,the re-\nsults showed that the predictedNPPwas consistentwith observed values,and it can more actually reflect the forestNPP\nthan Chikugo model.In order to validate theNPPmodel,a case study in InnerMongolia,China,was carried out.The re-\nsults showed that the total annualNPPin InnerMongolia in 2002 was 390.8 Mt C.The spatial changes ofNPPwere re-\nmarkable,and it decreased from northeast toward southwest .Moreover,seasonal variations ofNPPwere also large.Itwas\nabout 72.7% of the total annualNPPin the three month of June,July and August,and theNPPvalues was very low\n(3.59 Mt C per month) in January and February.

在GIS的支持下,利用地面气象数据和MODIS数据,考虑到最大光利用率在不同植被类型中的差异,构建了一个区域陆地植被NPP估算模型,并以2002年的内蒙古植被为例,研究了植被净初级生产力及其时空分布。结果表明:(1)该模型在数据获取了上比较容易,仅利用地面气象数据和遥感数据就可以对陆地植被NPP进行估算,使其实际的可操作性得到加强。(2)通过与NPP的实测资料及其他模型的对比研究表明:该模型对区域陆地值被NPP的模拟效果较好,与Chikugo模型相比,它更能反应森林NPP的实际情况。(3)2002年内蒙古植被净初级生产力为390.8MtC/a,总体分布趋势是由东北向西南递减,其季节变化也非常明显,在6月中旬至9月中旬的3个月时间里,NPP占了全年的72.7%,而1―2月份植物基本停止生长,净初级生产力极低,每月仅为3.59MtC。

... 朱文泉等^[20]利用光能利用率模型计算的2002年内蒙古草地NPP为259 ...

1990

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... 4%^[21] ...

... cm^-2,由东向西递增,年日照时数在2600~3400 h,自东北向西南递增^[17,18,21] ...

... 内蒙古土壤类型主要以草原土为主,自东向西依次分布黑土带-黑钙土带-栗钙土带-棕钙土带-漠钙土带-灰棕钙土带^[21] ...

... 根据第一次全国草地资源普查和《中国草地分类原则与分类系统》,内蒙古天然草原可划分为温性草甸草原类、温性草原类、温性荒漠草原类、温性草原化荒漠类、温性荒漠类、低地草甸类、山地草甸类和沼泽类8个大类、21个亚类以及476个草地型^[21](图1) ...

1996

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. 1996, 16(5):497-508

Biomass and net production of forest vegetation in China

我国森林植被的生物量和净生产量

Fang J Y , Liu G H , Xu S L

方精云, 刘国华, 徐嵩龄

Method for estimating biomass and net production of forest vegetation from stem volume of stand was proposed in this paper, and biological production all over China was estimated by using this methed. As a result, average biomass was smaller, and mean net preduction was higher in China than mean values of the world. Total biomass in Chinese forest vegetation was 9102. 9 × 106 t, of which 8592. 1 × 106 t for stands, 325. 7 × 106 t for economic forest, 185. 0 × 106 t for bamboo forests and 790. 5 × 10' t for ...

利用森林蓄积量推算森林生物量和净生产量的方法，系统研究了我国森林植被的生物生产力。结果表明，我国森林生物生产力的地理分布规律与世界总趋势一致，但量上有差异，具体表现在：我国森林生物量的平均值小于世界平均水平，而净生产量却显得较高；我国森林的总生物量是９１０２．８７×１０６ｔ，其中，林分为８５９２．１３×１０６ｔ，经济林３２５．７２×１０６ｔ；竹林１８５．０２×１０６ｔ，疏林、灌木林７９０．５４×１０６ｔ；森林和疏林（含灌木林）的总生产力分别是１１７７．３１×１０６ｔ／ａ和４５８．１６×１０６ｔ／ａ。研究结果还显示，用材积推算的生物量（材积源生物量）比用平均生物量计算的结果更符合实际。分析中国森林在中国及全球陆地碳库中的作用发现，与其他区域和世界平均水平相比较，中国森林在中国陆地植被中所起的主导作用较弱，它的生物量不足全球森林总生物量的１％，然而，它在保护中国土壤碳库功能方面起着其他植被类型所无法替代的作用。

... 45的系数^[22] ...

2000

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... 4 草原植被NPP对气候因子的响应水热是植被赖以生存的必要条件,水热供给不足会导致植被长势的下降以及植被种群退化^[23] ...

2015

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. 2015, 48(18):3719-3726 DOI:10.3864/j.issn.0578-1752.2015.18.015

Reflections on establishing a long-term mechanism of grassland ecological compensation in China

建立中国草原生态补偿长效机制的思考

Wei Q , Hou X Y

魏琦, 侯向阳

Chinese Academy of Agricultural Sciences, Beijing 100081

Ecological compensation is an important environmental economic policy for ecological environment protection, ecological civilization construction and ecological resources sustainable development. How to establish an equitable and efficient long-term mechanism of ecological compensation is a challenging long-term research issue in the theory and practice of ecological compensation at home and abroad, which is related to some key problems, including direction and focus of compensation policy, the effect and efficiency of policy implementation, ecological civilization construction and sustainable development. Extensive grasslands are important for producing livestock base, biodiversity conservation center, ecological safety shelter zone and food safety grounding. The grassland ecological compensation has been preliminarily established, both investment scale and coverage are larger, and obtained significant achievements, but the grassland ecological environment situation that the partial better and in whole worse has still no fundamental change. Therefore, discussing and establishing the ecological compensation mechanism, combining fairness with long-term efficiency, which is a vital measure for the coordination of multiple functions of grassland resources to achieve “win-win” outcomes for production, life and ecosystems, to ensure the sustainability of ecological resource protection and utilization. The study summarized the concept and theory of ecological compensation, the development trend of long-term mechanisms at home and abroad, demonstrated establishing the long-term mechanism of ecological compensation was very important for ecological environment protection and famers become rich. Based on field investigate on different grassland regional implementations of grasslands ecological compensation and analyzed the Herders’ production decision inherent behavior on grassland ecological compensation effects and the current implementation effects, the study considered the major challenges to grassland ecological compensation in China as follows: long-term debt leads to grassland ecological management so difficult. The grassland ecological investments are less and cycle shorter so that is difficult to effectively consolidate protection results. Herders have desirable stocking rate and inertia overstocking which affects livestock reduction for ecological compensation. The study proposes to further establish the policy suggestion for long-term mechanism of ecological compensation in accordance with the national situation of China, the main suggestions include as follows: elongate the period of ecological compensation policy, increase the award fund, implement diversified adaptive livestock reduction model, develop the grassland ecological animal husbandry management pattern and strengthen the institutional guarantee system of grassland animal husbandry. Objectives were to provide a theoretical basis and practical support for the scientific protection of fragile ecological resources, sustainable exploitation and utilization of grassland resources and ecological civilization construction in China.

生态补偿是生态环境保护、生态文明建设、生态资源可持续开发的重要环境经济政策。如何建立公平和效率相统一的生态补偿长效机制,是国内外生态补偿理论和实践中的一个具有长期挑战性的课题,关系着补偿政策的方向和重点、政策实施的效果和效率、生态文明建设和可持续发展的永续性的关键问题。草原作为中国重要的畜牧业生产基地、生物多样性保存中心、生态安全屏障和食物安全的接续地,草原生态补偿机制已初步建立,投资规模和覆盖面均较大,并已取得明显成效,但草原生态环境“局部好转、总体恶化”的形势仍然没有根本转变。因此,探讨和建立公平性和长效性相结合的生态补偿长效机制,是协调草原资源的多重功能、实现生态生产生活“多赢”、确保草原资源保护利用可持续性的重要手段。笔者通过对国内外生态补偿概念、理论和长效机制发展趋势的分析,阐述建立生态补偿长效机制在生态环境保护和农牧民致富中的必要性。通过对不同草原区域实施草原生态补偿进行实地调研、对牧户固有的生产决策行为对草原生态补偿效果的影响进行分析,以及对中国当前草原生态补偿政策实施效果分析,认为目前草原生态补偿存在如下主要问题：长期欠账,草原生态治理难度巨大；草原生态投入少、周期短,保护成果尚难以得到有效巩固；牧民存在心理载畜率和超载惯性,对生态补偿减畜产生影响。针对以上问题,提出进一步建立符合中国国情的草原生态补偿长效机制的政策建议：延长草原生态补奖政策期限；增加草原生态补奖经费；实行多样化的适应性减畜模式；大力发展草原生态畜牧业经营模式和加强草原畜牧业制度保障体系。旨在为中国脆弱性生态资源的科学保护和草原资源可持续开发利用以及生态文明建设提供理论依据和实践支撑。

... 此外,在实施草原生态保护补助奖励政策之前,超载过牧等不合理利用现象严重,不少地方载畜量长期高于牧草理论载畜量,导致草地大面积退化和沙化^[24,25,26] ...

2016

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2019

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