2001-2013年中国灌木生态系统净初级生产力的时空变化特征及其对气候变化的响应

doi:10.17521/cjpe.2016.0177

摘要/Abstract

摘要：

植被净初级生产力(NPP)是陆地生态系统碳库的主要来源, NPP的变化反映了生态系统对气候变化及土地利用变化的响应。在我国广泛地分布着相当于国土面积20%的灌木林, 其NPP在中国陆地生态系统碳平衡过程中发挥着重要作用。该文利用CASA (Carnegie-Ames-Stanford Approach)模型估算了中国6类主要灌木生态系统2001-2013年的NPP, 并分析了其季节和年际间的变化趋势及其与气候变化之间的关系。结果显示: 中国灌木生态系统的年平均NPP为281.82 g•m^-2•a^-1, 其中亚热带常绿灌木年平均NPP最高为420.47 g•m^-2•a^-1, 而高寒荒漠灌木半灌木年平均NPP最低为52.65 g•m^-2•a^-1。在2001-2013年间, 中国灌木生态系统的NPP以1.23 g•m^-2•a^-1的速度显著增加, 其相对变化速率达到了5.99%, 其中高寒荒漠灌木半灌木、温带荒漠灌木半灌木、温带落叶灌木以及亚热带常绿灌木的NPP都显著增加, 温带落叶灌木的NPP增长最快, 达到3.05 g•m^-2•a^-1, 亚高山常绿灌木则以0.73 g•m^-2•a^-1的速率显著下降, 亚高山落叶灌木则无显著变化趋势。不同灌木生态系统的NPP对不同季节气候变化的响应不同, 但总体上中国灌木生态系统NPP的变化更多受到降水变化的影响, 此外, 春季气温升高也对NPP的增加起到积极的促进作用。

关键词: CASA模型, 净初级生产力, 灌木, 碳平衡, 气候变化

Abstract:

Aims Net primary production (NPP) is the input to terrestrial ecosystem carbon pool. Climate and land use change affect NPP significantly. Shrublands occupy more than 20% of the terrestrial area of China, and their NPP is comparable to those of the forests. Our objective was to estimate China shrubland NPP from 2001 to 2013, and to analyze its variation and response to climate change.Methods We used a Carnegie-Ames-Stanford Approach (CASA) model to estimate the NPP of six shrubland types in China from 2001 to 2013. Furthermore, we used Theil-Sen slope combined with Mann-kendall test to analyze its spatial variation and a linear regression of one-variable model to analyze its inter- and intra-annual variation. Finally, a multi-factor linear regression model was used to analyze its response to climate change.Important findings We found the annual mean NPP of China shrubland was 281.82 g•m^-2•a^-1. The subtropical evergreen shrubland has the maximum NPP of 420.47 g•m^-2•a^-1, while the high cold desert shrubland has the minimum NPP of 52.65 g•m^-2•a^-1. The countrywide shrublands NPP increased at the rate of 1.23 g•m^-2•a^-1, the relative change rate was 5.99%. The temperate deciduous shrubland NPP increased the fastest with a speed of 3.05 g•m^-2•a^-1 and subalpine evergreen shrubland had a decreasing trend with a speed of -0.73 g•m^-2•a^-1. Moreover, the other four shrublands NPP had a growing trend, only subalpine deciduous shrubland NPP did not change significantly. The response of NPP to climate change of different seasons varies to different shrubland types. In general, the NPP variation was mainly affected by precipitation, and the spring warming also contributed to it. The increase of countrywide shrubland NPP may promote its contribution to the regional ecosystem function.

Key words: CASA model, net primary production (NPP), shrub, carbon balance, climate change

王亚林, 龚容, 吴凤敏, 范文武. 2001-2013年中国灌木生态系统净初级生产力的时空变化特征及其对气候变化的响应. 植物生态学报, 2017, 41(9): 925-937. DOI: 10.17521/cjpe.2016.0177

Ya-Lin WANG, Rong GONG, Feng-Min WU, Wen-Wu FAN. Temporal and spatial variation characteristics of China shrubland net primary production and its response to climate change from 2001 to 2013. Chinese Journal of Plant Ecology, 2017, 41(9): 925-937. DOI: 10.17521/cjpe.2016.0177

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链接本文: https://www.plant-ecology.com/CN/10.17521/cjpe.2016.0177

https://www.plant-ecology.com/CN/Y2017/V41/I9/925

图/表 11

表1 不同灌木类型的实际面积及实际计算的面积

Table 1 The actual area and actual calculated area of different shrubland types

	DCDSMT	DCDSTP	DSRTHC	DSRTTP	EVGNMT	EVGNST
实际面积 Actual area (km²)	87 701	163 077	113 031	1 068 218	188 952	467 142
实际计算面积 Actual calculated area (km²)	81 029	153 349	12 409	203 125	178 435	449 461

表2 中国灌木生态系统2001-2013年间平均净初级生产力和平均净初级生产力总量(平均值±标准偏差)

Table 2 China shrubland mean net primary production and mean total net primary production from 2001 to 2013 (mean ± SD)

灌木类型 Shrubland type	平均净初级生产力 Mean net primary production (g•m^-2•a^-1)	平均净初级生产力总量 Mean total net primary production (Tg)
DCDSMT	252.28 ± 8.64	20.44 ± 0.70
DCDSTP	247.24 ± 14.12	37.91 ± 2.17
DSRTHC	52.65 ± 3.05	0.65 ± 0.04
DSRTTP	72.33 ± 5.67	14.69 ± 1.15
EVGNMT	288.07 ± 11.84	51.40 ± 2.11
EVGNST	420.47 ± 16.96	188.98 ± 7.62
CONTRY	281.82 ± 10.13	302.94 ± 10.89

表3 中国灌木生态系统2001-2013年间净初级生产力空间变化趋势统计结果

Table 3 Statistical results of China shrubland net primary production spatial variation from 2001 to 2013

TS	Z	净初级生产力的变化趋势 Trend of net primary production	占总面积比例 Percentage of total area (%)
>0	>1.96	显著增加 Significantly increased	13.14
>0	-1.96-1.96	不显著增加 Insignificantly increased	58.09
0	-1.96-1.96	基本不变 Essentially unchanged	0.01
<0	-1.96-1.96	不显著减小 Insignificantly decreased	26.81
<0	<-1.96	显著减小 Significantly decreased	1.95

图1 中国灌木生态系统2001-2013年间净初级生产力(NPP)变化速率空间分布。图中的圈代表不同灌木类型的分布区域。DCDSMT、DCDSTP、DSRTHC、DSRTTP、EVGNMT和EVGNST分别代表亚高山落叶灌木、温带落叶灌木、高寒荒漠灌木半灌木、温带荒漠灌木半灌木、亚高山常绿灌木和亚热带常绿灌木。亚高山落叶灌木和亚高山常绿灌木用一个圈表示, 是因为两者之间没有明显的分界线, 亚高山落叶灌木主要分布在圆圈的上半部分, 而亚高山常绿灌木则主要分布在下半部分。

Fig. 1 Spatial distribution of China shrubland net primary production (NPP) change rate from 2001 to 2013. The circles indicate the distribution of different shrubland types. DCDSMT, DCDSTP, DSRTHC, DSRTTP, EVGNMT and EVGNST represent subalpine deciduous, temperate deciduous, high cold desert, temperate desert, subalpine evergreen, and subtropical evergreen shrubland, respectively. DCDSMT and EVGNMT are in one circle because there is no clear boundary between them, DCDSMT mainly distributed in the upper half of the circle and EVNGMT distributed in the bottom half.

图2 中国灌木生态系统2001-2013年间净初级生产力(NPP)变化趋势的空间分布。

Fig. 2 Spatial characteristics of China shrubland net primary production (NPP) trend from 2001 to 2013.

表4 中国灌木生态系统2001-2013年间净初级生产力(NPP)的年际和季节变化趋势

Table 4 Annual and seasonal trend of shrubland net primary production (NPP) in China from 2001 to 2013

灌木类型 Shrubland type	年际变化 Interannual change		春 Spring	夏 Summer	秋 Autumn	冬 Winter
灌木类型 Shrubland type	k (g•m^-2•a^-1)	ΔR (%)	k (g•m^-2•a^-1)
DCDSMT	0.37	2.02	0.16	0.39	-0.21	NA
DCDSTP	3.05^***	17.68	0.61^***	1.90^**	0.36^**	NA
DSRTHC	0.56^***	15.58	0.10^***	0.45^***	0.02	NA
DSRTTP	0.97^**	19.95	0.09^*	0.69^**	0.09^**	NA
EVGNMT	-0.73^*	-3.26	-0.07	0.12	-0.64^***	-0.01
EVGNST	1.76^**	5.71	0.83^*	0.31	0.66^**	-0.00
CONTRY	1.23^**	5.99	0.43^**	0.61^*	0.22^*	-0.00

表5 本文结果与其他研究结果的比较

Table 5 Comparisons with other study results

年份 Year	最大光能利用率 Maximum light use efficiency	净初级生产力 Net primary production (g•m^-2•a^-1)	标准化 Standardization	参考文献 Reference
2001-2013	0.429	281.82	281.82	本文 This study
1982-1999	0.405	257.80	273.08	Piao et al., 2005
1989-1993	0.429	367.70	367.70	Zhu et al., 2007
2001	0.389	362.38	399.64	Li, 2004

图3 中国灌木生态系统2001-2013年间平均净初级生产力的空间分布。

Fig. 3 Spatial distribution of shrubland annual mean net primary production in China from 2001 to 2013.

表6 中国灌木生态系统2001-2013年间降水量和平均气温的变化趋势

Table 6 Temporal trend of China shrubland precipitation and mean temperature from 2001 to 2013

灌木类型 Shrubland type	平均气温变化速率 Mean temperature change rate (℃∙a^-1)					降水量变化速率 Precipitation change rate (mm∙a^-1)
灌木类型 Shrubland type	年 Annual	春 Spring	夏 Summer	秋 Autumn	冬 Winter	年 Annual	春 Spring	夏 Summer	秋 Autumn	冬 Winter
DCDSMT	0.026 2	0.068 7^**	0.079 9^**	0.011 1	-0.005 6	2.94^*	0.53	1.97	0.54	0.26
DCDSTP	-0.048 6^*	-0.045 1	0.016 7	-0.009 1	-0.013 0^***	7.57^**	0.90	5.24^**	0.77	1.04^**
DSRTHC	0.020 7	0.060 7^*	0.043 5^***	0.040 6^*	-0.019 0	1.34^**	0.24	0.64	0.07	0.17^**
DSRTTP	-0.009 9	0.082 3	-0.013 0	0.032 0	-0.069 8^**	0.38	-0.28	1.11	-0.11	0.32
EVGNMT	0.030 3	0.053 3^*	0.079 8^**	0.006 3	0.001 2	-4.10^*	-0.29	-3.24	-0.32	-0.36
EVGNST	-0.016 7	-0.004 5	0.038 0^**	-0.001 7	-0.075 9^*	-4.22	-0.81	-7.67^*	5.21^**	-2.46^**
CONTRY	-0.006 6	0.039 9	0.018 3	-0.002 0	-0.081 1^**	-0.02	-0.24	-0.80	1.25^**	-0.49^**

表7 不同灌木生态系统年净初级生产力对季节降水和季节平均气温进行回归的系数

Table 7 Regression coefficients of annual net primary production on seasonal mean temperature and precipitation

灌木类型 Shrubland type	截距 Intercept	气温系数Air temperature coefficients (g∙m^-2∙a^-1∙℃^-1)				降水量系数Precipitation coefficients (g∙m^-2∙a^-1∙mm^-1)
灌木类型 Shrubland type	截距 Intercept	春 Spring	夏 Summer	秋 Autumn	冬 Winter	春 Spring	夏 Summer	秋 Autumn	冬 Winter
DCDSMT	199.60^***		7.68^***		-19.31^***	-1.19^***	0.08^**	-0.51^***
DCDSTP	91.12^***	3.76^***			7.83^***		0.51^***		-0.40^***
DSRTHC	7.45	1.62^**				0.17^*	0.26^***
DSRTTP	46.70^***					0.20^**	0.26^***	-0.14^*
EVGNMT	554.26 ^***			-8.15^**	-9.97^***	-0.24^**	-0.29^***	-0.21^**	-1.45^***
EVGNST	-86.92	43.47^***		-10.19^***	2.57^*	-0.21^***	-0.10^***	0.23^***	-0.35^***

图4 净初级生产力与气候因子回归模型预测值与CASA模型估算值的对比图。DCDSMT、DCDSTP、DSRTHC、DSRTTP、EVGNMT和EVGNST分别代表亚高山落叶灌木、温带落叶灌木、高寒荒漠灌木半灌木、温带荒漠灌木半灌木、亚高山常绿灌木和亚热带常绿灌木。

Fig. 4 Regression of annual net primary production of the six shrubland types on pertinent climate variables: Regression predicted vs. simulated values. DCDSMT, DCDSTP, DSRTHC, DSRTTP, EVGNMT and EVGNST represent subalpine deciduous, temperate deciduous, high cold desert, temperate desert, subalpine evergreen and subtropical evergreen shrubland, respectively.

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