青藏高原矮嵩草草甸地下和地上生物量分配格局及其与气象因子的关系
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摘要
基于2006—2015年青海海北站10年生物量及气候因子监测数据,分析了青藏高原高寒矮嵩草草甸生物量的季节及年际动态,并探讨了气候因子对其影响。结果表明:(1)季节尺度上,高寒矮嵩草草甸地上生物量表现为单峰变化曲线,8月为其峰值点,为(345.72±27.01) g/m~2,代表了高寒草甸的地上净初级生产力。而地下根系的现存量变化较为复杂,其中5—7月呈现持续上升趋势,8月快速下降,之后9月份急剧,且各月份之间未达到显著水平(P>0.05);年际尺度上,10年间高寒矮嵩草草甸地上生物量整体呈现波动增加趋势,2014年为其峰值点,达(437.12±32.01) g/m~2。地下生物量呈现波动性变化,变异较大,10年间平均值为(2566.99±138.11) g/m~2;(2)高寒草甸光合产物分配主要分布在地下,80%地下根系生物量分布于地表0—10 cm土层,且不同土层根系生物量占总地下生物量的比值在不同月份较为稳定。(3)气候因子中,大气相对湿度是影响高寒草甸地上生物量大小的主要因素;而气候因子对地下根系生物量的影响极为微弱。研究表明,高寒嵩草草甸对环境变化具有较高的自我调节能力,且高寒草甸的演化受制于人类干扰,而非气候变化。
Qinghai-Tibetan Plateau is the highest and largest plateau on earth,and almost 60% of its area is occupied by natural alpine grassland(alpine steppe and meadow). Owing to its unique climatic conditions,together with little human disturbance,it provides a unique opportunity to test the above-and belowground biomass allocation patterns and its response to meteorological factors. In the past,many studies have been conducted between above-and belowground biomass and environmental factors on alpine meadows in the Qinghai-Tibet plateau,but large uncertainties still exist owing to thedifficulty determining belowground biomass. Therefore,the allocation between above-and belowground biomass is still a central issue in plant ecology. In this study,we examined seasonal and interannual variations in biomass based on long-term monitoring data sets. Moreover,a general regression analysis was applied to examine the relationship between above-and belowground biomass and meteorological factors. The results showed that(1) at a seasonal scale,the aboveground biomass showed a unimodal relationship from May to August,with a peak in August(345.7±27.01) g/m~2 that represented the net primary productivity of alpine meadows,which then decreased from August to September. Thebelowground biomass was relatively complex than the aboveground biomass,which increased from May to July and decreased rapidly in August; no significant difference was observed in the belowground biomass among these months. At an interannual scale,aboveground biomass showed a significant increased trend during 2005—2015,reaching a maximum in 2014(437.12±32.01) g/m~2. The belowground biomass was relatively stable during 2005—2015,but the year-to-year variations in belowground biomass was larger than that of the aboveground biomass(CV = 24.30%); the 10-year average of belowground biomass was(2566.58±138.11) g/m~2;(2) the photosynthetic products were mainly distributed in the belowground biomass,with 80% root biomass distributed in the 0—10 cm soil layer. In addition,the distributed fraction was relatively stable across all soil depths(0—10,10—20,20—30,and 20—40 cm) among months;(3) the air relatively humidity was the most important factor affecting aboveground biomass,whereas the belowground biomass was less affected by climatic factors. Our results suggest that the alpine meadow ecosystem has a high self-regulation ability against environmental factors,and the evolution of alpine meadows is subject to the interference of human activities rather than climate change.
Qinghai-Tibetan Plateau is the highest and largest plateau on earth,and almost 60% of its area is occupied by natural alpine grassland(alpine steppe and meadow). Owing to its unique climatic conditions,together with little human disturbance,it provides a unique opportunity to test the above-and belowground biomass allocation patterns and its response to meteorological factors. In the past,many studies have been conducted between above-and belowground biomass and environmental factors on alpine meadows in the Qinghai-Tibet plateau,but large uncertainties still exist owing to thedifficulty determining belowground biomass. Therefore,the allocation between above-and belowground biomass is still a central issue in plant ecology. In this study,we examined seasonal and interannual variations in biomass based on long-term monitoring data sets. Moreover,a general regression analysis was applied to examine the relationship between above-and belowground biomass and meteorological factors. The results showed that(1) at a seasonal scale,the aboveground biomass showed a unimodal relationship from May to August,with a peak in August(345.7±27.01) g/m~2 that represented the net primary productivity of alpine meadows,which then decreased from August to September. Thebelowground biomass was relatively complex than the aboveground biomass,which increased from May to July and decreased rapidly in August; no significant difference was observed in the belowground biomass among these months. At an interannual scale,aboveground biomass showed a significant increased trend during 2005—2015,reaching a maximum in 2014(437.12±32.01) g/m~2. The belowground biomass was relatively stable during 2005—2015,but the year-to-year variations in belowground biomass was larger than that of the aboveground biomass(CV = 24.30%); the 10-year average of belowground biomass was(2566.58±138.11) g/m~2;(2) the photosynthetic products were mainly distributed in the belowground biomass,with 80% root biomass distributed in the 0—10 cm soil layer. In addition,the distributed fraction was relatively stable across all soil depths(0—10,10—20,20—30,and 20—40 cm) among months;(3) the air relatively humidity was the most important factor affecting aboveground biomass,whereas the belowground biomass was less affected by climatic factors. Our results suggest that the alpine meadow ecosystem has a high self-regulation ability against environmental factors,and the evolution of alpine meadows is subject to the interference of human activities rather than climate change.
引文
[1] Wang L,Niu K C,Yang Y H,Zhou P. Patterns of above-and belowground biomass allocation in China's grasslands:evidence from individual-level observations. Science China Life Sciences,2010,53(7):851-857.
[2] Wilson J B. A review of evidence on the control ofshoot:root ratio,in relation to models. Annals of Botany,1988,61(4):433-449.
[3] Yang Y H,Fang J Y,Ma W H,Guo D L,Mohammat A. Large-scale pattern of biomass partitioning across China's grasslands. Global Ecology and Biogeography,2010,19(2):268-277.
[4] Yang Y H,Fang J Y,Ji C Y,Han W X. Above-and belowground biomass allocation in Tibetan grasslands. Journal of Vegetation Science,2009,20(1):177-184.
[5] Gill R A,Kelly R H,Parton W J,Day K A,Jackson R B,Morgan J A,Scurlock J M O,Tieszen L L,Castle J V,Ojima D S,Zhang X S. Using simple environmental variables to estimate below-ground productivity in grasslands. Global Ecology and Biogeography,2002,11(1):79-86.
[6]周广胜,王玉辉,蒋延玲.全球变化与中国东北样带(NECT).地学前缘,2002,9(1):198-216.
[7]白永飞,李凌浩,王其兵,张丽霞,张焱,陈佐忠.锡林河流域草原群落植物多样性和初级生产力沿水热梯度变化的样带研究.植物生态学报,2000,24(6):667-673.
[8]韩彬,樊江文,钟华平.内蒙古草地样带植物群落生物量的梯度研究.植物生态学报,2006,30(4):553-562.
[9]王艳芬,汪诗平.不同放牧率对内蒙古典型草原地下生物量的影响.草地学报,1999,7(3):198-203.
[10]孙鸿烈,郑度,姚檀栋,张镱锂.青藏高原国家生态安全屏障保护与建设.地理学报,2012,67(1):3-12.
[11]林丽,张德罡,曹广民,欧阳经政,刘淑丽,张法伟,李以康,郭小伟.高寒嵩草草甸植物群落数量特征对不同利用强度的短期响应.生态学报,2016,36(24):8034-8043.
[12]杨秀静,黄玫,王军邦,刘洪升.青藏高原草地地下生物量与环境因子的关系.生态学报,2013,33(7):2032-2042.
[13]王代军,黄文惠,苏加楷.多年生黑麦草和白三叶人工草地生物量动态研究.草地学报,1995,3(2):135-143.
[14]杨福囤,王启基,史顺海.青海海北地区矮嵩草草甸生物量和能量的分配.植物生态学与地植物学学报,1987,(2):106-112.
[15]乐炎舟,鲍新奎,张金霞,赵宝莲.高山草甸土营养物质与植物生长关系的研究.中国草原,1980,(3):28-33,19-19.
[16] Jiang C M,Yu G R,Li Y N,Cao G M,Yang Z P,Sheng W P,Yu W T. Nutrient resorption of coexistence species in alpine meadow of the Qinghai-Tibetan Plateau explains plant adaptation to nutrient-poor environment. Ecological Engineering,2012,44:1-9.
[17] Xu M H,Peng F,You Q G,Guo J,Tian X F,Xue X,Liu M. Year-round warming and autumnal clipping lead to downward transport of root biomass,carbon and total nitrogen in soil of an alpine meadow. Environmental and Experimental Botany,2015,109:54-62.
[18]王敏,苏永中,杨荣,杨晓.黑河中游荒漠草地地上和地下生物量的分配格局.植物生态学报,2013,37(3):209-219.
[19]李以康,林丽,张法伟,梁东营,王溪,曹广民.小嵩草群落——高寒草甸地带性植被放牧压力下的偏途顶极群落.山地学报,2010,28(3):257-265.
[20]曹广民,杜岩功,梁东营,王启兰,王长庭.高寒嵩草草甸的被动与主动退化分异特征及其发生机理.山地学报,2007,25(6):641-648.
[21]曹广民,龙瑞军.放牧高寒嵩草草甸的稳定性及自我维持机制.中国农业气象,2009,30(4):553-559.
[22]李凯辉,王万林,胡玉昆,高国刚,公延明,尹伟.不同海拔梯度高寒草地地下生物量与环境因子的关系.应用生态学报,2008,19(11):2364-2368.
[23]朱宝文,周华坤,徐有绪,李英年,唐凯.青海湖北岸草甸草原牧草生物量季节动态研究.草业科学,2008,25(12):62-66.
[24]白永飞,许志信,李德新.羊草草原群落生物量季节动态研究.中国草地,1994,(3):1-5,9-9.
[25] Schenk H J,Jackson R B. The global biogeography of roots.Ecological Monographs,2002,72(3):311-328.
[26]方长明.相对稳定的草地生态系统碳库.中国科学:生命科学,2011,41(4):340-342.
[27] Lin L,Li Y K,Xu X L,Zhang F W,Du Y G,Liu S L,Guo X W,Cao G M. Predicting parameters of degradation succession processes of Tibetan Kobresia grasslands.Solid Earth,2015,6(4):1237-1246.
[28] Qiao N,Xu X L,Cao G M,Ouyang H,Kuzyakov Y. Land use change decreases soil carbon stocks in Tibetan grasslands. Plant and Soil,2015,395(1/2):231-241.
[2] Wilson J B. A review of evidence on the control ofshoot:root ratio,in relation to models. Annals of Botany,1988,61(4):433-449.
[3] Yang Y H,Fang J Y,Ma W H,Guo D L,Mohammat A. Large-scale pattern of biomass partitioning across China's grasslands. Global Ecology and Biogeography,2010,19(2):268-277.
[4] Yang Y H,Fang J Y,Ji C Y,Han W X. Above-and belowground biomass allocation in Tibetan grasslands. Journal of Vegetation Science,2009,20(1):177-184.
[5] Gill R A,Kelly R H,Parton W J,Day K A,Jackson R B,Morgan J A,Scurlock J M O,Tieszen L L,Castle J V,Ojima D S,Zhang X S. Using simple environmental variables to estimate below-ground productivity in grasslands. Global Ecology and Biogeography,2002,11(1):79-86.
[6]周广胜,王玉辉,蒋延玲.全球变化与中国东北样带(NECT).地学前缘,2002,9(1):198-216.
[7]白永飞,李凌浩,王其兵,张丽霞,张焱,陈佐忠.锡林河流域草原群落植物多样性和初级生产力沿水热梯度变化的样带研究.植物生态学报,2000,24(6):667-673.
[8]韩彬,樊江文,钟华平.内蒙古草地样带植物群落生物量的梯度研究.植物生态学报,2006,30(4):553-562.
[9]王艳芬,汪诗平.不同放牧率对内蒙古典型草原地下生物量的影响.草地学报,1999,7(3):198-203.
[10]孙鸿烈,郑度,姚檀栋,张镱锂.青藏高原国家生态安全屏障保护与建设.地理学报,2012,67(1):3-12.
[11]林丽,张德罡,曹广民,欧阳经政,刘淑丽,张法伟,李以康,郭小伟.高寒嵩草草甸植物群落数量特征对不同利用强度的短期响应.生态学报,2016,36(24):8034-8043.
[12]杨秀静,黄玫,王军邦,刘洪升.青藏高原草地地下生物量与环境因子的关系.生态学报,2013,33(7):2032-2042.
[13]王代军,黄文惠,苏加楷.多年生黑麦草和白三叶人工草地生物量动态研究.草地学报,1995,3(2):135-143.
[14]杨福囤,王启基,史顺海.青海海北地区矮嵩草草甸生物量和能量的分配.植物生态学与地植物学学报,1987,(2):106-112.
[15]乐炎舟,鲍新奎,张金霞,赵宝莲.高山草甸土营养物质与植物生长关系的研究.中国草原,1980,(3):28-33,19-19.
[16] Jiang C M,Yu G R,Li Y N,Cao G M,Yang Z P,Sheng W P,Yu W T. Nutrient resorption of coexistence species in alpine meadow of the Qinghai-Tibetan Plateau explains plant adaptation to nutrient-poor environment. Ecological Engineering,2012,44:1-9.
[17] Xu M H,Peng F,You Q G,Guo J,Tian X F,Xue X,Liu M. Year-round warming and autumnal clipping lead to downward transport of root biomass,carbon and total nitrogen in soil of an alpine meadow. Environmental and Experimental Botany,2015,109:54-62.
[18]王敏,苏永中,杨荣,杨晓.黑河中游荒漠草地地上和地下生物量的分配格局.植物生态学报,2013,37(3):209-219.
[19]李以康,林丽,张法伟,梁东营,王溪,曹广民.小嵩草群落——高寒草甸地带性植被放牧压力下的偏途顶极群落.山地学报,2010,28(3):257-265.
[20]曹广民,杜岩功,梁东营,王启兰,王长庭.高寒嵩草草甸的被动与主动退化分异特征及其发生机理.山地学报,2007,25(6):641-648.
[21]曹广民,龙瑞军.放牧高寒嵩草草甸的稳定性及自我维持机制.中国农业气象,2009,30(4):553-559.
[22]李凯辉,王万林,胡玉昆,高国刚,公延明,尹伟.不同海拔梯度高寒草地地下生物量与环境因子的关系.应用生态学报,2008,19(11):2364-2368.
[23]朱宝文,周华坤,徐有绪,李英年,唐凯.青海湖北岸草甸草原牧草生物量季节动态研究.草业科学,2008,25(12):62-66.
[24]白永飞,许志信,李德新.羊草草原群落生物量季节动态研究.中国草地,1994,(3):1-5,9-9.
[25] Schenk H J,Jackson R B. The global biogeography of roots.Ecological Monographs,2002,72(3):311-328.
[26]方长明.相对稳定的草地生态系统碳库.中国科学:生命科学,2011,41(4):340-342.
[27] Lin L,Li Y K,Xu X L,Zhang F W,Du Y G,Liu S L,Guo X W,Cao G M. Predicting parameters of degradation succession processes of Tibetan Kobresia grasslands.Solid Earth,2015,6(4):1237-1246.
[28] Qiao N,Xu X L,Cao G M,Ouyang H,Kuzyakov Y. Land use change decreases soil carbon stocks in Tibetan grasslands. Plant and Soil,2015,395(1/2):231-241.