鄂尔多斯高原草地灌丛化不同阶段主要植物水分利用特征
|
摘要
草地灌丛化是全球草地退化的普遍现象,理解草地灌丛化的过程和机制对灌丛化草地的恢复十分必要。目前有多种假说解释草地灌丛化现象,尽管大部分假说认为灌木和草本植物对土壤水分的不同利用方式在草地灌丛化过程中发挥着重要作用,但有关直接实验证据仍十分缺少。本文通过对鄂尔多斯高原流动沙地沙米群落、半固定沙地油蒿群落、固定沙地油蒿群落和固定沙地本氏针茅群落4个演替阶段植物群落的调查,采用稳定同位素分析的方法,分析不同阶段主要物种对不同水源的利用比例。结果表明:在不同演替阶段,草本植物对土壤水分的利用主要集中在土壤表层(0～20 cm),而灌木植物对中深层(50～200 cm)土壤水分的利用较多;灌木植物水分利用的可塑性强,在遭受水分胁迫时,灌木植物能够根据土壤水分的可利用性而改变对不同土层水分的利用。以上结果对于认识鄂尔多斯高原不同演替阶段主要植物水分利用策略具有一定意义,同时表明降低放牧等人为因素对表层土壤的干扰,改善表层土壤结构,提高表层土壤含水量是鄂尔多斯高原油蒿灌丛化草地恢复为地带性本氏针茅草原的关键。
Shrub encroachment occurs in degraded grasslands worldwide. Most hypotheses about shrub encroachment suggest that the differences of water use strategies between shrubs and herbaceous species are important,but with limited empirical evidence. Based on filed survey of four different succession stages( Agriophyllum squarrosum community in shifting sandy land,Artemisia ordosica community in semi-fixed sandy land,A. ordosica community in fixed sandy land,and Stipa bungeana community in fixed sandy land) on the Ordos Plateau,we examined the changes of water use characters of dominant species in different succession stages by determining water source through δ18O analysis. In different succession stages,herbaceous plants mainly used water from shallow soil layer( 0-20 cm),whereas shrubs predominantly used water from middle or deep soil layers( 50-200 cm). The plasticity of water use by shrubs was stronger than that of herbaceous plants. When suffering water stress,shrubs can change their water use sources to different soil layers according to water availability. These findings improve our understanding of water use strategy of the main species at different successional stages on the Ordos Plateau. The results suggest that it is crucial to reduce human disturbances such as overgrazing,to improve soil structure and increase soil moisture in shallow soil,and consequently to restore zonal S. bungeana steppe from A. ordosica encroached grassland on the Ordos Plateau.
Shrub encroachment occurs in degraded grasslands worldwide. Most hypotheses about shrub encroachment suggest that the differences of water use strategies between shrubs and herbaceous species are important,but with limited empirical evidence. Based on filed survey of four different succession stages( Agriophyllum squarrosum community in shifting sandy land,Artemisia ordosica community in semi-fixed sandy land,A. ordosica community in fixed sandy land,and Stipa bungeana community in fixed sandy land) on the Ordos Plateau,we examined the changes of water use characters of dominant species in different succession stages by determining water source through δ18O analysis. In different succession stages,herbaceous plants mainly used water from shallow soil layer( 0-20 cm),whereas shrubs predominantly used water from middle or deep soil layers( 50-200 cm). The plasticity of water use by shrubs was stronger than that of herbaceous plants. When suffering water stress,shrubs can change their water use sources to different soil layers according to water availability. These findings improve our understanding of water use strategy of the main species at different successional stages on the Ordos Plateau. The results suggest that it is crucial to reduce human disturbances such as overgrazing,to improve soil structure and increase soil moisture in shallow soil,and consequently to restore zonal S. bungeana steppe from A. ordosica encroached grassland on the Ordos Plateau.
引文
白永飞,黄建辉,郑淑霞,等.2014.草地和荒漠生态系统服务功能的形成与调控机制.植物生态学报,38(2):93-102.
郭柯.2000.毛乌素沙地油蒿群落的循环演替.植物生态学报,24(2):243-247.
贾慎修.1985.中国草地区划的商讨.资源科学,7(2):1-13.
李毓堂.2008.中国草原政策的变迁.草业科学,25(6):1-7.
林光辉.稳定同位素生态学.北京:高等教育出版社.
王庆锁,李博.1994.鄂尔多斯沙地油蒿群落生物量初步研究.植物生态学报,18(4):347-353.
张军红,吴波,杨文斌,等.2012.不同演替阶段油蒿群落土壤水分特征分析.中国沙漠,32(6):1597-1603.
张新时.1994.毛乌素沙地的生态背景及其草地建设的原则与优化模式.植物生态学报,18(1):1-16.
郑元润,张新时.1998.毛乌素沙地高效生态经济复合系统诊断与优化设计.植物生态学报,22(3):262-268.
Bai YF,Han XG,Wu J,et al.2004.Ecosystem stability and compensatory effects in the Inner Mongolia grassland.Nature,431:181-184.
Bartuszevige AM,Kennedy PL,Taylor RV.2014.Sixty-seven years of landscape change in the last,large remnant of the Pacific Northwest Bunchgrass Prairie.Natural Areas Journal,32:166-170.
Cipriotti PA,Aguiar MR,Wiegand T,et al.2014.A complex network of interactions controls coexistence and relative abundances in Patagonian grass-shrub steppes.Journal of Ecology,102:776-788.
Dai Y,Zheng XJ,Tang LS,et al.2015.Stable oxygen isotopes reveal distinct water use patterns of two Haloxylon species in the Gurbantonggut Desert.Plant and Soil,389:73-87.
Dixon AP,Faber-Langendoen D,Josse C,et al.2014.Distribution mapping of world grassland types.Journal of Biogeography,41:2003-2019.
Eggemeyer KD,Awada T,Harvey FE,et al.2009.Seasonal changes in depth of water uptake for encroaching trees Juniperus virginiana and Pinus ponderosa and two dominant C4grasses in a semiarid grassland.Tree Physiology,29:157-169.
Ehleringer JR,Phillips SL,Schuster WSF,et al.1991.Differential utilization of summer rains by desert plants.Oecologia,88:430-434.
Ehleringer JR,Dawson TE.1992.Water uptake by plants:Perspectives from stable isotope composition.Plant,Cell and Environment,15:1073-1082.
Ellsworth PZ,Williams DG.2007.Hydrogen isotope fractionation during water uptake by woody xerophytes.Plant and Soil,291:93-107.
Girard N,Duru M,Hazard L,et al.2008.Categorising farming practices to design sustainable land-use management in mountain areas.Agronomy for Sustainable Development,28:333-343.
Knapp AK,Briggs JM,Koelliker JK.2001.Frequency and extent of water limitation to primary production in a mesic temperate grassland.Ecosystems,4:19-28.
Lin G,Phillips SL,Ehleringer JR.1996.Monosoonal precipitation responses of shrubs in a cold desert community on the Colorado Plateau.Oecologia,106:8-17.
Liu W,Wang P,Li J,et al.2015.Plasticity of source-water acquisition in epiphytic,transitional and terrestrial growth phases of Ficus tinctoria.Ecohydrology,7:1524-1533.
Loreau M,Naeem S,Inchausti P,et al.2001.Biodiversity and ecosystem functioning:Current knowledge and future challenges.Science,294:804-808.
Mooney HA,Gulmon SL,Rundel PW,et al.1980.Further observations on the water relations of Prosopis tamarungo of the northern Atacama desert.Oecologia,44:177-180.
O’Connor TG,Puttick JR,Hoffman MT.2014.Bush encroachment in southern Africa:Changes and causes.African Journal of Range and Forage Science,31:67-88.
Silvertown J,Dodd ME,Gowing DJD,et al.1999.Hydrologically defined niches reveal a basis for species richness in plant communities.Nature,400:61-63.
Snyder KA,Williams DG.2000.Water sources used by riparian trees varies among stream types on the San Pedro River,Arizona.Agricultural and Forest Meteorology,105:227-240.
Walter H.1973.Vegetation of the earth in relation to climate and eco-physiological conditions.Quarterly Review of Biology,49:354-355.
White JWC,Cook ER,Lawrence JR,et al.1985.The ratios of sap in trees:Implications for water sources and tree ring ratios.Geochimica et Cosmochimica Acta,49:237-246.
Williams DG,Ehleringer JR.2000.Intra-and interspecific variation for summer precipitation use in pinyon-juniper woodlands.Ecological Monographs,70:517-537.
Wu Y,Zhou H,Zheng XJ,et al.2013.Seasonal changes in the water use strategies of three co-occurring desert shrubs.Hydrological Processes,28:6265-6275.
Wu H,Li XY,Jiang Z,et al.2016.Contrasting water use pattern of introduced and native plants in an alpine desert ecosystem,Northeast Qinghai-Tibet Plateau,China.Science of the Total Environment,542:182-191.
Yang Q,Xiao HL,Zhao LJ,et al.2010.Stable isotope techniques in plant water sources:A review.Sciences in Cold and Arid Regions,2:112-122.
郭柯.2000.毛乌素沙地油蒿群落的循环演替.植物生态学报,24(2):243-247.
贾慎修.1985.中国草地区划的商讨.资源科学,7(2):1-13.
李毓堂.2008.中国草原政策的变迁.草业科学,25(6):1-7.
林光辉.稳定同位素生态学.北京:高等教育出版社.
王庆锁,李博.1994.鄂尔多斯沙地油蒿群落生物量初步研究.植物生态学报,18(4):347-353.
张军红,吴波,杨文斌,等.2012.不同演替阶段油蒿群落土壤水分特征分析.中国沙漠,32(6):1597-1603.
张新时.1994.毛乌素沙地的生态背景及其草地建设的原则与优化模式.植物生态学报,18(1):1-16.
郑元润,张新时.1998.毛乌素沙地高效生态经济复合系统诊断与优化设计.植物生态学报,22(3):262-268.
Bai YF,Han XG,Wu J,et al.2004.Ecosystem stability and compensatory effects in the Inner Mongolia grassland.Nature,431:181-184.
Bartuszevige AM,Kennedy PL,Taylor RV.2014.Sixty-seven years of landscape change in the last,large remnant of the Pacific Northwest Bunchgrass Prairie.Natural Areas Journal,32:166-170.
Cipriotti PA,Aguiar MR,Wiegand T,et al.2014.A complex network of interactions controls coexistence and relative abundances in Patagonian grass-shrub steppes.Journal of Ecology,102:776-788.
Dai Y,Zheng XJ,Tang LS,et al.2015.Stable oxygen isotopes reveal distinct water use patterns of two Haloxylon species in the Gurbantonggut Desert.Plant and Soil,389:73-87.
Dixon AP,Faber-Langendoen D,Josse C,et al.2014.Distribution mapping of world grassland types.Journal of Biogeography,41:2003-2019.
Eggemeyer KD,Awada T,Harvey FE,et al.2009.Seasonal changes in depth of water uptake for encroaching trees Juniperus virginiana and Pinus ponderosa and two dominant C4grasses in a semiarid grassland.Tree Physiology,29:157-169.
Ehleringer JR,Phillips SL,Schuster WSF,et al.1991.Differential utilization of summer rains by desert plants.Oecologia,88:430-434.
Ehleringer JR,Dawson TE.1992.Water uptake by plants:Perspectives from stable isotope composition.Plant,Cell and Environment,15:1073-1082.
Ellsworth PZ,Williams DG.2007.Hydrogen isotope fractionation during water uptake by woody xerophytes.Plant and Soil,291:93-107.
Girard N,Duru M,Hazard L,et al.2008.Categorising farming practices to design sustainable land-use management in mountain areas.Agronomy for Sustainable Development,28:333-343.
Knapp AK,Briggs JM,Koelliker JK.2001.Frequency and extent of water limitation to primary production in a mesic temperate grassland.Ecosystems,4:19-28.
Lin G,Phillips SL,Ehleringer JR.1996.Monosoonal precipitation responses of shrubs in a cold desert community on the Colorado Plateau.Oecologia,106:8-17.
Liu W,Wang P,Li J,et al.2015.Plasticity of source-water acquisition in epiphytic,transitional and terrestrial growth phases of Ficus tinctoria.Ecohydrology,7:1524-1533.
Loreau M,Naeem S,Inchausti P,et al.2001.Biodiversity and ecosystem functioning:Current knowledge and future challenges.Science,294:804-808.
Mooney HA,Gulmon SL,Rundel PW,et al.1980.Further observations on the water relations of Prosopis tamarungo of the northern Atacama desert.Oecologia,44:177-180.
O’Connor TG,Puttick JR,Hoffman MT.2014.Bush encroachment in southern Africa:Changes and causes.African Journal of Range and Forage Science,31:67-88.
Silvertown J,Dodd ME,Gowing DJD,et al.1999.Hydrologically defined niches reveal a basis for species richness in plant communities.Nature,400:61-63.
Snyder KA,Williams DG.2000.Water sources used by riparian trees varies among stream types on the San Pedro River,Arizona.Agricultural and Forest Meteorology,105:227-240.
Walter H.1973.Vegetation of the earth in relation to climate and eco-physiological conditions.Quarterly Review of Biology,49:354-355.
White JWC,Cook ER,Lawrence JR,et al.1985.The ratios of sap in trees:Implications for water sources and tree ring ratios.Geochimica et Cosmochimica Acta,49:237-246.
Williams DG,Ehleringer JR.2000.Intra-and interspecific variation for summer precipitation use in pinyon-juniper woodlands.Ecological Monographs,70:517-537.
Wu Y,Zhou H,Zheng XJ,et al.2013.Seasonal changes in the water use strategies of three co-occurring desert shrubs.Hydrological Processes,28:6265-6275.
Wu H,Li XY,Jiang Z,et al.2016.Contrasting water use pattern of introduced and native plants in an alpine desert ecosystem,Northeast Qinghai-Tibet Plateau,China.Science of the Total Environment,542:182-191.
Yang Q,Xiao HL,Zhao LJ,et al.2010.Stable isotope techniques in plant water sources:A review.Sciences in Cold and Arid Regions,2:112-122.