模拟雪被变化对水曲柳和兴安落叶松凋落叶分解的影响
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摘要
气候变化引起的雪被变化会深刻地影响森林凋落物的分解过程.本研究采用人工控雪处理(对照、增雪、除雪)模拟研究雪被变化对两种温带树种——水曲柳和兴安落叶松凋落叶分解动态的影响.为期一年的分解试验表明:不同控雪处理下水曲柳和落叶松的凋落叶年分解率的变化范围分别为51.3%～57.4%和21.7%～31.4%;两者的分解系数(k)变化范围分别为0.048～0.057和0.022～0.030,其中增雪处理的k值最大、除雪处理的k值最小.与对照相比,增雪处理下水曲柳凋落叶50%和95%分解的时间分别缩短了1.1月和4.2月,落叶松则分别缩短了3.7月和15.5月;相反,除雪处理下相应的分解时间分别延长了1.8月和6.4月(水曲柳)及5.0月和21.1月(落叶松).此外,凋落叶分解率与树种、雪深、分解时间、土壤温度等密切相关,但其主要影响因子随分解阶段而异,表现为雪被期主要受土壤温度影响,而随后的无雪期主要受凋落叶初始质量的影响.本研究突显了雪被变化对凋落叶分解有显著的瞬时效应和延迟效应.
Changes in snowpack induced by climate change can profoundly affect forest litter decomposition. A snow-depth manipulation experiment with three treatments( i. e.,control,snowaddition,and snow-removal) was conducted to assess the effects of snow-depth changes on leaf litter decomposition of two temperate tree species [Manchurian ash( Fraxinus mandshurica) and Dahurian larch( Larix gmelinii) ]. The annual loss of the litter mass after one year decomposition varied between 51.3% and 57.4% for the ash and between 21. 7% and 31. 4% for the larch. The decomposition constants( k) ranged from 0.048 to 0.057 and from 0.022 to 0.030 for these two species respectively. The greatest k value occurred under the snow addition treatment,while the least occurred under the snow removal treatment. Snow addition treatment shortened the 50% and 95%decomposition time by 1.1 months and 4.2 months for the ash,respectively,and by 3.7 months and15.5 months for the larch,respectively. The snow removal treatment lengthened those decomposition time by 1.8 months and 6.4 months for the ash,and by 5.0 months and 21.1 months for the larch,respectively. Litter decomposition rate was significantly correlated with tree species,snow-depth,decomposition time,and soil temperature,but its major influencing factors varied with decomposition stage. Soil temperature and the initial litter quality were the major factors affecting decomposition rates during the snow-covered and following snow-free periods,respectively. Our findings highlight that changes in snow depth exert significantly instantaneous and prolonged effects on forest litter decomposition.
Changes in snowpack induced by climate change can profoundly affect forest litter decomposition. A snow-depth manipulation experiment with three treatments( i. e.,control,snowaddition,and snow-removal) was conducted to assess the effects of snow-depth changes on leaf litter decomposition of two temperate tree species [Manchurian ash( Fraxinus mandshurica) and Dahurian larch( Larix gmelinii) ]. The annual loss of the litter mass after one year decomposition varied between 51.3% and 57.4% for the ash and between 21. 7% and 31. 4% for the larch. The decomposition constants( k) ranged from 0.048 to 0.057 and from 0.022 to 0.030 for these two species respectively. The greatest k value occurred under the snow addition treatment,while the least occurred under the snow removal treatment. Snow addition treatment shortened the 50% and 95%decomposition time by 1.1 months and 4.2 months for the ash,respectively,and by 3.7 months and15.5 months for the larch,respectively. The snow removal treatment lengthened those decomposition time by 1.8 months and 6.4 months for the ash,and by 5.0 months and 21.1 months for the larch,respectively. Litter decomposition rate was significantly correlated with tree species,snow-depth,decomposition time,and soil temperature,but its major influencing factors varied with decomposition stage. Soil temperature and the initial litter quality were the major factors affecting decomposition rates during the snow-covered and following snow-free periods,respectively. Our findings highlight that changes in snow depth exert significantly instantaneous and prolonged effects on forest litter decomposition.
引文
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[19]Wu FZ,Yang WQ,Zhang J,et al.Litter decomposition in two subalpine forests during the freeze-thaw season.Acta Oecologica,2010,36:135-140
[20]Hicks Pries CE,Schuur EAG,Vogel JG,et al.Moisture drives surface decomposition in thawing tundra.Journal of Geophysical Research:Biogeosciences,2013,118:1133-1143
[21]Wu Q-Q(武启骞),Wu F-Z(吴福忠),Yang W-Q(杨万勤),et al.Effect of seasonal snow cover on litter decomposition in alpine forest.Chinese Journal of Plant Ecology(植物生态学报),2013,37(4):296-305(in Chinese)
[22]Hu X(胡霞),Wu N(吴宁),Wu Y(吴彦),et al.Effects of snow cover on the decomposition and nutrient dynamics of Sibiraea angustata leaf litter in western Sichuan plateau,Southwest China.Chinese Journal of Applied Ecology(应用生态学报),2012,23(5):1226-1232(in Chinese)
[23]Palm CA.Contribution of agroforestry trees to nutrient requirements of intercropped plants.Agroforestry Systems,1995,30:105-124
[24]Allison SD.Soil minerals and humic acids alter enzyme stability:Implications for ecosystem processes.Biogeochemistry,2006,81:361-373
[25]Bokhorst S,Metcalfe DB,Wardle DA.Reduction in snow depth negatively affects decomposers but impact on decomposition rates is substrate dependent.Soil Biology and Biochemistry,2013,62:157-164
[26]Aerts R,Van Bodgom PM,Cornelissen JHC.Litter stoichiometric traits of plant species of high-latitude ecosystems show high responsiveness to global change without causing strong variation in litter decomposition.New Phytologist,2012,196:181-188
[27]Groffman PM,Driscoll CT,Fahey TJ,et al.Effects of mild winter freezing on soil nitrogen and carbon dynamics in a northern hardwood forest.Biogeochemistry,2001,56:191-213
[28]Lemma B,Nilsson I,Kleja DB,et al.Decomposition and substrate quality of leaf litters and fine roots from three exotic plantations and a native forest in the southwestern highlands of Ethiopia.Soil Biology and Biochemistry,2007,39:2317-2328
[29]Blok D,Elberling B,Michelsen A.Initial stages of tundra shrub litter decomposition may be accelerated by deeper winter snow but slowed down by spring warming.Ecosystems,2016,19:155-169
[30]Freppaz M,Celi L,Marchelli M,et al.Snow removal and its influence on temperature and N dynamics in alpine soils(Vallee d’Aoste,northwest Italy).Journal of Plant Nutrition and Soil Science,2008,171:672-680
[31]Kreyling J,Haei M,Laudon H.Snow removal reduces annual cellulose decomposition in a riparian boreal forest.Canadian Journal of Soil Science,2013,93:427-433
[32]Aerts R,de Caluwe H.Nutritional and plant-mediated controls on leaf litter decomposition of Carex species.Ecology,1997,78:244-260
[2]Polyakova O,Billor N.Impact of deciduous tree species on litter fall quality,decomposition rates and nutrient circulation in pine stands.Forest Ecology and Management,2007,253:11-18
[3]Tan B,Wu FZ,Yang WQ,et al.Snow removal alters soil microbial biomass and enzyme activity in a Tibetan alpine forest.Applied Soil Ecology,2014,76:34-41
[4]Konstantin S.Dynamics of alpine plant litter decomposition in a changing climate.Plant and Soil,2010,337:19-32
[5]IPCC.Climate Change 2007:The Physical Science Basis.Cambridge:Cambridge University Press,2007
[6]Mote PW,Hamlet AF,Clark MP,et al.Declining mountain snowpack in western North America.Bulletin of the American Meteorological Society,2005,86:39-49
[7]Risnen J.Warmer climate:Less or more snow?Climate Dynamics,2008,30:307-319
[8]Cline DW.Snow surface energy exchanges and snowmelt at a continental,midlatitude alpine site.Water Resources Research,1997,33:689-701
[9]Tan B(谭波),Wu F-Z(吴福忠),Yang W-Q(杨万勤),et al.Effects of snow pack removal on the dynamics of winter-time soil temperature,carbon,nitrogen,and phosphorus in alpine forests of west Sichuan.Chinese Journal of Applied Ecology(应用生态学报),2011,22(10):2553-2559(in Chinese)
[10]Wu Q-Q(武启骞),Wang C-K(王传宽).Effects of changes in seasonal snow-cover on litter decomposition and soil nitrogen dynamics in forests.Chinese Journal of Applied Ecology(应用生态学报),2018,29(7):2422-2432(in Chinese)
[11]Yang J-Y(杨金艳),Wang C-K(王传宽).Soil carbon storage and flux of temperate forest ecosystems in northeastern China.Acta Ecologica Sinica(生态学报),2005,25(11):2875-2882(in Chinese)
[12]Wang C.Biomass allometric equations for 10 co-occurring tree species in Chinese temperate forests.Forest Ecology and Management,2006,222:9-16
[13]Wang C,Han Y,Chen J,et al.Seasonality of soil CO2efflux in a temperate forest:Biophysical effects of snowpack and spring freeze-thaw cycles.Agricultural and Forest Meteorology,2013,177:83-92
[14]Zhang QZ,Wang CK.Carbon density and distribution of six Chinese temperate forests.Science China:Life Sciences,2010,53:831-840
[15]Vanderbilt KL,White CS,Hopkins O,et al.Aboveground decomposition in arid environments:Results of a long-term study in central New Mexico.Journal of Arid Environments,2008,72:696-709
[16]Olsson PQ,Sturm M,Racine CH,et al.Five stages of the Alaskan Arctic cold season with ecosystem implications.Arctic,Antarctic,and Alpine Research,2003,35:74-81
[17]Konestabo HS,Michelsen A,Holmstrup M.Responses of springtail and mite populations to prolonged periods of soil freeze-thaw cycles in a sub-arctic ecosystem.Applied Soil Ecology,2007,36:136-146
[18]Olson JS.Energy storage and the balance of producers and decomposers in ecological systems.Ecology,1963,44:322-331
[19]Wu FZ,Yang WQ,Zhang J,et al.Litter decomposition in two subalpine forests during the freeze-thaw season.Acta Oecologica,2010,36:135-140
[20]Hicks Pries CE,Schuur EAG,Vogel JG,et al.Moisture drives surface decomposition in thawing tundra.Journal of Geophysical Research:Biogeosciences,2013,118:1133-1143
[21]Wu Q-Q(武启骞),Wu F-Z(吴福忠),Yang W-Q(杨万勤),et al.Effect of seasonal snow cover on litter decomposition in alpine forest.Chinese Journal of Plant Ecology(植物生态学报),2013,37(4):296-305(in Chinese)
[22]Hu X(胡霞),Wu N(吴宁),Wu Y(吴彦),et al.Effects of snow cover on the decomposition and nutrient dynamics of Sibiraea angustata leaf litter in western Sichuan plateau,Southwest China.Chinese Journal of Applied Ecology(应用生态学报),2012,23(5):1226-1232(in Chinese)
[23]Palm CA.Contribution of agroforestry trees to nutrient requirements of intercropped plants.Agroforestry Systems,1995,30:105-124
[24]Allison SD.Soil minerals and humic acids alter enzyme stability:Implications for ecosystem processes.Biogeochemistry,2006,81:361-373
[25]Bokhorst S,Metcalfe DB,Wardle DA.Reduction in snow depth negatively affects decomposers but impact on decomposition rates is substrate dependent.Soil Biology and Biochemistry,2013,62:157-164
[26]Aerts R,Van Bodgom PM,Cornelissen JHC.Litter stoichiometric traits of plant species of high-latitude ecosystems show high responsiveness to global change without causing strong variation in litter decomposition.New Phytologist,2012,196:181-188
[27]Groffman PM,Driscoll CT,Fahey TJ,et al.Effects of mild winter freezing on soil nitrogen and carbon dynamics in a northern hardwood forest.Biogeochemistry,2001,56:191-213
[28]Lemma B,Nilsson I,Kleja DB,et al.Decomposition and substrate quality of leaf litters and fine roots from three exotic plantations and a native forest in the southwestern highlands of Ethiopia.Soil Biology and Biochemistry,2007,39:2317-2328
[29]Blok D,Elberling B,Michelsen A.Initial stages of tundra shrub litter decomposition may be accelerated by deeper winter snow but slowed down by spring warming.Ecosystems,2016,19:155-169
[30]Freppaz M,Celi L,Marchelli M,et al.Snow removal and its influence on temperature and N dynamics in alpine soils(Vallee d’Aoste,northwest Italy).Journal of Plant Nutrition and Soil Science,2008,171:672-680
[31]Kreyling J,Haei M,Laudon H.Snow removal reduces annual cellulose decomposition in a riparian boreal forest.Canadian Journal of Soil Science,2013,93:427-433
[32]Aerts R,de Caluwe H.Nutritional and plant-mediated controls on leaf litter decomposition of Carex species.Ecology,1997,78:244-260