青藏高原东缘高山森林-苔原交错带土壤微生物生物量碳、氮和可培养微生物数量的季节动态

doi:10.3724/SP.J.1258.2012.00382

摘要/Abstract

摘要：

为了了解青藏高原东缘高山森林-苔原交错带土壤微生物的特征和季节变化, 研究了米亚罗鹧鸪山原始针叶林、林线、树线、密灌丛、疏灌丛和高山草甸土壤微生物生物量碳(MBC)、氮(MBN)和可培养微生物数量的季节动态。结果表明, 植被类型和季节动态对MBC、MBN和微生物数量都有显著影响。不同时期的微生物在各植被类型间分布有差异, 植物生长季初期和生长季中期, 树线以上群落的MBC高于树线下的群落, 而到生长季末期恰恰相反, 暗针叶林、林线和树线的MBC显著升高, 各植被之间MBC的差异减小; 微生物数量基本上也是以树线为界, 树线以下群落土壤微生物数量显著低于树线以上群落, 其中密灌丛的细菌数量最高; 可培养微生物数量为生长季末期>生长季初期>生长季中期。生长季末期真菌数量显著增加, 且MBC/MBN最高。统计分析表明, MBN与细菌、真菌、放线菌数量存在显著的相关关系, 而MBC仅与真菌数量存在显著相关关系( p < 0.05)。植物生长季末期大量的凋落物输入和雪被覆盖可能是微生物季节变异的外在因素, 而土壤微生物和高山植物对有效氮的竞争可能是微生物季节变异的内在因素。植物生长季初期对氮的吸收和土壤微生物在植物生长季末期对氮的固定加强了高山生态系统对氮的利用。气候变暖可能会延长高山植物的生长季, 增加高山土壤微生物生物量, 加速土壤有机质的分解, 进而改变高山土壤碳的固存速率。

关键词: 高山森林-苔原交错带, 季节动态, 土壤微生物生物量, 土壤微生物数量

Abstract:

Aims The forest-alpine tundra ecotone is one of the most conspicuous climate-driven ecological boundaries. However, dynamics of soil microbial biomass and quantity during different stages of the growing season in the ecotone remain unclear. Our objective was to understand the temporal and spatial variations of microbial biomass and quantity to explore the main drivers in the ecotone.
Methods We collected soil samples in a forest-alpine tundra ecotone (dark-conifer forest, timberline, treeline, dense shrub, sparse shrub and alpine meadow) during early, mid and late growing season (EGS, MGS and LGS). The number and species composition of soil microorganisms were determined by means of the plate count method. Soil microbial biomass carbon (MBC) and nitrogen (MBN) were measured by the chloroform fumigation leaching method.
Important findings Vegetation and seasonality significantly influence MBC, MBN and microbial community structure. Microbial biomass distribution among vegetation types was different in the three stages of the growing season. MBC above treeline was higher than below during EGS and MGS. The MBC of dark-conifer forest, timberline and treeline during LGS was significantly increased, and MBC differences among different vegetation types decreased. There were significant differences in measured soil microbial quantity between above- and below-treeline vegetation types; bacteria of dense shrub were highest among vegetation types. The amount of cultivated microorganisms was LGS>EGS>MGS. The ratio of MBC to MBN was the highest and the quantity of fungi increased largely late in the growing season. Statistical analysis showed that there were significant correlations between MBN and bacteria, fungi and actinomyces quantity, while only MBC and fungi quantity were significantly correlated (p < 0.05). Litter input and snow cover late in the growing season were external factors of microbial seasonal variation. Soil microbes and alpine plants competing for nitrogen may be internal factors. Plant nitrogen absorption early in the growing season and microorganisms’ nitrogen fixation late in the growing season enhanced the alpine ecosystem’s nitrogen fixation and utilization. Climate warming may extend the growing season of alpine plants, increasing the alpine soil microbial biomass, and accelerate the decomposition of soil organic matter, which may change soil carbon sequestration rates in the alpine ecosystem.

Key words: forest-alpine tundra ecotone, seasonal dynamics, soil microbial biomass, soil microbial quantity

刘洋, 张健, 闫帮国, 黄旭, 徐振锋, 吴福忠. 青藏高原东缘高山森林-苔原交错带土壤微生物生物量碳、氮和可培养微生物数量的季节动态. 植物生态学报, 2012, 36(5): 382-392. DOI: 10.3724/SP.J.1258.2012.00382

LIU Yang, ZHANG Jian, YAN Bang-Guo, HUANG Xu, XU Zhen-Feng, WU Fu-Zhong. Seasonal dynamics in soil microbial biomass carbon and nitrogen and microbial quantity in a forest-alpine tundra ecotone, Eastern Qinghai-Tibetan Plateau, China. Chinese Journal of Plant Ecology, 2012, 36(5): 382-392. DOI: 10.3724/SP.J.1258.2012.00382

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链接本文: https://www.plant-ecology.com/CN/10.3724/SP.J.1258.2012.00382

https://www.plant-ecology.com/CN/Y2012/V36/I5/382

图/表 5

表1 高山森林-苔原交错带基本特征

Table 1 Basic characteristics of alpine forest-tundra ecotone

样带 Belt transect	暗针叶林Dark-conifer forest	林线Timberline	树线 Treeline	密灌丛 Dense shrub	疏灌丛 Sparse shrub	高山草甸 Alpine meadow
海拔 Elevation (m)	3 900	3 975	4 050	4 105	4 135	4 200
坡向 Slope aspect (°)	EN 5	EN 4	EN 5	EN 5	EN 3	EN 3
坡度 Slope degree (°)	32	34	40	36	38	34
木本植物平均高度 Wood average height (m)	22.0	14.0	8.0	5.0	1.5	–
草本植物平均高度 Herbage average height (cm)	10	20	50	35	20	10
郁闭度 Crown density (%)	80	75	70	65	20	–
草本植物盖度 Cover degree of herb (%)	20	30	40	60	90	85
苔藓厚度 Thickness of moss (cm)	10.0	4.5	4.0	1.8	0.5	0.6
枯落物厚度 Thickness of litter (cm)	9.0	8.0	5.8	4.5	2.5	1.2

图1 2009年5月至10月高山森林-苔原交错带日平均气温(A)和土壤月平均温度(B)动态。AM, 高山草甸; DCF, 暗针叶林; DS, 密灌丛; SS, 疏灌丛; Ti, 林线; Tr, 树线。

Fig. 1 Dynamics of average daily air temperature (A) and soil temperature at 10 cm depth by month (B) from May to October, 2009 in the forest-alpine tundra ecotone. AM, alpine meadow; DCF, dark-conifer forest; DS, dense shrub; SS, sparse shrub; Ti, timberline; Tr, treeline.

图2 高山森林-苔原交错带土壤微生物生物量碳(A)、氮(B)和碳氮比(C)和可培养细菌(D)、真菌(E)、放线菌(F)数量的季节变化(平均值±标准偏差)。不同小写字母表示相同季节里植被之间差异显著(p < 0.05); 不同大写字母表示相同植被在不同季节之间差异显著(p < 0.05)。EGS, 生长季初期; LGS, 生长季末期; MGS, 生长季中期。AM, 高山草甸; DCF, 暗针叶林; DS, 密灌丛; SS, 疏灌丛; Ti, 林线; Tr, 树线。

Fig. 2 Seasonal changes of soil microbial biomass carbon (A), nitrogen (B) and C: N (C), as well as quantity of cultivate bacteria (D), fungi (E) and actinomycetes (F) of soil in forest-alpine tundra ecotone (mean ± SD). Lower case letters indicate significant differences among different vegetations within same season (p < 0.05); upper case letters indicate significant differences among different seasons within same vegetation (p < 0.05). EGS, early in the growing season; LGS, late in the growing season; MGS, middle in the growing season. AM, alpine meadow; DCF, dark-conifer forest; DS, dense shrub; SS, sparse shrub; Ti, timberline; Tr, treeline.

表2 植被类型(从暗针叶林到高山草甸)和季节(5-10月三次采样)及其交互作用对高山森林-苔原交错带10 cm深处土壤微生物生物量碳、氮和微生物数量的双因素方差分析结果

Table 2 Results of two-way ANOVA for the analysis of the main effects of vegetation types (from dark-conifer forest to alpine meadow), season (three times collections from May to October) and their interactions for soil microbial biomass C, N and microbe quantity determined in 10-cm depth soil layer in forest-alpine tundra ecotone

变量 Variable	植被 Vegetation			季节 Season			植被×季节 Vegetation×season
变量 Variable	df	F	p	df	F	p	df	F	p
微生物生物量碳 MBC	5	20.64	<0.001	2	481.75	<0.001	10	14.40	<0.001
微生物生物量氮 MBN	5	120.48	<0.001	2	7.44	0.004	10	20.21	<0.001
微生物生物量碳氮比 MBC/MBN	5	26.53	<0.001	2	541.92	<0.001	10	17.07	<0.001
细菌 Bacteria	5	86.20	<0.001	2	22.59	<0.001	10	7.16	<0.001
真菌 Fungi	5	55.36	<0.001	2	166.69	<0.001	10	14.13	<0.001
放线菌 Actinomycetes	5	51.18	<0.001	2	58.46	<0.001	10	14.37	<0.001

图3 土壤微生物生物量碳、氮与细菌、真菌、放线菌数量的相关关系。

Fig. 3 Relationships between soil microbial biomass carbon, nitrogen and bacteria, fungi, actinomycetes quantity.

参考文献 48

[1]	ACIA Secretariat (2005). Arctic Climate Impact Assessment. Cambridge University Press, Cambridge, UK. 1042.
[2]	Alftine KJ, Malanson GP, Fagre DB (2003). Feedback-driven response to multidecadal climatic variability at an Alpine treeline. Physical Geography, 24, 520-535.
[3]	Balser TC, Firestone MK (2004). Linking microbial community composition and soil processes in a California annual grassland and mixed-conifer forest. Biogeochemistry, 73, 395-415. DOI URL
[4]	Bardgett RD, Lovell RD, Hobbs PJ, Jarvis SC (1999). Seasonal changes in soil microbial communities along a fertility gradient of temperate grasslands. Soil Biology & Biochemistry, 31, 1021-1030.
[5]	Bardgett RD, McAlister E (1999). The measurement of soil fungal: bacterial biomass ratios as an indicator of ecosystem self-regulation in temperate meadow grasslands. Biology and Fertility of Soils, 19, 282-290.
[6]	Björk RG, Björkman MP, Andersson MX, Klemedtsson L (2008). Temporal variation in soil microbial communities in Alpine tundra. Soil Biology & Biochemistry, 40, 266-268.
[7]	Butler DR, Malanson GP, Cairns DM (1994). Stability of alpine treeline in Northern Montana, USA. Phytocoenologia, 22, 485-500.
[8]	Callaway RM, Brooker RW, Choler P, Kikvidze Z, Lortie CJ, Michalet R, Paolini L, Pugnaire FL, Newingham B, Asc- hehoug ET, Armas C, Kikodze D, Cook BJ (2002). Posi- tive interactions among alpine plants increase with stress. Nature, 417, 844-848.
[9]	Chu HY, Grogan P (2010). Soil microbial biomass, nutrient availability and nitrogen mineralization potential among vegetation-types in a low arctic tundra landscape. Plant and Soil, 329, 411-420.
[10]	Devi NB, Yadava PS (2006). Seasonal dynamics in soil microbial biomass C, N and P in a mixed-oak forest ecosystem of Manipur, North-east India. Applied Soil Ecology, 31, 220-227.
[11]	Díaz-Varela RA, Colombo R, Meroni M, Calvo-Iglesias MS, Buffoni A, Tagliaferri A (2010). Spatio-temporal analysis of alpine ecotones: a spatial explicit model targeting altitudinal vegetation shifts. Ecological Modelling, 221, 621-633.
[12]	Ding LL (丁玲玲), Qi B (祁彪), Shang ZH (尚占环), Long RJ (龙瑞军), Zhou QX (周启星) (2007). The characteristics of soil microorganism quantity under different alpine grasslands in eastern Qilian Mountain. Journal of Agro-Environment Science (农业环境科学学报), 26, 2104-2111. (in Chinese with English abstract)
[13]	Fauci MF, Dick RP (1994). Microbial biomass as an indicator of soil quality: effects of long-term management and recent soil amendments. In: Doran JW, Coleman DC, Bezdicek DF, Stewart BA eds. Defining Soil Quality for a Sustainable Environment. Soil Science Society of America, Minneapolis, USA. 229-234.
[14]	He R (何容), Wang JS (汪家社), Shi Z (施政), Fang YH (方燕鸿), Xu ZK (徐自坤), Quan W (权伟), Zhang ZX (张增信), Ruan HH (阮宏华) (2009). Variations of soil microbial biomass across four different plant communities along an elevation gradient in Wuyi Mountains, China. Acta Ecologica Sinica (生态学报), 29, 5138-5144. (in Chinese with English abstract)
[15]	Holtmeier FK (2003). Mountain Timberlines: Ecology, Patchiness, and Dynamics. Kluwer Academic Publishers, Dordrecht, the Netherlands.
[16]	Imberger KT, Chiu CY (2001). Spatial changes of soil fungal and bacterial biomass from a sub-alpine coniferous forest to grassland in a humid, sub-tropical region. Biology and Fertility of Soils, 33, 105-110.
[17]	IPCC (Intergovernmental Panel on Climate Change) (2007). Contribution of working group III to the fourth assessment report of the intergovernmental panel on climate change. In: Metz B, Davidson OR, Bosch PR, Dave R, Meyer LA eds. Climate Change in 2007: Mitigation. Cambridge University Press, Cambridge, UK.
[18]	Jaeger CH, Monson RK, Fisk MC, Schmidt SK (1999). Seasonal partitioning of nitrogen by plants and soil microorganisms in an alpine ecosystem. Ecology, 80, 1883-1891.
[19]	Koponen HT, Jaakkola T, Keinänen-Toivola MM, Kaipainen S, Tuomainen J, Servomaa K, Martikainen PJ (2006). Microbial communities, biomass, and activities in soils as affected by freeze thaw cycles. Soil Biology & Biochemistry, 38, 1861-1871.
[20]	Körner C, Paulsen J (2004). A world-wide study of high altitude treeline temperatures. Journal of Biogeography, 31, 713-732.
[21]	Krajick K (2006). Living the high life: the mountaintop environment of the Andes harbors a Noah’s ark of previously undocumented species. Natural History, 115, 44-50.
[22]	Kupfer JA, Cairns DM (1996). The suitability of montane ecotones as indicators of global climatic change. Progress in Physical Geography, 20, 253-272.
[23]	Lipson DA, Monson RK (1998). Plant-microbe competition for soil amino acids in the alpine tundra: effects of freeze- thaw and dry-rewet events. Oecologia, 113, 406-414. DOI URL PMID
[24]	Lipson DA, Schadt CW, Schmidt SK (2002). Changes in soil microbial community structure and function in an alpine dry meadow following spring snow melt. Microbial Ecology, 43, 307-314. URL PMID
[25]	Liu MQ (刘满强), Hu F (胡锋), He YQ (何园球), Li HX (李辉信) (2003). Seasonal dynamics of soil microbial biomass and its significance to indicate soil quality under different vegetations restored on degraded red soils. Acta Pedologica Sinica (土壤学报), 40, 937-943. (in Chinese with English abstract)
[26]	Liu Y (刘洋), Zhang J (张健), Yang WQ (杨万勤) (2009). Responses of alpine biodiversity to climate change. Biodiversity Science (生物多样性), 17, 88-96. (in Chinese with English abstract)
[27]	Microbial Room of Nanjing Institute of Soil Science, Chinese Academy of Sciences (中国科学院南京土壤研究所微生物室) (1985). Method of Soil Microbial Research (土壤微生物研究法). Science Press, Beijing. (in Chinese)
[28]	Miller AE, Schimel JP, Sickman JO, Skeen K, Meixner T, Melack JM (2009). Seasonal variation in nitrogen uptake and turnover in two high-elevation soils: mineralization responses are site-dependent. Biogeochemistry, 93, 253-270.
[29]	Monson RK, Lipson DL, Burns SP, Turnipseed AA, Delany AC, Williams MW, Schmidt SK (2006). Winter forest soil respiration controlled by climate and microbial community composition. Nature, 439, 711-714.
[30]	Nielsen PL, Andresen LC, Michelsen A, Schmid IK, Kongstad J (2009). Seasonal variations and effects of nutrient applications on N and P and microbial biomass under two temperate heathland plants. Applied Soil Ecology, 42, 279-287.
[31]	Pauli H, Gottfried M, Reiter K, Klettner C, Grabherr G (2007). Signals of range expansions and contractions of vascular plants in the high Alps: observations (1994-2004) at the GLORIA master site Schrankogel, Tyrol, Austria. Global Change Biology, 13, 147-156. DOI URL
[32]	Pennisi E (2003). Neither cold nor snow stops tundra fungi. Science, 301, 1307. DOI URL PMID
[33]	Qi ZM (齐泽民), Wang KY (王开运) (2009). Soil properties of the subalpine timberline ecotone in Western Sichuan. Journal of Soil and Water Conservation (水土保持学报), 23, 158-162. (in Chinese with English abstract)
[34]	Qi ZM (齐泽民), Wang KY (王开运), Zhang YB (张远彬), Xie YH (谢玉华) (2009). The soil properties of the subalpine timberline ecotone and adjacent vegetations in Western Sichuan. Acta Ecologica Sinica (生态学报), 29, 6325-6332. (in Chinese with English abstract)
[35]	Rajaniemi TK, Allison VJ (2009). Abiotic conditions and plant cover differentially affect microbial biomass and community composition on dune gradients. Soil Biology & Biochemistry, 41, 102-109.
[36]	Risser PG (1995). The status of the science examining ecotones. BioScience, 45, 318-325.
[37]	Schadt CW, Martin AP, Lipson DA, Schmidt SK (2003). Seasonal dynamics of previously unknown fungal lineages in tundra soils. Science, 301, 1359-1361. URL PMID
[38]	Schmidt SK, Costello EK, Nemergut DR, Cleveland CC, Reed SC, Weintraub MN, Meyer AF, Martin AP (2007). Biogeochemical consequences of rapid microbial turnover and seasonal succession in soil. Ecology, 88, 1379-1385. URL PMID
[39]	Shao BL (邵宝林), Gong GS (龚国淑), Zhang SR (张世熔), Yu X (余霞), Yang DL (杨丹玲), Zhang H (张洪) (2006). Soil microbial quantity and its relations with ecological factors in northern alp region of Hengduan Mountains. Chinese Journal of Ecology (生态学杂志), 25, 885-890. (in Chinese with English abstract)
[40]	Sun G, Luo P, Wu N, Qiu PF, Gao YH, Chen H, Shi FS (2009). Stellera chamaejasme L. increases soil N availability, turnover rates and microbial biomass in an alpine meadow ecosystem on the eastern Tibetan Plateau of China. Soil Biology & Biochemistry, 41, 86-91.
[41]	Waldrop MP, Firestone MK (2006). Seasonal dynamics of microbial community composition and function in oak canopy and open grassland soils. Microbial Ecology, 52, 470-479. DOI URL PMID
[42]	Walther GR, Beißner S, Pott R (2005). Climate change and high mountain vegetation shifts. In: Broll G, Keplin B eds. Mountain Ecosystems, Studies in Treeline Ecology. Springer, Berlin. 77-95.
[43]	Walther GR, Post E, Convey P, Menzel A, Parmesan C, Beebee TJC, Fromentin JM, Guldberg OH, Bairlein F (2002). Ecological responses to recent climate change. Nature, 416, 389-395. DOI URL PMID
[44]	West AW (1986). Improvement of the selective respiratory inhibition technique to measure eukaryote: prokaryote ratios in soils. Journal of Microbiological Methods, 5, 125-138.
[45]	Wu JS (吴金水) (2006). Soil Microbial Biomass Measurement Method and Its Application (土壤微生物生物量测定方法及其应用). China Meteorological Press, Beijing. (in Chinese)
[46]	Wu FZ, Yang WQ, Zhang J, Deng RJ (2010). Litter decomposition in two subalpine forests during the freeze-thaw season. Acta Oecologica, 36, 135-140.
[47]	Yang WQ (杨万勤), Zhang J (张健), Hu TX (胡庭兴) (2006). Forest Soil Ecology (森林土壤生态学). Sichuan Science and Technology Press, Chengdu. (in Chinese)
[48]	Zhou XQ (周晓庆), Wu FZ (吴福忠), Yang WQ (杨万勤), Zhu JX (朱剑霄) (2011). Dynamics of microbial biomass during litter decomposition in the alpine forest. Acta Ecologica Sinica (生态学报), 31, 4144-4152. (in Chinese with English abstract)