控雪处理下红松和蒙古栎凋落叶分解动态

doi:10.17521/cjpe.2017.0184

摘要/Abstract

摘要：

气候变化导致的冬季雪被格局变化将改变地表水热环境及分解者活性, 从而显著影响高寒地区森林凋落物分解过程。2014-2016年采用凋落物分解袋法, 研究了帽儿山森林生态站人工林控雪模拟试验下红松(Pinus koraiensis)和蒙古栎(Quercus mongolica)的凋落叶于雪被期和无雪期不同阶段的分解动态。控雪试验包括增雪、除雪和对照3个处理。结果发现: 树种、控雪处理、分解阶段以及环境因子(凋落物层平均温度、冻融循环次数、有机层全氮、全磷含量等)均影响着凋落叶分解率。分解试验的两年内, 不同控雪处理下红松凋落叶的分解率为52.1%-54.5%, 蒙古栎为53.9%-59.1%。两种凋落叶的分解系数均以增雪处理最大, 除雪处理最小。此外, 控雪处理改变了两种凋落叶雪被期或无雪期对分解总量的贡献率。与对照相比, 增雪处理使红松和蒙古栎凋落叶雪被期的分解贡献率分别提高9.1%和10.4%; 而除雪处理使两种凋落叶无雪期的分解贡献率分别提高10.4%和12.7%。因此, 由气候变化带来的冬季雪被改变不但会显著影响温带森林凋落叶的分解过程, 而且会改变雪被期和无雪期的分解量对年分解总量的贡献率。

关键词: 控雪, 温带森林, 凋落物分解, 气候变化, 雪被期, 无雪期

Abstract:

Aims Changes in snowpack induced by climate change may alter water and heat regimes at the ground surface, thus influencing activities of decomposers and litter decomposition in snow-covered regions. However, effects of snow-depth changes on litter decomposition are unclear. Our objective was to characterize the decomposition dynamics of two contrasting tree species—Korean pine (Pinus koraiensis) and Mongolian oak (Quercus mongolica) in a snow-depth manipulation experiment.

Methods The snow-depth manipulation experiment that included three treatments (i.e., snow-addition, snow-removal, and control) was conducted in a temperate Korean pine plantation in the Maoershan Forest Ecosystem Research Station, Northeast China. Air-dried foliar litter of the pine or oak (10 g litter per bag) was sealed in a nylon litterbag (15 cm × 20 cm). A total of 648 litterbags (3 plots × 3 treatments × 2 tree species × 3 replicates × 12 sampling dates) were placed evenly on the forest floor in October 2014. Three replicate litterbags per species were buried in each treatment plot and sampled 12 times (i.e., freezing onset stage, deep freezing stage, thawing stage, early, middle and late snow-free seasons) during the two-year period (2014-2016) to determine the temporal variation of the decomposition rate. Associated factors (i.e., mean temperature at litter layer, freeze-thaw cycle, available nitrogen and phosphorus at the organic layer) were measured simultaneously.

Important findings Tree species, snow-depth treatment, decomposition stage, and the measured associated factors all influenced the decomposition rates of the foliar litter. The litter mass loss was 52.1%-54.5% for the pine, and 53.9%-59.1% for the oak during the two-year period. The decomposition coefficients for the litter of the two species were the highest in the snow-addition plot, and the lowest in the snow-removal plot. Moreover, the snow-depth manipulation dramatically changed the relative contribution of the mass loss (R ratio) during the snow-covered or snow-free seasons to the yearly total loss. Compared with the control, the snow-addition treatment increased the R ratio during the snow-covered season by 9.1% for the pine and 10.4% for the oak, while the snow-removal treatment increased the R ratio during the snow-free season by 10.4% and 12.7%, respectively. In conclusion, changes in snowpack induced by climate change may significantly affect the foliar decomposition in temperate forests, and also alter the relative contribution of the litter decomposition in the snow-covered and snow-free seasons to the yearly decomposition.

Key words: snow-depth manipulation, temperate forest, foliar litter decomposition, climate change, snow-covered season, snow-free season

武启骞, 王传宽. 控雪处理下红松和蒙古栎凋落叶分解动态. 植物生态学报, 2018, 42(2): 153-163. DOI: 10.17521/cjpe.2017.0184

WU Qi-Qian, WANG Chuan-Kuan. Dynamics in foliar litter decomposition for Pinus koraiensis and Quercus mongolica in a snow-depth manipulation experiment. Chinese Journal of Plant Ecology, 2018, 42(2): 153-163. DOI: 10.17521/cjpe.2017.0184

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链接本文: https://www.plant-ecology.com/CN/10.17521/cjpe.2017.0184

https://www.plant-ecology.com/CN/Y2018/V42/I2/153

图/表 9

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树种 Tree species	有机碳 Organic carbon (g·kg^-1)	全氮 Total nitrogen (g·kg^-1)	全磷 Total phosphorus (g·kg^-1)	碳/氮 C/N	碳/磷 C/P	氮/磷 N/P	木质素 Lignin (%)	纤维素 Cellulose (%)	木质素/氮 Lignin/N
红松 Pinus koraiensis	489.6 ± 1.4^a	4.5 ± 0.1^b	0.55 ± 0.01^b	107.0 ± 1.2^a	893.5 ± 6.1^a	8.1 ± 0.5^a	29.8 ± 0.3^a	14.6 ± 0.4^a	66.8 ± 0.2^a
蒙古栎 Quercus mongolica	458.8 ± 5.1^b	6.5 ± 0.1^a	1.30 ± 0.05^a	71.1 ± 0.6^b	351.7 ± 13.5^b	4.9 ± 0.2^b	16.1 ± 0.1^b	12.9 ± 0.1^b	25.0 ± 0.6^b

树种 Tree species	有机碳 Organic carbon (g·kg^-1)	全氮 Total nitrogen (g·kg^-1)	全磷 Total phosphorus (g·kg^-1)	碳/氮 C/N	碳/磷 C/P	氮/磷 N/P	木质素 Lignin (%)	纤维素 Cellulose (%)	木质素/氮 Lignin/N
红松 Pinus koraiensis	489.6 ± 1.4^a	4.5 ± 0.1^b	0.55 ± 0.01^b	107.0 ± 1.2^a	893.5 ± 6.1^a	8.1 ± 0.5^a	29.8 ± 0.3^a	14.6 ± 0.4^a	66.8 ± 0.2^a
蒙古栎 Quercus mongolica	458.8 ± 5.1^b	6.5 ± 0.1^a	1.30 ± 0.05^a	71.1 ± 0.6^b	351.7 ± 13.5^b	4.9 ± 0.2^b	16.1 ± 0.1^b	12.9 ± 0.1^b	25.0 ± 0.6^b

取样顺序 Sampling order	取样阶段 Sampling stage	取样日期 Sampling date	分解天数 Decomposing days
1	第一年冻结初期 1st year freezing onset stage	2014-12-02	49
2	第一年深冻期 1st year deep freezing stage	2015-03-18	145
3	第一年融化期 1st year thawing stage	2015-04-18	176
4	第一年无雪初期 1st year early snow-free season	2015-06-20	239
5	第一年无雪中期 1st year mid snow-free season	2015-08-20	300
6	第一年无雪末期 1st year late snow-free season	2015-10-20	366
7	第二年冻结初期 2nd year freezing onset stage	2015-12-25	407
8	第二年深冻期 2nd year deep freezing stage	2016-03-25	516
9	第二年融化期 2nd year thawing stage	2016-04-22	544
10	第二年无雪初期 2nd year early snow-free season	2016-06-20	603
11	第二年无雪中期 2nd year mid snow-free season	2016-08-22	666
12	第二年无雪末期 2nd year late snow-free season	2016-10-24	732

取样顺序 Sampling order	取样阶段 Sampling stage	取样日期 Sampling date	分解天数 Decomposing days
1	第一年冻结初期 1st year freezing onset stage	2014-12-02	49
2	第一年深冻期 1st year deep freezing stage	2015-03-18	145
3	第一年融化期 1st year thawing stage	2015-04-18	176
4	第一年无雪初期 1st year early snow-free season	2015-06-20	239
5	第一年无雪中期 1st year mid snow-free season	2015-08-20	300
6	第一年无雪末期 1st year late snow-free season	2015-10-20	366
7	第二年冻结初期 2nd year freezing onset stage	2015-12-25	407
8	第二年深冻期 2nd year deep freezing stage	2016-03-25	516
9	第二年融化期 2nd year thawing stage	2016-04-22	544
10	第二年无雪初期 2nd year early snow-free season	2016-06-20	603
11	第二年无雪中期 2nd year mid snow-free season	2016-08-22	666
12	第二年无雪末期 2nd year late snow-free season	2016-10-24	732

处理 Treatment	凋落物层平均温度 Average temperature in litter layer (°C)	凋落物层冻融循环 Freeze-thaw cycle in litter layer	有机层有机碳 Organic carbon in organic layer (g·kg^-1)	有机层全氮 Total nitrogen in organic layer (g·kg^-1)	有机层全磷 Total phosphorus in organic layer (g·kg^-1)	有机层碳/氮 C/N in organic layer	有机层碳/磷 C/P in organic layer	有机层氮/磷 N/P in organic layer
增雪 Snow-addition	4.4 ± 0.3^a	58 ± 1^c	81.4 ± 2.2^a	7.4 ± 0.2^a	1.3 ± 0.1^a	10.9 ± 0.2^b	62.4 ± 0.3^c	5.5 ± 0.2^c
对照 Control	3.8 ± 0.2^b	70 ± 1^b	75.4 ± 1.1^b	6.6 ± 0.3^b	0.9 ± 0.2^b	11.2 ± 0.2^b	83.9 ± 0.4^b	7.2 ± 0.1^b
除雪 Snow-removal	2.7 ± 0.5^c	84 ± 2^a	72.6 ± 0.6^c	6.1 ± 0.1^c	0.7 ± 0.1^c	12.0 ± 0.3^a	104.3 ± 0.6^a	8.7 ± 0.3^a