Effect of shrub coverage on grassland ecosystem carbon pool in southwestern China

doi:10.17521/cjpe.2017.0062

Abstract

Abstract:

AimsThe grassland in southwestern China is mainly warm and tropical grass and shrub grassland, accounting for approximately one-tenth of the national grassland area. Analysis of the relationship between shrub coverage and the grassland carbon pool and its composition is of great significance for accurately assessing carbon storage in the southwestern grassland, which grassland is still in the secondary succession stage.
MethodsIn a field investigation, 41 representative plots of different geomorphic types in southwestern China were divided into three types according to shrub coverage: no shrub grassland community (shrub coverage is 0), low shrub coverage grassland community (shrub coverage is 0-10%) and high shrub coverage grassland community (shrub coverage is 10%-30%). Carbon density was calculated by measuring the aboveground and underground biomass and litter biomass of grassland communities at different shrub coverage levels, as well as plant and soil carbon content.
Important findings The results showed that with increasing shrub coverage and species richness in grasslands, the ecosystem vegetation carbon density increased from 0.304 kg·m ^-2 to 1.574 kg·m ^-2, and the roots and litter carbon density also showed growth trends. The soil carbon density increased from 7.215 kg·m ^-2 to 9.735 kg·m ^-2, and the ecosystem carbon density increased from 7.519 kg·m ^-2 to 11.309 kg·m ^-2, with increasing shrub coverage. Regarding the composition of the grassland carbon pool, the soil carbon pool of the low shrub coverage grassland accounted for the smallest proportion of the ecosystem carbon pool. In summary, the increase in shrub coverage changes the composition of the grassland ecosystem carbon pool and leads to an increase in the amount of ecosystem carbon. Therefore, when estimating the grassland ecosystem carbon pool, it is necessary to overall plan for and take into account the changes in grassland shrub coverage in southern China.

http://jtp.cnki.net/bilingual/detail/html/ZWSB201904009

Key words: southwestern China, grassland community, shrub coverage, vegetation carbon pool, soil carbon pool

XUE Jing-Yue, WANG Li-Hua, XIE Yu, GAO Jing, HE Jun-Dong, WU Yan. Effect of shrub coverage on grassland ecosystem carbon pool in southwestern China[J]. Chin J Plant Ecol, 2019, 43(4): 365-373.

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https://www.plant-ecology.com/EN/Y2019/V43/I4/365

Figures/Tables 5

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地点 Place	样地数 No. of sites	经度 Longitude (E)	纬度 Latitude (N)	海拔 Altitude (m)	地貌类型 Landform	样地编号 Site number
四川达州 Dazhou, Sichuan	2	107.60°-108.18°	31.86°-32.17°	1 055-1 060	盆周山地 Mountain area of basin	7, 14
四川绵阳 Mianyang, Sichuan	1	102.09°	26.93°	1 296	紫色丘陵区 Purple hilly area	8
四川雅安 Ya’an, Sichuan	3	102.49°-102.87°	29.29°-29.61°	1 171-1 592	盆周山地 Mountain area of basin	10, 15, 37
四川凉山 Liangshan, Sichuan	15	102.03°-103.77°	26.26°-29.08°	1 042-1 998	干热河谷及中山区 Dry-hot valley and Middle mountain	2, 4, 5, 6, 13, 19, 20, 21, 23, 24, 31, 32, 36, 39, 41
四川攀枝花 Panzhihua, Sichuan	5	101.73°-101.85°	26.42°-26.82°	1 044-1 398	干热河谷 Dry-hot valley	1, 3, 9, 17, 18
云南曲靖 Qujing, Yunnan	3	103.47°-104.27°	24.83°-26.77°	1 669-1 948	滇中丘陵区 Central Yunnan hilly area	33, 34, 35
云南红河 Honghe, Yunnan	1	103.74°	24.36°	1 851	干热河谷 Dry-hot valley	25
云南昆明 Kunming, Yunnan	1	102.41°	26.27°	1 184	滇中丘陵区 Central Yunnan hilly area	11
重庆 Chongqing	8	108.71°-109.14°	30.58°-32.06°	1 201-1 886	盆周山地 Mountain area of basin	16, 26, 27, 28, 29, 30, 38, 40
贵州黔南 Qiannan, Guizhou	2	105.08°-106.84°	25.28°-26.34°	1 469-1 504	喀斯特石漠化山区 Karst rocky desertification mountain area	12, 22

地点 Place	样地数 No. of sites	经度 Longitude (E)	纬度 Latitude (N)	海拔 Altitude (m)	地貌类型 Landform	样地编号 Site number
四川达州 Dazhou, Sichuan	2	107.60°-108.18°	31.86°-32.17°	1 055-1 060	盆周山地 Mountain area of basin	7, 14
四川绵阳 Mianyang, Sichuan	1	102.09°	26.93°	1 296	紫色丘陵区 Purple hilly area	8
四川雅安 Ya’an, Sichuan	3	102.49°-102.87°	29.29°-29.61°	1 171-1 592	盆周山地 Mountain area of basin	10, 15, 37
四川凉山 Liangshan, Sichuan	15	102.03°-103.77°	26.26°-29.08°	1 042-1 998	干热河谷及中山区 Dry-hot valley and Middle mountain	2, 4, 5, 6, 13, 19, 20, 21, 23, 24, 31, 32, 36, 39, 41
四川攀枝花 Panzhihua, Sichuan	5	101.73°-101.85°	26.42°-26.82°	1 044-1 398	干热河谷 Dry-hot valley	1, 3, 9, 17, 18
云南曲靖 Qujing, Yunnan	3	103.47°-104.27°	24.83°-26.77°	1 669-1 948	滇中丘陵区 Central Yunnan hilly area	33, 34, 35
云南红河 Honghe, Yunnan	1	103.74°	24.36°	1 851	干热河谷 Dry-hot valley	25
云南昆明 Kunming, Yunnan	1	102.41°	26.27°	1 184	滇中丘陵区 Central Yunnan hilly area	11
重庆 Chongqing	8	108.71°-109.14°	30.58°-32.06°	1 201-1 886	盆周山地 Mountain area of basin	16, 26, 27, 28, 29, 30, 38, 40
贵州黔南 Qiannan, Guizhou	2	105.08°-106.84°	25.28°-26.34°	1 469-1 504	喀斯特石漠化山区 Karst rocky desertification mountain area	12, 22

灌木植物盖度 Shrub coverage	样地编号 Plots No.	草地类型 Vegetation types	主要物种 Main species
I	2, 5, 11, 13, 16, 20, 21, 23, 24, 30, 33, 34, 35, 37, 38, 39, 40, 41	暖性草丛, 白茅型 Warm-temperate tussock, Imperata cylindrica grassland type	白茅、荩草、车前、老鹳草、小蓬草、天名精 Imperata cylindrica, Arthraxon hispidus, Plantago asiatica, Geranium wilfordii, Conyza canadensis, Carpesium abrotanoides
II	1, 3, 4, 8, 9, 10, 12, 14, 15, 17, 18, 19, 22, 25, 27, 29, 31, 32	热性灌草丛, 具灌木的扭黄茅型 Tropical shrub tussock, Heteropogon contortus grassland type	车桑子、川滇绣线菊、野蔷薇、马桑、扭黄茅、野古草属植物 Dodonaea viscosa, Spiraea schneideriana, Rosa multiflora, Coriaria nepalensis, Heteropogon contortus, Arundinella spp.
III	6, 7, 26, 28, 36	暖性灌草丛, 具灌木的荩草型Warm-temperate shrub tussock, Arthraxon hispidus grassland type	车桑子、川滇绣线菊、野蔷薇、火棘、蜡莲绣球、悬钩子属植物、车前、风轮菜、荩草、老鹳草 Dodonaea viscosa, Spiraea schneideriana, Rosa multiflora, Pyracantha fortuneana, Hydrangea strigosa, Rubus ssp., Plantago asiatica, Clinopodium chinense, Arthraxon hispidus, Geranium wilfordii

灌木植物盖度 Shrub coverage	样地编号 Plots No.	草地类型 Vegetation types	主要物种 Main species
I	2, 5, 11, 13, 16, 20, 21, 23, 24, 30, 33, 34, 35, 37, 38, 39, 40, 41	暖性草丛, 白茅型 Warm-temperate tussock, Imperata cylindrica grassland type	白茅、荩草、车前、老鹳草、小蓬草、天名精 Imperata cylindrica, Arthraxon hispidus, Plantago asiatica, Geranium wilfordii, Conyza canadensis, Carpesium abrotanoides
II	1, 3, 4, 8, 9, 10, 12, 14, 15, 17, 18, 19, 22, 25, 27, 29, 31, 32	热性灌草丛, 具灌木的扭黄茅型 Tropical shrub tussock, Heteropogon contortus grassland type	车桑子、川滇绣线菊、野蔷薇、马桑、扭黄茅、野古草属植物 Dodonaea viscosa, Spiraea schneideriana, Rosa multiflora, Coriaria nepalensis, Heteropogon contortus, Arundinella spp.
III	6, 7, 26, 28, 36	暖性灌草丛, 具灌木的荩草型Warm-temperate shrub tussock, Arthraxon hispidus grassland type	车桑子、川滇绣线菊、野蔷薇、火棘、蜡莲绣球、悬钩子属植物、车前、风轮菜、荩草、老鹳草 Dodonaea viscosa, Spiraea schneideriana, Rosa multiflora, Pyracantha fortuneana, Hydrangea strigosa, Rubus ssp., Plantago asiatica, Clinopodium chinense, Arthraxon hispidus, Geranium wilfordii

灌木植物盖度 Shrub coverage	植被碳库 Carbon pool of vegetation (kg·m^-2)	土壤碳库 Soil carbon pool (kg·m^-2)	生态系统碳库 Carbon pool of ecosystem (kg·m^-2)	0-50 cm土层碳库 Soil carbon pool of 0-50 cm layer (kg·m^-2)	植被碳库占生态系统碳库比例 Ratio of vegetation and ecosystem (%)	土壤碳库占生态系统碳库比例 Ratio of soil and ecosystem (%)
I	0.304 ± 0.036^a	7.215 ± 0.507^a	7.519 ± 0.505^a	6.870 ± 0.468^a	4.33 ± 0.79^a	95.67 ± 0.79^a
II	1.407 ± 0.204^b	6.031 ± 0.736^a	7.438 ± 0.717^a	5.485 ± 0.722^a	19.70 ± 3.57^b	80.30 ± 3.57^b
III	1.574 ± 0.675^b	9.735 ± 0.444^b	11.309 ± 1.011^b	7.166 ± 0.374^b	12.54 ± 4.36^ab	87.46 ± 4.36^ab
F	11.459	1.610	5.734	1.287	9.053	9.053
p	<0.001	0.213	0.007	0.288	0.001	0.001