Effect of change of plant community composition along degradation gradients on water conditions in an alpine swamp wetland on the Qinghai-Tibetan Plateau of China

doi:10.3724/SP.J.1258.2012.00403

Abstract

Abstract:

Aims Wetlands degradation has drawn increased concern recently. Many researchers have reported the changes of plant communities and the relevant degradation mechanism of wetlands. However, few studies have explored the effects of plant community change on the water conditions of swamp meadow. Our objective was to investigate how change of alpine swamp meadow along degradation gradients affects its water conditions.
Methods The study was conducted at the Research Station of Alpine Meadow and Wetland Ecosystems of Lanzhou University (Maqu Branch Station) (33°39′ N, 101°53′ E). We examined 47 species (15 families) selected from a degradation gradient of alpine swamp meadow. Net photosynthesis rate (P_n), transpiration rate (T_r) and stomatal conductance (G_s) were measured simultaneously with a portable gas exchange system LI-6400 (Li-COR, Lincoln, NE, USA). Measurements were performed from 9:00 am to 12:00 am on clear days in mid-July and mid-August, using photosynthetically active radiation (PAR) = 1 800 μmol·m^-2·s^-1and flow = 750 μmol·s^-1. The value of water use efficiency (WUE) was determined by P_n/T_r. We also investigated the cover of different functional groups (grasses, sedges, legumes and other forbs) at different degradation levels.
Important findings The photosynthetic physiology traits were different among species and functional groups (p < 0.01). The sequence of P_n values of functional groups was grasses > sedges > legumes and other forbs, and WUE was sedges > grasses > legumes and other forbs. Species composition of the plant community had been changed due to the degradation of the swamp meadow. The abundance of forbs increased with degradation. WUE was lower for forbs than other functional groups, which implied that more soil water is transpired, exacerbating the drought condition of degraded meadows. Successful restoration requires protection and replenishment of the typical native species.

Key words: alpine wetland, degradation, photosynthetic physiology trait, plant community, water use efficiency

LI Hong-Lin, XU Dang-Hui, DU Guo-Zhen. Effect of change of plant community composition along degradation gradients on water conditions in an alpine swamp wetland on the Qinghai-Tibetan Plateau of China[J]. Chin J Plant Ecol, 2012, 36(5): 403-410.

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Figures/Tables 5

References 25

[1]	Anonymous (1993). Introduction: water-use in relation to productivity. In: Ehleringer JR, Hall AE, Farquhar GD eds. Stable Isotopes and Plant Carbon-Water Relations. Academic Press, New York. 3-8.
[2]	Chen SP, Bai YF, Lin GH, Liang Y, Han XG (2005). Effects of grazing on photosynthetic characteristics of major steppe species in the Xilin River Basin, Inner Mongolia, China. Photosynthetica, 43, 559-565.
[3]	Chu CJ, Maestre FT, Xiao S, Weiner J, Wang YS, Duan ZH, Wang G (2008). Balance between facilitation and resource competition determines biomass―density relationships in plant populations. Ecology Letters, 11, 1189-1197. DOI URL PMID
[4]	Cyranoski D (2009). Putting China’s wetlands on the map. Nature, 458, 134. URL PMID
[5]	Díaz S, Lavorel S, McIntyer S, Falczuk V, Casanoves F, Milchunas DG, Skarpe C, Rush G, Sternberg M, Noy-Meir I, Landsberg J, Zhang W, Clark H, Campbell BD (2007). Plant trait responses to grazing―a global synthesis. Global Change Biology, 13, 313-341.
[6]	Farquhar GD, Ehleringer JR, Hubick KT (1989). Carbon isotope discrimination and photosynthesis. Annual Review of Plant Physiology and Plant Molecular Biology, 40, 503-537.
[7]	Hamid A, Agata W, Kawamitsu Y (1990). Photosynthesis, transpiration and water use efficiency in four cultivars of mungbean, Vigna radiata(L.) Wilczek. Photosynthetica, 24, 96-101.
[8]	Heschel MS, Donohue K, Hausmann N, Schmitt J (2002). Population differentiation and natural selection for water- use efficiency in Impatiens capensis(Balsaminaceae). International Journal of Plant Science, 163, 907-912.
[9]	Hou Y (后源), Guo ZG (郭正刚), Long RJ (龙瑞军) (2009). Changes of plant community structure and species diversity in degradation process of Shouqu wetland of Yellow River. Chinese Journal of Applied Ecology (应用生态学报), 20, 27-32. (in Chinese with English abstract)
[10]	Jiang GM (蒋高明), He WM (何维明) (1999). Species- and habitat-variability of photosynthesis, transpiration and water use efficiency of different plant species in Maowusu Sand Area. Acta Botanica Sinica (植物学报), 41, 1114-1124. (in Chinese with English abstract)
[11]	Kramer PJ, Kozlowski TT (1979). Physiology of Woody Plants. Academic Press, London. 443-444.
[12]	Li WL (李文龙), Li ZZ (李自珍), Wang G (王刚) (2004). Meadow conservation and optimal utilization of the alpine wetland in the Western China. Acta Botanica Boreali- Occidentalia Sinica (西北植物学报), 24, 1640-1645. (in Chinese with English abstract)
[13]	Li ZZ (李自珍), Han XZ (韩晓卓), Li WW (李文龙), Du GZ (杜国祯) (2004). Conservation of species diversity and strategies of ecological restoration in alpine wetland plant community. Acta Botanica Boreali-Occidentalia Sinica (西北植物学报), 24, 363-369. (in Chinese with English abstract)
[14]	Niu SL (牛书丽), Jiang GM (蒋高明), Gao LM (高雷明), Li YG (李永庚), Liu MZ (刘美珍) (2003). Comparison of gas exchange traits of different plant species in Hunshandak Sand Area. Acta Phytoecologica Sinica (植物生态学报), 27, 318-324. (in English with Chinese abstract)
[15]	Niu SW (牛叔文), Ma LB (马利邦), Zeng MM (曾明明) (2008). Effect of overgrazing on grassland desertification in Maqu County. Acta Ecologica Sinica (生态学报), 28, 145-153. (in Chinese with English abstract)
[16]	Pan XB, Zhang JY, Luo ZK, Mao LM, Jin HG, Guo LP, Bi XL, Zhao YP (2011). Natural wetland in China. African Journal of Environmental Science and Technology, 5, 45-55.
[17]	Smith EC, Griffiths H (1998). Intraspecific variation in photosynthetic responses of trebouxioid lichens with reference to the activity of a carbon-concentrating mechanism. Oecologia, 113, 360-439. URL PMID
[18]	Suding KN, Collins SL, Gough L, Clark C, Cleland EE, Gross KL, Milchunas DG, Pennings S (2005). Functional- and abundance-based mechanisms explain diversity loss due to N fertilization. Proceedings of the National Academy of Sciences of the United States of America, 102, 4387-4392. URL PMID
[19]	Wang GX (王根绪), Li YS (李元寿), Wang YB (王一博), Chen L (陈玲) (2007). Typical alpine wetland system changes on the Qinghai-Tibet Plateau in recent 40 years. Acta Geographica Sinica (地理学报), 62, 481-491. (in Chinese with English abstract)
[20]	Wang SP (王素萍), Song LC (宋连春), Han YX (韩永翔), Feng JY (冯建英) (2006). Impacts of climate change on ecological environment in Maqu grassland, Gansu. Journal of Glaciology and Geocryology (冰川冻土), 28, 556-561. (in Chinese with English abstract)
[21]	Wang YS, Chu CJ, Maestre FT, Wang G (2008). On the relevance of facilitation in alpine meadow communities: an experimental assessment with multiple species differing in their ecological optimum. Acta Oecologica, 33, 108-113.
[22]	Xu XL (徐新良), Liu JY (刘纪远), Shao QQ (邵全琴), Fan JW (樊江文) (2007). The dynamic changes of ecosystem spatial pattern and structure in the Three-River Headwaters region in Qinghai Province during recent 30 years. Geographical Research (地理研究), 27, 829-838. (in Chinese with English abstract)
[23]	Yang YX (杨永兴) (1999). Ecological environment deterioration, mire degeneration and their formation mechanism in the Zoige Plateau. Journal of Mountain Science (山地学报), 17, 318-323. (in Chinese with English abstract)
[24]	Zhang M (张明), Wang WJ (王文进), Liu DF (刘福德), An SQ (安树青), Zheng JW (郑建伟), Zhang ST (张世挺), Wang ZS (王中生), Xu HG (徐海根) (2007). Photosynthetic capacity and water use efficiency of tropical montane rainforest seedlings or saplings in Hainan Island. Chinese Journal of Applied Ecology (应用生态学报), 18, 2160-2166. (in Chinese with English abstract) URL PMID
[25]	Zhang XY (张晓云), Lü XG (吕宪国), Gu HJ (顾海军) (2005). To analysis threats, to describe present conservation situation and to provide management advices of the Ruoergai Marshes. Wetland Science (湿地科学), 3, 292-297. (in Chinese with English abstract)

退化梯度 Degradation gradient	主要植物种 Main plant species	盖度 Coverage (%)	高度 Height (cm)	土壤含水量 Soil water content (v/v %)
典型湿地 Typical wetland	乌拉薹草 Carex meyeriana、华扁穗草 Blysmus sinocompressus	85-98	36.7 ± 1.44	56.9 ± 0.77
中度退化 Moderate degradation	线叶嵩草 Kobresia capilifolia、垂穗披碱草Elymus nutans、鹅绒委陵菜 Potentilla anserina、矮地榆 Sanguisorba filiformis、甘松 Nardostachys chinensis	90-95	24.3 ± 0.87	49.4 ± 0.63
重度退化 Heavy degradation	甘肃薹草 Carex kansuensis、胡氏剪股颖 Agrostis hugoniana、鹅绒委陵菜 Potentilla anserina、长毛风毛菊 Saussurea hieracioides、巴天酸模 Rumex patientia、黄帚橐吾 Ligularia virgaurea	87-94	9.5 ± 0.49	43.3 ± 1.00

退化梯度 Degradation gradient	主要植物种 Main plant species	盖度 Coverage (%)	高度 Height (cm)	土壤含水量 Soil water content (v/v %)
典型湿地 Typical wetland	乌拉薹草 Carex meyeriana、华扁穗草 Blysmus sinocompressus	85-98	36.7 ± 1.44	56.9 ± 0.77
中度退化 Moderate degradation	线叶嵩草 Kobresia capilifolia、垂穗披碱草Elymus nutans、鹅绒委陵菜 Potentilla anserina、矮地榆 Sanguisorba filiformis、甘松 Nardostachys chinensis	90-95	24.3 ± 0.87	49.4 ± 0.63
重度退化 Heavy degradation	甘肃薹草 Carex kansuensis、胡氏剪股颖 Agrostis hugoniana、鹅绒委陵菜 Potentilla anserina、长毛风毛菊 Saussurea hieracioides、巴天酸模 Rumex patientia、黄帚橐吾 Ligularia virgaurea	87-94	9.5 ± 0.49	43.3 ± 1.00

功能群 Functional group	净光合速率P_n Net photosynthesis rate (μmol CO₂·m^-2·s^-1)	气孔导度G_s Stomatal conductance (mmol·m^-2·s^-1)	蒸腾速率T_r Transpiration rate (mmol H₂O·m^-2·s^-1)	水分利用效率WUE Water use efficiency (μmol CO₂·mmol^-1 H₂O)
禾草 Grass	54.5 ± 1.79^a	0.13 ± 0.11^a	14.2 ± 0.28^a	3.9 ± 0.18^b
莎草 Sedge	58.2 ± 2.64^a	0.41 ± 0.02^b	9.2 ± 0.52^b	6.6 ± 0.14^a
豆科 Legume	32.0 ± 1.78^b	0.46 ± 0.02^bc	9.7 ± 0.45^b	3.5 ± 0.17^bc
其他双子叶类杂草 Other forb	33.0 ± 0.93^b	0.53 ± 0.01^c	10.0 ± 0.16^b	3.2 ± 0.06^c

功能群 Functional group	净光合速率P_n Net photosynthesis rate (μmol CO₂·m^-2·s^-1)	气孔导度G_s Stomatal conductance (mmol·m^-2·s^-1)	蒸腾速率T_r Transpiration rate (mmol H₂O·m^-2·s^-1)	水分利用效率WUE Water use efficiency (μmol CO₂·mmol^-1 H₂O)
禾草 Grass	54.5 ± 1.79^a	0.13 ± 0.11^a	14.2 ± 0.28^a	3.9 ± 0.18^b
莎草 Sedge	58.2 ± 2.64^a	0.41 ± 0.02^b	9.2 ± 0.52^b	6.6 ± 0.14^a
豆科 Legume	32.0 ± 1.78^b	0.46 ± 0.02^bc	9.7 ± 0.45^b	3.5 ± 0.17^bc
其他双子叶类杂草 Other forb	33.0 ± 0.93^b	0.53 ± 0.01^c	10.0 ± 0.16^b	3.2 ± 0.06^c

植物种 Plant species	科 Family	P_n (μmol CO₂·m^-2·s^-1)	G_s (mmol·m^-2·s^-1)	T_r (mmol H₂O·m^-2·s^-1)	WUE (μmol CO₂·mmol^-1 H₂O)
草	禾本科	59.4 ± 0.94	0.07 ± 0.00	12.2 ± 0.34	4.9 ± 0.06
Koeleria macrantha	Gramineae
密花早熟禾	禾本科	44.2 ± 0.85	0.16 ± 0.00	15.1 ± 0.32	2.9 ± 0.02
Poa pachyantha	Gramineae
垂穗披碱草	禾本科	46.0 ± 1.19	0.23 ± 0.01	15.8 ± 0.51	2.9 ± 0.02
Elymus nutans	Gramineae
胡氏剪股颍	禾本科	71.2 ± 1.61	0.06 ± 0.00	13.2 ± 0.18	5.4 ± 0.19
Agrostis hugoniana	Gramineae
大华嵩草	莎草科	65.0 ± 0.58	0.43 ± 0.02	10.1 ± 0.32	6.5 ± 0.28
Kobresia macrantha	Cyperaceae
乌拉薹草	莎草科	27.7 ± 1.39	0.17 ± 0.01	3.9 ± 0.22	7.2 ± 0.18
Carex meyeriana	Cyperaceae
甘肃薹草	莎草科	65.2 ± 3.25	0.51 ± 0.06	11.0 ± 1.09	6.4 ± 0.44
Carex kansuensis	Cyperaceae
华扁穗草	莎草科	70.2 ± 1.29	0.54 ± 0.01	11.6 ± 0.22	6.1 ± 0.11
Blysmus sinocompressus	Cyperaceae
线叶嵩草	莎草科	75.8 ± 0.21	0.40 ± 0.00	11.0 ± 0.05	6.9 ± 0.02
Kobresia capilifolia	Cyperaceae
唐古特岩黄芪	豆科	25.7 ± 1.13	0.21 ± 0.03	5.8 ± 0.60	4.8 ± 0.36
Hedysarum tanguticum	Leguminosae
高山豆	豆科	30.8 ± 0.54	0.55 ± 0.02	12.3 ± 0.42	2.5 ± 0.09
Tibetia himalaica	Leguminosae
多枝黄芪	豆科	40.3 ± 0.97	0.39 ± 0.03	10.7 ± 0.68	3.9 ± 0.21
Astragalus polycladus	Leguminosae
广布野豌豆	豆科	67.0 ± 1.76	0.63 ± 0.00	14.6 ± 0.09	4.6 ± 0.15
Vicia cracca	Leguminosae
甘肃棘豆	豆科	19.8 ± 0.59	0.61 ± 0.02	8.2 ± 0.22	2.4 ± 0.04
Oxytropis kansuensis	Leguminosae
莓叶委陵菜	蔷薇科	25.5 ± 2.08	0.15 ± 0.02	7.9 ± 0.83	3.3 ± 0.08
Potentilla fragarioides	Rosaceae
矮地榆	蔷薇科	37.3 ± 0.32	0.61 ± 0.03	10.6 ± 0.18	3.5 ± 0.04
Sanguisorba filiformis	Rosaceae
鹅绒委陵菜	蔷薇科	26.3 ± 0.44	0.54 ± 0.00	10.6 ± 0.17	2.5 ± 0.01
Potentilla anserine	Rosaceae
青藏大戟	大戟科	41.3 ± 2.21	0.07 ± 0.00	9.2 ± 0.32	4.5 ± 0.10
Euphorbia altotibetica	Euphorbiaceae
湿生扁蕾	龙胆科	19.5 ± 0.94	0.44 ± 0.01	9.0 ± 0.36	2.2 ± 0.06
Gentianopsis paludosa	Gentianaceae
椭圆叶花锚	龙胆科	31.3 ± 1.00	0.61 ± 0.04	9.6 ± 0.41	3.3 ± 0.11
Halenia elliptica	Gentianaceae
麻花艽	龙胆科	20.7 ± 0.85	0.33 ± 0.02	6.1 ± 0.21	3.5 ± 0.29
Gentiana straminea	Gentianaceae
长毛风毛菊	菊科	19.4 ± 0.23	0.71 ± 0.02	8.3 ± 0.10	2.3 ± 0.02
Saussurea hieracioides	Compositae
黄帚橐吾	菊科	19.8 ± 0.13	0.73 ± 0.02	9.7 ± 0.15	2.0 ± 0.04
Ligularia virgaurea	Compositae
侧茎垂头菊	菊科	23.3 ± 0.09	0.50 ± 0.01	8.0 ± 0.06	2.9 ± 0.01
Cremanthodium pleurocaule	Compositae
植物种 Plant species	科 Family	P_n (μmol CO₂·m^-2·s^-1)	G_s (mmol·m^-2·s^-1)	T_r (mmol H₂O·m^-2·s^-1)	WUE (μmol CO₂·mmol^-1 H₂O)
铃铃香青	菊科	46.6 ± 1.62	0.55 ± 0.05	10.3 ± 0.69	5.0 ± 0.57
Anaphalis hancockii	Compositae
香芸火绒草	菊科	65.7 ± 4.26	0.75 ± 0.09	13.8 ± 1.40	5.0 ± 0.25
Leontopodium haplophylloides	Compositae
大籽蒿	菊科	27.0 ± 2.19	0.54 ± 0.03	9.2 ± 0.36	2.9 ± 0.18
Artemisia sieversiana	Compositae
缘毛紫菀	菊科	25.4 ± 0.10	0.53 ± 0.01	9.0 ± 0.02	2.8 ± 0.02
Aster souliei	Compositae
珠芽蓼	蓼科	19.7 ± 0.16	0.45 ± 0.01	7.1 ± 0.12	2.8 ± 0.07
Polygonum viviparum	Polygonaceae
巴天酸模	蓼科	20.2 ± 0.79	0.40 ± 0.03	7.2 ± 0.32	2.8 ± 0.07
Rumex patientia	Polygonaceae
水生酸模	蓼科	17.0 ± 0.93	0.26 ± 0.01	6.5 ± 0.13	2.6 ± 0.11
Rumex aquaticus	Polygonaceae
西伯利亚蓼	蓼科	32.0 ± 0.72	0.61 ± 0.01	10.4 ± 0.17	3.1 ± 0.07
Polygonum sibiricum	Polygonaceae
小花草玉梅	毛茛科	19.3 ± 0.59	0.47 ± 0.02	10.3 ± 0.15	1.9 ± 0.05
Anemone rivularis var. flore-minore	Ranunculaceae
矮金莲花	毛茛科	22.0 ± 0.57	0.52 ± 0.05	9.4 ± 0.47	2.4 ± 0.07
Trollius farreri	Ranunculaceae
驴蹄草	毛茛科	20.5 ± 0.36	0.50 ± 0.02	8.7 ± 0.12	2.4 ± 0.08
Caltha palustris	Ranunculaceae
条叶银莲花	毛茛科	24.7 ± 0.92	0.46 ± 0.01	8.1 ± 0.22	3.1 ± 0.08
Anemone coelestina var. linearis	Ranunculaceae
丝叶毛茛	毛茛科	88.4 ± 1.46	0.67 ± 0.03	15.0 ± 0.52	5.9 ± 0.11
Panunculus tanguticus var. capillaceus	Ranunculaceae
高山唐松草	毛茛科	71.8 ± 3.55	0.44 ± 0.03	10.9 ± 0.64	6.7 ± 0.17
Thalictrum alpinum	Ranunculaceae
独一味	唇形科	19.3 ± 0.47	0.50 ± 0.01	9.0 ± 0.05	2.1 ± 0.04
Lamiophlomis rotata	Lamiaceae
矮泽芹	伞形科	38.6 ± 1.23	0.61 ± 0.01	10.2 ± 0.18	3.8 ± 0.07
Chamaesium paradoxum	Umbelliferae
甘松	败酱科	28.8 ± 0.29	0.42 ± 0.03	8.4 ± 0.38	3.5 ± 0.19
Nardostachys chinensis	Valerianaceae
平车前	车前科	24.6 ± 0.91	0.61 ± 0.03	11.5 ± 0.32	2.1 ± 0.07
Plantago depressa	Plantaginaceae
四川马先蒿	玄参科	77.9 ± 1.85	1.28 ± 0.04	22.4 ± 0.28	3.5 ± 0.08
Pedicularis szetschuanica	Scrophulariaceae
中国马先蒿	玄参科	30.5 ± 0.28	0.74 ± 0.01	13.0 ± 0.16	2.4 ± 0.04
Pedicularis chinensis	Scrophulariaceae
拟鼻花马先蒿	玄参科	61.3 ± 3.32	0.53 ± 0.05	12.9 ± 1.06	4.8 ± 0.14
Pedicularis rhinanthoides	Scrophulariaceae
肉果草	玄参科	26.2 ± 0.76	0.33 ± 0.02	7.4 ± 0.41	3.6 ± 0.11
Lancea tibetica	Scrophulariaceae
折被韭	百合科	52.9 ± 2.23	0.61 ± 0.01	12.2 ± 0.39	4.3 ± 0.05
Allium chrysocephalum	Liliaceae