气候变化领域集成服务门户(CCPortal): Causes for the unimodal pattern of biomass and productivity in alpine grasslands along a large altitudinal gradient in semi-arid regions

CCPortal

DOI	10.1111/j.1654-1103.2012.01442.x
	Causes for the unimodal pattern of biomass and productivity in alpine grasslands along a large altitudinal gradient in semi-arid regions
	Wang, Zhong; Luo, Tianxiang; Li, Ruicheng; Tang, Yanhong; Du, Mingyuan
通讯作者	Luo, TX (通讯作者)
发表日期	2013
ISSN	1100-9233
EISSN	1654-1103
起始页码	189
结束页码	201
卷号	24 期号:1
英文摘要	Questions How can we understand the limitations to plant growth at high altitudes? Our aim was to test the hypotheses that for alpine grasslands along a large altitudinal gradient in semi-arid regions, plant growth is mainly limited by drought at low altitudes but by low temperature at high altitudes, resulting in a unimodal pattern of biomass and productivity associated with an optimal combination of temperature and precipitation. Such knowledge is important to understanding the response of alpine ecosystems to climate change. Location We conducted a 5-yr livestock exclosure experiment along the south-facing slope of the Nyaiqentanglha Mountains, central Tibetan Plateau. Methods We measured above- and below-ground biomass, species richness, leaf d13C and water potential, and related climate and soil variables across 42 fenced and unfenced quadrats near seven HOBO weather stations along the slope. The vegetation changed from alpine steppe-meadow at 43904500 m to alpine meadow at 46005210 m. Results Total above- and below-ground biomass across fenced and unfenced quadrats increased with increasing altitude up to 49505100 m, and then decreased above 5100 m. Altitudinal trends in leaf d13C and water potential of dominant species also showed a unimodal pattern corresponding to that of vegetation biomass. Total above- and below-ground biomass as well as sedge above-ground biomass all showed a quadratic relationship with mean temperatures and the ratio of growing season precipitation (GSP) to =5 degrees C accumulated temperature (AccT; R2 = 0.83-0.88, P < 0.001). In general, above- and below-ground biomass increased with increasing water availability when the GSP/AccT ratio was lower than the threshold level of 0.800.84, but decreased when the GSP/AccT ratio was higher than this threshold level. No significant relationship was found between residuals of above-ground biomass and species richness after removing the effects of climate factors on both stand variables. Conclusions The results support our hypotheses, further suggesting a threshold of water limitation that is consistent with the model prediction over the Tibetan Plateau. Species richness per se appears to weakly affect community-level productivity. The response of alpine grasslands to climate warming may vary with altitude because of altitudinal shifts in factors limiting plant growth.
关键词	CARBON-ISOTOPE DISCRIMINATION NET PRIMARY PRODUCTIVITY SPECIES-DIVERSITY ENVIRONMENTAL-FACTORS NITROGEN LIMITATION PLANT-COMMUNITIES NATURAL-ABUNDANCE DELTA-C-13 PRECIPITATION VEGETATION
英文关键词	Alpine grassland; Biomass; Functional groups; Leaf water potential; Net primary productivity; Plant-climate interactions; Species richness
语种	英语
WOS研究方向	Plant Sciences ; Environmental Sciences & Ecology ; Forestry
WOS类目	Plant Sciences ; Ecology ; Forestry
WOS记录号	WOS:000312156600020
来源期刊	JOURNAL OF VEGETATION SCIENCE
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/258185
推荐引用方式 GB/T 7714	Wang, Zhong,Luo, Tianxiang,Li, Ruicheng,et al. Causes for the unimodal pattern of biomass and productivity in alpine grasslands along a large altitudinal gradient in semi-arid regions[J]. 中国科学院青藏高原研究所,2013,24(1).
APA	Wang, Zhong,Luo, Tianxiang,Li, Ruicheng,Tang, Yanhong,&Du, Mingyuan.(2013).Causes for the unimodal pattern of biomass and productivity in alpine grasslands along a large altitudinal gradient in semi-arid regions.JOURNAL OF VEGETATION SCIENCE,24(1).
MLA	Wang, Zhong,et al."Causes for the unimodal pattern of biomass and productivity in alpine grasslands along a large altitudinal gradient in semi-arid regions".JOURNAL OF VEGETATION SCIENCE 24.1(2013).