Different inter-annual responses to availability and form of nitrogen explain species coexistence in an alpine meadow community after release from grazing

	Different inter-annual responses to availability and form of nitrogen explain species coexistence in an alpine meadow community after release from grazing
	Song, Ming-Hua ; Yu, Fei-Hai ; Ouyang, Hua ; Cao, Guang-Min ; Xu, Xing-Liang ; Cornelissen, Johannes H. C.
刊名	GLOBAL CHANGE BIOLOGY ; Wang, YQ; Zhang, B; Liu, BL; Zhang, HG; Liu, DC.Different inter-annual responses to availability and form of nitrogen explain species coexistence in an alpine meadow community after release from grazing,GLOBAL CHANGE BIOLOGY,2012,18(10):3100-3111
	2012-10-01
英文摘要	Plant species and functional groups in nitrogen (N) limited communities may coexist through strong eco-physiological niche differentiation, leading to idiosyncratic responses to multiple nutrition and disturbance regimes. Very little is known about how such responses depend on the availability of N in different chemical forms. Here we hypothesize that idiosyncratic year-to-year responses of plant functional groups to availability and form of nitrogen explain species coexistence in an alpine meadow community after release from grazing. We conducted a 6year N addition experiment in an alpine meadow on the Tibetan Plateau released from grazing by livestock. The experimental design featured three N forms (ammonium, nitrate, and ammonium nitrate), crossed with three levels of N supply rates (0.375, 1.500 and 7.500gNm-2yr-1), with unfertilized treatments without and with light grazing as controls. All treatments showed increasing productivity and decreasing species richness after cessation of grazing and these responses were stronger at higher N rates. Although N forms did not affect aboveground biomass at community level, different functional groups did show different responses to N chemical form and supply rate and these responses varied from year to year. In support of our hypothesis, these idiosyncratic responses seemed to enable a substantial diversity and biomass of sedges, forbs, and legumes to still coexist with the increasingly productive grasses in the absence of grazing, at least at low and intermediate N availability regimes. This study provides direct field-based evidence in support of the hypothesis that idiosyncratic and annually varying responses to both N quantity and quality may be a key driver of community structure and species coexistence. This finding has important implications for the diversity and functioning of other ecosystems with spatial and temporal variation in available N quantity and quality as related to changing atmospheric N deposition, land-use, and climate-induced soil warming.; Plant species and functional groups in nitrogen (N) limited communities may coexist through strong eco-physiological niche differentiation, leading to idiosyncratic responses to multiple nutrition and disturbance regimes. Very little is known about how such responses depend on the availability of N in different chemical forms. Here we hypothesize that idiosyncratic year-to-year responses of plant functional groups to availability and form of nitrogen explain species coexistence in an alpine meadow community after release from grazing. We conducted a 6year N addition experiment in an alpine meadow on the Tibetan Plateau released from grazing by livestock. The experimental design featured three N forms (ammonium, nitrate, and ammonium nitrate), crossed with three levels of N supply rates (0.375, 1.500 and 7.500gNm-2yr-1), with unfertilized treatments without and with light grazing as controls. All treatments showed increasing productivity and decreasing species richness after cessation of grazing and these responses were stronger at higher N rates. Although N forms did not affect aboveground biomass at community level, different functional groups did show different responses to N chemical form and supply rate and these responses varied from year to year. In support of our hypothesis, these idiosyncratic responses seemed to enable a substantial diversity and biomass of sedges, forbs, and legumes to still coexist with the increasingly productive grasses in the absence of grazing, at least at low and intermediate N availability regimes. This study provides direct field-based evidence in support of the hypothesis that idiosyncratic and annually varying responses to both N quantity and quality may be a key driver of community structure and species coexistence. This finding has important implications for the diversity and functioning of other ecosystems with spatial and temporal variation in available N quantity and quality as related to changing atmospheric N deposition, land-use, and climate-induced soil warming.
内容类型	期刊论文
源URL	[http://ir.nwipb.ac.cn/handle/363003/3608]
专题	西北高原生物研究所_中国科学院西北高原生物研究所
推荐引用方式 GB/T 7714	Song, Ming-Hua,Yu, Fei-Hai,Ouyang, Hua,et al. Different inter-annual responses to availability and form of nitrogen explain species coexistence in an alpine meadow community after release from grazing[J]. GLOBAL CHANGE BIOLOGY, Wang, YQ; Zhang, B; Liu, BL; Zhang, HG; Liu, DC.Different inter-annual responses to availability and form of nitrogen explain species coexistence in an alpine meadow community after release from grazing,GLOBAL CHANGE BIOLOGY,2012,18(10):3100-3111,2012.
APA	Song, Ming-Hua,Yu, Fei-Hai,Ouyang, Hua,Cao, Guang-Min,Xu, Xing-Liang,&Cornelissen, Johannes H. C..(2012).Different inter-annual responses to availability and form of nitrogen explain species coexistence in an alpine meadow community after release from grazing.GLOBAL CHANGE BIOLOGY.
MLA	Song, Ming-Hua,et al."Different inter-annual responses to availability and form of nitrogen explain species coexistence in an alpine meadow community after release from grazing".GLOBAL CHANGE BIOLOGY (2012).