Stoichiometric homeostasis does not affect species dominance and stability in an alpine steppe, Tibetan Plateau

Figures & data

Figure 1. Location of study area and experimental sites on the Tibetan Plateau.

Figure 2. Changing in foliar N  of six plant species response to N and P addition. Grasses: S. purpurea, P. litwinowiana; Sedge: C. moorcrofii; Forbs: A. nanschanica, L. nanum; Legume: A. densiflorus. Different lowercase letters above bars denote significant difference among treatments (p<0.05).

Figure 3. Changing of  foliar N in six plant species with N and P addition (A) and the difference between Non-legumes (S. purpurea, P. litwinowiana; C. moorcrofii; A. nanschanica, L. nanum) and Legumes (A. densiflorus) (B). Different lowercase letters above bars denote significant difference among treatments (p<0.05).

Figure 4. N:P ratios in the foliage of different types of plants on the addition of N and P. Grasses: S. purpurea, P. litwinowiana; sedge: C. moorcrofii; forbs: A. nanschanica, L. nanum; and legume: A. densiflorus. Different lowercase letters above bars denote significant difference among treatments (p<0.05).

Table 1. Stoichiometric homeostasis (H_N) for six alpine plant species.

Species	Type	HN	R^2	p
S. purpurea	Grass	1.75	0.69	<0.05
P. litwinowiana	Grass	1.96	0.51	<0.05
C. moorcrofii	Sedge	1.95	0.78	<0.05
A. nanschanica	Forb	1.72	0.76	<0.05
L. nanum	Forb	1.72	0.75	<0.05
A. densiflorus	Legume	4.32	0.43	0.099

Note: H_N was calculated using non–line regression analysis with the homoeostatic model equation y = cx^1/H, which described the relationship between the concentration of N in foliage (y) and soil inorganic N (x).

Table 2. Foliage H_N values for different plant genera in different types of grasslands.

	HN
Grassland Type Genus	Alpine Grasslands (present study)	Temperate Grasslands (Yu et al. 2010)	Grasslands with Tall Grass (Yu et al. 2015)
Stipa	1.75	5.40	–
Poa	1.96	4.61	–
Carex	1.95	5.03	4.45

Yu, Q., Q. Chen, J. J. Elser, N. He, H. Wu, G. Zhang, J. Wu, Y. Bai, and X. Han. 2010. Linking stoichiometric homoeostasis with ecosystem structure, functioning and stability. Ecology Letters 13:1390–99. doi:10.1111/j.1461-0248.2010.01532.x.

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Yu, Q., K. Wilcox, P. K. La, A. K. Knapp, X. Han, and M. D. Smith. 2015. Stoichiometric homeostasis predicts plant species dominance, temporal stability, and responses to global change. Ecology 96:2328–35.

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