Table 2.

Eigen-values of frequency distributions of chlorophyll concentrations by dry weight (DW) and ratio grouped by regions.

	Chla (mg·g-1 DW)				Chlb (mg·g-1 DW)				Chla+b (mg·g-1 DW)				Chla/b
	All*	MP*	LP*	TP*	All*	MP*	LP*	TP*	All*	MP*	LP*	TP*	All*	MP*	LP	TP
Mean	5.49	5.55a	5.90a	4.65b	1.83	1.87a	1.91a	1.63b	7.32	7.42a	7.81a	6.29b	3.02	3.01b	3.11a	2.88c
SD	3.35	3.79	3.34	2.41	1.13	1.32	1.10	0.84	4.46	5.06	4.42	3.22	0.49	0.63	0.34	0.42
Variance	11.24	14.40	11.13	5.80	1.29	1.73	1.22	0.70	19.85	25.64	19.55	10.36	0.24	0.40	0.12	0.17
CV	0.61	0.68	0.57	0.52	0.62	0.71	0.58	0.52	0.61	0.68	0.57	0.51	0.16	0.21	0.11	0.15
Min	0.52	0.78	0.52	0.59	0.15	0.16	0.15	0.22	0.67	1.25	0.67	0.81	1.28	1.28	1.81	1.42
Max	28.33	28.33	26.19	17.95	12.11	12.11	9.43	6.22	39.29	39.29	35.62	23.73	7.84	7.84	4.14	4.57
Median	4.61	4.46	5.06	4.29	1.55	1.55	1.63	1.48	6.15	5.97	6.71	5.81	3.00	2.90	3.10	2.91
Skewness	2.27	2.61	1.68	2.10	2.90	3.45	2.03	2.07	2.39	2.77	1.76	2.11	2.42	3.29	0.04	-0.02
Kurtosis	8.40	9.94	4.60	7.53	15.56	18.87	7.24	7.43	9.70	11.56	5.20	7.65	20.02	19.44	1.03	2.11

All, all species along northern hemisphere grassland transects (n=1049); MP, Mongolia Plateau (n=367); LP, Loess Plateau (n=437); TP, Tibet Plateau (n=245). The asterisks behind the abbreviation of regions denote significant differences with normal distributions. Bold lowercase letters behind means denote significant differences among regions (p < 0.05).