Figure 6
Redundancy analyses (RDA) of environmental effects on chlorophyll distribution (a) and sketches explaining alterations in CV (b), skewness (c) and kurtosis (d). The hollow circles in (a) represent the 30 sites of northern hemispheric grassland. Blue arrows denote environmental factors. PAR photosynthetically active radiation, MAP mean annual precipitation, MAT mean annual temperature, NP the ratio of soil nitrogen to soil phosphorus. Red diamonds denote chlorophyll distribution indicators. Chl chlorophyll, CV coefficients of variation, S skewness, K kurtosis. The asterisks denote significance (p < 0.01**). The black dashed curves in (b–d) represent the original or normal distributions, and the black solid lines represent the distribution shifts.
