3.3 Plant-environment relationships
Redundancy analysis (RDA) was applied to further investigate the contribution of soil water content and electrical conductivity to functional traits of P. australis . As shown in Figure 3, selected environmental variables completely explained 15.43% of the variance in functional trait variables (F=7.8, P<0.01). The first axis explained 14.34% in the ordination with electric conductivity. The second axis explained 1.08%, with soil water content. The relationships with electrical conductivity were negative, including SPAD, height, and stem traits, but the functional trait variables had almost no correlation with soil water content. The response of leaf traits to environmental variables were inconsistent. Leaf water content had positive relationships with soil water content and electrical conductivity. Leaf thickness had a strong positive relationship with electrical conductivity, while leaf area and specific leaf area had strong negative correlations with electrical conductivity.