Figure 2. a) Structural equation model representing the direct
and indirect effects of trait values on individual performances, with
all species included. We used the trait measurements of November 2020
for this analysis. Trait values were standardized separately for each
species to get rid of variance due to species identity. The initial
model is presented in Supporting information 6 and was reduced with
lavaan package through variable selection based on AIC criteria. All
variables were calculated at pond level. Single dark headed arrows
indicate direct effects. Double headed blue arrows indicate correlation
between two model variables. Standardized path coefficients are given in
blue for correlations and in black for direct effects with their
p-values: ***p < 0.001; **p < 0.01; ‘.’ 0.05
< p < 0.1; no asterisk p ≥ 0.1 not significant. The
widths of the lines are proportional to the strength of relationships
(values of path coefficients). Solid and dashed lines respectively
indicated positive or negative direct effects. Grey paths and grey
variables indicated paths and variables that did not have any
significant direct or indirect effects on species performance. R² values
were the variance proportion of response variables explained by their
explanatory variables. b) Absolute direct and indirect effects of trait
values on individual performance.
Among all tested traits, LDMC did not affect individual biomass, while
we identified multiple direct or indirect effects of all other traits
(Fig. 2). Traits related to resource acquisition (aerial, and root
traits) did not have a stronger influence on individual performance than
clonal traits. On the one hand, traits directly influencing individual
biomass (i.e. height, and all clonal and root traits), also
supported the biomass, with height (0.38***) and specific internode mass
(0.43***) displaying the strongest effects. These direct effects on
individual performances were additionally modulated i.e.amplified or decreased, by their correlations (Fig. 2). For example,
internode length and specific root mass were correlated to height,
indirectly supporting their total positive effect on individual
performance, while specific internode mass indirectly and positively
impacted individual performance via its correlation with
internode length and specific root mass. On the other hand, SLA did not
have any direct effects on individual performances, yet influencing it
negatively through its relationship with specific internode mass
(-0.20*). Finally, when considering total trait effects on plant
performance (Fig. 2b), only SLA had a negative impact, while all other
traits displayed overall positive effects.