In the analysis of sea urchins and environmental variables in
all reefs the reduced model was significant with six of nine tested
variables, with the first three axes being significant (F6, 309 = 13.1,
p < 0.001). Only the variables that contributed significantly to axis
are shown in Fig. 4. Axes 1 and 2 of the RDA accounted for 93.6%
of explained variance (Radjusted = 0.19, Fig. 4(a)), and the third axis
is not shown in figures due to the low contribution to the model
explanation. The first axis was positively associated with depth and
CCA, and negatively with SM, while the second axis was negatively
influenced by: crevice (C), SM, depth and complexity (Fig. 4(a)).
Echinometra lucunter was positively associated with SM, while A.