the parent materials was strongly affected by the earthworms’ activity over the
course of the vermicomposting process. Earthworms can directly modify the microbial diversity of the substrate by selectively feeding on and/or stimulating specific
taxa during transit through the earthworm gut (Aira et al. 2015). The changes
occurred through the gut-associated processes may have further consequences on
Type of plant material
Grape marc
Distilled grape marc
Scotch broom
Process
Vermicompost
Raw material
−0.25
0.00
0.25
−0.2
0.0
0.2
0.4
PCoA1 (44.73 %)
)
%
6
7
.
3
3
(
2
A
o
C
P
−0.25
0.00
0.25
0.50
−0.2
0.0
0.2
0.4
A
o
C
P )
%
9
9
.
6
1
(
2
PCo A 1 (20.99 %)
PCoA 1, type x process F = 28.42, P < 0.001
3,16
PCoA 1, type x process F = 370.55, P < 0.001
3,16
PCoA 2, type x process F = 1739.66, P < 0.001
3,16
PCoA 2, type x process F = 2384.05, P < 0.001
3,16
Acd
Aa
Ce
Df
Aa
Bd
Eb
Fb
Bc
Cf
Dg
Ac
Cb
Be
Ea
Bd
Acacia
a)
b)
Type of plant material
Grape marc
Distilled grape marc
Scotch broom
Process
Vermicompost
Raw material
Acacia
Fig. 8.4 Changes in bacterial β-diversity assessed as principal coordinate analysis of (a) Bray–
Curtis and (b) weighted UniFrac distances of the fresh plant materials (Scotch broom, acacia, raw
and distilled grape marcs) and the respective vermicomposts. Capital and lowercase letters indicate
significant differences among fresh plant materials and vermicomposts in PCoA1 and PCoA2
scores, respectively (Tukey HSD test, FDR corrected)
134
M. Gómez-Brandón et al.