Diversity
In general, considering not only richness, but also evenness and
dominance, resulted in more significant differences between treatments
at all taxonomic levels, except for Order.
Using COI, we found significant differences in MOTU diversity among
treatments when considering all 72 trees (𝜒2 = 10.493;
p = 0.005). Pairwise analysis showed that the diversity under
one-year-exclusion trees was marginally significantly higher than under
control trees (estimate = -0.467; T = -3.183; p = 0.063), while no
differences were found between control trees and those with long-term
livestock exclusion (estimate = -0.303; T = -2.111; p = 0.095), although
it was slightly higher in the latter (Figure 3, bottom left panel A).
Restricting the analysis to just the three farms with control and
one-year exclosures, Treatment had significant effects on the MOTU
diversity (𝜒2 = 10.188; p = 0.001), but not Farm
(𝜒2 = 1.104; p = 0.576). Post hoc tests indicated that
it was significantly higher at short-term livestock exclosures at the
three farms (Figure 3, bottom left panel B).
Using 16S, the results were very similar to COI. We found significant
differences due to Treatment in the analysis involving the three of them
(𝜒2 = 14.417; p < 0.001), although Tukey
tests indicated that only in one-year exclosures MOTU diversity was
higher than at the controls (estimate = -0.439; T = 3.684; p = 0.001)
(Figure 3, bottom right panel A). Considering only the farms with
control and one-year exclosure trees, both Farm (𝜒2 =
30.058; p < 0.001) and Treatment (𝜒2 =
13.677; p < 0.001) had significant effects on the diversity of
the arthropod community. Post hoc analysis showed that the diversity
beneath the canopies of one-year-exclusion trees was higher in all three
farms in comparison with their control pairs (Figure 3, bottom right
panel B).
At family level we found significant differences due to Treatment
(𝜒2 = 11.099; p = 0.004) in the analysis that included
the three categories. Interestingly, in this case the post hoc analysis
showed that not only the diversity under the one-year exclusion trees
was significantly higher than under the control trees (estimate =
-0.442; T = -3.183; p = 0.006), the same happened when control trees
were compared with those at abandoned farms (estimate = -0.336; T =
-2.414; p = 0.048) (Figure 4C). Removing the long-term-exclusion trees,
we found differences due to Treatment (𝜒2 = 10.687; p
= 0.001) but not Farm (𝜒2 = 1.127; p =0.568).
Arthropod diversity at Family level was higher at short-term exclosures
compared to controls in all the three farms (Figure 4D).
At Order level, similarly to the results obtained looking only at
richness, we found no significant differences in any case.