2.5 Biogeographical analysis
The biogeographical relationships between samples were implemented with
the software PRIMER 7 (Plymouth Routines In Multivariate Ecological
Research). In the Neotropical region, we pre-assigned a set of smaller
hierarchical geographical areas (zones), following Morrone et al.
(2022), to enable hypothesis testing using non-metric multidimensional
scaling (nMDS). The faunal similarity between zones and between larger
regions was quantitatively measured using Sørensen similarity index of
presence/absence data, and the significance of the geographical
groupings was assessed using the ANOSIM test (see Appendices S1 & S2).
Species accumulation curves were implemented by the vegan package
(Oksanen et al., 2017) in the software R (R Development Core Team, 2021)
using 100 randomizations. Accumulation curves are randomized plots of
the presence or absence of each species (here delimited by the sGMYC
algorithm) against the number of observations.