Network metrics
We observed 179 interactions between 40 liana species and 38 tree
species in edge site of Asenanyo Forest Reserve (Appendix 1a). A total
of 123 and 119 interactions were recorded in interior (involving 34
liana species and 28 tree species; Appendix 1b) and deep-interior
(between 31 liana species and 35 tree species; Appendix 1c),
respectively. On the part of Suhuma Forest Reserve, 44 liana species
interacted with 63 tree species in edge site and produced a total of 202
interactions (Appendix 1d). In interior site, 44 liana species
interacted with 46 tree species, resulting in 173 interactions (Appendix
1e). We recorded an interaction involving 42 liana species and 46 tree
species in deep-interior site, giving rise to 175 interactions (Appendix
1f).
In the Asenanyo Forest Reserve, the observed nestedness metric was
significantly lower than the means of the null model in the three forest
sites (Table 2). Likewise, the liana-tree networks were less connected
than the null models of the three networks. However, the three networks
were more modular and specialised compared to the null networks. The
significant modularity of the networks resulted in the formation of a
number of modules in edge site (14 modules), which was more than the
number of modules in deep-interior (11 modules), which in turn, was more
than that in interior site (7 modules) (Figure 2a-c; Appendix 2). The
size of the modules varied greatly in the networks, ranging from 2-13
species in edge site, 5-13 species in interior site, and 2-12 species in
deep-interior site.
We did not observe significant differences in nestedness between the
observed and null models in the three forest sites in the Suhuma Forest
Reserve. Nevertheless, the three liana-tree networks in the forest
recorded significantly higher modularity and specialisation than
expected by chance. The networks in deep-interior forest site
(deep-interior: 14 modules) exhibited higher number of modules than the
other sites (edge site: 9 modules, interior site: 9 modules) (Figure
3a-c; Appendix 2). Furthermore, the networks showed much variation in
the size of the modules (edge: 5-19 species, interior: 6-15 species,
deep-interior: 3-11 species). Connectance of the three networks was
significantly lower than that of the null models. The specialisation
asymmetric values of the networks in the Asenanyo Forest Reserve were
close to zero, indicating weak asymmetry. The specialisation asymmetry
value of interior site network was consistent with that of the null
model; those of the other networks were significantly higher than
randomised expectations. The networks in the Suhuma Forest Reserve did
not only show weak asymmetry, but they also did not differ significantly
from that expected by chance.