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.