Edge disturbance shapes liana diversity and abundance but not liana-tree
interaction network patterns in moist semi-deciduous forests, Ghana
Abstract
We evaluated the response of liana community structure and the patterns
of liana-tree interaction structure to forest edge in two moist
semi-deciduous forests in Ghana (Asenanyo and Suhuma Forest Reserves:
AFR and SFR, respectively). Liana community structure and liana-tree
interactions were assessed in 24 50 × 50 m randomly located plots in
three forest sites in each forest: edge, interior and deep-interior
established at 0-50 m, 200 m and 400 m from edge. Edge effects
positively and negatively influenced liana diversity in forest edges of
AFR and SFR, respectively. There was a positive influence of edge
disturbance on liana abundance in both forests. More liana species
experienced positive magnitude of edge influence (MEI) on their
abundance. We observed anti-nested structure in all the liana-tree
networks in AFR, while no nestedness was observed in the three networks
in SFR. The networks in both forests were less connected, and more
modular and specialised than their null models. Many liana and tree
species were specialised, with the specialisation tending to be
symmetrical. Topologically, most of the species were peripherals, with
only a few connectors, module hubs, and network hubs. Some of the
species showed consistency in their topological roles from one site to
another, while the roles of other species changed. Generally, liana
species co-occurred randomly on tree species in all the forest sites
except edge site in the Asenanyo Forest Reserve. The findings of the
study deepen our understanding of liana-tree interactions, provide
implications for conservation, and may contribute to development of a
robust edge theory.