Intercontinental comparison of liana community assemblages in tropical forests of Ghana and Malaysia

Abstract

Liana research has increased in the past two decades, yet there is still inadequate comparison of liana communities at a cross-con- tinental scale. We compared liana assemblages in tropical forest ecosystems of Ghana and Malaysia, thereby determining patterns and mechanisms that are common or unique to the regions. Liana diversity, community structure and taxonomic composition were determined in 60 plots of 40 × 40 m2 in three forest types (primary, disturbed secondary, selectively logged) in each biogeo- graphic area. Two traits, climbing mechanisms and dispersal modes were determined for all species and individuals via direct field observation and with published literature. Data were analyzed at biogeographic (using combined forest data) and forest-type levels. Both observed and rarefied–extrapolated species richness of lianas were significantly higher in Ghanaian forests compared to Malaysian forests. In most cases, species diversity indices (Shannon diversity index, Margalef, Fisher’s alpha) showed significantly higher liana diversity at Ghanaian forests at biogeographic and forest-type lev- els. Similarly, Ghanaian forests harbored significantly higher values of liana abundance and basal area than Malaysian forests at both biogeographic and forest-type levels. The taxonomic composition of lianas differed considerably between the two biogeographic areas at all levels, although similarity in composition increased at generic and family levels. Though above-ground biomass of lianas was simi- lar between the two biogeographic regions, variations occurred at forest-type level between the two regions. The two biogeographic areas showed some similarities in assemblages of liana climbing mechanisms. Although more species of lianas were adapted for animal dispersal than other dispersal modes in both countries, the majority of liana individuals in Ghana were wind dispersed whereas the majority of liana individuals in Malaysia were animal dispersed. We speculate that the differences in liana community assemblages between the two biogeographic areas are due to historical and evo- lutionary processes, as well as climatic variation between the two biogeographic regions.