Liana abundance and relationships to sapling and tree hosts in an East African primary forest

Abstract

Lianas are an important structural component of tropical rain forests. Recent concern regarding a putative global rise in liana abundance, and its implications for forest conservation, calls for data collection across biomes. We here provide a first assessment and baseline data for a geographical gap in liana surveys to date. We surveyed liana (diameter at breast height [DBH] > 1 cm), tree (DBH > 10 cm) and sapling (DBH ≤ 10 cm) abundance and basal area, as well as liana–host relationships, in a tropical East African primary forest. We recorded a total of 347 liana stems (DBH > 1 cm) in 0.31 ha, with an average basal area of 1.21 m 2 /ha. Lianas were found to be widespread, with 24% of saplings and 57% of trees colonised by at least one liana, independently of bark texture or host diameter. The dominant liana colonisation strategy was to associate with a single host, through stem twining. We found no evidence of liana density being influenced by host density. We synthesised published liana density data across continents and report that our estimate of liana density for Kibale's primary forest fits within the expected range of liana densities for primary tropical forests. This synthesis further highlights a neotropical sampling bias, which our findings make a step towards addressing.