Species abundance and richness
We used as data for the abundance and basal area of liana species from
the Gentry’s transects, accessed through the BIEN Database (R package
“BIEN” version 4.1.1, Maitner et al., 2017). We restricted our
analyses to plots only across the tropics, using the same criteria as
Schnitzer (2005). In summary, we restricted the data set to forests that
were classified as tropical lowland dry, moist or wet forests (according
to Holdridge, 1967) and which had ≥ 500 mm annual precipitation and were
≤ 1,000 m above sea level to reduce the confounding effects of latitude,
elevation and temperature among the sites. Abundance was defined as the
total number of individuals and richness as the total number of species,
per plot, for each type of climbing mechanism (active and passive). All
plot data comes from the Gentry’s transects, openly available through
the BIEN Database. We chose these data because they are standardized and
represent one of the most comprehensive available inventory data on the
liana species richness and abundance across the tropics.