Climbing mechanisms and the diversification of neotropical climbing plants across time and space

Abstract

Summary Climbers germinate on the ground but need external support to sustain their stems, which are maintained attached to supports through modified organs, that is, climbing mechanisms. Specialized climbing mechanisms have been linked to higher diversification rates. Also, different mechanisms may have different support diameter restrictions, which might influence climbers' spatial distribution. We test these assumptions by linking climbing mechanisms to the spatiotemporal diversification of neotropical climbers. A dataset of climbing mechanisms is presented for 9071 species. WCVP was used to standardize species names, map geographical distributions, and estimate diversification rates of lineages with different mechanisms. Twiners appear concentrated in the Dry Diagonal of South America and climbers with adhesive roots in the Chocó region and Central America. However, climbing mechanisms do not significantly influence the distribution of neotropical climbers. Also, we found no strong support for correlations between specialized climbing mechanisms and higher diversification rates. Climbing mechanisms do not strongly impact the spatiotemporal diversification of neotropical climbers on a macroevolutionary scale. We argue that the climbing habit is a synnovation, meaning the spatiotemporal diversification it promotes is due to the sum effect of all the habit's traits rather than isolated traits, such as climbing mechanisms.

Why plant diversity and distribution matter

“…Interestingly, Sperotto et al . (2023) do not find that climbing growth forms influenced evolutionary diversification rates as inferred from phylogenetic trees, at least not in Neotropical climbers. Discrepancies in diversity across Neotropical angiosperm lineages are therefore probably not related to specific climbing mechanisms.…”

Climbing mechanisms as a central trait to understand the ecology of lianas across the tropics

“…We found that phylogenetic relatedness plays an even more important role than climate and paleoclimate in explaining the distribution of active and passive climbing mechanisms. The stronger effect of phylogeny on the representation of active and passive climbing species may be related to the limited number of lineages that undergo local radiations, rather than by the convergence of climbing mechanisms in regions with similar climates (Sperotto et al, 2020(Sperotto et al, , 2023. For instance, when species concentrated in a given climate or region are represented by a few families, this pattern might be a consequence of shared ancestry rather than independent events of the evolution of that climbing mechanism (Sperotto et al, 2023).…”