Biomes as evolutionary arenas: convergence and conservatism in the trans-continental Succulent Biome

Aim: Biomes are globally-distributed, structurally and functionally similar vegetation units, but there is debate about whether these similarities are superficial, and about how biomes are defined and mapped. We propose that combined assessment of evolutionary convergence of plant functional traits and phylogenetic biome conservatism provides a useful approach for characterising biomes. We focus on the little-known succulent biome, a trans-continentally distributed assemblage of succulent-rich, drought-deciduous, fire-free forest, thicket and scrub vegetation as a useful exemplar biome to gain insights into these questions.

Location: Global lowland (sub)tropics.

Time period: Present.

Major taxa studied: Angiosperms.

Methods: We use a model-ensemble approach to model the distribution of 884 species of stem succulents, a plant functional group representing a striking example of evolutionary convergence. Using this model, phylogenies, and species occurrence data, we quantify ph...