The contribution of plant life and growth forms to global gradients of vascular plant diversity

Abstract

Plant life and growth forms (shortened to plant forms) represent key functional strategies of plants in relation to their environment and provide important insights into the ecological constraints acting on the distribution of biodiversity. Despite their ecological importance, how the spectra of plant forms contribute to global gradients of plant diversity is unresolved. Using a novel dataset comprising >295,000 species, we quantify the contribution of different plant forms to global gradients of vascular plant diversity. Further, we establish how plant form distributions in different biogeographical regions are associated with contemporary and paleoclimate conditions, environmental heterogeneity, and phylogeny. We find a major shift in representation by woody perennials in tropical latitudes to herb-dominated floras in temperate and boreal regions, following a sharp latitudinal gradient in plant form diversity from the tropics to the poles. We also find significant functional differences between regions, mirroring life and growth form responses to environmental conditions, which is mostly explained by contemporary climate (18-87%), and phylogeny (6-62%), with paleoclimate and heterogeneity playing only a minor role (<23%). This research highlights variation in the importance of different plant forms to diversity gradients worldwide, providing a much-needed quantification for long-standing ideas and concepts structuring plant assemblages.

The global distribution of angiosperm genome size is shaped by climate

“…Due to genome size variations among different plant growth forms (Bennett, 1987; Beaulieu et al ., 2008; Veselý et al ., 2013), and the presence of latitudinal trends in growth form proportions (Taylor et al ., 2023; Fig. S11 here), we investigated whether the observed S‐shape (Fig.…”

Climate and ant diversity explain the global distribution of ant‐plant mutualisms

“…To address the potential confounding effects of phylogenetic relatedness between regions, we included phylogenetic eigenvectors as explanatory variables in our analyses, in accordance with the methodology proposed by Taylor et al (2023). We quantified the phylogenetic beta diversity of ant‐associated plants between regions using the Simpson index, which is insensitive to the variation of species richness between regions (Baselga 2010).…”

Why plant diversity and distribution matter

“…For example, Taylor et al . (2023) use a global approach to show how woody perennials dominate ecosystems in tropical latitudes, whereas herbs increase in ecological dominance in temperate and boreal regions, thus illustrating a latitudinal gradient in plant form. Besides the importance of contemporary climate to explain this pattern, the authors show that the evolutionary history of lineages plays a role as well.…”