Phylogenetic diversity and the functioning of ecosystems

TLDR

Phylogenetic diversity quantifies the total evolutionary distance among species, and while its determinants have been studied, its influence on ecosystem functioning is only now being explored, partly because many traits exhibit phylogenetic signals that link PD to functional trait space and ecosystem processes. The authors contend that phylogenetic diversity can predict ecosystem functions across community types and that a synthetic approach integrating evolutionary insights into traits and interactions is essential for understanding extinction cascades and functional outcomes. They propose a framework that synthesizes evolutionary knowledge of trait and interaction evolution to guide future research on the links between phylogenetic diversity and ecosystem functioning. Early evidence aligns with these predictions, yet the usefulness of phylogenetic diversity depends on the strength of phylogenetic signals in traits and interactions, and incorporating these complexities may ultimately unify evolutionary biology with ecosystem ecology.

Abstract

Phylogenetic diversity (PD) describes the total amount of phylogenetic distance among species in a community. Although there has been substantial research on the factors that determine community PD, exploration of the consequences of PD for ecosystem functioning is just beginning. We argue that PD may be useful in predicting ecosystem functions in a range of communities, from single-trophic to complex networks. Many traits show a phylogenetic signal, suggesting that PD can estimate the functional trait space of a community, and thus ecosystem functioning. Phylogeny also determines interactions among species, and so could help predict how extinctions cascade through ecological networks and thus impact ecosystem functions. Although the initial evidence available suggests patterns consistent with these predictions, we caution that the utility of PD depends critically on the strength of phylogenetic signals to both traits and interactions. We advocate for a synthetic approach that incorporates a deeper understanding of how traits and interactions are shaped by evolution, and outline key areas for future research. If these complexities can be incorporated into future studies, relationships between PD and ecosystem function bear promise in conceptually unifying evolutionary biology with ecosystem ecology.