Community phylogenetics meets biogeography and macroevolution: towards an integrative process-based framework

Background/Question/Methods

The field of community phylogenetics seeks to understand current (competition, environmental filters) and historical factors (niche conservatism, speciation, historical dispersal) processes generating and maintaining ecological communities. Previous paradigms to explain assembly processes suggested the integration of three different research programs: Community Niche Structure, Biogeography, and Character Evolution. More recent work focused on the development of metrics of diversity to incorporate phylogenetic information with the promise that they could reveal ecological and historical processes acting on community assembly. However, the utility of metrics to understand some of the historical questions that Ecophylogenetics seeks to answer are not clear, and much of the methodological approaches rely only on the interpretation of patterns that are proved equivocal. In this work, we propose a theoretical framework to understand the relative importance of the current and historical factors in shaping communities. Our framework incorporate ancestral area reconstruction methods in the calculation of commonly used metrics in community phylogenetic ecology. By using ancestral area reconstruction and decomposing the phylogenetic tree in slices that represent speciation and dispersal events we can understand, for example, the amount of phylogenetic diversity, or phylogenetic structure that can be explained by the balance between these two important historical processes.

Results/Conclusions

Our proposition advances in two different ways the field of Ecophylogenetics, from a theoretical perspective we provide an integrative framework for character evolution, biogeography, and community ecology. This integration shows that patterns of phylogenetic structure previously attributed to, for example, in situ diversification can be actually a result of a balance between both historical dispersal and diversification, depending on the macroevolutionary dynamics of ancestral habitat occupation of present-day species. Also, from a practical perspective, we can apply the new process-based metrics to help in conservation decisions, since through our approach we can understand if patterns in high Phylogenetic Endemism of Phylogenetic Diversity areas are dependent on a source area (dependent of historical dispersal) during the evolution of those communities. Preliminary results show that some areas considered of high Phylogenetic Endemism depend on the exchange of species from other areas, indicating that to protect the biodiversity on a large temporal scale we need to incorporate the evolutionary dynamics into the currently available phylogenetic metrics. Our proposed framework aims to be flexible enough to accommodate other questions that are still open, like, the relationship between colonization of new areas, trait dynamics, and diversification.