The Deep Past Controls the Phylogenetic Structure of Present, Local Communities

Coexisting species may be evolutionarily proximate or distant, resulting in phylogenetically poor or rich communities. This variation is often considered to result from present assembly processes. We argue that, under certain conditions, deep-past processes might control the phylogenetic diversity of communities. First, deep-past effects involve macroevolutionary processes, such as diversification rate, niche conservatism, or dispersal, in the lineages that constitute communities. Second, deep-past processes in the respective region or in the habitat type play a role, for instance, through age, area, stability, or connectivity. Third, the deep past may affect communities via trophic interactions (i.e., communities of enemies or mutualists or communities of hosts). We suggest that deep-past effects can be identified in local communities by measuring phylogenetic diversity in different species pools. We also show how community phylogenetic diversity results in positive or negative eco-evolutionary feedback, and we identify present-day conservation challenges that may profit from a deep-time perspective.