Incorporating eco-evolutionary interactions into a spatially explicit
phylogenetic Janzen-Connell model predicts realistic macroecological and
macroevolutionary patterns
Abstract
The Janzen-Connell (J-C) hypothesis states that species-specific natural
enemies (pathogens, predators) induce local-density dependence which
explains high diversity observed in tropical tree communities. However,
these natural enemies often attack phylogenetically related species as
well. Here, we use a spatially explicit model in which the continuously
changing phylogeny and abundances affect recruitment to study the
predictions for common diversity and phylogenetic patterns. The
species-area relationship is triphasic, while the species-abundance
distribution has a rare species mode (neutral scenario), a two modes
(large dispersal distance) or a single interior mode (small dispersal
distance). Small dispersal distance forms clusters of species with large
phylogenetic distance to the community while large dispersal distance
makes species distribute uniformly. Phylogenetic trees show
diversification slowdowns and imbalance, consistent with empirical
patterns. However, the phylogenetic relatedness effect reduces
diversity. We conclude that the spatially explicit phylogenetic J-C
effect explains commonly observed diversity and phylogenetic patterns.