The Phylogenetic Limits to Diversity-Dependent Diversification

Area of Science:

• Evolutionary Biology
• Island Biogeography
• Phylogenetics

Background:

• Macroevolutionary competition's role is less understood than microevolutionary competition.
• Phylogenetic evidence suggests lineage diversity can decelerate diversification rates.
• It remains unclear if this diversity-dependence is limited to closely related species or extends to distantly related ones.

Purpose of the Study:

• To investigate phylogenetic limits of diversity-dependence in macroevolution.
• To differentiate between clade-specific (CS) and island-wide (IW) diversity-dependence models.
• To apply these models to the diversification of Eleutherodactylus frogs on Hispaniola.

Main Methods:

• Developed a new island-wide (IW) diversity-dependence model within the DAISIE (Dynamic Assembly of Island biota through Speciation Immigration and Extinction) framework.
• Introduced a method to compute model likelihoods using phylogenetic data on colonization and branching events.
• Employed likelihood ratio bootstrapping for robust comparison between CS and IW models.

Main Results:

• The clade-specific (CS) diversity-dependence model provided a significantly better fit to the Eleutherodactylus frog diversification data than the island-wide (IW) model.
• This indicates that distinct colonizations, despite similar ecotypes, do not strongly interact.
• Non-overlapping distributions between clades do not necessarily imply CS diversity-dependence.

Conclusions:

• Diversification on islands is primarily driven by clade-specific interactions, not island-wide ones.
• Phylogenetic data, rather than distributional data, is crucial for inferring the limits of diversity-dependent diversification.
• The developed modeling approach offers a powerful tool for future evolutionary and biogeographic studies.