Selective extinction against redundant species buffers functional diversity

Area of Science:

• Paleontology
• Ecology
• Evolutionary Biology

Background:

• Species extinction can disrupt ecological processes.
• Functional diversity, encompassing functional richness and redundancy, is key to ecological stability.
• Limited deep-time, trait-based data hinders understanding of long-term functional diversity responses.

Purpose of the Study:

• To reconstruct mollusc diversity dynamics over 23 million years.
• To analyze changes in functional diversity (richness and redundancy).
• To investigate extinction selectivity and its impact on functional diversity.

Main Methods:

• Compiled a large trait dataset of fossil molluscs from the Caribbean (34,011 records, 4422 species).
• Developed a novel Bayesian model for multi-trait-dependent diversification.
• Reconstructed diversity dynamics, functional diversity, and extinction patterns over 23 million years.

Main Results:

• High diversification occurred between 23-5 Mya, increasing functional richness and redundancy.
• Recent extinctions (last 3 million years) led to a 49% species loss but only a 3% loss in functional richness.
• Extinction rates were higher for small, functionally redundant species, indicating competition's role.

Conclusions:

• Long-term diversification and selective extinction of redundant species promoted functional diversity growth.
• Functional diversity buffered ecological functions against extinction impacts.
• Competition may mediate species' responses to environmental change over geological timescales.