Trait-based species richness: ecology and macroevolution

Area of Science:

• Ecology and evolutionary biology
• Investigates patterns of species richness

Background:

• Traditional research focuses on spatial and clade-based species richness patterns.
• Trait-based species richness, focusing on character states (e.g., diet, body size), is underemphasized despite its relevance to ecology and evolution.
• Origins of trait-based richness patterns are poorly understood.

Approach:

• Introduces a conceptual framework for understanding trait-based richness patterns.
• Conducts a systematic review to analyze the drivers of trait-based richness patterns.
• Compares trait-based richness patterns with spatial and clade-based patterns.

Key Points:

• Trait-based richness patterns are primarily explained by the age of character states, with older states typically exhibiting higher richness.
• Differences in transition rates among states or faster diversification rates of certain traits are less significant drivers.
• Many studies on spatial richness patterns may actually be examining trait-based richness, potentially leading to confounding causes.

Conclusions:

• Highlights the importance of trait-based species richness as a distinct category of ecological patterns.
• Contrasts findings with the common emphasis on diversification rates in richness research.
• Identifies numerous unanswered questions and future research directions for trait-based richness patterns.