Including intraspecific variability in functional diversity.

Area of Science:

• Ecology
• Ecosystem Science

Background:

• Linking species and ecosystems often relies on functional diversity (FD), measured by species' trait dispersion.
• Including intraspecific variability (variation within species) in FD measures remains a challenge.

Purpose of the Study:

• To extend existing functional diversity measures to incorporate intraspecific variability.
• To evaluate the behavior of this new measure using simulations and analyze natural plant communities.

Main Methods:

• Developed an extended functional diversity measure accounting for individual variation within species.
• Used simulations to compare the new measure with traditional species-level FD.
• Applied the measure to analyze functional diversity and species richness in natural plant communities.

Main Results:

• Individual-level FD showed a weaker association with species richness in single trait dimensions compared to species-level FD.
• In multiple trait dimensions, individual- and species-level FD were strongly associated with richness.
• The correlation between the two FD measures decreased as intraspecific variability increased.
• Analysis of plant communities revealed no direct relationship between species richness and functional diversity when considering only individual variation.

Conclusions:

• The extended FD measure provides a more comprehensive understanding of individual-ecosystem links.
• Incorporating intraspecific variation is crucial for accurate ecosystem process predictions.
• This approach can reveal site-specific differences in intraspecific variability and its ecological impact.