Extinction debt and functional traits mediate community saturation over large spatiotemporal scales

Area of Science:

• Ecology
• Community Ecology
• Biogeography

Background:

• Ecological community saturation is crucial for understanding species assembly, invasions, and climate change impacts.
• Previous research often neglects extinction debt and functional trait diversity's role in saturation patterns.
• The Great American Biotic Interchange offers a unique case study for examining colonization and its effect on species richness.

Purpose of the Study:

• To investigate if post-Great American Biotic Interchange colonization events increased species richness in Dipsadidae snake communities.
• To assess if functional trait diversity and local environmental conditions mediate community saturation patterns.
• To determine the influence of dispersal events on community assembly and saturation.

Main Methods:

• Combined biodiversity survey data with functional and phylogenetic data for Dipsadidae snakes.
• Estimated ancestral areas using Bayesian time-calibrated phylogenetic analysis to track dispersal events.
• Evaluated the relationship between community saturation, functional trait similarity, and environmental variables.

Main Results:

• Colonized communities did not exhibit higher species richness than uncolonized ones.
• No association was found between functional diversity and colonization by dispersing lineages.
• Species richness variation was best predicted by time since colonization and local environmental factors.

Conclusions:

• Neotropical Dipsadidae snake communities are likely saturated.
• Extinction debt and species' functional traits are critical considerations for studying community saturation.
• Colonization alone does not necessarily increase species richness in established communities.