Observing character displacement from process to pattern in a novel vertebrate community

Area of Science:

• Ecology
• Evolutionary Biology
• Herpetology

Background:

• Ecological character displacement is a key driver of community assembly and adaptive radiation.
• Evidence for character displacement often relies on macro-scale patterns, with direct tests of natural selection being rare.
• Understanding the role of natural selection is crucial for explaining evolutionary divergence.

Purpose of the Study:

• To directly test the hypothesis of divergent natural selection driving character displacement in wild populations.
• To document character displacement in two ecologically similar lizard species (Anolis sagrei and A. cristatellus) experiencing novel contact.
• To connect short-term natural selection to long-term trait divergence patterns.

Main Methods:

• Observing ecological character displacement in lizards with novel sympatry.
• Identifying directional natural selection in incipient stages of species interaction.
• Comparing trait divergence in new communities with established sympatric communities.

Main Results:

• Directional selection was identified during the early stages of sympatry between Anolis sagrei and A. cristatellus.
• Observed trait divergence in the new community mirrored patterns in established sympatric communities.
• Direct evidence of natural selection driving character displacement was documented.

Conclusions:

• Natural selection actively drives ecological character displacement, even in novel interactions.
• Short-term selection pressures can lead to significant evolutionary divergence over time.
• This study provides a direct link between microevolutionary processes and macroevolutionary patterns of trait distribution.