Human-induced morphological shifts in an island lizard

Area of Science:

• Evolutionary biology
• Ecology
• Conservation biology

Background:

• Anthropogenic change is altering natural habitats globally.
• Species with broad environmental tolerances may persist and adapt to human-disturbed environments.
• The brown anole (Anolis sagrei) is a model organism for studying adaptation to human-altered habitats.

Purpose of the Study:

• To investigate the evolutionary consequences of anthropogenic habitat alteration on the brown anole.
• To examine morphological divergence between brown anole populations in natural versus human-disturbed habitats.
• To determine if observed morphological differences are driven by genetic differentiation or in situ adaptation.

Main Methods:

• Analysis of morphological data (snout-vent length, hindspan, mass) from brown anole populations.
• Comparison of populations from natural and human-disturbed habitats across different islands.
• Genetic analysis to assess population differentiation between habitat types.

Main Results:

• Populations in disturbed habitats were significantly larger in snout-vent length, hindspan, and mass.
• Hindspan divergence was strongly linked to human-induced changes in habitat structure.
• Populations were genetically distinct among islands but not between habitat types within islands.
• Morphological differences arose in situ, not due to separate founding events.

Conclusions:

• Anthropogenic habitat alteration drives rapid in situ morphological evolution in persisting species.
• The brown anole demonstrates adaptive responses to human-induced environmental changes.
• Understanding these evolutionary trajectories is crucial for predicting species' responses to global change.