Rapid reshaping: the evolution of morphological changes in an introduced beach daisy

Area of Science:

• Evolutionary biology
• Ecology
• Plant sciences

Background:

• Species introductions offer insights into evolutionary adaptation to new environments.
• Previous studies often confound evolutionary change by comparing introduced populations to diverse native ranges.

Purpose of the Study:

• To investigate rapid morphological evolution in introduced beach daisy (Arctotheca populifolia) populations.
• To compare introduced Australian populations with their specific South African source population.

Main Methods:

• Microsatellite analysis to identify the native source population of introduced beach daisies.
• Common-environment experiment comparing source and introduced populations.
• Assessment of heritable morphological differences.

Main Results:

• Substantial heritable morphological differences were observed between source and introduced populations of A. populifolia within 100 years.
• Introduced plants were shorter and had smaller, thicker leaves than source plants, contrary to predictions.
• Introduced plants retained juvenile leaf morphology into adulthood, unlike source plants.

Conclusions:

• Rapid evolution occurs in introduced species, leading to significant morphological changes.
• Observed evolutionary changes in A. populifolia do not consistently support established hypotheses like the evolution of increased competitive ability.
• Environmental factors in the introduced range may drive rapid, non-predicted evolutionary trajectories.