Long-distance dispersal maximizes evolutionary potential during rapid geographic range expansion

Area of Science:

• Evolutionary biology
• Ecology
• Population genetics

Background:

• Geographic range expansion often leads to reduced genetic diversity due to sequential founder events.
• This erosion of genetic diversity can limit a species' adaptive capacity and evolutionary potential at the expanding range front.
• Understanding the genetic dynamics of invasive species is crucial for predicting their ecological impact.

Purpose of the Study:

• To investigate the genetic diversity patterns of invasive European starlings (Sturnus vulgaris) during their range expansion in South Africa.
• To determine the role of dispersal in maintaining genetic diversity at the expanding range margin.
• To assess the influence of environmental conditions on dispersal strategies and genetic variation.

Main Methods:

• Utilized population genetic analyses to assess genetic diversity across the expanding range of European starlings.
• Employed molecular markers to detect signatures of selection and infer dispersal patterns.
• Correlated genetic data with environmental variables to understand the drivers of dispersal.

Main Results:

• Invasive European starlings preserved significant genetic diversity during their range expansion in South Africa.
• Frequent long-distance dispersal events were identified as a key mechanism for maintaining this diversity.
• Unfavorable environmental conditions were associated with enhanced dispersal, bringing novel genetic variation to the expansion front.
• Signatures of selection were detected across the expanding range, indicating adaptation to new environments.

Conclusions:

• Dispersal strategies play a critical role in maintaining genetic diversity during range expansion, counteracting the effects of sequential founding.
• Invasive species can retain high evolutionary potential at range margins through effective dispersal mechanisms.
• Understanding dispersal in novel environments is essential for predicting species' ecological and evolutionary responses to global environmental change.