Genetic diversity and gene flow decline with elevation in montane mayflies

Area of Science:

• Ecology
• Evolutionary Biology
• Conservation Genetics

Background:

• Montane environments are biodiversity hotspots and crucial reservoirs of genetic diversity.
• Montane species face higher vulnerability to environmental change due to limited ranges and dispersal.
• Congeneric mayflies (Baetis bicaudatus and B. tricaudatus) were studied along an elevation gradient.

Purpose of the Study:

• To describe genetic diversity and population structure in montane mayflies across an elevation gradient.
• To identify environmental drivers of genetic differentiation using landscape analyses.
• To pinpoint outlier loci potentially involved in adaptive divergence.

Main Methods:

• Single-nucleotide polymorphism (SNP) genotyping was used to assess genetic diversity and population structure.
• Spatially explicit landscape analyses were performed to identify environmental drivers of differentiation.
• Population structure, heterozygosity, effective population sizes, and gene flow were analyzed across elevation gradients.

Main Results:

• Genetic diversity and gene flow decreased with increasing elevation, leading to significant population structure in higher-elevation species (B. bicaudatus).
• Lower elevation populations exhibited greater genetic similarity and ongoing gene flow.
• Isolation by distance was observed at lower elevations, while landscape barriers were more influential at higher elevations, restricting dispersal.

Conclusions:

• Montane mayflies exhibit genetic differentiation over small spatial scales along elevation gradients.
• Higher elevation populations are more isolated due to landscape effects, highlighting their vulnerability.
• Preserving genetic diversity in isolated high-elevation populations is essential for montane biodiversity conservation.