Lower genetic diversity in the limpet Patella caerulea on urban coastal structures compared to natural rocky habitats

TL;DR

This study shows that urban coastal structures reduce genetic diversity in the limpet Patella caerulea compared to natural rocky habitats, indicating potential negative impacts of human-made structures on marine genetic variation.

Contribution

It provides the first comparative genetic analysis of Patella caerulea in natural versus artificial habitats along the Adriatic coast.

Findings

Genetic diversity is higher in natural habitats.

Weak genetic differentiation exists among populations.

Urban structures may cause regional genetic diversity loss.

Abstract

Human-made structures are increasingly found in marine coastal habitats. The aim of the present study was to explore whether urban coastal structures can affect the genetic variation of hard-bottom species. We conducted a population genetic analysis on the limpet Patella caerulea sampled in both natural and artificial habitats along the Adriatic coast. Five microsatellite loci were used to test for differences in genetic diversity and structure among samples. Three microsatellite loci showed strong Hardy-Weinberg disequilibrium likely linked with the presence of null alleles. Genetic diversity was significantly higher in natural habitat than in artificial habitat. A weak but significant differentiation over all limpet samples was observed, but not related to the type of habitat. While the exact causes of the differences in genetic diversity deserve further investigation, these results clearly point that the expansion of urban structures can lead to genetic diversity loss at regional scales.