Skip to main content
Dryad

Immigration allows population persistence and maintains genetic diversity despite an attempted experimental extinction

Data files

Jul 17, 2024 version files 452.38 KB

Abstract

Widespread fragmentation and degradation of habitats make organisms increasingly vulnerable to declines in population. Immigration is a key process potentially affecting the rescue and persistence of populations in the face of such pressures. Field research addressing severe demographic declines in the context of immigration among interconnected local populations is limited due to difficulties in detecting such demographic events and the need for long-term monitoring of populations. In a 17-subpopulation metapopulation of the butterfly, Parnassius smintheus, all adults observed in two adjacent patches were removed over eight consecutive generations. Despite this severe and long-term reduction in survival and reproduction, the targeted populations did not go extinct. Here, we use genetic data to assess the role of immigration versus in situ reproduction in allowing the persistence of these populations. We genotyped 471 samples collected from the targeted populations throughout the removal experiment at 171 single nucleotide polymorphisms. We found no reduction of genetic diversity of the targeted populations over time, but a decrease in number of loci in Hardy-Weinberg equilibrium, consistent with a high level of immigration from multiple, surrounding populations. Our results highlight the role of connectivity and movement in making metapopulations resilient to even severe and protracted localized population reductions.