Effects of subpopulation extinction on effective size (Ne) of metapopulations

作者：Sara Kurland, Nils Ryman, Ola Hössjer, Linda Laikre · 发表于：Conservation Genetics · 年份：2023 · DOI：10.1007/s10592-023-01510-9 · 被引用次数：19 · 研究领域：Genetic diversity and population structure、Evolution and Genetic Dynamics、Species Distribution and Climate Change

Abstract Population extinction is ubiquitous in all taxa. Such extirpations can reduce intraspecific diversity, but the extent to which genetic diversity of surviving populations are affected remains largely unclear. A key concept in this context is the effective population size ( N e ), which quantifies the rate at which genetic diversity within populations is lost. N e was developed for single, isolated populations while many natural populations are instead connected to other populations via gene flow. Recent analytical approaches and software permit modelling of N e of interconnected populations (metapopulations). Here, we apply such tools to investigate how extinction of subpopulations affects N e of the metapopulation ( N eMeta ) and of separate surviving subpopulations ( N eRx ) under different rates and patterns of genetic exchange between subpopulations. We assess extinction effects before and at migration-drift equilibrium. We find that the effect of extinction on N eMeta increases with reduced connectivity, suggesting that stepping stone models of migration are more impacted than island-migration models when the same number of subpopulations are lost. Furthermore, in stepping stone models, after extinction and before a new equilibrium has been reached, N eRx can vary drastically among surviving subpopulations and depends on their initial spatial position relative to extinct ones. Our results demonstrate that extinctions can have far more complex effects on the reten...