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How density dependence, genetic erosion and the extinction vortex impact evolutionary rescue

Following severe environmental change that reduces mean population fitness below replacement, populations must adapt to avoid eventual extinction, a process called evolutionary rescue. Models of evolutionary rescue demonstrate that initial size, genetic variation and degree of maladaptation influenc...

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Autores principales: Nordstrom, Scott W., Hufbauer, Ruth A., Olazcuaga, Laure, Durkee, Lily F., Melbourne, Brett A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10688442/
https://www.ncbi.nlm.nih.gov/pubmed/37989246
http://dx.doi.org/10.1098/rspb.2023.1228
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author Nordstrom, Scott W.
Hufbauer, Ruth A.
Olazcuaga, Laure
Durkee, Lily F.
Melbourne, Brett A.
author_facet Nordstrom, Scott W.
Hufbauer, Ruth A.
Olazcuaga, Laure
Durkee, Lily F.
Melbourne, Brett A.
author_sort Nordstrom, Scott W.
collection PubMed
description Following severe environmental change that reduces mean population fitness below replacement, populations must adapt to avoid eventual extinction, a process called evolutionary rescue. Models of evolutionary rescue demonstrate that initial size, genetic variation and degree of maladaptation influence population fates. However, many models feature populations that grow without negative density dependence or with constant genetic diversity despite precipitous population decline, assumptions likely to be violated in conservation settings. We examined the simultaneous influences of density-dependent growth and erosion of genetic diversity on populations adapting to novel environmental change using stochastic, individual-based simulations. Density dependence decreased the probability of rescue and increased the probability of extinction, especially in large and initially well-adapted populations that previously have been predicted to be at low risk. Increased extinction occurred shortly following environmental change, as populations under density dependence experienced more rapid decline and reached smaller sizes. Populations that experienced evolutionary rescue lost genetic diversity through drift and adaptation, particularly under density dependence. Populations that declined to extinction entered an extinction vortex, where small size increased drift, loss of genetic diversity and the fixation of maladaptive alleles, hindered adaptation and kept populations at small densities where they were vulnerable to extinction via demographic stochasticity.
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spelling pubmed-106884422023-11-30 How density dependence, genetic erosion and the extinction vortex impact evolutionary rescue Nordstrom, Scott W. Hufbauer, Ruth A. Olazcuaga, Laure Durkee, Lily F. Melbourne, Brett A. Proc Biol Sci Ecology Following severe environmental change that reduces mean population fitness below replacement, populations must adapt to avoid eventual extinction, a process called evolutionary rescue. Models of evolutionary rescue demonstrate that initial size, genetic variation and degree of maladaptation influence population fates. However, many models feature populations that grow without negative density dependence or with constant genetic diversity despite precipitous population decline, assumptions likely to be violated in conservation settings. We examined the simultaneous influences of density-dependent growth and erosion of genetic diversity on populations adapting to novel environmental change using stochastic, individual-based simulations. Density dependence decreased the probability of rescue and increased the probability of extinction, especially in large and initially well-adapted populations that previously have been predicted to be at low risk. Increased extinction occurred shortly following environmental change, as populations under density dependence experienced more rapid decline and reached smaller sizes. Populations that experienced evolutionary rescue lost genetic diversity through drift and adaptation, particularly under density dependence. Populations that declined to extinction entered an extinction vortex, where small size increased drift, loss of genetic diversity and the fixation of maladaptive alleles, hindered adaptation and kept populations at small densities where they were vulnerable to extinction via demographic stochasticity. The Royal Society 2023-11-22 /pmc/articles/PMC10688442/ /pubmed/37989246 http://dx.doi.org/10.1098/rspb.2023.1228 Text en © 2023 The Authors. https://creativecommons.org/licenses/by/4.0/Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, provided the original author and source are credited.
spellingShingle Ecology
Nordstrom, Scott W.
Hufbauer, Ruth A.
Olazcuaga, Laure
Durkee, Lily F.
Melbourne, Brett A.
How density dependence, genetic erosion and the extinction vortex impact evolutionary rescue
title How density dependence, genetic erosion and the extinction vortex impact evolutionary rescue
title_full How density dependence, genetic erosion and the extinction vortex impact evolutionary rescue
title_fullStr How density dependence, genetic erosion and the extinction vortex impact evolutionary rescue
title_full_unstemmed How density dependence, genetic erosion and the extinction vortex impact evolutionary rescue
title_short How density dependence, genetic erosion and the extinction vortex impact evolutionary rescue
title_sort how density dependence, genetic erosion and the extinction vortex impact evolutionary rescue
topic Ecology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10688442/
https://www.ncbi.nlm.nih.gov/pubmed/37989246
http://dx.doi.org/10.1098/rspb.2023.1228
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