Three types of rescue can avert extinction in a changing environment

Setting aside high-quality large areas of habitat to protect threatened populations is becoming increasingly difficult as humans fragment and degrade the environment. Biologists and managers therefore must determine the best way to shepherd small populations through the dual challenges of reductions...

Full description

Saved in:
Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS Vol. 112; no. 33; pp. 10557 - 10562
Main Authors: Hufbauer, Ruth A, Szűcs, Marianna, Kasyon, Emily, Youngberg, Courtney, Koontz, Michael J, Richards, Christopher, Tuff, Ty, Melbourne, Brett A
Format: Journal Article
Language:English
Published: United States 18.08.2015
Subjects:
Animals
Biodiversity
Biological Evolution
Ecosystem
Environment
Evolution, Molecular
Extinction, Biological
Female
Genetic Fitness
Genetic Variation
Genetics, Population
Male
Microsatellite Repeats
Models, Genetic
Population Density
Probability
Tribolium - genetics
migration
adaptation
extinction
genetic rescue
evolutionary rescue
ISSN:1091-6490
Online Access:Get more information
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Setting aside high-quality large areas of habitat to protect threatened populations is becoming increasingly difficult as humans fragment and degrade the environment. Biologists and managers therefore must determine the best way to shepherd small populations through the dual challenges of reductions in both the number of individuals and genetic variability. By bringing in additional individuals, threatened populations can be increased in size (demographic rescue) or provided with variation to facilitate adaptation and reduce inbreeding (genetic rescue). The relative strengths of demographic and genetic rescue for reducing extinction and increasing growth of threatened populations are untested, and which type of rescue is effective may vary with population size. Using the flour beetle (Tribolium castaneum) in a microcosm experiment, we disentangled the genetic and demographic components of rescue, and compared them with adaptation from standing genetic variation (evolutionary rescue in the strictest sense) using 244 experimental populations founded at either a smaller (50 individuals) or larger (150 individuals) size. Both types of rescue reduced extinction, and those effects were additive. Over the course of six generations, genetic rescue increased population sizes and intrinsic fitness substantially. Both large and small populations showed evidence of being able to adapt from standing genetic variation. Our results support the practice of genetic rescue in facilitating adaptation and reducing inbreeding depression, and suggest that demographic rescue alone may suffice in larger populations even if only moderately inbred individuals are available for addition.
Bibliography:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:1091-6490
DOI:10.1073/pnas.1504732112