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Experimental separation of genetic and demographic factors on extinction risk in wild populations
Author(s) -
Wootton J. Timothy,
Pfister Catherine A.
Publication year - 2013
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.1890/12-1828.1
Subject(s) - allee effect , inbreeding depression , extinction (optical mineralogy) , genetic diversity , biology , ecology , small population size , genetic drift , population , inbreeding , demography , paleontology , sociology , habitat
When populations reach small size, an extinction risk vortex may arise from genetic (inbreeding depression, genetic drift) and ecological (demographic stochasticity, Allee effects, environmental fluctuation) processes. The relative contribution of these processes to extinction in wild populations is unknown, but important for conserving endangered species. In experimental field populations of a harvested kelp ( Postelsia palmaeformis ), in which we independently varied initial genetic diversity (completely inbred, control, outbred) and population size, ecological processes dominated the risk of extinction, whereas the contribution of genetic diversity was slight. Our results match theoretical predictions that demographic processes will generally doom small populations to extinction before genetic effects act strongly, prioritize detailed ecological analysis over descriptions of genetic structure in assessing conservation of at‐risk species, and highlight the need for field experiments manipulating both demographics and genetic structure on long‐term extinction risk.