Effective population size, genetic variation, and their use in population management

Lande, Russell; Barrowclough, George F.

doi:10.1017/cbo9780511623400.007

Cited by 866 publications

(670 citation statements)

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“…Probable adaptive genetic differentiation was greater between small and large populations or among small populations than among large populations, based on signatures of balancing and/or diversifying selection at SNPs linked to phenotypic traits. These patterns were stronger for estimates of N b than N, an important finding given that theoretically it is through N b that selection should influence the magnitude of adaptive genetic differentiation [20,35]. What we did not find was evidence of reduced signatures of selection in small populations relative to large populations, despite that overall genetic variation (multi-locus heterozygosity) and neutral differentiation ( pairwise neutral F ST ) were consistent with pronounced genetic drift in small populations.…”

Section: Discussioncontrasting

confidence: 63%

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Population size, habitat fragmentation, and the nature of adaptive variation in a stream fish

Fraser

Debes²,

Bernatchez

et al. 2014

Proc. R. Soc. B.

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Whether and how habitat fragmentation and population size jointly affect adaptive genetic variation and adaptive population differentiation are largely unexplored. Owing to pronounced genetic drift, small, fragmented populations are thought to exhibit reduced adaptive genetic variation relative to large populations. Yet fragmentation is known to increase variability within and among habitats as population size decreases. Such variability might instead favour the maintenance of adaptive polymorphisms and/or generate more variability in adaptive differentiation at smaller population size. We investigated these alternative hypotheses by analysing coding-gene, singlenucleotide polymorphisms associated with different biological functions in fragmented brook trout populations of variable sizes. Putative adaptive differentiation was greater between small and large populations or among small populations than among large populations. These trends were stronger for genetic population size measures than demographic ones and were present despite pronounced drift in small populations. Our results suggest that fragmentation affects natural selection and that the changes elicited in the adaptive genetic composition and differentiation of fragmented populations vary with population size. By generating more variable evolutionary responses, the alteration of selective pressures during habitat fragmentation may affect future population persistence independently of, and perhaps long before, the effects of demographic and genetic stochasticity are manifest.

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Section: Discussioncontrasting

confidence: 63%

“…[19]). It is also the genetic parameter N b -not the ecological parameter N-that selection is associated with and that influences the magnitude of adaptive genetic variation and differentiation [20].…”

Section: Introductionmentioning

confidence: 99%

Population size, habitat fragmentation, and the nature of adaptive variation in a stream fish

Fraser

Debes²,

Bernatchez

et al. 2014

Proc. R. Soc. B.

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show abstract

“…In previous models [3,34], where the rate of evolution is determined by additive genetic variation instead of mutational input, the relationship between population size and the rate of evolution can be weaker (reviewed in [65]). Although non-additive genetic effects, such as epistasis and dominance, and temporal fluctuations in abundance (leading to lower effective population sizes) can weaken the relationship between population size and the rate of evolution [66], they do not qualitatively alter our results, but merely lead to a slower rate of evolution than predicted.…”

Section: Discussioncontrasting

confidence: 53%

How competition affects evolutionary rescue

Osmond

Mazancourt

2013

Phil. Trans. R. Soc. B

110

142

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Populations facing novel environments can persist by adapting. In nature, the ability to adapt and persist will depend on interactions between coexisting individuals. Here we use an adaptive dynamic model to assess how the potential for evolutionary rescue is affected by intra- and interspecific competition. Intraspecific competition (negative density-dependence) lowers abundance, which decreases the supply rate of beneficial mutations, hindering evolutionary rescue. On the other hand, interspecific competition can aid evolutionary rescue when it speeds adaptation by increasing the strength of selection. Our results clarify this point and give an additional requirement: competition must increase selection pressure enough to overcome the negative effect of reduced abundance. We therefore expect evolutionary rescue to be most likely in communities which facilitate rapid niche displacement. Our model, which aligns to previous quantitative and population genetic models in the absence of competition, provides a first analysis of when competitors should help or hinder evolutionary rescue.

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“…For instance, rainy days at the beginning of the light period in 1983 were found to inluence individual development in Euphydryas editha bayensis, resulting in the irst females emerging 14 days after males, which had a clear negative efect on the population dynamics of the species (Dobkin et al 1987;Baughman 1991). Furthermore, a high level of temporal fragmentation, namely short individual life span in relation to long light period, in combination with protandry seriously reduced the efective population size (sensu Lande and Barrowclough 1987;Hill 1972), thus accelerating the loss of genetic variability in small populations. In contrast to several earlier studies, which suggested that extinction risk in butterlies decreases with lengthening light period (Komonen et al 2004;Kotiaho et al 2005;Franzen and;Johannesson 2007), our analyses did not reveal any link between light period length alone and species conservation status.…”

Section: Discussionmentioning

confidence: 99%

Adult longevity and its relationship with conservation status in European butterflies

et al. 2016

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Effective population size, genetic variation, and their use in population management

Cited by 866 publications

References 0 publications

Population size, habitat fragmentation, and the nature of adaptive variation in a stream fish

Population size, habitat fragmentation, and the nature of adaptive variation in a stream fish

How competition affects evolutionary rescue

Adult longevity and its relationship with conservation status in European butterflies

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