Limits...
Climate change drives microevolution in a wild bird.

Karell P, Ahola K, Karstinen T, Valkama J, Brommer JE - Nat Commun (2011)

Bottom Line: As winter conditions became milder in the last decades, selection against the brown morph diminished.Concurrent with this reduced selection, the frequency of brown morphs increased rapidly in our study population during the last 28 years and nationwide during the last 48 years.Hence, we show the first evidence that recent climate change alters natural selection in a wild population leading to a microevolutionary response, which demonstrates the ability of wild populations to evolve in response to climate change.

View Article: PubMed Central - PubMed

Affiliation: Bird Ecology Unit, Department of Biosciences, University of Helsinki, PO Box 65 (Viikinkaari 1), Helsinki FI-00014, Finland. patrik.karell@helsinki.fi

ABSTRACT
To ensure long-term persistence, organisms must adapt to climate change, but an evolutionary response to a quantified selection pressure driven by climate change has not been empirically demonstrated in a wild population. Here, we show that pheomelanin-based plumage colouration in tawny owls is a highly heritable trait, consistent with a simple Mendelian pattern of brown (dark) dominance over grey (pale). We show that strong viability selection against the brown morph occurs, but only under snow-rich winters. As winter conditions became milder in the last decades, selection against the brown morph diminished. Concurrent with this reduced selection, the frequency of brown morphs increased rapidly in our study population during the last 28 years and nationwide during the last 48 years. Hence, we show the first evidence that recent climate change alters natural selection in a wild population leading to a microevolutionary response, which demonstrates the ability of wild populations to evolve in response to climate change.

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Related in: MedlinePlus

Factors explaining the increase in the proportion of the brown morph in the study population.Number of brown (a) and grey (b) survivors (denoted by diamonds, solid line), immigrants (circles, dashed line) and recruits (triangles, dashed-dotted line) in the breeding population during the study period.
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f5: Factors explaining the increase in the proportion of the brown morph in the study population.Number of brown (a) and grey (b) survivors (denoted by diamonds, solid line), immigrants (circles, dashed line) and recruits (triangles, dashed-dotted line) in the breeding population during the study period.

Mentions: Apart from selection, immigration is an important population dynamical feature in our study population24. A proportional increase in immigrating brown morphs could account for the observed increase in their frequency in the population. To test the relative importance of morph-specific immigration, local recruitment and selection on the proportional increase of the brown morph, we categorized all breeding individuals into immigrants (first breeder that is unmarked or marked outside the study area), local recruits (first breeders marked as young) and old breeders (survivors from a previous breeding attempt). We then analysed the relative contribution of grey and brown survivors, immigrants and local recruits over time to the observed increase in the frequency of the brown morph. We found that the increase in frequency of the brown morph in the population was explained only by an increase in the number of brown survivors over time, and not by any other numeral trend (binomial generalized linear model: b=0.18±0.09 s.e.m., z=2.11, N=28, P=0.035, Fig. 5). We used our observed parent–offspring inheritance pattern to retrospectively infer the morphs of offspring produced during the last three decades. There was no morph-specific temporal trend in reproductive success or recruitment rate (Supplementary Information), which illustrates that the increase in the proportion of brown morphs in the population is not driven by a change in productivity of the brown morph. Furthermore, we found no evidence for a phenotypically plastic within-individual colouration change as winter climate gets milder (Supplementary Information). We conclude that improved survival of brown adult tawny owls caused by warmer winters with less snow is the most likely candidate to drive the observed temporal increase in the brown morph.


Climate change drives microevolution in a wild bird.

Karell P, Ahola K, Karstinen T, Valkama J, Brommer JE - Nat Commun (2011)

Factors explaining the increase in the proportion of the brown morph in the study population.Number of brown (a) and grey (b) survivors (denoted by diamonds, solid line), immigrants (circles, dashed line) and recruits (triangles, dashed-dotted line) in the breeding population during the study period.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3105316&req=5

f5: Factors explaining the increase in the proportion of the brown morph in the study population.Number of brown (a) and grey (b) survivors (denoted by diamonds, solid line), immigrants (circles, dashed line) and recruits (triangles, dashed-dotted line) in the breeding population during the study period.
Mentions: Apart from selection, immigration is an important population dynamical feature in our study population24. A proportional increase in immigrating brown morphs could account for the observed increase in their frequency in the population. To test the relative importance of morph-specific immigration, local recruitment and selection on the proportional increase of the brown morph, we categorized all breeding individuals into immigrants (first breeder that is unmarked or marked outside the study area), local recruits (first breeders marked as young) and old breeders (survivors from a previous breeding attempt). We then analysed the relative contribution of grey and brown survivors, immigrants and local recruits over time to the observed increase in the frequency of the brown morph. We found that the increase in frequency of the brown morph in the population was explained only by an increase in the number of brown survivors over time, and not by any other numeral trend (binomial generalized linear model: b=0.18±0.09 s.e.m., z=2.11, N=28, P=0.035, Fig. 5). We used our observed parent–offspring inheritance pattern to retrospectively infer the morphs of offspring produced during the last three decades. There was no morph-specific temporal trend in reproductive success or recruitment rate (Supplementary Information), which illustrates that the increase in the proportion of brown morphs in the population is not driven by a change in productivity of the brown morph. Furthermore, we found no evidence for a phenotypically plastic within-individual colouration change as winter climate gets milder (Supplementary Information). We conclude that improved survival of brown adult tawny owls caused by warmer winters with less snow is the most likely candidate to drive the observed temporal increase in the brown morph.

Bottom Line: As winter conditions became milder in the last decades, selection against the brown morph diminished.Concurrent with this reduced selection, the frequency of brown morphs increased rapidly in our study population during the last 28 years and nationwide during the last 48 years.Hence, we show the first evidence that recent climate change alters natural selection in a wild population leading to a microevolutionary response, which demonstrates the ability of wild populations to evolve in response to climate change.

View Article: PubMed Central - PubMed

Affiliation: Bird Ecology Unit, Department of Biosciences, University of Helsinki, PO Box 65 (Viikinkaari 1), Helsinki FI-00014, Finland. patrik.karell@helsinki.fi

ABSTRACT
To ensure long-term persistence, organisms must adapt to climate change, but an evolutionary response to a quantified selection pressure driven by climate change has not been empirically demonstrated in a wild population. Here, we show that pheomelanin-based plumage colouration in tawny owls is a highly heritable trait, consistent with a simple Mendelian pattern of brown (dark) dominance over grey (pale). We show that strong viability selection against the brown morph occurs, but only under snow-rich winters. As winter conditions became milder in the last decades, selection against the brown morph diminished. Concurrent with this reduced selection, the frequency of brown morphs increased rapidly in our study population during the last 28 years and nationwide during the last 48 years. Hence, we show the first evidence that recent climate change alters natural selection in a wild population leading to a microevolutionary response, which demonstrates the ability of wild populations to evolve in response to climate change.

Show MeSH
Related in: MedlinePlus