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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

Survival of grey and brown tawny owls in relation to changes in snow depth.Survival estimates are based on averaging all candidate capture–mark–recapture models considering the effects of food supply (vole abundance), average snow depth and average temperature during a critical period in winter (see Supplementary Information). Climatic data are derived from the database of the Finnish Meteorological Institute. (a) Survival of brown and grey tawny owl colour morphs in relation to snow depth. (b) Snow depth during the critical period for tawny owl survival during 1981–2008 in Southern Finland. (c) Survival of grey and brown tawny owl colour morphs during 1981–2008. Grey tawny owls are denoted by grey circles and brown ones by red diamonds. Error bars are standard errors of the estimated survival and the lines are regression slopes based on the data.
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f3: Survival of grey and brown tawny owls in relation to changes in snow depth.Survival estimates are based on averaging all candidate capture–mark–recapture models considering the effects of food supply (vole abundance), average snow depth and average temperature during a critical period in winter (see Supplementary Information). Climatic data are derived from the database of the Finnish Meteorological Institute. (a) Survival of brown and grey tawny owl colour morphs in relation to snow depth. (b) Snow depth during the critical period for tawny owl survival during 1981–2008 in Southern Finland. (c) Survival of grey and brown tawny owl colour morphs during 1981–2008. Grey tawny owls are denoted by grey circles and brown ones by red diamonds. Error bars are standard errors of the estimated survival and the lines are regression slopes based on the data.

Mentions: Model averaging of all candidate models (N=175) revealed that variation in snow depth explained most of the variation in survival of the colour morphs. In our case, 99.4% of support stems from the four best models (Table 1) and the averaging can therefore be considered to mainly describe the common features included in these models (that is, colour morph–snow depth interaction). As snow depth increased, survival of the brown morph decreased more strongly than for the grey morph (Fig. 3a). Simultaneously, snow depth has decreased over time (Fig. 3b; linear model, year: b=−0.37±0.13, F1,25=8.49, P=0.007). As a consequence, there was a time trend in survival of the colour morphs from 1981–2008, in which survival of the grey morph was fairly stable across years, whereas survival of brown individuals improved dramatically towards the end of the time series (Fig. 3c). Thus, we provide evidence that climate-driven selection against the brown morph has decreased in recent years such that the survival propensity of the morphs have equalized in recent, mild winters.


Climate change drives microevolution in a wild bird.

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

Survival of grey and brown tawny owls in relation to changes in snow depth.Survival estimates are based on averaging all candidate capture–mark–recapture models considering the effects of food supply (vole abundance), average snow depth and average temperature during a critical period in winter (see Supplementary Information). Climatic data are derived from the database of the Finnish Meteorological Institute. (a) Survival of brown and grey tawny owl colour morphs in relation to snow depth. (b) Snow depth during the critical period for tawny owl survival during 1981–2008 in Southern Finland. (c) Survival of grey and brown tawny owl colour morphs during 1981–2008. Grey tawny owls are denoted by grey circles and brown ones by red diamonds. Error bars are standard errors of the estimated survival and the lines are regression slopes based on the data.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f3: Survival of grey and brown tawny owls in relation to changes in snow depth.Survival estimates are based on averaging all candidate capture–mark–recapture models considering the effects of food supply (vole abundance), average snow depth and average temperature during a critical period in winter (see Supplementary Information). Climatic data are derived from the database of the Finnish Meteorological Institute. (a) Survival of brown and grey tawny owl colour morphs in relation to snow depth. (b) Snow depth during the critical period for tawny owl survival during 1981–2008 in Southern Finland. (c) Survival of grey and brown tawny owl colour morphs during 1981–2008. Grey tawny owls are denoted by grey circles and brown ones by red diamonds. Error bars are standard errors of the estimated survival and the lines are regression slopes based on the data.
Mentions: Model averaging of all candidate models (N=175) revealed that variation in snow depth explained most of the variation in survival of the colour morphs. In our case, 99.4% of support stems from the four best models (Table 1) and the averaging can therefore be considered to mainly describe the common features included in these models (that is, colour morph–snow depth interaction). As snow depth increased, survival of the brown morph decreased more strongly than for the grey morph (Fig. 3a). Simultaneously, snow depth has decreased over time (Fig. 3b; linear model, year: b=−0.37±0.13, F1,25=8.49, P=0.007). As a consequence, there was a time trend in survival of the colour morphs from 1981–2008, in which survival of the grey morph was fairly stable across years, whereas survival of brown individuals improved dramatically towards the end of the time series (Fig. 3c). Thus, we provide evidence that climate-driven selection against the brown morph has decreased in recent years such that the survival propensity of the morphs have equalized in recent, mild winters.

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