Increased male bias in eider ducks can be explained by sex-specific survival of prime-age breeders
In contrast to theoretical predictions of even adult sex ratios, males are dominating in many bird populations. Such bias among adults may be critical to population growth and viability. Nevertheless, demographic mechanisms for biased adult sex ratios are still poorly understood. Here, we examined p...
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ftunivhelsihelda:oai:helda.helsinki.fi:10138/299200 2024-01-07T09:46:41+01:00 Increased male bias in eider ducks can be explained by sex-specific survival of prime-age breeders Ramula, Satu Öst, Markus Lindén, Andreas Karell, Patrik Kilpi, Mikael Tvärminne Zoological Station 2019-02-19T09:55:01Z 13 application/pdf http://hdl.handle.net/10138/299200 eng eng PUBLIC LIBRARY OF SCIENCE 10.1371/journal.pone.0195415 This work was supported by the Academy of Finland (#285746 to SR, #309992 to PK), the Swedish Cultural Foundation in Finland (to MO) and the Walter and Andree de Nottbeck Foundation (to MK). Ramula , S , Öst , M , Lindén , A , Karell , P & Kilpi , M 2018 , ' Increased male bias in eider ducks can be explained by sex-specific survival of prime-age breeders ' , PLoS One , vol. 13 , no. 4 , 0195415 . https://doi.org/10.1371/journal.pone.0195415 85045289596 af61acb5-9c5d-440a-9995-37a71bbbc0ba http://hdl.handle.net/10138/299200 000429522200030 cc_by openAccess info:eu-repo/semantics/openAccess ADULT COMMON EIDERS SOMATERIA-MOLLISSIMA RATIO POPULATION BIRD DYNAMICS MODELS SYSTEM COST CONSEQUENCES 1181 Ecology evolutionary biology Article publishedVersion 2019 ftunivhelsihelda 2023-12-14T00:05:01Z In contrast to theoretical predictions of even adult sex ratios, males are dominating in many bird populations. Such bias among adults may be critical to population growth and viability. Nevertheless, demographic mechanisms for biased adult sex ratios are still poorly understood. Here, we examined potential demographic mechanisms for the recent dramatic shift from a slight female bias among adult eider ducks (Somateria mollissima) to a male bias (about 65% males) in the Baltic Sea, where the species is currently declining. We analysed a nine-year dataset on offspring sex ratio at hatching based on molecularly sexed ducklings of individually known mothers. Moreover, using demographic data from long-term individual-based capture-recapture records, we investigated how sex-specific survival at different ages after fledgling can modify the adult sex ratio. More specifically, we constructed a stochastic two-sex matrix population model and simulated scenarios of different survival probabilities for males and females. We found that sex ratio at hatching was slightly female-biased (52.8%) and therefore unlikely to explain the observed male bias among adult birds. Our stochastic simulations with higher survival for males than for females revealed that despite a slight female bias at hatching, study populations shifted to a male-biased adult sex ratio (> 60% males) in a few decades. This shift was driven by prime reproductive-age individuals(>5-year-old), with sex-specific survival of younger age classes playing a minor role. Hence, different age classes contributed disproportion ally to population dynamics. We argue that an alternative explanation for the observed male dominance among adults sex-biased dispersal can be considered redundant and is unlikely, given the ecology of the species. The present study highlights the importance of considering population structure and age-specific vital rates when assessing population dynamics and management targets. Peer reviewed Article in Journal/Newspaper Somateria mollissima HELDA – University of Helsinki Open Repository PLOS ONE 13 4 e0195415 |
institution |
Open Polar |
collection |
HELDA – University of Helsinki Open Repository |
op_collection_id |
ftunivhelsihelda |
language |
English |
topic |
ADULT COMMON EIDERS SOMATERIA-MOLLISSIMA RATIO POPULATION BIRD DYNAMICS MODELS SYSTEM COST CONSEQUENCES 1181 Ecology evolutionary biology |
spellingShingle |
ADULT COMMON EIDERS SOMATERIA-MOLLISSIMA RATIO POPULATION BIRD DYNAMICS MODELS SYSTEM COST CONSEQUENCES 1181 Ecology evolutionary biology Ramula, Satu Öst, Markus Lindén, Andreas Karell, Patrik Kilpi, Mikael Increased male bias in eider ducks can be explained by sex-specific survival of prime-age breeders |
topic_facet |
ADULT COMMON EIDERS SOMATERIA-MOLLISSIMA RATIO POPULATION BIRD DYNAMICS MODELS SYSTEM COST CONSEQUENCES 1181 Ecology evolutionary biology |
description |
In contrast to theoretical predictions of even adult sex ratios, males are dominating in many bird populations. Such bias among adults may be critical to population growth and viability. Nevertheless, demographic mechanisms for biased adult sex ratios are still poorly understood. Here, we examined potential demographic mechanisms for the recent dramatic shift from a slight female bias among adult eider ducks (Somateria mollissima) to a male bias (about 65% males) in the Baltic Sea, where the species is currently declining. We analysed a nine-year dataset on offspring sex ratio at hatching based on molecularly sexed ducklings of individually known mothers. Moreover, using demographic data from long-term individual-based capture-recapture records, we investigated how sex-specific survival at different ages after fledgling can modify the adult sex ratio. More specifically, we constructed a stochastic two-sex matrix population model and simulated scenarios of different survival probabilities for males and females. We found that sex ratio at hatching was slightly female-biased (52.8%) and therefore unlikely to explain the observed male bias among adult birds. Our stochastic simulations with higher survival for males than for females revealed that despite a slight female bias at hatching, study populations shifted to a male-biased adult sex ratio (> 60% males) in a few decades. This shift was driven by prime reproductive-age individuals(>5-year-old), with sex-specific survival of younger age classes playing a minor role. Hence, different age classes contributed disproportion ally to population dynamics. We argue that an alternative explanation for the observed male dominance among adults sex-biased dispersal can be considered redundant and is unlikely, given the ecology of the species. The present study highlights the importance of considering population structure and age-specific vital rates when assessing population dynamics and management targets. Peer reviewed |
author2 |
Tvärminne Zoological Station |
format |
Article in Journal/Newspaper |
author |
Ramula, Satu Öst, Markus Lindén, Andreas Karell, Patrik Kilpi, Mikael |
author_facet |
Ramula, Satu Öst, Markus Lindén, Andreas Karell, Patrik Kilpi, Mikael |
author_sort |
Ramula, Satu |
title |
Increased male bias in eider ducks can be explained by sex-specific survival of prime-age breeders |
title_short |
Increased male bias in eider ducks can be explained by sex-specific survival of prime-age breeders |
title_full |
Increased male bias in eider ducks can be explained by sex-specific survival of prime-age breeders |
title_fullStr |
Increased male bias in eider ducks can be explained by sex-specific survival of prime-age breeders |
title_full_unstemmed |
Increased male bias in eider ducks can be explained by sex-specific survival of prime-age breeders |
title_sort |
increased male bias in eider ducks can be explained by sex-specific survival of prime-age breeders |
publisher |
PUBLIC LIBRARY OF SCIENCE |
publishDate |
2019 |
url |
http://hdl.handle.net/10138/299200 |
genre |
Somateria mollissima |
genre_facet |
Somateria mollissima |
op_relation |
10.1371/journal.pone.0195415 This work was supported by the Academy of Finland (#285746 to SR, #309992 to PK), the Swedish Cultural Foundation in Finland (to MO) and the Walter and Andree de Nottbeck Foundation (to MK). Ramula , S , Öst , M , Lindén , A , Karell , P & Kilpi , M 2018 , ' Increased male bias in eider ducks can be explained by sex-specific survival of prime-age breeders ' , PLoS One , vol. 13 , no. 4 , 0195415 . https://doi.org/10.1371/journal.pone.0195415 85045289596 af61acb5-9c5d-440a-9995-37a71bbbc0ba http://hdl.handle.net/10138/299200 000429522200030 |
op_rights |
cc_by openAccess info:eu-repo/semantics/openAccess |
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PLOS ONE |
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13 |
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4 |
container_start_page |
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