Changes in the adult sex ratio of six duck species breeding populations over two decades

Despite all efforts, long-term changes in the adult sex ratios of breeding duck populations are still unclear; this uncertainty is especially true for male-bias populations, which are often under the scrutiny of researchers lacking convenient results for the active protection of endangered species....

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Main Authors: Monika Homolková, Petr Musil, Diego Pavón-Jordán, Dorota Gajdošová, Zuzana Musilová, Šárka Neužilová, Jan Zouhar
Format: Article
Language:English
Published: KeAi Communications Co., Ltd. 2024-01-01
Series:Avian Research
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Online Access:http://www.sciencedirect.com/science/article/pii/S2053716624000306
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author Monika Homolková
Petr Musil
Diego Pavón-Jordán
Dorota Gajdošová
Zuzana Musilová
Šárka Neužilová
Jan Zouhar
author_facet Monika Homolková
Petr Musil
Diego Pavón-Jordán
Dorota Gajdošová
Zuzana Musilová
Šárka Neužilová
Jan Zouhar
author_sort Monika Homolková
collection DOAJ
description Despite all efforts, long-term changes in the adult sex ratios of breeding duck populations are still unclear; this uncertainty is especially true for male-bias populations, which are often under the scrutiny of researchers lacking convenient results for the active protection of endangered species. Species with male-bias populations are usually strongly affected by a decline in population size that leads to a higher extinction risk. In this study, we examined our long-term data of the abundance of breeding populations in six duck species (Mallard Anas platyrhynchos, Gadwall Mareca strepera, Red-crested Pochard Netta rufina, Common Pochard Aythya ferina, Tufted Duck Aythya fuligula, and Common Goldeneye Bucephala clangula) from fishponds in South Bohemia, Czechia, between 2004 and 2022. This evidence was used to assess long-term changes in the adult sex ratio in these breeding populations and investigate the possible effects of the NAO index (North Atlantic Oscillation index) on them, indicating climate conditions in winter. We determined a long-term decrease of the proportion of females in the breeding season in two of the six examined species: Common Pochard and Red-crested Pochard, which is driven by the long-term increase in the number of males in contrast to the decreasing or stable number of females likely caused by different migration behaviours between females and males. In the case of Common Pochard, in breeding populations, we estimated 60–65% of males in the early 2000s rising to 75–80% in the early 2020s. However, we establish no significant effects linked to climate conditions of the previous winter in these species as a crucial cause of the changes of the proportion of females in the breeding population.
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spelling doaj-art-bd5f4218f3b7408fad8012f3b7cc77392024-12-08T06:09:32ZengKeAi Communications Co., Ltd.Avian Research2053-71662024-01-0115100187Changes in the adult sex ratio of six duck species breeding populations over two decadesMonika Homolková0Petr Musil1Diego Pavón-Jordán2Dorota Gajdošová3Zuzana Musilová4Šárka Neužilová5Jan Zouhar6Department of Ecology, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, CZ-165 21, Prague – Suchdol, Czech Republic; Corresponding author.Department of Ecology, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, CZ-165 21, Prague – Suchdol, Czech RepublicDepartment of Terrestrial Ecology, Norwegian Institute for Nature Research (NINA), PO Box 5685 Torgarden, Trondheim, N-7485, NorwayDepartment of Ecology, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, CZ-165 21, Prague – Suchdol, Czech RepublicDepartment of Ecology, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, CZ-165 21, Prague – Suchdol, Czech RepublicDepartment of Ecology, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, CZ-165 21, Prague – Suchdol, Czech RepublicDepartment of Ecology, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, CZ-165 21, Prague – Suchdol, Czech Republic; Department of Econometrics, Faculty of Informatics and Statistics, University of Economics, nám. W. Churchilla 4, CZ-130 67, Prague 3, Czech RepublicDespite all efforts, long-term changes in the adult sex ratios of breeding duck populations are still unclear; this uncertainty is especially true for male-bias populations, which are often under the scrutiny of researchers lacking convenient results for the active protection of endangered species. Species with male-bias populations are usually strongly affected by a decline in population size that leads to a higher extinction risk. In this study, we examined our long-term data of the abundance of breeding populations in six duck species (Mallard Anas platyrhynchos, Gadwall Mareca strepera, Red-crested Pochard Netta rufina, Common Pochard Aythya ferina, Tufted Duck Aythya fuligula, and Common Goldeneye Bucephala clangula) from fishponds in South Bohemia, Czechia, between 2004 and 2022. This evidence was used to assess long-term changes in the adult sex ratio in these breeding populations and investigate the possible effects of the NAO index (North Atlantic Oscillation index) on them, indicating climate conditions in winter. We determined a long-term decrease of the proportion of females in the breeding season in two of the six examined species: Common Pochard and Red-crested Pochard, which is driven by the long-term increase in the number of males in contrast to the decreasing or stable number of females likely caused by different migration behaviours between females and males. In the case of Common Pochard, in breeding populations, we estimated 60–65% of males in the early 2000s rising to 75–80% in the early 2020s. However, we establish no significant effects linked to climate conditions of the previous winter in these species as a crucial cause of the changes of the proportion of females in the breeding population.http://www.sciencedirect.com/science/article/pii/S2053716624000306Adult sex ratioBreeding populationPopulation dynamicsRed-listed speciesWaterfowlWinter weather conditions
spellingShingle Monika Homolková
Petr Musil
Diego Pavón-Jordán
Dorota Gajdošová
Zuzana Musilová
Šárka Neužilová
Jan Zouhar
Changes in the adult sex ratio of six duck species breeding populations over two decades
Avian Research
Adult sex ratio
Breeding population
Population dynamics
Red-listed species
Waterfowl
Winter weather conditions
title Changes in the adult sex ratio of six duck species breeding populations over two decades
title_full Changes in the adult sex ratio of six duck species breeding populations over two decades
title_fullStr Changes in the adult sex ratio of six duck species breeding populations over two decades
title_full_unstemmed Changes in the adult sex ratio of six duck species breeding populations over two decades
title_short Changes in the adult sex ratio of six duck species breeding populations over two decades
title_sort changes in the adult sex ratio of six duck species breeding populations over two decades
topic Adult sex ratio
Breeding population
Population dynamics
Red-listed species
Waterfowl
Winter weather conditions
url http://www.sciencedirect.com/science/article/pii/S2053716624000306
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