1
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Morland F, Ewen JG, Santure AW, Brekke P, Hemmings N. Demographic drivers of reproductive failure in a threatened bird: Insights from a decade of data. Proc Natl Acad Sci U S A 2024; 121:e2319104121. [PMID: 39186647 PMCID: PMC11388365 DOI: 10.1073/pnas.2319104121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 07/10/2024] [Indexed: 08/28/2024] Open
Abstract
Hatching failure affects up to 77% of eggs laid by threatened bird species, yet the true prevalence and drivers of egg fertilization failure versus embryo mortality as underlying mechanisms of hatching failure are unknown. Here, using ten years of data comprising 4,371 eggs laid by a population of a threatened bird, the hihi (Notiomystis cincta), we investigate the relative importance of infertility and embryo death as drivers of hatching failure and explore population-level factors associated with them. We show that of the 1,438 eggs that failed to hatch (33% of laid eggs) between 2010 and 2020, 83% failed due to embryo mortality, with the majority failing in the early stages of embryonic development. In the most comprehensive estimates of infertility rates in a wild bird population to date, we find that fertilization failure accounts for around 17% of hatching failure overall and is more prevalent in years where the population is smaller and more male biased. Male embryos are more likely to die during early development than females, but we find no overall effect of sex on the successful development of embryos. Offspring fathered by within-pair males have significantly higher inbreeding levels than extra-pair offspring; however, we find no effect of inbreeding nor extra-pair paternity on embryo mortality. Accurately distinguishing between infertility and embryo mortality in this study provides unique insight into the underlying causes of reproductive failure over a long-term scale and reveals the complex risks of small population sizes to the reproduction of threatened species.
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Affiliation(s)
- Fay Morland
- Department of Biosciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
- Institute of Zoology, Zoological Society of London, London NW8 7LS, United Kingdom
- Department of Anatomy, University of Otago, Dunedin 9016, New Zealand
| | - John G Ewen
- Institute of Zoology, Zoological Society of London, London NW8 7LS, United Kingdom
| | - Anna W Santure
- School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand
| | - Patricia Brekke
- Institute of Zoology, Zoological Society of London, London NW8 7LS, United Kingdom
| | - Nicola Hemmings
- Department of Biosciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
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2
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Schacht R, Beissinger SR, Wedekind C, Jennions MD, Geffroy B, Liker A, Kappeler PM, Weissing FJ, Kramer KL, Hesketh T, Boissier J, Uggla C, Hollingshaus M, Székely T. Adult sex ratios: causes of variation and implications for animal and human societies. Commun Biol 2022; 5:1273. [PMID: 36402823 PMCID: PMC9675760 DOI: 10.1038/s42003-022-04223-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 11/03/2022] [Indexed: 11/21/2022] Open
Abstract
Converging lines of inquiry from across the social and biological sciences target the adult sex ratio (ASR; the proportion of males in the adult population) as a fundamental population-level determinant of behavior. The ASR, which indicates the relative number of potential mates to competitors in a population, frames the selective arena for competition, mate choice, and social interactions. Here we review a growing literature, focusing on methodological developments that sharpen knowledge of the demographic variables underlying ASR variation, experiments that enhance understanding of the consequences of ASR imbalance across societies, and phylogenetic analyses that provide novel insights into social evolution. We additionally highlight areas where research advances are expected to make accelerating contributions across the social sciences, evolutionary biology, and biodiversity conservation.
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Affiliation(s)
- Ryan Schacht
- Department of Anthropology, East Carolina University, Greenville, NC, USA.
| | - Steven R Beissinger
- Department of Environmental Science, Policy and Management and Museum of Vertebrate Zoology, University of California, Berkeley, CA, 94720, USA
| | - Claus Wedekind
- Department of Ecology and Evolution, University of Lausanne, 1015, Lausanne, Switzerland
| | - Michael D Jennions
- Ecology & Evolution, Research School of Biology, The Australian National University, Acton, Canberra, 2601, Australia
| | - Benjamin Geffroy
- MARBEC Univ Montpellier, CNRS, Ifremer, IRD, Montpellier, France
| | - András Liker
- ELKH-PE Evolutionary Ecology Research Group, University of Pannonia, 8210, Veszprém, Hungary
- Behavioural Ecology Research Group, Center for Natural Sciences, University of Pannonia, 8210, Veszprém, Hungary
| | - Peter M Kappeler
- Behavioral Ecology and Sociobiology Unit, German Primate Center, Leibniz Institute of Primate Biology, 37077, Göttingen, Germany
- Department of Sociobiology/Anthropology, University of Göttingen, 37077, Göttingen, Germany
| | - Franz J Weissing
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - Karen L Kramer
- Department of Anthropology, University of Utah, Salt Lake City, UT, USA
| | - Therese Hesketh
- Institute of Global Health, University College London, London, UK
- Centre for Global Health, Zhejiang University School of Medicine, Hangzhou, P.R. China
| | - Jérôme Boissier
- IHPE Univ Perpignan Via Domitia, CNRS, Ifremer, Univ Montpellier, Perpignan, France
| | - Caroline Uggla
- Stockholm University Demography Unit, Sociology Department, Stockholm University, 106 91, Stockholm, Sweden
| | - Mike Hollingshaus
- Kem C. Gardner Policy Institute, David Eccles School of Business, University of Utah, Salt Lake City, UT, USA
| | - Tamás Székely
- Milner Centre for Evolution, University of Bath, Bath, BA2 7AY, UK.
- ELKH-DE Reproductive Strategies Research Group, Department of Zoology and Human Biology, University of Debrecen, H-4032, Debrecen, Hungary.
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3
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Kahn JE, Watterson JC, Hager CH, Mathies N, Hartman KJ. Calculating adult sex ratios from observed breeding sex ratios for wide‐ranging, intermittently breeding species. Ecosphere 2021. [DOI: 10.1002/ecs2.3504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- J. E. Kahn
- National Marine Fisheries Service Silver Spring Maryland20910USA
| | - J. C. Watterson
- U.S. Department of the Navy Naval Facilities Engineering Command, Atlantic Norfolk Virginia23508USA
| | - C. H. Hager
- Chesapeake Scientific Williamsburg Virginia23185USA
| | - N. Mathies
- Chesapeake Scientific Williamsburg Virginia23185USA
| | - K. J. Hartman
- Division of Forestry and Natural Resources West Virginia University Morgantown West Virginia26506USA
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4
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Morrison CA, Butler SJ, Robinson RA, Clark JA, Arizaga J, Aunins A, Baltà O, Cepák J, Chodkiewicz T, Escandell V, Foppen RPB, Gregory RD, Husby M, Jiguet F, Kålås JA, Lehikoinen A, Lindström Å, Moshøj CM, Nagy K, Nebot AL, Piha M, Reif J, Sattler T, Škorpilová J, Szép T, Teufelbauer N, Thorup K, van Turnhout C, Wenninger T, Gill JA. Covariation in population trends and demography reveals targets for conservation action. Proc Biol Sci 2021; 288:20202955. [PMID: 33653129 PMCID: PMC7934962 DOI: 10.1098/rspb.2020.2955] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Wildlife conservation policies directed at common and widespread, but declining, species are difficult to design and implement effectively, as multiple environmental changes are likely to contribute to population declines. Conservation actions ultimately aim to influence demographic rates, but targeting actions towards feasible improvements in these is challenging in widespread species with ranges that encompass a wide range of environmental conditions. Across Europe, sharp declines in the abundance of migratory landbirds have driven international calls for action, but actions that could feasibly contribute to population recovery have yet to be identified. Targeted actions to improve conditions on poor-quality sites could be an effective approach, but only if local conditions consistently influence local demography and hence population trends. Using long-term measures of abundance and demography of breeding birds at survey sites across Europe, we show that co-occurring species with differing migration behaviours have similar directions of local population trends and magnitudes of productivity, but not survival rates. Targeted actions to boost local productivity within Europe, alongside large-scale (non-targeted) environmental protection across non-breeding ranges, could therefore help address the urgent need to halt migrant landbird declines. Such demographic routes to recovery are likely to be increasingly needed to address global wildlife declines.
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Affiliation(s)
- Catriona A Morrison
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Simon J Butler
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | | | - Jacquie A Clark
- British Trust for Ornithology, The Nunnery, Thetford IP24 2PU, UK
| | - Juan Arizaga
- Department of Ornithology, Aranzadi Sciences Society, Zorroagagaina 11, E20014 Donostia, Spain
| | - Ainars Aunins
- Department of Zoology and Animal Ecology, Faculty of Biology, University of Latvia, Jelgavas iela 1, Riga, LV-1004, Latvia.,Latvian Ornithological Society, Skolas iela 3, Riga, LV-1010, Latvia
| | - Oriol Baltà
- Catalan Ornithological Institute, Nat-Museu de Ciències Naturals de Barcelona, Pl. Leonardo da Vinci, 4-5 08019 Barcelona, Spain
| | - Jaroslav Cepák
- Bird Ringing Centre, National Museum, Hornoměcholupská 34, CZ-10200 Praha 10, Czech Republic
| | - Tomasz Chodkiewicz
- Museum and Institute of Zoology, Polish Academy of Sciences, Wilcza 64, 00-679 Warszawa, Poland.,Polish Society for the Protection of Birds (OTOP), Odrowaza 24, 05-270 Marki, Poland
| | - Virginia Escandell
- Estudio y Seguimiento de Aves SEO/BirdLife, Melquíades Biencinto, Madrid, Spain
| | - Ruud P B Foppen
- Sovon Dutch Centre for Field Ornithology, PO Box 6521, 6503 GA Nijmegen, The Netherlands.,Department of Animal Ecology and Physiology, Institute for Water and Wetland Research, Radboud University, PO Box 9010, 6500 GL Nijmegen, The Netherlands
| | | | - Magne Husby
- Nord University, Røstad, 7600 Levanger, Norway.,BirdLife Norway, Sandgata 30B, 7012 Trondheim, Norway
| | - Frédéric Jiguet
- Centre d'Ecologie et des Sciences de la Conservation (CESCO) UMR 7204, Museum National d'Histoire Naturelle, Paris, France
| | - John Atle Kålås
- Norwegian Institute for Nature Research, PO Box 5685 Torgarden, NO-7485 Trondheim, Norway
| | - Aleksi Lehikoinen
- Finnish Museum of Natural History, FI-00014 University of Helsinki, PO Box 17, Finland
| | - Åke Lindström
- Department of Biology, Lund University, Lund, Sweden
| | - Charlotte M Moshøj
- Dansk Ornitologisk Forening, BirdLife Denmark, Vesterbrogade 138-140, DK-1620 København V, Denmark
| | - Károly Nagy
- MME BirdLife Hungary, Monitoring Centre, H-4401 Nyiregyháza 1. PO Box 286, Hungary
| | - Arantza Leal Nebot
- SEO/BirdLife, Ciencia Ciudadana, C/Melquiades Biencinto, 34 - 28053 Madrid, Spain
| | - Markus Piha
- Finnish Museum of Natural History - LUOMUS, PO Box 17, FI-00014, University of Helsinki, Finland
| | - Jiří Reif
- Institute for Environmental Studies, Faculty of Science, Charles University, Prague, Benatska 2, 128 01 Praha 2, Czech Republic.,Department of Zoology and Laboratory of Ornithology, Faculty of Science, Palacky University, 771 46 Olomouc, Czech Republic.,Czech Society for Ornithology, Na Belidle 34, 150 00 Praha 5, Czech Republic
| | - Thomas Sattler
- Swiss Ornithological Institute, Seerose 1, CH-6204 Sempach, Switzerland
| | - Jana Škorpilová
- Pan-European Common Bird Monitoring Scheme, Czech Society for Ornithology, Na Bělidle, CZ-150 00 Prague 5, Czech Republic
| | - Tibor Szép
- University of Nyíregyháza & MME/BirdLife Hungary, Nyíregyháza, Hungary
| | | | - Kasper Thorup
- Center for Macroecology, Evolution and Climate, Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark
| | - Chris van Turnhout
- Sovon Dutch Centre for Field Ornithology, PO Box 6521, 6503 GA Nijmegen, The Netherlands.,Department of Animal Ecology and Physiology, Institute for Water and Wetland Research, Radboud University, PO Box 9010, 6500 GL Nijmegen, The Netherlands
| | - Thomas Wenninger
- Swedish Museum of Natural History, Bird Ringing Centre, Box 50007, S-104 05 Stockholm, Sweden
| | - Jennifer A Gill
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
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Zhang J, Nie C, Li X, Ning Z, Chen Y, Jia Y, Han J, Wang L, Lv X, Yang W, Qu L. Genome-Wide Population Genetic Analysis of Commercial, Indigenous, Game, and Wild Chickens Using 600K SNP Microarray Data. Front Genet 2020; 11:543294. [PMID: 33101376 PMCID: PMC7545075 DOI: 10.3389/fgene.2020.543294] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 09/02/2020] [Indexed: 12/13/2022] Open
Abstract
Following chicken domestication, diversified chicken breeds were developed by both natural and artificial selection, which led to the accumulation of abundant genetic and phenotypic variations, making chickens an ideal genetic research model. To better understand the genetic structure of chicken breeds under different selection pressures, we genotyped various chicken populations with specific selection targets, including indigenous, commercial, gamecock, and wild ancestral chickens, using the 600K SNP array. We analyzed the population structure, genetic relationships, run of homozygosity (ROH), effective population number (Ne), and other genetic parameters. The wild ancestral population, red junglefowl (RJF), possessed the highest diversity, in comparison with all other domesticated populations, which was supported by linkage disequilibrium decay (LD), effective population number, and ROH analyses. The gamecock breeds, which were subjected to stronger male-biased selection for fighting-related traits, also presented higher variation than the commercial and indigenous breeds. Admixture analysis also indicated that game breed is a relatively independent branch of Chinese local breeds. Following intense selection for reproductive and productive traits, the commercial lines showed the least diversity. We also observed that the European local chickens had lower genetic variation than the Chinese local breeds, which could be attributed to the shorter history of the European breed. ROH were present in a breed specific manner and 191 ROH island were detected on four groups (commercial, local, game and wild chickens). These ROH islands were involved in egg production, growth and silky feathers and other traits. Moreover, we estimated the effective sex ratio of these breeds to demonstrate the change in the ratio of the two sexes. We found that commercial chickens had a greater sex imbalance between females and males. The commercial lines showed the highest female-to-male ratios. Interestingly, RJF comprised a greater proportion of males than females. Our results show the population genetics of chickens under selection pressures, and can aid in the development of better conservation strategies for different chicken breeds.
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Affiliation(s)
- Jinxin Zhang
- Department of Animal Genetics and Breeding, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Changsheng Nie
- Department of Animal Genetics and Breeding, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Xinghua Li
- Department of Animal Genetics and Breeding, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Zhonghua Ning
- Department of Animal Genetics and Breeding, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Yu Chen
- Beijing Municipal General Station of Animal Science, Beijing, China
| | - Yaxiong Jia
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jianlin Han
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Liang Wang
- Beijing Municipal General Station of Animal Science, Beijing, China
| | - Xueze Lv
- Beijing Municipal General Station of Animal Science, Beijing, China
| | - Weifang Yang
- Beijing Municipal General Station of Animal Science, Beijing, China
| | - Lujiang Qu
- Department of Animal Genetics and Breeding, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
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6
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Schaub M, Ullrich B. A drop in immigration results in the extinction of a local woodchat shrike population. Anim Conserv 2020. [DOI: 10.1111/acv.12639] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- M. Schaub
- Swiss Ornithological Institute Sempach Switzerland
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7
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Gownaris NJ, García Borboroglu P, Boersma PD. Sex ratio is variable and increasingly male biased at two colonies of Magellanic Penguins. Ecology 2020; 101:e02939. [DOI: 10.1002/ecy.2939] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 10/18/2019] [Indexed: 11/06/2022]
Affiliation(s)
- Natasha J. Gownaris
- Environmental Studies Department Gettysburg College Gettysburg Pennsylvania 17325 USA
| | - Pablo García Borboroglu
- Department of Biology and Center for Ecosystem Sentinels University of Washington Seattle Washington 98103 USA
- Global Penguin Society Puerto Madryn Argentina
| | - P. Dee Boersma
- Department of Biology and Center for Ecosystem Sentinels University of Washington Seattle Washington 98103 USA
- Global Penguin Society Puerto Madryn Argentina
- CESIMAR CCT Cenpat‐CONICET 9120Puerto Madryn Chubut Argentina
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8
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Abstract
The adult sex ratio (ASR) is an important property of populations. Comparative phylogenetic analyses have shown that unequal sex ratios are associated with the frequency of changing mates, extrapair mating (EPM), mating system and parental care, sex-specific survival, and population dynamics. Comparative demographic analyses are needed to validate the inferences, and to identify the causes and consequences of sex ratio inequalities in changing environments. We tested expected consequences of biased sex ratios in two species of Darwin's finches in the Galápagos, where annual variation in rainfall, food supply, and survival is pronounced. Environmental perturbations cause sex ratios to become strongly male-biased, and when this happens, females have increased opportunities to choose high-quality males. The choice of a mate is influenced by early experience of parental morphology (sexual imprinting), and since morphological traits are highly heritable, mate choice is expressed as a positive correlation between mates. The expected assortative mating was demonstrated when the Geospiza scandens population was strongly male-biased, and not present in the contemporary Geospiza fortis population with an equal sex ratio. Initial effects of parental imprinting were subsequently overridden by other factors when females changed mates, some repeatedly. Females of both species were more frequently polyandrous in male-biased populations, and fledged more offspring by changing mates. The ASR ratio indirectly affected the frequency of EPM (and hybridization), but this did not lead to social mate choice. The study provides a strong demonstration of how mating patterns change when environmental fluctuations lead to altered sex ratios through differential mortality.
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9
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Tschumi M, Humbel J, Erbes J, Fattebert J, Fischer J, Fritz G, Geiger B, van Harxen R, Hoos B, Hurst J, Jacobsen LB, Keil H, Kneule W, Michel VT, Michels H, Möbius L, Perrig M, Rößler P, Schneider D, Schuch S, Stroeken P, Naef-Daenzer B, Grüebler MU. Parental sex allocation and sex-specific survival drive offspring sex ratio bias in little owls. Behav Ecol Sociobiol 2019. [DOI: 10.1007/s00265-019-2694-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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10
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Loonstra AHJ, Verhoeven MA, Senner NR, Hooijmeijer JCEW, Piersma T, Kentie R. Natal habitat and sex-specific survival rates result in a male-biased adult sex ratio. Behav Ecol 2019; 30:843-851. [PMID: 31210724 PMCID: PMC6562303 DOI: 10.1093/beheco/arz021] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 01/24/2019] [Accepted: 01/29/2019] [Indexed: 01/10/2023] Open
Abstract
The adult sex ratio (ASR) is a crucial component of the ecological and evolutionary forces shaping the dynamics of a population. Although in many declining populations ASRs have been reported to be skewed, empirical studies exploring the demographic factors shaping ASRs are still rare. In this study of the socially monogamous and sexually dimorphic Black-tailed Godwit (Limosa limosa limosa), we aim to evaluate the sex ratio of chicks at hatch and the subsequent sex-specific survival differences occurring over 3 subsequent life stages. We found that, at hatch, the sex ratio did not deviate from parity. However, the survival of pre-fledged females was 15-30% lower than that of males and the sex bias in survival was higher in low-quality habitat. Additionally, survival of adult females was almost 5% lower than that of adult males. Because survival rates of males and females did not differ during other life-history stages, the ASR in the population was biased toward males. Because females are larger than males, food limitations during development or sex-specific differences in the duration of development may explain the lower survival of female chicks. Differences among adults are less obvious and suggest previously unknown sex-related selection pressures. Irrespective of the underlying causes, by reducing the available number of females in this socially monogamous species, a male-biased ASR is likely to contribute to the ongoing decline of the Dutch godwit population.
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Affiliation(s)
- A H Jelle Loonstra
- Conservation Ecology Group, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, The Netherlands
| | - Mo A Verhoeven
- Conservation Ecology Group, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, The Netherlands
| | - Nathan R Senner
- Conservation Ecology Group, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, The Netherlands
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Jos C E W Hooijmeijer
- Conservation Ecology Group, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, The Netherlands
| | - Theunis Piersma
- Conservation Ecology Group, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, The Netherlands
- NIOZ Royal Netherlands Institute for Sea Research, Department of Coastal Systems, Utrecht University, Texel, The Netherlands
| | - Rosemarie Kentie
- Conservation Ecology Group, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, The Netherlands
- Department of Zoology, University of Oxford, Oxford, UK
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11
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Gownaris NJ, Boersma PD. Sex-biased survival contributes to population decline in a long-lived seabird, the Magellanic Penguin. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2019; 29:e01826. [PMID: 30601594 PMCID: PMC6849821 DOI: 10.1002/eap.1826] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 09/12/2018] [Accepted: 10/16/2018] [Indexed: 05/29/2023]
Abstract
We developed a Hidden Markov mark-recapture model (R package marked) to examine sex-specific demography in Magellanic Penguins (Spheniscus magellanicus). Our model was based on 33 yr of resightings at Punta Tombo, Argentina, where we banded ~44,000 chicks from 1983 to 2010. Because we sexed only 57% of individuals over their lifetime, we treated sex as an uncertain state in our model. Our goals were to provide insight into the population dynamics of this declining colony, to inform conservation of this species, and to highlight the importance of considering sex-specific vital rates in demographic seabird studies. Like many other seabirds, Magellanic Penguins are long-lived, serially monogamous, and exhibit obligate biparental care. We found that the non-breeding-season survival of females was lower than that of males and that the magnitude of this bias was highest for juveniles. Biases in survival accumulated as cohorts aged, leading to increasingly skewed sex ratios. The survival bias was greatest in years when overall survival was low, that is, females fared disproportionality worse when conditions were unfavorable. Our model-estimated survival patterns are consistent with independent data on carcasses from the species' non-breeding grounds, showing that mortality is higher for juveniles than for adults and higher for females than for males. Juveniles may be less efficient foragers than adults are and, because of their smaller size, females may show less resilience to food scarcity than males. We used perturbation analysis of a population matrix model to determine the impact of sex-biased survival on adult sex ratio and population growth rate at Punta Tombo. We found that adult sex ratio and population growth rate have the greatest proportional response, that is, elasticity, to female pre-breeder and adult survival. Sex bias in juvenile survival (i.e., lower survival of females) made the greatest contribution to population declines from 1990 to 2009. Because starvation is a leading cause of morality in juveniles and adults, precautionary fisheries and spatial management in the region could help to slow population decline. Our data add to growing evidence that knowledge of sex-specific demography and sex ratios are necessary for accurate assessment of seabird population trends.
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Affiliation(s)
- N. J. Gownaris
- Department of Biology and Center for Ecosystem SentinelsUniversity of WashingtonSeattleWashington98103USA
| | - P. D. Boersma
- Department of Biology and Center for Ecosystem SentinelsUniversity of WashingtonSeattleWashington98103USA
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12
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Abstract
Understanding how breeding populations are spatially and temporarily associated with one another over the annual cycle has important implications for population dynamics. Migratory connectivity typically assumes that populations mix randomly; yet, in many species and populations, sex-, age- or other subgroups migrate separately, and/or spend the non-breeding period separated from each other-a phenomenon coined differential migration. These subgroups likely experience varying environmental conditions, which may carry-over to affect body condition, reproductive success and survival. We argue that environmental or habitat changes can have disproportional effects on a population's demographic rates under differential migration compared to random mixing. Depending on the relative contribution of each of these subgroups to population growth, environmental perturbations may be buffered (under-proportional) or amplified (over-proportional). Thus, differential migration may result in differential mortality and carry-over effects that can have concomitant consequences for dynamics and resilience of the populations. Recognizing the role of differential migration in migratory connectivity and its consequences on population dynamics can assist in developing conservation actions that are tailored to the most influential demographic group(s) and the times and places where they are at peril.
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Affiliation(s)
- Martins Briedis
- Swiss Ornithological Institute , Seerose 1, 6204 Sempach , Switzerland
| | - Silke Bauer
- Swiss Ornithological Institute , Seerose 1, 6204 Sempach , Switzerland
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13
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Ramula S, Öst M, Lindén A, Karell P, Kilpi M. Increased male bias in eider ducks can be explained by sex-specific survival of prime-age breeders. PLoS One 2018; 13:e0195415. [PMID: 29634733 PMCID: PMC5892891 DOI: 10.1371/journal.pone.0195415] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 03/21/2018] [Indexed: 12/02/2022] Open
Abstract
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 disproportionally 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.
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Affiliation(s)
- Satu Ramula
- Department of Biology, University of Turku, Turku, Finland
| | - Markus Öst
- Bioeconomy Research Team, Novia University of Applied Sciences, Ekenäs, Finland.,Environmental and Marine Biology, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - Andreas Lindén
- Bioeconomy Research Team, Novia University of Applied Sciences, Ekenäs, Finland
| | - Patrik Karell
- Bioeconomy Research Team, Novia University of Applied Sciences, Ekenäs, Finland
| | - Mikael Kilpi
- Bioeconomy Research Team, Novia University of Applied Sciences, Ekenäs, Finland
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14
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Ancona S, Dénes FV, Krüger O, Székely T, Beissinger SR. Estimating adult sex ratios in nature. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0313. [PMID: 28760756 DOI: 10.1098/rstb.2016.0313] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/27/2017] [Indexed: 11/12/2022] Open
Abstract
Adult sex ratio (ASR, the proportion of males in the adult population) is a central concept in population and evolutionary biology, and is also emerging as a major factor influencing mate choice, pair bonding and parental cooperation in both human and non-human societies. However, estimating ASR is fraught with difficulties stemming from the effects of spatial and temporal variation in the numbers of males and females, and detection/capture probabilities that differ between the sexes. Here, we critically evaluate methods for estimating ASR in wild animal populations, reviewing how recent statistical advances can be applied to handle some of these challenges. We review methods that directly account for detection differences between the sexes using counts of unmarked individuals (observed, trapped or killed) and counts of marked individuals using mark-recapture models. We review a third class of methods that do not directly sample the number of males and females, but instead estimate the sex ratio indirectly using relationships that emerge from demographic measures, such as survival, age structure, reproduction and assumed dynamics. We recommend that detection-based methods be used for estimating ASR in most situations, and point out that studies are needed that compare different ASR estimation methods and control for sex differences in dispersal.This article is part of the themed issue 'Adult sex ratios and reproductive decisions: a critical re-examination of sex differences in human and animal societies'.
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Affiliation(s)
- Sergio Ancona
- Centro Tlaxcala de Biología de la Conducta, Universidad Autónoma de Tlaxcala, Tlaxcala 90070, Mexico .,Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
| | - Francisco V Dénes
- Department of Conservation Biology, Estación Biológica de Doñana, CSIC, Sevilla E-41092, Spain
| | - Oliver Krüger
- Department of Animal Behaviour, University of Bielefeld, PO Box 100131, Bielefeld 33501, Germany
| | - Tamás Székely
- Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK.,Institute for Advanced Study Berlin (Wissenschaftskolleg zu Berlin), Berlin 14193, Germany
| | - Steven R Beissinger
- Department of Environmental Science, Policy and Management and Museum of Vertebrate Zoology, University of California, Berkeley, California CA 94720-3110, USA.,Institute for Advanced Study Berlin (Wissenschaftskolleg zu Berlin), Berlin 14193, Germany
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15
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Winiarski JM, Moorman CE, Carpenter JP, Hess GR. Reproductive consequences of habitat fragmentation for a declining resident bird of the longleaf pine ecosystem. Ecosphere 2017. [DOI: 10.1002/ecs2.1898] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Jason M. Winiarski
- Fisheries, Wildlife, and Conservation Biology Program; Department of Forestry and Environmental Resources; North Carolina State University; Raleigh North Carolina 27695 USA
| | - Christopher E. Moorman
- Fisheries, Wildlife, and Conservation Biology Program; Department of Forestry and Environmental Resources; North Carolina State University; Raleigh North Carolina 27695 USA
| | - John P. Carpenter
- North Carolina Wildlife Resources Commission; 1751 Varsity Drive Raleigh North Carolina 27606 USA
| | - George R. Hess
- Fisheries, Wildlife, and Conservation Biology Program; Department of Forestry and Environmental Resources; North Carolina State University; Raleigh North Carolina 27695 USA
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16
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Awade M, Candia-Gallardo C, Cornelius C, Metzger JP. High Emigration Propensity and Low Mortality on Transfer Drives Female-Biased Dispersal of Pyriglena leucoptera in Fragmented Landscapes. PLoS One 2017; 12:e0170493. [PMID: 28107517 PMCID: PMC5249090 DOI: 10.1371/journal.pone.0170493] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 01/05/2017] [Indexed: 11/19/2022] Open
Abstract
Dispersal is a biological process performed in three stages: emigration, transfer and immigration. Intra-specific variation on dispersal behavior, such as sex-bias, is very common in nature, particularly in birds and mammals. However, dispersal is difficult to measure in the field and many hypotheses concerning the causes of sex-biased dispersal remain without empirical confirmation. An important limitation of most empirical studies is that inferences about sex-biased dispersal are based only on emigration proneness or immigration success data. Thus, we still do not know whether sex-biased immigration in fragmented landscapes occurs during emigration, transfer or in both stages. We conducted translocation and radiotracking experiments to assess i) whether inter-patch dispersal movements of a rainforest bird (Pyriglena leucoptera) is sex-biased and ii) how dispersal stages and the perceptual range of the individuals are integrated to generate dispersal patterns. Our results showed that inter-patch dispersal is sex-biased at all stages for P. leucoptera, as females not only exhibit a higher emigration propensity but are subjected to a lower risk of predation when moving through the matrix. Moreover, our data support a perceptual range of 80 m and our results showed that dispersal success decreases considerably when inter-patch distances exceeds this perceptual range. In this case, birds have a higher probability of travelling over longer routes and, as a consequence, the risk of predation increases, specially for males. Overall, results supported that assuming dispersal as a single-stage process to describe dispersal behavior may be misleading. In this way, our study advanced our understanding of processes and patterns related to inter-patch dispersal of neotropical forest birds, shedding light on potential implications for population dynamics and for the management of fragmented landscapes.
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Affiliation(s)
- Marcelo Awade
- Department of Ecology, Institute of Biosciences, University of São Paulo (USP), São Paulo, SP, Brazil
- * E-mail:
| | - Carlos Candia-Gallardo
- Department of Ecology, Institute of Biosciences, University of São Paulo (USP), São Paulo, SP, Brazil
| | - Cintia Cornelius
- Department of Biology, Institute of Biological Sciences, Federal University of Amazonas (UFAM), Manaus, AM, Brazil
| | - Jean Paul Metzger
- Department of Ecology, Institute of Biosciences, University of São Paulo (USP), São Paulo, SP, Brazil
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17
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Morrison CA, Robinson RA, Butler SJ, Clark JA, Gill JA. Demographic drivers of decline and recovery in an Afro-Palaearctic migratory bird population. Proc Biol Sci 2016; 283:rspb.2016.1387. [PMID: 27807267 PMCID: PMC5124090 DOI: 10.1098/rspb.2016.1387] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Accepted: 10/06/2016] [Indexed: 11/26/2022] Open
Abstract
Across Europe, rapid population declines are ongoing in many Afro-Palaearctic migratory bird species, but the development of appropriate conservation actions across such large migratory ranges is severely constrained by lack of understanding of the demographic drivers of these declines. By constructing regional integrated population models (IPMs) for one of the suite of migratory species that is declining in the southeast of Britain but increasing in the northwest, we show that, while annual population growth rates in both regions vary with adult survival, the divergent regional trajectories are primarily a consequence of differences in productivity. Between 1994 and 2012, annual survival and productivity rates ranged over similar levels in both regions, but high productivity rates were rarer in the declining southeast population and never coincided with high survival rates. By contrast, population growth in the northwest was fuelled by several years in which higher productivity coincided with high survival rates. Simulated population trajectories suggest that realistic improvements in productivity could have reversed the decline (i.e. recovery of the population index to more than or equal to 1) in the southeast. Consequently, actions to improve productivity on European breeding grounds are likely to be a more fruitful and achievable means of reversing migrant declines than actions to improve survival on breeding, passage or sub-Saharan wintering grounds.
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Affiliation(s)
- Catriona A Morrison
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | | | - Simon J Butler
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | | | - Jennifer A Gill
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
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