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Zhang K, Qiu D, Zhao L, Yan C, Jin L, Liao W. Geographical Variation in Body Size in the Asian Common Toad ( Duttaphrynus melanostictus). Life (Basel) 2023; 13:2219. [PMID: 38004360 PMCID: PMC10672612 DOI: 10.3390/life13112219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 11/10/2023] [Accepted: 11/15/2023] [Indexed: 11/26/2023] Open
Abstract
The geographic variation in life-history traits of organisms and the mechanisms underlying adaptation are interesting ideas in evolutionary biology. This study investigated age and body size of the Asian common toad (Duttaphrynus melanostictus) among five populations along a geographical gradient. We found that geographical variation in age was non-significant among populations but there was a significant and positive correlation between mean age and body size. Although the body size values at 1043 m are quite different from other sites, after controlling for age effects, there was a significant positive correlation between altitude and body size. Our findings followed the predictions of Bergmann's rule, suggesting that the body size of D. melanostictus is potentially influenced by the low air temperatures at higher altitudes.
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Affiliation(s)
- Kunhao Zhang
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637009, China; (K.Z.); (D.Q.); (L.Z.); (C.Y.)
- Key Laboratory of Artificial Propagation and Utilization in Anurans of Nanchong City, China West Normal University, Nanchong 637009, China
| | - Duojing Qiu
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637009, China; (K.Z.); (D.Q.); (L.Z.); (C.Y.)
- Key Laboratory of Artificial Propagation and Utilization in Anurans of Nanchong City, China West Normal University, Nanchong 637009, China
| | - Li Zhao
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637009, China; (K.Z.); (D.Q.); (L.Z.); (C.Y.)
- Key Laboratory of Artificial Propagation and Utilization in Anurans of Nanchong City, China West Normal University, Nanchong 637009, China
| | - Chengzhi Yan
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637009, China; (K.Z.); (D.Q.); (L.Z.); (C.Y.)
- Key Laboratory of Artificial Propagation and Utilization in Anurans of Nanchong City, China West Normal University, Nanchong 637009, China
| | - Long Jin
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637009, China; (K.Z.); (D.Q.); (L.Z.); (C.Y.)
- Key Laboratory of Artificial Propagation and Utilization in Anurans of Nanchong City, China West Normal University, Nanchong 637009, China
| | - Wenbo Liao
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong 637009, China; (K.Z.); (D.Q.); (L.Z.); (C.Y.)
- Key Laboratory of Artificial Propagation and Utilization in Anurans of Nanchong City, China West Normal University, Nanchong 637009, China
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Cook PA, Costello RA, Formica VA, Brodie ED. Individual and Population Age Impact Social Behavior and Network Structure in a Long-Lived Insect. Am Nat 2023; 202:667-680. [PMID: 37963123 DOI: 10.1086/726063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2023]
Abstract
AbstractSocial behaviors vary among individuals, and social networks vary among groups. Understanding the causes of such variation is important for predicting or altering ecological processes such as infectious disease outbreaks. Here, we ask whether age contributes to variation in social behavior at multiple levels of organization: within individuals over time, among individuals of different ages, among local social environments, and among populations. We used experimental manipulations of captive populations and a longitudinal dataset to test whether social behavior is associated with age across these levels in a long-lived insect, the forked fungus beetle (Bolitotherus cornutus). In cross-sectional analyses, we found that older beetles were less connected in their social networks. Longitudinal data confirmed that this effect was due in part to changes in behavior over time; beetles became less social over 2 years, possibly because of increased social selectivity or reproductive investment. Beetles of different ages also occupied different local social neighborhoods. The effects of age on behavior scaled up: populations of older individuals had fewer interactions, fewer but more variable relationships, longer network path lengths, and lower clustering than populations of young individuals. Age therefore impacted not only individual sociality but also the network structures that mediate critical population processes.
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Hernandez KM, O'Neill KB, Bors EK, Steel D, Zoller JA, Constantine R, Horvath S, Baker CS. Using epigenetic clocks to investigate changes in the age structure of critically endangered Māui dolphins. Ecol Evol 2023; 13:e10562. [PMID: 37780090 PMCID: PMC10534197 DOI: 10.1002/ece3.10562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 09/11/2023] [Indexed: 10/03/2023] Open
Abstract
The age of an individual is an essential demographic parameter but is difficult to estimate without long-term monitoring or invasive sampling. Epigenetic approaches are increasingly used to age organisms, including nonmodel organisms such as cetaceans. Māui dolphins (Cephalorhynchus hectori maui) are a critically endangered subspecies endemic to Aotearoa New Zealand, and the age structure of this population is important for informing conservation. Here we present an epigenetic clock for aging Māui and Hector's dolphins (C. h. hectori) developed from methylation data using DNA from tooth aged individuals (n = 48). Based on this training data set, the optimal model required only eight methylation sites, provided an age correlation of .95, and had a median absolute age error of 1.54 years. A leave-one-out cross-validation analysis with the same parameters resulted in an age correlation of .87 and median absolute age error of 2.09 years. To improve age estimation, we included previously published beluga whale (Delphinapterus leucas) data to develop a joint beluga/dolphin clock, resulting in a clock with comparable performance and improved estimation of older individuals. Application of the models to DNA from skin biopsy samples of living Māui dolphins revealed a shift from a median age of 8-9 years to a younger population aged 7-8 years 10 years later. These models could be applied to other dolphin species and demonstrate the ability to construct a clock even when the number of known age samples is limited, removing this impediment to estimating demographic parameters vital to the conservation of critically endangered species.
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Affiliation(s)
| | | | - Eleanor K. Bors
- Marine Mammal InstituteOregon State UniversityOregonNewportUSA
| | - Debbie Steel
- Marine Mammal InstituteOregon State UniversityOregonNewportUSA
| | - Joseph A. Zoller
- Fielding School of Public Health, Department of BiostatisticsUniversity of CaliforniaCaliforniaLos AngelesUSA
| | - Rochelle Constantine
- School of Biological Sciences & Institute of Marine ScienceUniversity of Auckland – Waipapa Taumata RauAucklandNew Zealand
| | - Steve Horvath
- Fielding School of Public Health, Department of BiostatisticsUniversity of CaliforniaCaliforniaLos AngelesUSA
- David Geffen School of Medicine, Department of Human GeneticsUniversity of CaliforniaCaliforniaLos AngelesUSA
- Altos LabsCaliforniaSan DiegoUSA
| | - C. Scott Baker
- Marine Mammal InstituteOregon State UniversityOregonNewportUSA
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Abate D, Girma Z. Population structure and distribution of geladas ( Theropithicus gelada, Ruppell 1835) in Kotu forest, Northern Ethiopia. Ecol Evol 2023; 13:e10206. [PMID: 37396027 PMCID: PMC10307796 DOI: 10.1002/ece3.10206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 05/06/2023] [Accepted: 05/22/2023] [Indexed: 07/04/2023] Open
Abstract
Endemic gelada populations outside protected areas are less investigated, and population census data are not available. As a result, a study was conducted to investigate the population size, structure, and distribution of geladas in Kotu forest and associated grasslands, in northern Ethiopia. The study area was stratified into five dominant habitat types namely, grassland, wooded grassland, plantation forest, natural forest, and bushland based on dominant vegetation type. Each habitat type was further divided into blocks, and a total counting technique was used to count the individuals of gelada. The total mean population size of gelada in Kotu forest was 229 ± 6.11. The mean ratio of male to female was 1:1.178. The gelada age composition comprised is as follows: 113 (49.34%) adults, 77 (33.62%) sub-adults, and 39 (17.03%) juveniles. The mean number of group one-male unit ranged from 1.5 ± 0.2 in the plantation forest to 4.5 ± 0.7 in the grassland habitat. On the other hand, all-male unit social system group was recorded only from grassland (1.5) and plantation forest (1) habitats. The average band size (number of individuals per band) was 45.0 ± 2.53. The largest number of geladas was recorded from grassland habitat 68 (29.87%), and the lowest was recorded from plantation forest habitat 34 (14.74%). Even though, the sex ratio was female biased, the proportion of juveniles to other age classes was very low compared with geladas in relatively well-protected areas, indicating negative consequences for the future viability of the gelada populations in the area. Geladas were widely distributed over open grassland habitat. Therefore, for sustainable conservation of the geladas in the area, there is a need for integrated management of the area with special attention on the conservation of the grassland habitat.
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Affiliation(s)
- Degu Abate
- Department of Natural Resource ManagementMekdela Amba UniversityTuluawliyaEthiopia
| | - Zerihun Girma
- Wondo Genet College of Forestry and Natural ResourceHawassa UniversityWondo GentEthiopia
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Pifarré i Arolas H, Acosta E, Dudel C, Mhairi Hale J, Myrskylä M. US Racial-Ethnic Mortality Gap Adjusted for Population Structure. Epidemiology 2023; 34:402-410. [PMID: 36863061 PMCID: PMC10069756 DOI: 10.1097/ede.0000000000001595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 01/24/2023] [Indexed: 03/04/2023]
Abstract
BACKGROUND US racial-ethnic mortality disparities are well documented and central to debates on social inequalities in health. Standard measures, such as life expectancy or years of life lost, are based on synthetic populations and do not account for the real underlying populations experiencing the inequalities. METHODS We analyze US mortality disparities comparing Asian Americans, Blacks, Hispanics, and Native Americans/Alaska Natives to Whites using 2019 CDC and NCHS data, using a novel approach that estimates the mortality gap, adjusted for population structure by accounting for real-population exposures. This measure is tailored for analyses where age structures are fundamental, not merely a confounder. We highlight the magnitude of inequalities by comparing the population structure-adjusted mortality gap against standard metrics' estimates of loss of life due to leading causes. RESULTS Based on the population structure-adjusted mortality gap, Black and Native American mortality disadvantage exceedsmortality from circulatory diseases. The disadvantage is 72% among Blacks (men: 47%, women: 98%) and 65% among Native Americans (men: 45%, women: 92%), larger than life expectancy measured disadvantage. In contrast, estimated advantages for Asian Americans are over three times (men: 176%, women: 283%) and, for Hispanics, two times (men: 123%; women: 190%) larger than those based on life expectancy. CONCLUSIONS Mortality inequalities based on standard metrics' synthetic populations can differ markedly from estimates of the population structure-adjusted mortality gap. We demonstrate that standard metrics underestimate racial-ethnic disparities through disregarding actual population age structures. Exposure-corrected measures of inequality may better inform health policies around allocation of scarce resources.
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Affiliation(s)
- Héctor Pifarré i Arolas
- From the La Follette School of Public Affairs, University of Wisconsin—Madison, Madison, WI
- Center for Demography and Ecology, University of Wisconsin–Madison, Madison, WI
| | - Enrique Acosta
- Max Planck Institute for Demographic Research, Rostock, Germany
| | - Christian Dudel
- Max Planck Institute for Demographic Research, Rostock, Germany
- Federal Institute for Population Research, Wiesbaden, Germany
| | - Jo Mhairi Hale
- Max Planck Institute for Demographic Research, Rostock, Germany
- School of Geography and Sustainable Development, University of St Andrews, St Andrews, Scotland
| | - Mikko Myrskylä
- Federal Institute for Population Research, Wiesbaden, Germany
- Center for Social Data Science and Population Research Unit, University of Helsinki, Helsinki, Finland
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Rasmussen SL, Berg TB, Martens HJ, Jones OR. Anyone Can Get Old-All You Have to Do Is Live Long Enough: Understanding Mortality and Life Expectancy in European Hedgehogs ( Erinaceus europaeus). Animals (Basel) 2023; 13:ani13040626. [PMID: 36830413 PMCID: PMC9951656 DOI: 10.3390/ani13040626] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 02/04/2023] [Accepted: 02/06/2023] [Indexed: 02/15/2023] Open
Abstract
The European hedgehog is in decline, triggering a need to monitor population dynamics to optimise conservation initiatives directed at this species. By counting periosteal growth lines, we determined the age of 388 dead European hedgehogs collected through citizen science in Denmark. The overall mean age was 1.8 years (1.6 years for females and 2.1 years for males), ranging between 0 and 16 years. We constructed life tables showing life expectancies at 2.1 years for females and 2.6 years for males. We discovered that male hedgehogs were more likely to have died in traffic than females, but traffic-related deaths peaked in July for both sexes. A sex difference was detected for non-traffic deaths, as most males died in July, and most females died in September. We created empirical survivorship curves and hazard curves showing that the risk of death for male hedgehogs remains approximately constant with age. In contrast, the risk of death for females increases with age. Most of the collected road-killed individuals died in rural habitats. The degree of inbreeding did not influence longevity. These new insights are important for preparing conservation strategies for the European hedgehog.
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Affiliation(s)
- Sophie Lund Rasmussen
- Wildlife Conservation Research Unit, Department of Biology, University of Oxford, The Recanati-Kaplan Centre, Tubney House, Abingdon Road, Tubney, Abingdon OX13 5QL, UK
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, DK-9220 Aalborg, Denmark
- Correspondence:
| | - Thomas B. Berg
- Naturama, 30 Dronningemaen, DK-5700 Svendborg, Denmark
- Department of Biology, University of Southern Denmark, 55 Campusvej, DK-5230 Odense M, Denmark
| | - Helle Jakobe Martens
- Department of Geosciences and Natural Resource Management, Section for Forest, Nature and Biomass, Copenhagen University, 23 Rolighedsvej, DK-1958 Frederiksberg C, Denmark
| | - Owen R. Jones
- Department of Biology, University of Southern Denmark, 55 Campusvej, DK-5230 Odense M, Denmark
- Interdisciplinary Centre on Population Dynamics (CPop), University of Southern Denmark, 55 Campusvej, DK-5230 Odense M, Denmark
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Ohlberger J, Cline TJ, Schindler DE, Lewis B. Declines in body size of sockeye salmon associated with increased competition in the ocean. Proc Biol Sci 2023; 290:20222248. [PMID: 36750195 PMCID: PMC9904942 DOI: 10.1098/rspb.2022.2248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
Declining body sizes have been documented for several species of Pacific salmon; however, whether size declines are caused mainly by ocean warming or other ecological factors, and whether they result primarily from trends in age at maturation or changing growth rates remain poorly understood. We quantified changes in mean body size and contributions from shifting size-at-age and age structure of mature sockeye salmon returning to Bristol Bay, Alaska, over the past 60 years. Mean length declined by 3%, corresponding to a 10% decline in mean body mass, since the early 1960s, though much of this decline occurred since the early 2000s. Changes in size-at-age were the dominant cause of body size declines and were more consistent than trends in age structure among the major rivers that flow into Bristol Bay. Annual variation in size-at-age was largely explained by competition among Bristol Bay sockeye salmon and interspecific competition with other salmon in the North Pacific Ocean. Warm winters were associated with better growth of sockeye salmon, whereas warm summers were associated with reduced growth. Our findings point to competition at sea as the main driver of sockeye salmon size declines, and emphasize the trade-off between fish abundance and body size.
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Affiliation(s)
- Jan Ohlberger
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98195, USA
| | - Timothy J. Cline
- Department of Ecology, Montana State University, Bozeman, MT, 59717, USA
| | - Daniel E. Schindler
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98195, USA
| | - Bert Lewis
- Alaska Department of Fish and Game, Commercial Fisheries Division, Anchorage, AK 99518, USA
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Ottersen G, Holt RE. Long-term variability in spawning stock age structure influences climate-recruitment link for Barents Sea cod. Fish Oceanogr 2023; 32:91-105. [PMID: 37063112 PMCID: PMC10087206 DOI: 10.1111/fog.12605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 07/01/2022] [Accepted: 07/05/2022] [Indexed: 06/19/2023]
Abstract
Fish populations may spawn a vast number of offspring, while only a small and highly variable fraction of a new cohort survives long enough to enter into the fisheries as recruits. It is intuitive that the size and state of the spawning stock, the adult part of the fish population, is important for recruitment. Additionally, environmental conditions can greatly influence survival through vulnerable early life stages until recruitment. To understand what regulates recruitment, an essential part of fish population dynamics, it is thus necessary to explain the impact of fluctuations in both spawning stock and environment, including interactions. Here, we examine if the connection between the environment and recruitment is affected by the state of the spawning stock, including biomass, mean age and age diversity. Specifically, we re-evaluate the hypothesis stating that recruitment from a spawning stock dominated by young fish and few age classes is more vulnerable to environmental fluctuations. We expand upon earlier work on the Barents Sea stock of Atlantic cod, now with data series extended in time both backwards and forwards to cover the period 1922-2019. While our findings are correlative and cannot prove a specific cause and effect mechanism, they support earlier work and strengthen the evidence for the hypothesis above. Furthermore, this study supports that advice to fisheries management should include considerations of environmental status.
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Affiliation(s)
- Geir Ottersen
- Institute of Marine ResearchBergenNorway
- Centre for Ecological and Evolutionary Synthesis, Department of BiosciencesUniversity of OsloOsloNorway
| | - Rebecca E. Holt
- Centre for Ecological and Evolutionary Synthesis, Department of BiosciencesUniversity of OsloOsloNorway
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Vorobyova OD, Topilin AV, Nioradze GV, Khrolenko TS. [The demographic aging of population: regional trends in Russia]. Probl Sotsialnoi Gig Zdravookhranenniiai Istor Med 2022; 30:1230-1235. [PMID: 36541299 DOI: 10.32687/0869-866x-2022-30-6-1230-1235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Indexed: 06/17/2023]
Abstract
The article considers evolution of research and views on challenges and menaces of demographic aging process in the works of national and foreign scientists. The characteristics of this process in regions of the Russian Federation consist in special diversity of social economic, climatic, geographical and mental conditions in which demographic processes proceed. This determined availability of various types and stages of demographic aging in regions of the Russian Federation as well as opportunities to temper negative consequences of this process.
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Affiliation(s)
- O D Vorobyova
- The Institute of Demographic Research - the Separate Division of The Federal State Budget Institution of Science "The Federal Research Sociological Center of The Russian Academy of Sciences"
| | - A V Topilin
- The Institute of Demographic Research - the Separate Division of The Federal State Budget Institution of Science "The Federal Research Sociological Center of The Russian Academy of Sciences"
| | - G V Nioradze
- The Institute of Demographic Research - the Separate Division of The Federal State Budget Institution of Science "The Federal Research Sociological Center of The Russian Academy of Sciences"
| | - T S Khrolenko
- The Institute of Demographic Research - the Separate Division of The Federal State Budget Institution of Science "The Federal Research Sociological Center of The Russian Academy of Sciences"
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10
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Volnuhin AV, Samokhina EO, Andrievsky MV, Zaugol'nikova TV, Chegaeva TV, Reze AG, Gertsog AA, Morozova TE. [The gender and age characteristics of general practitioners in Moscow]. Probl Sotsialnoi Gig Zdravookhranenniiai Istor Med 2022; 30:1265-1270. [PMID: 36541306 DOI: 10.32687/0869-866x-2022-30-6-1265-1270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Indexed: 06/17/2023]
Abstract
The feminization and middle age decreasing in general practitioner profession is a worldwide trend.Purpose of the study is to explore gender and age structure, professional characteristics of general practitioners in Moscow.The retrospective analysis of personal records of students of the Chair of General Medical Practice of the Institute of Professional Education of the The I. M. Sechenov First Moscow State Medical University trained from 2016 to 2020 (n = 400).It is established that women made 80.5% out of them. The average age was 50.7 ± 0.7 years; average general professional experience - 28.8 ± 0.8 years, in general medical practice - 9.7 ± 0.3 years. The internship/residency in therapy was graduated by 84.2% of students. Up to 96.3% worked in state medical organizations. The majority (97.0%) had no academic degree. Indicators with positive dynamics: share of women, physicians with internship/residency in therapy, employees of state medical organizations, without an academic degree. Indicators with negative dynamics: age, professional experience. Differences between men and women were established for residency and professional experience in general medical practice.The average social and professional portrait of general practitioner in Moscow: woman 50 years old graduated internship/residency in therapy, professional experience of more than 20 years, with professional retraining about 10 years ago, working in state medical organization, no academic degree.The activities were proposed considering gender and age specifics, professional characteristics of general practitioners, directed to increasing efficiency and comfort of training.
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Affiliation(s)
- A V Volnuhin
- The Federal State Autonomous Educational Institution of Higher Education "The I. M. Sechenov First Moscow State Medical University" (Sechenov University) of Minzdrav of Russia
| | - E O Samokhina
- The Federal State Autonomous Educational Institution of Higher Education "The I. M. Sechenov First Moscow State Medical University" (Sechenov University) of Minzdrav of Russia
| | - M V Andrievsky
- The Federal State Autonomous Educational Institution of Higher Education "The I. M. Sechenov First Moscow State Medical University" (Sechenov University) of Minzdrav of Russia
| | - T V Zaugol'nikova
- The Federal State Autonomous Educational Institution of Higher Education "The I. M. Sechenov First Moscow State Medical University" (Sechenov University) of Minzdrav of Russia
| | - T V Chegaeva
- The Federal State Autonomous Educational Institution of Higher Education "The I. M. Sechenov First Moscow State Medical University" (Sechenov University) of Minzdrav of Russia
| | - A G Reze
- The Federal State Autonomous Educational Institution of Higher Education "The I. M. Sechenov First Moscow State Medical University" (Sechenov University) of Minzdrav of Russia
| | - A A Gertsog
- The Federal State Autonomous Educational Institution of Higher Education "The I. M. Sechenov First Moscow State Medical University" (Sechenov University) of Minzdrav of Russia
| | - T E Morozova
- The Federal State Autonomous Educational Institution of Higher Education "The I. M. Sechenov First Moscow State Medical University" (Sechenov University) of Minzdrav of Russia
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Ohlberger J, Langangen Ø, Stige LC. Age structure affects population productivity in an exploited fish species. Ecol Appl 2022; 32:e2614. [PMID: 35365955 DOI: 10.1002/eap.2614] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 12/09/2021] [Accepted: 01/14/2022] [Indexed: 06/14/2023]
Abstract
Long-term changes in the age and size structure of animal populations are well documented, yet their impacts on population productivity are poorly understood. Fishery exploitation can be a major driver of changes in population age-size structure because fisheries significantly increase mortality and often selectively remove larger and older fish. Climate change is another potential driver of shifts in the demographic structure of fish populations. Northeast Arctic (NEA) cod is the largest population of Atlantic cod (Gadus morhua) and one of the world's most important commercial fish stocks. This population has experienced considerable changes in population age-size structure over the past century, largely in response to fishing. In this study, we investigate whether changes in spawner age structure have affected population productivity in NEA cod, measured as recruits per spawning stock biomass, over the past 75 years. We find evidence that shifts in age structure toward younger spawners negatively affect population productivity, implying higher recruitment success when the spawning stock is composed of older individuals. The positive effect of an older spawning stock is likely linked to maternal effects and higher reproductive output of larger females. Our results indicate a threefold difference in productivity between the youngest and oldest spawning stock that has been observed since the 1950s. Further, our results suggest a positive effect of environmental temperature and a negative effect of intraspecific cannibalism by older juveniles on population productivity, which partly masked the effect of spawner age structure unless accounted for in the model. Collectively, these findings emphasize the importance of population age structure for the productivity of fish populations and suggest that harvest-induced demographic changes can have negative feedbacks for fisheries that lead to a younger spawning stock. Incorporating demographic data into harvest strategies could thus facilitate sustainable fishery management.
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Affiliation(s)
- Jan Ohlberger
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington, USA
| | | | - Leif Chr Stige
- Department of Biosciences, University of Oslo, Oslo, Norway
- Norwegian Veterinary Institute, Ås, Norway
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12
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Brandell EE, Cross PC, Smith DW, Rogers W, Galloway N, MacNulty DR, Stahler DR, Treanor J, Hudson PJ. Examination of the interaction between age-specific predation and chronic disease in the Greater Yellowstone Ecosystem. J Anim Ecol 2022; 91:1373-1384. [PMID: 34994978 PMCID: PMC9912199 DOI: 10.1111/1365-2656.13661] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 12/28/2021] [Indexed: 11/27/2022]
Abstract
Predators may create healthier prey populations by selectively removing diseased individuals. Predators typically prefer some ages of prey over others, which may, or may not, align with those prey ages that are most likely to be diseased. The interaction of age-specific infection and predation has not been previously explored and likely has sizable effects on disease dynamics. We hypothesize that predator cleansing effects will be greater when the disease and predation occur in the same prey age groups. We examine the predator cleansing effect using a model where both vulnerability to predators and pathogen prevalence vary with age. We tailor this model to chronic wasting disease (CWD) in mule deer and elk populations in the Greater Yellowstone Ecosystem, with empirical data from Yellowstone grey wolves and cougars. Model results suggest that under moderate, yet realistic, predation pressure from cougars and wolves independently, predators may decrease CWD outbreak size substantially and delay the accumulation of symptomatic deer and elk. The magnitude of this effect is driven by the ability of predators to selectively remove late-stage CWD infections that are likely the most responsible for transmission, but this may not be the age class they typically select. Thus, predators that select for infected young adults over uninfected juveniles have a stronger cleansing effect, and these effects are strengthened when transmission rates increase with increasing prey morbidity. There are also trade-offs from a management perspective-that is, increasing predator kill rates can result in opposing forces on prey abundance and CWD prevalence. Our modelling exploration shows that predators have the potential to reduce prevalence in prey populations when prey age and disease severity are considered, yet the strength of this effect is influenced by predators' selection for demography or body condition. Current CWD management focuses on increasing cervid hunting as the primary management tool, and our results suggest predators may also be a useful tool under certain conditions, but not necessarily without additional impacts on host abundance and demography. Protected areas with predator populations will play a large role in informing the debate over predator impacts on disease.
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Affiliation(s)
- Ellen E. Brandell
- Center for Infectious Disease Dynamics and Department of Biology, Huck Institutes of the Life SciencesPennsylvania State UniversityUniversity ParkPAUSA,Wisconsin Cooperative Wildlife Research Unit, Department of Forest and Wildlife EcologyUniversity of Wisconsin‐MadisonMadisonWIUSA
| | - Paul C. Cross
- U.S. Geological SurveyNorthern Rocky Mountain Science CenterBozemanMTUSA
| | - Douglas W. Smith
- Yellowstone Center for ResourcesYellowstone National ParkWyomingWYUSA
| | - Will Rogers
- Department of EcologyMontana State UniversityBozemanMTUSA
| | | | | | - Daniel R. Stahler
- Yellowstone Center for ResourcesYellowstone National ParkWyomingWYUSA
| | - John Treanor
- Yellowstone Center for ResourcesYellowstone National ParkWyomingWYUSA
| | - Peter J. Hudson
- Center for Infectious Disease Dynamics and Department of Biology, Huck Institutes of the Life SciencesPennsylvania State UniversityUniversity ParkPAUSA
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13
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Zuo C, Meng Z, Zhu F, Zheng Y, Ling Y. Assessing Vaccination Prioritization Strategies for COVID-19 in South Africa Based on Age-Specific Compartment Model. Front Public Health 2022; 10:876551. [PMID: 35784231 PMCID: PMC9240634 DOI: 10.3389/fpubh.2022.876551] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 05/11/2022] [Indexed: 02/05/2023] Open
Abstract
The vaccines are considered to be important for the prevention and control of coronavirus disease 2019 (COVID-19). However, considering the limited vaccine supply within an extended period of time in many countries where COVID-19 vaccine booster shot are taken and new vaccines are developed to suppress the mutation of virus, designing an effective vaccination strategy is extremely important to reduce the number of deaths and infections. Then, the simulations were implemented to study the relative reduction in morbidity and mortality of vaccine allocation strategies by using the proposed model and actual South Africa's epidemiological data. Our results indicated that in light of South Africa's demographics, vaccinating older age groups (>60 years) largely reduced the cumulative deaths and the "0-20 first" strategy was the most effective way to reduce confirmed cases. In addition, "21-30 first" and "31-40 first" strategies have also had a positive effect. Partial vaccination resulted in lower numbers of infections and deaths under different control measures compared with full vaccination in low-income countries. In addition, we analyzed the sensitivity of daily testing volume and infection rate, which are critical to optimize vaccine allocation. However, comprehensive reduction in infections was mainly affected by the vaccine proportion of the target age group. An increase in the proportion of vaccines given priority to "0-20" groups always had a favorable effect, and the prioritizing vaccine allocation among the "60+" age group with 60% of the total amount of vaccine consistently resulted in the greatest reduction in deaths. Meanwhile, we observed a significant distinction in the effect of COVID-19 vaccine allocation policies under varying priority strategies on relative reductions in the effective reproduction number. Our results could help evaluate to control measures performance and the improvement of vaccine allocation strategy for COVID-19 epidemic.
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Affiliation(s)
- Chao Zuo
- School of Management Engineering and E-Commerce, Zhejiang Gongshang University, Hangzhou, China
| | | | | | | | - Yuting Ling
- School of Management Engineering and E-Commerce, Zhejiang Gongshang University, Hangzhou, China
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14
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Peeters B, Grøtan V, Gamelon M, Veiberg V, Lee AM, Fryxell JM, Albon SD, Saether BE, Engen S, Loe LE, Hansen BB. Harvesting can stabilise population fluctuations and buffer the impacts of extreme climatic events. Ecol Lett 2022; 25:863-875. [PMID: 35103374 DOI: 10.1111/ele.13963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 11/02/2021] [Accepted: 12/16/2021] [Indexed: 11/29/2022]
Abstract
Harvesting can magnify the destabilising effects of environmental perturbations on population dynamics and, thereby, increase extinction risk. However, population-dynamic theory predicts that impacts of harvesting depend on the type and strength of density-dependent regulation. Here, we used logistic population growth models and an empirical reindeer case study to show that low to moderate harvesting can actually buffer populations against environmental perturbations. This occurs because of density-dependent environmental stochasticity, where negative environmental impacts on vital rates are amplified at high population density due to intra-specific resource competition. Simulations from our population models show that even low levels of harvesting may prevent overabundance, thereby dampening population fluctuations and reducing the risk of population collapse and quasi-extinction following environmental perturbations. Thus, depending on the species' life history and the strength of density-dependent environmental drivers, low to moderate harvesting can improve population resistance to increased climate variability and extreme weather expected under global warming.
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Affiliation(s)
- Bart Peeters
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Vidar Grøtan
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Marlène Gamelon
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway.,Laboratoire de Biométrie et Biologie Évolutive, Université Claude Bernard Lyon 1, Villeurbanne Cedex, France
| | | | - Aline M Lee
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - John M Fryxell
- Biodiversity Institute of Ontario, University of Guelph, Guelph, Ontario, Canada
| | | | - Bernt-Erik Saether
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Steinar Engen
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Leif Egil Loe
- Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway
| | - Brage Bremset Hansen
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway.,Norwegian Institute for Nature Research, Trondheim, Norway
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15
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Yuan P, Aruffo E, Gatov E, Tan Y, Li Q, Ogden N, Collier S, Nasri B, Moyles I, Zhu H. School and community reopening during the COVID-19 pandemic: a mathematical modelling study. R Soc Open Sci 2022; 9:211883. [PMID: 35127115 PMCID: PMC8808096 DOI: 10.1098/rsos.211883] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/04/2022] [Indexed: 05/03/2023]
Abstract
Operating schools safely during the COVID-19 pandemic requires a balance between health risks and the need for in-person learning. Using demographic and epidemiological data between 31 July and 23 November 2020 from Toronto, Canada, we developed a compartmental transmission model with age, household and setting structure to study the impact of schools reopening in September 2020. The model simulates transmission in the home, community and schools, accounting for differences in infectiousness between adults and children, and accounting for work-from-home and virtual learning. While we found a slight increase in infections among adults (2.2%) and children (4.5%) within the first eight weeks of school reopening, transmission in schools was not the key driver of the virus resurgence in autumn 2020. Rather, it was community spread that determined the outbreak trajectory, primarily due to increases in contact rates among adults in the community after school reopening. Analyses of cross-infection among households, communities and schools revealed that home transmission is crucial for epidemic progression and safely operating schools, while the degree of in-person attendance has a larger impact than other control measures in schools. This study suggests that safe school reopening requires the strict maintenance of public health measures in the community.
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Affiliation(s)
- Pei Yuan
- Laboratory of Mathematical Parallel Systems (LAMPS), Department of Mathematics and Statistics, York University, Toronto, Canada
- Canadian Centre for Diseases Modeling (CCDM), York University, Toronto, Canada
- Department of Mathematics and Statistics, York University, Toronto, Canada
| | - Elena Aruffo
- Laboratory of Mathematical Parallel Systems (LAMPS), Department of Mathematics and Statistics, York University, Toronto, Canada
- Canadian Centre for Diseases Modeling (CCDM), York University, Toronto, Canada
- Department of Mathematics and Statistics, York University, Toronto, Canada
| | - Evgenia Gatov
- Toronto Public Health, City of Toronto, Toronto, Ontario, Canada
| | - Yi Tan
- Laboratory of Mathematical Parallel Systems (LAMPS), Department of Mathematics and Statistics, York University, Toronto, Canada
- Canadian Centre for Diseases Modeling (CCDM), York University, Toronto, Canada
- Department of Mathematics and Statistics, York University, Toronto, Canada
| | - Qi Li
- Laboratory of Mathematical Parallel Systems (LAMPS), Department of Mathematics and Statistics, York University, Toronto, Canada
- Department of Mathematics, Shanghai Normal University, Shanghai, People's Republic of China
| | - Nick Ogden
- Canadian Centre for Diseases Modeling (CCDM), York University, Toronto, Canada
- Public Health Risk Sciences Division, National Microbiology Laboratory, Public Health Agency of Canada, Quebec, Canada
| | - Sarah Collier
- Toronto Public Health, City of Toronto, Toronto, Ontario, Canada
| | - Bouchra Nasri
- Canadian Centre for Diseases Modeling (CCDM), York University, Toronto, Canada
- Department of Social and Preventive Medicine, Université de Montréal, Montréal, Quebec, Canada
| | - Iain Moyles
- Canadian Centre for Diseases Modeling (CCDM), York University, Toronto, Canada
- Department of Mathematics and Statistics, York University, Toronto, Canada
| | - Huaiping Zhu
- Laboratory of Mathematical Parallel Systems (LAMPS), Department of Mathematics and Statistics, York University, Toronto, Canada
- Canadian Centre for Diseases Modeling (CCDM), York University, Toronto, Canada
- Department of Mathematics and Statistics, York University, Toronto, Canada
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16
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Favas C, Jarrett P, Ratnayake R, Watson OJ, Checchi F. Country differences in transmissibility, age distribution and case-fatality of SARS-CoV-2: a global ecological analysis. Int J Infect Dis 2022; 114:210-218. [PMID: 34749011 PMCID: PMC8571103 DOI: 10.1016/j.ijid.2021.11.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 09/27/2021] [Accepted: 11/01/2021] [Indexed: 12/15/2022] Open
Abstract
Objectives The first COVID-19 pandemic waves in many low-income countries appeared milder than initially forecasted. We conducted a country-level ecological study to describe patterns in key SARS-CoV-2 outcomes by country and region and explore associations with potential explanatory factors, including population age structure and prior exposure to endemic parasitic infections. Methods We collected publicly available data and compared them using standardisation techniques. We then explored the association between exposures and outcomes using random forest and linear regression. We adjusted for potential confounders and plausible effect modifications. Results While mean time-varying reproduction number was highest in the European and Americas regions, median age of death was lower in the Africa region, with a broadly similar case-fatality ratio. Population age was strongly associated with mean (β=0.01, 95% CI, 0.005, 0.011) and median age of cases (β=-0.40, 95% CI, -0.53, -0.26) and deaths (β= 0.40, 95% CI, 0.17, 0.62). Conclusions Population age seems an important country-level factor explaining both transmissibility and age distribution of observed cases and deaths. Endemic infections seem unlikely, from this analysis, to be key drivers of the variation in observed epidemic trends. Our study was limited by the availability of outcome data and its causally uncertain ecological design.
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Affiliation(s)
- Caroline Favas
- Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, Keppel St, Bloomsbury, London, WC1E 7HT, United Kingdom.
| | - Prudence Jarrett
- Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, Keppel St, Bloomsbury, London, WC1E 7HT, United Kingdom
| | - Ruwan Ratnayake
- Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, Keppel St, Bloomsbury, London, WC1E 7HT, United Kingdom
| | - Oliver J Watson
- Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Francesco Checchi
- Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, Keppel St, Bloomsbury, London, WC1E 7HT, United Kingdom
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17
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Rodrigues AMM, Gardner A. Reproductive value and the evolution of altruism. Trends Ecol Evol 2021; 37:346-358. [PMID: 34949484 DOI: 10.1016/j.tree.2021.11.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 11/05/2021] [Accepted: 11/09/2021] [Indexed: 11/26/2022]
Abstract
Altruism is favored by natural selection provided that it delivers sufficient benefits to relatives. An altruist's valuation of her relatives depends upon the extent to which they carry copies of her genes - relatedness - and also on the extent to which they are able to transmit their own genes to future generations - reproductive value. However, although relatedness has received a great deal of attention with regard to altruism, reproductive value has been surprisingly neglected. We review how reproductive value modulates patterns of altruism in relation to individual differences in age, sex, and general condition, and discuss how social partners may manipulate each other's reproductive value to incentivize altruism. This topic presents opportunities for tight interplay between theoretical and empirical research.
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Affiliation(s)
- António M M Rodrigues
- Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect Street, New Haven, CT 06511, USA.
| | - Andy Gardner
- School of Biology, University of St Andrews, Greenside Place, St Andrews KY16 9TH, UK
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18
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Hulíková Tesárková K, Dzúrová D. The age structure of cases as the key of COVID-19 severity: Longitudinal population-based analysis of European countries during 150 days. Scand J Public Health 2021; 50:738-747. [PMID: 34923870 DOI: 10.1177/14034948211042486] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
AIMS Over a million confirmed cases of the coronavirus disease (COVID-19) across 16 European countries were observed during the first wave of the pandemic. Epidemiological measures like the case fatality rate (CFR) are generally used to determine the severity of the illness. The aim is to investigate the impact of the age structure of reported cases on the reported CFR and possibilities of its demographic adjustment for a better cross-country comparison (age-standardized CFRs, time delay between cases detection and death). METHODS This longitudinal study uses prospective, population-based data covering 150 days, starting on the day of confirmation of the 100th case in each country. COVerAGE-DB and the Human Mortality Database were used in this regard. The age-standardized CFRs were calculated with and without the time delay of the number of deaths after the confirmation of the cases. RESULTS The observed decline in the CFRs at the end of the first wave is partly given by the changes in the age structure of confirmed cases. Using the adjusted (age-standardized) CFRs with time delay, the risk of death among confirmed cases is much more stable in comparison to crude (observed) CFRs. CONCLUSIONS Preventing the spread of COVID-19 among the elderly is an important way to positively influence the overall fatality rate, decrease the number of deaths, and not overload the health systems. The crude CFRs (still often presented) are not sufficient for a proper evaluation of the development across populations nor as a means of identifying the influencing factors.
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Affiliation(s)
- Klára Hulíková Tesárková
- Department of Demography and Geodemography, Faculty of Science, Charles University, Prague, Czech Republic
| | - Dagmar Dzúrová
- Department of Social Geography and Regional Development, Faculty of Science, Charles University, Prague, Czech Republic
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19
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Bull JC, Jones OR, Börger L, Franconi N, Banga R, Lock K, Stringell TB. Climate causes shifts in grey seal phenology by modifying age structure. Proc Biol Sci 2021; 288:20212284. [PMID: 34847765 PMCID: PMC8634623 DOI: 10.1098/rspb.2021.2284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 11/08/2021] [Indexed: 11/12/2022] Open
Abstract
There are numerous examples of phenological shifts that are recognized both as indicators of climate change and drivers of ecosystem change. A pressing challenge is to understand the causal mechanisms by which climate affects phenology. We combined annual population census data and individual longitudinal data (1992-2018) on grey seals, Halicheorus grypus, to quantify the relationship between pupping season phenology and sea surface temperature. A temperature increase of 2°C was associated with a pupping season advance of approximately seven days at the population level. However, we found that maternal age, rather than sea temperature, accounted for changes in pupping date by individuals. Warmer years were associated with an older average age of mothers, allowing us to explain phenological observations in terms of a changing population age structure. Finally, we developed a matrix population model to test whether our observations were consistent with changes to the stable age distribution. This could not fully account for observed phenological shift, strongly suggesting transient modification of population age structure, for example owing to immigration. We demonstrate a novel mechanism for phenological shifts under climate change in long-lived, age- or stage-structured species with broad implications for dynamics and resilience, as well as population management.
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Affiliation(s)
- James C. Bull
- Department of Biosciences, Swansea University, Swansea SA2 8PP, UK
| | - Owen R. Jones
- Department of Biology, University of Southern Denmark, Odense, Denmark
- Interdisciplinary Centre on Population Dynamics (CPOP), University of Southern Denmark, Odense, Denmark
| | - Luca Börger
- Department of Biosciences, Swansea University, Swansea SA2 8PP, UK
| | - Novella Franconi
- Department of Biosciences, Swansea University, Swansea SA2 8PP, UK
| | - Roma Banga
- Department of Biosciences, Swansea University, Swansea SA2 8PP, UK
| | - Kate Lock
- Natural Resources Wales, Martin's Haven, Pembrokeshire, UK
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20
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Pirrie A, Ashby B. Does differential mortality after parental investment affect sex ratio evolution? No. Evolution 2021; 75:3175-3180. [PMID: 34633080 DOI: 10.1111/evo.14374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 09/01/2021] [Accepted: 09/10/2021] [Indexed: 11/30/2022]
Abstract
The classical view of sex ratio evolution, popularized by R. A. Fisher, is that the sex ratio at birth should be equal when males and females require the same level of parental investment. Thus, although differences in mortality between the sexes during parental investment will cause deviations from an equal sex ratio at birth, differential mortality after parental investment should have no effect. However, a recent theoretical model appears to contradict this view, suggesting that differential mortality after the period of parental investment does cause deviations from an equal sex ratio at birth. Moreover, the life stage at which mortality differs (juvenile vs. adult) is predicted to cause contrasting effects on sex ratio evolution. These results are in stark contrast with Fisher's hypothesis. Here, we resolve this disparity by analyzing a stage- and sex- structured model of population dynamics. We find that selection always drives the population to an equal sex ratio at birth regardless of differential mortality effects after parental investment, thus confirming Fisher's hypothesis. The disparity appears to be due to incorrect accounting of mutant-resident unions, which we avoid by considering separate union classes for different types of mutant-resident unions.
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Affiliation(s)
- Alistair Pirrie
- Department of Mathematical Sciences, University of Bath, Bath, BA2 7AY, United Kingdom
| | - Ben Ashby
- Department of Mathematical Sciences, University of Bath, Bath, BA2 7AY, United Kingdom
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21
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Marquez JF, Saether BE, Aanes S, Engen S, Salthaug A, Lee AM. Age-dependent patterns of spatial autocorrelation in fish populations. Ecology 2021; 102:e03523. [PMID: 34460952 DOI: 10.1002/ecy.3523] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 05/28/2021] [Accepted: 06/21/2021] [Indexed: 12/25/2022]
Abstract
The degree of spatial autocorrelation in population fluctuations increases with dispersal and geographical covariation in the environment, and decreases with strength of density dependence. Because the effects of these processes can vary throughout an individual's lifespan, we studied how spatial autocorrelation in abundance changed with age in three marine fish species in the Barents Sea. We found large interspecific differences in age-dependent patterns of spatial autocorrelation in density. Spatial autocorrelation increased with age in cod, the reverse trend was found in beaked redfish, while it remained constant among age classes in haddock. We also accounted for the average effect of local cohort dynamics, i.e. the expected local density of an age class given last year's local density of the cohort, with the goal of disentangling spatial autocorrelation patterns acting on an age class from those formed during younger age classes and being carried over. We found that the spatial autocorrelation pattern of older age classes became increasingly determined by the distribution of the cohort during the previous year. Lastly, we found high degrees of autocorrelation over long distances for the three species, suggesting the presence of far-reaching autocorrelating processes on these populations. We discuss how differences in the species' life history strategies could cause the observed differences in age-specific variation in spatial autocorrelation. As spatial autocorrelation can differ among age classes, our study indicates that fluctuations in age structure can influence the spatio-temporal variation in abundance of marine fish populations.
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Affiliation(s)
- Jonatan F Marquez
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, 7491, Trondheim, Norway
| | - Bernt-Erik Saether
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, 7491, Trondheim, Norway
| | | | - Steinar Engen
- Centre for Biodiversity Dynamics, Department of Mathematical Sciences, Norwegian University of Science and Technology, 7491, Trondheim, Norway
| | - Are Salthaug
- Institute of Marine Research, Postbox 1870 Nordnes, 5817, Bergen, Norway
| | - Aline Magdalena Lee
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, 7491, Trondheim, Norway
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22
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Mueller JP, Getachew T, Rekik M, Rischkowsky B, Abate Z, Goshme S, Wale Y, Haile A. Three easy fixes for sire use can enhance genetic progress in community-based breeding programmes. J Anim Breed Genet 2021; 138:719-730. [PMID: 34337791 DOI: 10.1111/jbg.12639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 05/24/2021] [Accepted: 07/19/2021] [Indexed: 11/27/2022]
Abstract
We analysed options to optimize the use of sires in sheep and goat community-based breeding programmes (CBBP) for three scenarios occurring under field conditions: premature sale of selection candidates, fixed service periods of selected sires and incomplete sire pedigrees. The first scenario was studied by looking at the outcome of combinations of selection pressures in successive selection stages. A compromise of early sale of sire candidates and genetic progress can be obtained by selecting in two stages, such that selection pressure in the first stage is chosen in terms of achieving an acceptable selection potential after the second stage. Simulations showed the dependency of this compromise on selection accuracies and correlation between selection criteria. For a typical sheep CBBP, only 20% of the top three months weighting male lambs need to be retained to achieve 80% of the potential selection differential on six months weight. For the second scenario, two alternatives to fixed service periods were analysed. When across-age BLUP EBVs are not available, individual sires can be programmed to stay in service according to their initial ranking. In typical sheep, CBBPs genetic progress can be increased by about 9% over response to selection with optimum fixed sire service periods. When BLUP EBVs are available, a simulated retrospective analyses of across-age selection of sires in two current sheep CBBPs increased more than twofold the average breeding values actually observed. Thirdly, we studied the benefit of considering possible sires and their mating probabilities when estimating BLUP breeding values instead of setting such sires as unknown. In a current goat CBBP with up to three possible sires included in the pedigree, the accuracy of breeding values nears the accuracy when sires are known and are higher than accuracies when sires are unknown or when possible sires are ignored.
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Affiliation(s)
- Joaquín P Mueller
- National Institute for Agricultural Technology (INTA), Bariloche, Argentina
| | - Tesfaye Getachew
- International Centre for Agricultural Research in the Dry Areas (ICARDA), Addis Ababa, Ethiopia
| | - Mourad Rekik
- International Centre for Agricultural Research in the Dry Areas (ICARDA), Tunis, Tunisia
| | - Barbara Rischkowsky
- International Centre for Agricultural Research in the Dry Areas (ICARDA), Addis Ababa, Ethiopia
| | | | | | | | - Aynalem Haile
- International Centre for Agricultural Research in the Dry Areas (ICARDA), Addis Ababa, Ethiopia
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23
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Abstract
AbstractReproduction, mortality, and immune function often change with age but do not invariably deteriorate. Across the tree of life, there is extensive variation in age-specific performance and changes to key life-history traits. These changes occur on a spectrum from classic senescence, where performance declines with age, to juvenescence, where performance improves with age. Reproduction, mortality, and immune function are also important factors influencing the spread of infectious disease, yet there exists no comprehensive investigation into how the aging spectrum of these traits impacts epidemics. We used a model laboratory infection system to compile an aging profile of a single organism, including traits directly linked to pathogen susceptibility and those that should indirectly alter pathogen transmission by influencing demography. We then developed generalizable epidemiological models demonstrating that different patterns of aging produce dramatically different transmission landscapes: in many cases, aging can reduce the probability of epidemics, but it can also promote severity. This work provides context and tools for use across taxa by empiricists, demographers, and epidemiologists, advancing our ability to accurately predict factors contributing to epidemics or the potential repercussions of senescence manipulation.
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Altunışık A, Gül S, Özdemir N. Impact of various ecological parameters on the life-history characteristics of Bufotes viridis sitibundus from Turkey. Anat Rec (Hoboken) 2020; 304:1745-1758. [PMID: 33190367 DOI: 10.1002/ar.24571] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 09/15/2020] [Accepted: 09/29/2020] [Indexed: 11/09/2022]
Abstract
In this study, we used the skeletochronology method to estimate various growth parameters, such as age structure, minimum and maximum life span, age of sexual maturity, and the relationship between body size and weight of eight different populations of the variable toad, Bufotes viridis sitibundus, in Turkey. Further, we determined the relationship between these parameters and ecologic factors using the partial Mantel test. A significant difference was found among the populations with respect to age, body size, and body weight in both males and females. On average, the maximum life span was recorded as 10 years for males and 11 years for females. In the studied populations, the average age of sexual maturity ranged between 2 and 4 years for both sexes. Sexual dimorphism in terms of snout-vent length (SVL) was not observed between males and females in all the populations. Toads from the higher altitudes tended to be significantly larger, older, and heavier than those from lower altitudes. We concluded that altitude and temperature have an impact on the growth rate, body size, and body mass.
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Affiliation(s)
- Abdullah Altunışık
- Department of Biology, Faculty of Arts and Sciences, Recep Tayyip Erdoğan University, Rize, Turkey
| | - Serkan Gül
- Department of Biology, Faculty of Arts and Sciences, Recep Tayyip Erdoğan University, Rize, Turkey
| | - Nurhayat Özdemir
- Department of Biology, Faculty of Arts and Sciences, Recep Tayyip Erdoğan University, Rize, Turkey
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25
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Young JM, Yeiser BG, Whittington JA, Dutka-Gianelli J. Maturation of female common snook Centropomus undecimalis: implications for managing protandrous fishes. J Fish Biol 2020; 97:1317-1331. [PMID: 32725619 DOI: 10.1111/jfb.14475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 07/17/2020] [Accepted: 07/23/2020] [Indexed: 06/11/2023]
Abstract
The assumption for hermaphroditic fish species that mature individuals of the terminal sex arise directly from mature individuals of the primary sex has led to the use of sex ratios as a proxy for age at maturity (A50 ). The timing of transition and deficient energy reserves, however, can result in a delay between transition and spawning. To test the assumption of female maturity and investigate the relationship between maturation and energy reserves, common snook, Centropomus undecimalis, a protandrous hermaphrodite, were collected from rivers, estuaries, inlets and offshore habitats on the east coast of Florida during 2010-2015. Immature females were observed every month, with lowest proportions during the peak spawning months of July and August. When calculated based on sex ratio, A50 (8.1 years) overestimated the age at which 50% of the female population was, in fact, mature (4.1-4.9 years). Best-fit models indicate that mesenteric fat index (IF ) and hepato-somatic index (IH ) were significantly affected by gonad phase, month and size and weakly by habitat. In post hoc analysis, immature female IF did not differ significantly from developing and regenerating females, but immature female IH was significantly lower than that for all mature phases except animals in the regressing phase. Although immature females may have sufficient energy in terms of fat, it appears that energy is not allocated to reproductive processes, as evidenced by lower IH . Nonetheless, approximately 95% of females were spawning-capable during peak spawning months, suggesting that the energy threshold at which immature females reach maturity is met by most females each spawning cycle.
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Affiliation(s)
- Joy M Young
- Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, Tequesta Field Laboratory, Tequesta, Florida, USA
| | - Beau G Yeiser
- Florida Fish and Wildlife Conservation Commission, South Regional Office, West Palm Beach, Florida, USA
| | - James A Whittington
- Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, Tequesta Field Laboratory, Tequesta, Florida, USA
| | - Jynessa Dutka-Gianelli
- Gloucester Marine Station, University of Massachusetts Amherst, Gloucester, Massachusetts, USA
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26
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Lim H, Kim J, Jo HH. Population Age Structure and Greenhouse Gas Emissions from Road Transportation: A Panel Cointegration Analysis of 21 OECD Countries. Int J Environ Res Public Health 2020; 17:E7734. [PMID: 33105881 DOI: 10.3390/ijerph17217734] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/14/2020] [Accepted: 10/18/2020] [Indexed: 11/16/2022]
Abstract
Using panel data from 21 Organization for Economic Cooperation and Development (OECD) countries collected between 2000 and 2016, this study analyzes the effect of age structure on greenhouse gas (GHG) emissions from road transportation. Previous studies have failed to reflect the driver's behavior patterns, especially by age group. We apply the Fully-Modified Ordinary Least Squares (FMOLS) method, including the age structure effect by reorganizing 17 age groups into a polynomial structure. The age structure exhibits an asymmetric inverted U-shaped effect on GHG emissions. Initially, people emit more GHGs as they age, and reach peak emissions in their late 20s, after which emissions fall until around the age of 70, when GHG emissions remain constant because of minimum mobility demand. Factors, such as higher income, increased vehicle ownership, and raised transport volumes increase emission rates. On the other hand, fuel transition and increased fuel price, population density, urbanization rate, and fuel economy reduce GHG emissions. Furthermore, we perform a projection of GHG emissions until 2050, and conclude that the effect of age structure is limited because of the minimum mobility demand of the elderly. We conclude that various policy measures, such as increased fuel economy and urbanization, must be considered in order to achieve sustainable transport.
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Abstract
The demographic dividend has long been viewed as an important factor for economic development and provided a rationale for policies aiming at a more balanced age structure through birth control and family planning. Assessing the relative importance of age structure and increases in human capital, recent work has argued that the demographic dividend is related to education and has suggested a dominance of improving education over age structure. Here we reconsider the empirical relevance of shifts in the age distribution for development for a panel of 159 countries over the period 1950 to 2015. Based on a flexible model of age-structured human capital endowments, the results document important interactions between age structure and human capital endowments, suggesting that arguments of clear dominance of education over age structure are unwarranted and lead to potentially misleading policy conclusions. An increase in the working-age population share has a strong and significant positive effect on growth, even conditional on human capital, in line with the conventional notion of a demographic dividend. An increase in human capital only has positive growth effects if combined with a suitable age structure. An increasing share of the most productive age groups has an additional positive effect on economic performance. Finally, the results show considerable heterogeneity in the effect of age structure and human capital for different levels of development. Successful policies for sustainable development should take this heterogeneity into account to avoid detrimental implications of a unidimensional focus on human capital without accounting for demography.
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28
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Guo LZ, Zhao H, Lyu JY, Wang KL, Liu KS, Wang K, Huang D. [Population structure and quantitative dynamics of Stellera chamaejasme in degraded typical steppe]. Ying Yong Sheng Tai Xue Bao 2020; 31:2977-2984. [PMID: 33345498 DOI: 10.13287/j.1001-9332.202009.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Stellera chamaejasme is one of most common poisonous plant species in degraded grasslands of China. S. chamaejasme could dominate the community in some severely degraded grasslands, which is a serious threat to the sustainable development of animal husbandry in natural grasslands. In this study, S. chamaejasme population was divided into 10 age classes according to the number of branches. We investigated the age structure of S. chamaejasme population and population dynamic indices, and quantified the survival status of S. chamaejasme population by compiling a static life table, drawing a survival curve, conducting survival analysis. The age structure of S. chamaejasme population in the study area was growth type. The number of individuals in Ⅰ age class was sufficient but with relatively low survival rate. The population structure of S. chamaejasme was fitted the growing type. The development process of population was fluctuating. The number of individuals would drop sharply in Ⅱ and Ⅷ, indicating that these two age classes were the bottleneck period in the development of S. chamaejasme population. The survival curves of S. chamaejasme population was the Deevey-Ⅱ type. The results of survival analysis showed that the population had a sharp decrease in the early stage and was stable in the later stage, which was because the value of fx and λx of S. chamaejasme in Ⅰ or Ⅱ age class were the highest. In conclusion, sufficient young individuals (Ⅰ) was the basis for the expansion of S. chamaejasme population in the degraded typical steppe. The low transformation rate of young individuals to adults might be one of the reasons explaining why S. chamaejasme population could not expand rapidly in the early stage of grassland degradation. Therefore, it was suggested to intervene early when the number of S. chamaejasme was limited.
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Affiliation(s)
- Li-Zhu Guo
- College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China.,Guyuan National Grassland Ecosystem Field Station, Guyuan 076550, Hebei, China
| | - Huan Zhao
- College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China.,Guyuan National Grassland Ecosystem Field Station, Guyuan 076550, Hebei, China
| | - Jin-Ying Lyu
- College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China.,Guyuan National Grassland Ecosystem Field Station, Guyuan 076550, Hebei, China
| | - Kai-Li Wang
- College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China.,Guyuan National Grassland Ecosystem Field Station, Guyuan 076550, Hebei, China
| | - Ke-Si Liu
- College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China.,Guyuan National Grassland Ecosystem Field Station, Guyuan 076550, Hebei, China
| | - Kun Wang
- College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China.,Guyuan National Grassland Ecosystem Field Station, Guyuan 076550, Hebei, China
| | - Ding Huang
- College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China.,Guyuan National Grassland Ecosystem Field Station, Guyuan 076550, Hebei, China
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29
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Skjerpen T, Tønnessen M. Using future age profiles to improve immigration projections. Popul Stud (Camb) 2020; 75:255-267. [PMID: 32811289 DOI: 10.1080/00324728.2020.1794019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Young adults migrate more than older people. As populations in many countries get older, this may affect out-migration-and thus immigration to other countries. This is not usually accounted for in projections of future immigration, even though considerable ageing is expected globally. We show how United Nations projections of future age profiles in origin regions can be combined with those regions' emigration rates by age group to improve national projections of immigration to a destination country, exemplified by Norway. Using various methods for projecting future migration, we show that projected immigration tends to be lower when taking expected ageing in origin regions into account. This may have a considerable effect on population projections: for Norway, taking changing age profiles in origin regions into account in immigration projections would have an effect on the projected population of Norway equivalent to that of reducing the fertility assumptions by 0.1 children per woman.
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30
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Abstract
Females and males may face different selection pressures. Accordingly, alleles that confer a benefit for one sex often incur a cost for the other. Classic evolutionary theory holds that the X chromosome, whose sex-biased transmission sees it spending more time in females, should value females more than males, whereas autosomes, whose transmission is unbiased, should value both sexes equally. However, recent mathematical and empirical studies indicate that male-beneficial alleles may be more favoured by the X chromosome than by autosomes. Here we develop a gene's-eye-view approach that reconciles the classic view with these recent discordant results, by separating a gene's valuation of female versus male fitness from its ability to induce fitness effects in either sex. We use this framework to generate new comparative predictions for sexually antagonistic evolution in relation to dosage compensation, sex-specific mortality and assortative mating, revealing how molecular mechanisms, ecology and demography drive variation in masculinization versus feminization across the genome.
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Affiliation(s)
| | - Andy Gardner
- School of Biology, University of St Andrews, St Andrews KY16 9TH, UK
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31
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Saito H. Population Dynamics of Lancelet Branchiostoma japonicum in the Seto Inland Sea, Japan. Zoolog Sci 2020; 37:331-337. [PMID: 32729711 DOI: 10.2108/zs200007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 04/06/2020] [Indexed: 11/17/2022]
Abstract
The population dynamics of lancelet Branchiostoma japonicum are reported for six sampling sites in the Seto Inland Sea, Japan, for November 2007-2016. Lancelet growth and life span varied spatially, being faster and shorter, respectively, at Stn 3 (off Marugame, western Bisan-seto) than at other sites; average body length at Stn 3 was 36.1 mm for 2-year-old lancelets, and 38.9-42.1 mm for 4-year-old lancelets at sites 1, 2, 4 and 6. Stepwise multiple regression analysis revealed adult growth rate to be significantly positively related to chlorophyll a concentration, and negatively correlated to lancelet density. Density of newly settled and adult lancelets varied spatially. Chlorophyll a concentration best predicted the density of newly settled lancelets, and sediment particle size best predicted that of adults, indicating that factors affecting lancelet density differ during their life history.
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Affiliation(s)
- Hidetoshi Saito
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima 739-8528, Japan,
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32
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Dowd JB, Andriano L, Brazel DM, Rotondi V, Block P, Ding X, Liu Y, Mills MC. Demographic science aids in understanding the spread and fatality rates of COVID-19. Proc Natl Acad Sci U S A 2020. [PMID: 32300018 DOI: 10.1101/2020.03.15.20036293] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2023] Open
Abstract
Governments around the world must rapidly mobilize and make difficult policy decisions to mitigate the coronavirus disease 2019 (COVID-19) pandemic. Because deaths have been concentrated at older ages, we highlight the important role of demography, particularly, how the age structure of a population may help explain differences in fatality rates across countries and how transmission unfolds. We examine the role of age structure in deaths thus far in Italy and South Korea and illustrate how the pandemic could unfold in populations with similar population sizes but different age structures, showing a dramatically higher burden of mortality in countries with older versus younger populations. This powerful interaction of demography and current age-specific mortality for COVID-19 suggests that social distancing and other policies to slow transmission should consider the age composition of local and national contexts as well as intergenerational interactions. We also call for countries to provide case and fatality data disaggregated by age and sex to improve real-time targeted forecasting of hospitalization and critical care needs.
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Affiliation(s)
- Jennifer Beam Dowd
- Leverhulme Centre for Demographic Science, Nuffield College, University of Oxford, Oxford OX1 3UQ, United Kingdom
| | - Liliana Andriano
- Leverhulme Centre for Demographic Science, Nuffield College, University of Oxford, Oxford OX1 3UQ, United Kingdom
| | - David M Brazel
- Leverhulme Centre for Demographic Science, Nuffield College, University of Oxford, Oxford OX1 3UQ, United Kingdom
| | - Valentina Rotondi
- Leverhulme Centre for Demographic Science, Nuffield College, University of Oxford, Oxford OX1 3UQ, United Kingdom
| | - Per Block
- Leverhulme Centre for Demographic Science, Nuffield College, University of Oxford, Oxford OX1 3UQ, United Kingdom
| | - Xuejie Ding
- Leverhulme Centre for Demographic Science, Nuffield College, University of Oxford, Oxford OX1 3UQ, United Kingdom
| | - Yan Liu
- Leverhulme Centre for Demographic Science, Nuffield College, University of Oxford, Oxford OX1 3UQ, United Kingdom
| | - Melinda C Mills
- Leverhulme Centre for Demographic Science, Nuffield College, University of Oxford, Oxford OX1 3UQ, United Kingdom
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33
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Dowd JB, Andriano L, Brazel DM, Rotondi V, Block P, Ding X, Liu Y, Mills MC. Demographic science aids in understanding the spread and fatality rates of COVID-19. Proc Natl Acad Sci U S A 2020; 117:9696-9698. [PMID: 32300018 PMCID: PMC7211934 DOI: 10.1073/pnas.2004911117] [Citation(s) in RCA: 469] [Impact Index Per Article: 117.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Governments around the world must rapidly mobilize and make difficult policy decisions to mitigate the coronavirus disease 2019 (COVID-19) pandemic. Because deaths have been concentrated at older ages, we highlight the important role of demography, particularly, how the age structure of a population may help explain differences in fatality rates across countries and how transmission unfolds. We examine the role of age structure in deaths thus far in Italy and South Korea and illustrate how the pandemic could unfold in populations with similar population sizes but different age structures, showing a dramatically higher burden of mortality in countries with older versus younger populations. This powerful interaction of demography and current age-specific mortality for COVID-19 suggests that social distancing and other policies to slow transmission should consider the age composition of local and national contexts as well as intergenerational interactions. We also call for countries to provide case and fatality data disaggregated by age and sex to improve real-time targeted forecasting of hospitalization and critical care needs.
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Affiliation(s)
- Jennifer Beam Dowd
- Leverhulme Centre for Demographic Science, Nuffield College, University of Oxford, Oxford OX1 3UQ, United Kingdom
| | - Liliana Andriano
- Leverhulme Centre for Demographic Science, Nuffield College, University of Oxford, Oxford OX1 3UQ, United Kingdom
| | - David M Brazel
- Leverhulme Centre for Demographic Science, Nuffield College, University of Oxford, Oxford OX1 3UQ, United Kingdom
| | - Valentina Rotondi
- Leverhulme Centre for Demographic Science, Nuffield College, University of Oxford, Oxford OX1 3UQ, United Kingdom
| | - Per Block
- Leverhulme Centre for Demographic Science, Nuffield College, University of Oxford, Oxford OX1 3UQ, United Kingdom
| | - Xuejie Ding
- Leverhulme Centre for Demographic Science, Nuffield College, University of Oxford, Oxford OX1 3UQ, United Kingdom
| | - Yan Liu
- Leverhulme Centre for Demographic Science, Nuffield College, University of Oxford, Oxford OX1 3UQ, United Kingdom
| | - Melinda C Mills
- Leverhulme Centre for Demographic Science, Nuffield College, University of Oxford, Oxford OX1 3UQ, United Kingdom
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Kim J, Lim H, Jo HH. Do Aging and Low Fertility Reduce Carbon Emissions in Korea? Evidence from IPAT Augmented EKC Analysis. Int J Environ Res Public Health 2020; 17:E2972. [PMID: 32344741 DOI: 10.3390/ijerph17082972] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 04/20/2020] [Accepted: 04/21/2020] [Indexed: 11/16/2022]
Abstract
The purpose of this article is to empirically find the Environmental Kuznets Curve (EKC) relationship between income and carbon dioxide (CO2) emissions and to analyze the influence of population aging on such emissions. We utilize Korean regional panel data of 16 provinces during the period from 1998 to 2016. To account for the nonstationary time series in the panel, we employ a fully modified ordinary least squares (FMOLS) and estimate long-run elasticity. From the empirical results, we can find the nonlinear relationship between income and CO2 emissions. Additionally, we verify the fact that population aging reduces CO2 emissions. A 1% increase in the proportion of the elderly results in a 0.4% decrease in CO2 emissions. On the other hand, the younger population increases CO2 emissions. These results were in line with those of additional analysis on residential and transportation CO2 emissions, for the robustness check.
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35
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Kissler SM, Viboud C, Grenfell BT, Gog JR. Symbolic transfer entropy reveals the age structure of pandemic influenza transmission from high-volume influenza-like illness data. J R Soc Interface 2020; 17:20190628. [PMID: 32183640 PMCID: PMC7115222 DOI: 10.1098/rsif.2019.0628] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Existing methods to infer the relative roles of age groups in epidemic transmission can normally only accommodate a few age classes, and/or require data that are highly specific for the disease being studied. Here, symbolic transfer entropy (STE), a measure developed to identify asymmetric transfer of information between stochastic processes, is presented as a way to reveal asymmetric transmission patterns between age groups in an epidemic. STE provides a ranking of which age groups may dominate transmission, rather than a reconstruction of the explicit between-age-group transmission matrix. Using simulations, we establish that STE can identify which age groups dominate transmission even when there are differences in reporting rates between age groups and even if the data are noisy. Then, the pairwise STE is calculated between time series of influenza-like illness for 12 age groups in 884 US cities during the autumn of 2009. Elevated STE from 5 to 19 year-olds indicates that school-aged children were likely the most important transmitters of infection during the autumn wave of the 2009 pandemic in the USA. The results may be partially confounded by higher rates of physician-seeking behaviour in children compared to adults, but it is unlikely that differences in reporting rates can explain the observed differences in STE.
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Affiliation(s)
- Stephen M Kissler
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge, UK.,Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Cécile Viboud
- Fogarty International Center, National Institutes of Health, Bethesda, MA, USA
| | - Bryan T Grenfell
- Department of Ecology and Evolutionary Biology, University of Princeton, Princeton, NJ, USA
| | - Julia R Gog
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge, UK
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36
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Wilmers CC, Metz MC, Stahler DR, Kohl MT, Geremia C, Smith DW. How climate impacts the composition of wolf-killed elk in northern Yellowstone National Park. J Anim Ecol 2020; 89:1511-1519. [PMID: 32145069 PMCID: PMC7317765 DOI: 10.1111/1365-2656.13200] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 02/04/2020] [Indexed: 11/30/2022]
Abstract
While the functional response of predators is commonly measured, recent work has revealed that the age and sex composition of prey killed is often a better predictor of prey population dynamics because the reproductive value of adult females is usually higher than that of males or juveniles. Climate is often an important mediating factor in determining the composition of predator kills, but we currently lack a mechanistic understanding of how the multiple facets of climate interact with prey abundance and demography to influence the composition of predator kills. Over 20 winters, we monitored 17 wolf packs in Yellowstone National Park and recorded the sex, age and nutritional condition of kills of their dominant prey—elk—in both early and late winter periods when elk are in relatively good and relatively poor condition, respectively. Nutritional condition (as indicated by per cent marrow fat) of wolf‐killed elk varied markedly with summer plant productivity, snow water equivalent (SWE) and winter period. Moreover, marrow was poorer for wolf‐killed bulls and especially for calves than it was for cows. Wolf prey composition was influenced by a complex set of climatic and endogenous variables. In early winter, poor plant growth in either year t or t − 1, or relatively low elk abundance, increased the odds of wolves killing bulls relative to cows. Calves were most likely to get killed when elk abundance was high and when the forage productivity they experienced in utero was poor. In late winter, low SWE and a relatively large elk population increased the odds of wolves killing calves relative to cows, whereas low SWE and poor vegetation productivity 1 year prior together increased the likelihood of wolves killing a bull instead of a cow. Since climate has a strong influence on whether wolves prey on cows (who, depending on their age, are the key reproductive components of the population) or lower reproductive value of calves and bulls, our results suggest that climate can drive wolf predation to be more or less additive from year to year.
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Affiliation(s)
- Christopher C Wilmers
- Center for Integrated Spatial Research, Environmental Studies Department, University of California, Santa Cruz, CA, USA
| | - Matthew C Metz
- Yellowstone Center for Resources, Yellowstone National Park, WY, USA.,Wildlife Biology Program, Department of Ecosystem and Conservation Sciences, University of Montana, Missoula, MT, USA
| | - Daniel R Stahler
- Yellowstone Center for Resources, Yellowstone National Park, WY, USA
| | - Michel T Kohl
- Department of Wildland Resources and Ecology Center, Utah State University, Logan, UT, USA
| | - Chris Geremia
- Yellowstone Center for Resources, Yellowstone National Park, WY, USA
| | - Douglas W Smith
- Yellowstone Center for Resources, Yellowstone National Park, WY, USA
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37
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Spînu AP, Niklasson M, Zin E. Mesophication in temperate Europe: A dendrochronological reconstruction of tree succession and fires in a mixed deciduous stand in Białowieża Forest. Ecol Evol 2020; 10:1029-1041. [PMID: 32015862 PMCID: PMC6988544 DOI: 10.1002/ece3.5966] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 10/08/2019] [Accepted: 11/25/2019] [Indexed: 11/06/2022] Open
Abstract
The shift from shade-intolerant species to shade-tolerant mesophytic species in deciduous and mixed forests of the temperate zone is well described in studies from North America. This process has been termed mesophication and it has been linked to changes in fire regime. Fire suppression results in the cessation of establishment of heliophytic, fire-dependent tree species such as oak (Quercus) and pine (Pinus). Due to the scarcity of old-growth forests in Europe, data on long-term compositional changes in mixed forests are very limited, as is the number of studies exploring whether fire played a role in shaping the dynamics.The aim of this study was to reconstruct tree succession in a 43-ha natural mixed deciduous forest stand in Białowieża Forest (BF), Poland using dendrochronological methods. In addition, the presence of aboveground fire legacies (charred and fire-scarred deadwood) enabled the fire history reconstruction.Dendrochronological data revealed tree establishment (Quercus) back to the end of the 1500s and fires back to 1659. Under a regime of frequent fires until the end of the 18th century, only oak and pine regenerated, sporadically. A shift in the fire regime in the first half of the 19th century triggered oak and pine cohort regeneration, then gradually spruce (Picea) encroached. Under an increasingly dense canopy and less flammable conditions, regeneration of shade-tolerant Carpinus, Tilia, and Acer began simultaneously with the cessation of oak and pine recruitment. Synthesis. The study reports the first evidence of mesophication in temperate Europe and proves that fire was involved in shaping the long-term dynamics of mixed deciduous forest ecosystems. Our data suggest that fire exclusion promoted a gradual recruitment of fire-sensitive, shade-tolerant species that inhibited the regeneration of oak and pine in BF.
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Affiliation(s)
- Andreea P. Spînu
- Southern Swedish Forest Research CentreSwedish University of Agricultural Sciences (SLU)AlnarpSweden
- Chair of SilvicultureUniversity of FreiburgFreiburgGermany
| | - Mats Niklasson
- Southern Swedish Forest Research CentreSwedish University of Agricultural Sciences (SLU)AlnarpSweden
- Nordens Ark FoundationHunnebostrandSweden
| | - Ewa Zin
- Southern Swedish Forest Research CentreSwedish University of Agricultural Sciences (SLU)AlnarpSweden
- Department of Natural ForestsForest Research Institute (IBL)BiałowieżaPoland
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Mingazova EN, Schepin VO, Gasaynieva MM. [The characteristics of medical demographic development of the Republic of Dagestan]. Probl Sotsialnoi Gig Zdravookhranenniiai Istor Med 2019; 27:1015-1021. [PMID: 31884760 DOI: 10.32687/0869-866x-2019-27-6-1015-1021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Accepted: 10/29/2019] [Indexed: 11/06/2022]
Abstract
The issues of assessing medical and demographic processes and improving public health are very actual in Russia. The article analyzes the current state and regional characteristics of medical and demographic development using the example of the Republic of Dagestan. The positive tendency of the main fertility indicators was determined, including the analysis of the age structure of the population and population size alterations.
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Affiliation(s)
- E N Mingazova
- The Federal State Budget Scientific Institution "The N. A. Semashko National Research Institute of Public Health", 105064, Moscow, Russia, .,The Federal State Budget Institution of High Education "The Kazan State Medical University" 420012, Kazan, Russia.,The Federal State Budget Educational Institution of Higher Education "N. I. Pirogov Russian National Research Medical University" Minzdrav of Russia, 117997, Moscow, Russia
| | - V O Schepin
- The Federal State Budget Scientific Institution "The N. A. Semashko National Research Institute of Public Health", 105064, Moscow, Russia
| | - M M Gasaynieva
- The Federal State Budget Educational Institution of Higher Education "The Dagestan State Medical University", 367000, Makhachkala, Russia
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Comas M, Reguera S, Zamora-Camacho FJ, Moreno-Rueda G. Age structure of a lizard along an elevational gradient reveals nonlinear lifespan patterns with altitude. Curr Zool 2019; 66:373-382. [PMID: 32939218 PMCID: PMC7485750 DOI: 10.1093/cz/zoz063] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Accepted: 12/23/2019] [Indexed: 11/14/2022] Open
Abstract
Lifespan is one of the main components of life history. Shorter lifespans can be expected
in marginal habitats. However, in the case of ectotherms, lifespan typically increases
with altitude, even though temperature—one of the main factors to determine ectotherms’
life history—declines with elevation. This pattern can be explained by the fact that a
shorter activity time favors survival. In this study, we analyzed how lifespan and other
life-history traits of the lizard Psammodromus algirus vary along a
2,200 m elevational gradient in Sierra Nevada (SE Spain). Populations at intermediate
altitudes (1,200–1,700 m), corresponding to the optimal habitat for this species, had the
shortest lifespans, whereas populations inhabiting marginal habitats (at both low and at
high altitudes) lived longest. Therefore, this lizard did not follow the typical pattern
of ectotherms, as it also lived longer at the lower limit of its distribution, nor did it
show a longer lifespan in areas with optimal habitats. These results might be explained by
a complex combination of different gradients along the mountain, namely that activity time
decreases with altitude whereas food availability increases. This could explain why
lifespan was maximum at both high (limited activity time) and low (limited food
availability) altitudes, resulting in similar lifespans in areas with contrasting
environmental conditions. Our findings also indicated that reproductive investment and
body condition increase with elevation, suggesting that alpine populations are locally
adapted.
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Affiliation(s)
- Mar Comas
- Departamento de Zoología, Facultad de Ciencias, Universidad de Granada, Granada, E-18071, Spain.,Estación Biológica de Doñana (EBD-CSIC), Américo Vespucio 26, Sevilla, E-41092, Spain
| | - Senda Reguera
- Departamento de Zoología, Facultad de Ciencias, Universidad de Granada, Granada, E-18071, Spain
| | - Francisco J Zamora-Camacho
- Departamento de Zoología, Facultad de Ciencias, Universidad de Granada, Granada, E-18071, Spain.,Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
| | - Gregorio Moreno-Rueda
- Departamento de Zoología, Facultad de Ciencias, Universidad de Granada, Granada, E-18071, Spain
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Abstract
Backward bifurcation has significant implications for disease control. Deriving necessary and sufficient conditions for backward bifurcation is of paramount importance to understand the reasons for its occurrence and devise effective control strategies. In this paper, we review the methods that lead to necessary and sufficient conditions for backward bifurcation in infectious disease models. We review separately the methods that apply to ODEs and methods that apply to PDEs. We further propose a new method, applicable to both ODEs and PDEs. We illustrate the methods on three examples: a novel ODE model of cholera with vaccination, a PDE version of the cholera model with vaccination, and on an eight equation model of dengue, taken from the literature.
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Affiliation(s)
- Maia Martcheva
- a Department of Mathematics, University of Florida , Gainesville , FL , USA
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Lin J, Xu R, Tian X. Global dynamics of an age-structured cholera model with multiple transmissions, saturation incidence and imperfect vaccination. J Biol Dyn 2019; 13:69-102. [PMID: 30696390 DOI: 10.1080/17513758.2019.1570362] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Accepted: 01/06/2019] [Indexed: 06/09/2023]
Abstract
In this paper, an age-structured cholera model with multiple transmissions, saturation incidence and imperfect vaccination is proposed. In the model, we consider both the infection age of infected individuals and the biological age of Vibrio cholerae in the aquatic environment. Asymptotic smoothness is verified as a necessary argument. By analysing the characteristic equations, the local stability of disease-free and endemic steady states is established. By using Lyapunov functionals and LaSalle's invariance principle, it is proved that the global dynamics of the model can be completely determined by basic reproduction number. The study of optimal control helps us seek cost-effective solutions of time-dependent vaccination strategy against cholera outbreaks. Numerical simulations are carried out to illustrate the corresponding theoretical results.
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Affiliation(s)
- Jiazhe Lin
- a Institute of Applied Mathematics , Army Engineering University , Shijiazhuang , People's Republic of China
| | - Rui Xu
- b Complex Systems Research Center , Shanxi University , Taiyuan , People's Republic of China
- c Shanxi Key Laboratory of Mathematical Techniques and Big Data Analysis on Disease Control and Prevention , Shanxi University , Taiyuan , People's Republic of China
| | - Xiaohong Tian
- b Complex Systems Research Center , Shanxi University , Taiyuan , People's Republic of China
- c Shanxi Key Laboratory of Mathematical Techniques and Big Data Analysis on Disease Control and Prevention , Shanxi University , Taiyuan , People's Republic of China
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Lee AM, Myhre AM, Markussen SS, Engen S, Solberg EJ, Haanes H, Røed K, Herfindal I, Heim M, Saether BE. Decomposing demographic contributions to the effective population size with moose as a case study. Mol Ecol 2019; 29:56-70. [PMID: 31732991 DOI: 10.1111/mec.15309] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 11/01/2019] [Accepted: 11/06/2019] [Indexed: 11/30/2022]
Abstract
Levels of random genetic drift are influenced by demographic factors, such as mating system, sex ratio and age structure. The effective population size (Ne ) is a useful measure for quantifying genetic drift. Evaluating relative contributions of different demographic factors to Ne is therefore important to identify what makes a population vulnerable to loss of genetic variation. Until recently, models for estimating Ne have required many simplifying assumptions, making them unsuitable for this task. Here, using data from a small, harvested moose population, we demonstrate the use of a stochastic demographic framework allowing for fluctuations in both population size and age distribution to estimate and decompose the total demographic variance and hence the ratio of effective to total population size (Ne /N) into components originating from sex, age, survival and reproduction. We not only show which components contribute most to Ne /N currently, but also which components have the greatest potential for changing Ne /N. In this relatively long-lived polygynous system we show that Ne /N is most sensitive to the demographic variance of older males, and that both reproductive autocorrelations (i.e., a tendency for the same individuals to be successful several years in a row) and covariance between survival and reproduction contribute to decreasing Ne /N (increasing genetic drift). These conditions are common in nature and can be caused by common hunting strategies. Thus, the framework presented here has great potential to increase our understanding of the demographic processes that contribute to genetic drift and viability of populations, and to inform management decisions.
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Affiliation(s)
- Aline Magdalena Lee
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Ane Marlene Myhre
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Stine Svalheim Markussen
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Steinar Engen
- Centre for Biodiversity Dynamics, Department of Mathematical Sciences, Norwegian University of Science and Technology, Trondheim, Norway
| | | | - Hallvard Haanes
- Norwegian Radiation and Nuclear Safety Authority (DSA), Oslo, Norway
| | - Knut Røed
- Department of Basic Sciences and Aquatic Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Ivar Herfindal
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Morten Heim
- Norwegian Institute for Nature Research (NINA), Trondheim, Norway
| | - Bernt-Erik Saether
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
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Gruzieva TS, Diachuk MD, Inshakova HV, Zamkevych VB. Modern demographic trends in Ukraine as a ground for realization of prevention strategies. Wiad Lek 2019; 72:2033-2039. [PMID: 31983148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
INTRODUCTION The data of the world statistics show that the process of demographic ageing becomes significant in modern conditions, and the number of elderly people annually increases by 3%. Owing to the global tendencies for ageing, the health care and social security systems are facing important challenges to ensure healthy lives and promote the well-being for this segment of population, provide affordable and quality medical care according to needs. THE AIM Establishing modern peculiarities and trends of medical and demographic situation in Ukraine in the context of ageing population in order to substantiate medical and preventive measures. MATERIAL AND METHODS According to the data of the State Service of Statistics of Ukraine of the Ministry of Public Health for 1990-2017 the tendencies of medical and demographic characteristics of the population of Ukraine have been identified. The national medical and demographic indicators have been compared with the indicators of the countries of WHO European Region according to the data of the European Database “Health for everybody”. Using the least squares method, a forecast of the Ukrainian population and its age structure for the period up to 2030 has been made. REVIEW A tendency for Ukrainian population decline by 18,1% over the course of 1990-2017, which is caused by, along with other reasons, decrease in population birth rate by 25,4% and increase in mortality by 19,8%, has been identified. A steady tendency for a decline in the proportion of children’s population up to the age 14 years inclusive for the twenty-seven-year period from 21,5% till 15,5%, and for an increase in the proportion of population aged more than 60 years from 18,3 till 22,9% has been detected. The share of people over 65 in the age structure of population has increased from 12,0% till 16,5%. The analysis of regional indicators confirms that there are unfavorable demographic tendencies in the southeastern, northeastern and central provinces, and more favorable tendencies in the provinces of the West Region of the country. The proportion of children’s population up to the age 14 years inclusive was in Ukraine close to the indicator in the countries of European Union and less than the average in WHO European Region (17,8%), the proportion of people over 65 - close to European regional indicator (15,5%) and less than the indicator in the countries of European Union (19,0%). A forecast of the population and its age structure up to 2030 has been made, according to which less than 40 million will live in Ukraine, and the proportion of persons over 65 years will reach 19,1%. CONCLUSIONS The tendencies for Ukrainian population decline and changes in its age structure towards ageing make it necessary to take measures to prevent negative medical and demographic trends and provide conditions for healthy ageing, to increase the affordability and quality of medical care, including for persons of senior age groups, and improve the work of health care facilities on prophylaxis of diseases.
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Affiliation(s)
- Tetiana S Gruzieva
- Bogomolets National Medical University, Kyiv, Ukraine
- State Institution of Science «Research And Practical Center of Preventive and Clinical Medicine» State Administrative Department, Kyiv, Ukraine
| | - Mykhailo D Diachuk
- Bogomolets National Medical University, Kyiv, Ukraine
- State Institution of Science «Research And Practical Center of Preventive and Clinical Medicine» State Administrative Department, Kyiv, Ukraine
| | - Hanna V Inshakova
- Bogomolets National Medical University, Kyiv, Ukraine
- State Institution of Science «Research And Practical Center of Preventive and Clinical Medicine» State Administrative Department, Kyiv, Ukraine
| | - Viktoria B Zamkevych
- Bogomolets National Medical University, Kyiv, Ukraine
- State Institution of Science «Research And Practical Center of Preventive and Clinical Medicine» State Administrative Department, Kyiv, Ukraine
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Kaplan KA, Yamane L, Botsford LW, Baskett ML, Hastings A, Worden S, White JW. Setting expected timelines of fished population recovery for the adaptive management of a marine protected area network. Ecol Appl 2019; 29:e01949. [PMID: 31188493 PMCID: PMC9285580 DOI: 10.1002/eap.1949] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 04/15/2019] [Accepted: 05/17/2019] [Indexed: 05/19/2023]
Abstract
Adaptive management of marine protected areas (MPAs) requires developing methods to evaluate whether monitoring data indicate that they are performing as expected. Modeling the expected responses of targeted species to an MPA network, with a clear timeline for those expectations, can aid in the development of a monitoring program that efficiently evaluates expectations over appropriate time frames. Here, we describe the expected trajectories in abundance and biomass following MPA implementation for populations of 19 nearshore fishery species in California. To capture the process of filling in the age structure truncated by fishing, we used age-structured population models with stochastic larval recruitment to predict responses to MPA implementation. We implemented both demographically open (high larval immigration) and closed (high self-recruitment) populations to model the range of possible trajectories as they depend on recruitment dynamics. From these simulations, we quantified the time scales over which anticipated increases in abundance and biomass inside MPAs would become statistically detectable. Predicted population biomass responses range from little change, for species with low fishing rates, to increasing by a factor of nearly seven, for species with high fishing rates before MPA establishment. Increases in biomass following MPA implementation are usually greater in both magnitude and statistical detectability than increases in abundance. For most species, increases in abundance would not begin to become detectable for at least 10 years after implementation. Overall, these results inform potential indicator metrics (biomass), potential indicator species (those with a high fishing : natural mortality ratio), and time frame (>10 yr) for MPA monitoring assessment as part of the adaptive management process.
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Affiliation(s)
- Katherine A. Kaplan
- Department of Evolution and Ecology, Coastal and Marine Sciences InstituteUniversity of California DavisOne Shields AvenueDavisCalifornia95616USA
- California Department of Fish and WildlifeMarine Region350 Harbor BoulevardBelmontCalifornia94002USA
| | - Lauren Yamane
- Department of Evolution and Ecology, Coastal and Marine Sciences InstituteUniversity of California DavisOne Shields AvenueDavisCalifornia95616USA
- California Department of Fish and WildlifeMarine Region350 Harbor BoulevardBelmontCalifornia94002USA
| | - Louis W. Botsford
- Department of WildlifeFish and Conservation BiologyUniversity of California DavisOne Shields AvenueDavisCalifornia95616USA
| | - Marissa L. Baskett
- Department of Environmental Science and PolicyUniversity of California DavisOne Shields AvenueDavisCalifornia95616USA
| | - Alan Hastings
- Department of Environmental Science and PolicyUniversity of California DavisOne Shields AvenueDavisCalifornia95616USA
| | - Sara Worden
- California Department of Fish and WildlifeMarine Region350 Harbor BoulevardBelmontCalifornia94002USA
| | - J. Wilson White
- Department of Fisheries and WildlifeCoastal Oregon Marine Experiment StationOregon State UniversityNewportOregon97365USA
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Abstract
In this paper, we investigate an SIRS epidemic model with chronological age structure in a demographic steady state. Although the age-structured SIRS model is a simple extension of the well-known age-structured SIR epidemic model, we have to develop new technique to deal with problems due to the reversion of susceptibility for recovered individuals. First we give a standard proof for the well-posedness of the normalized age-structured SIRS model. Next we examine existence of endemic steady states by fixed point arguments and bifurcation method, where we introduce the next generation operator and the basic reproduction number R0 to formulate endemic threshold results. Thirdly we investigate stability of steady states by the bifurcation calculation and the comparison method, and we show existence of a compact attractor and discuss the global behavior based on the population persistence theory. Finally we give some numerical examples and discuss the effect of mass-vaccination on R0 and the critical coverage of immunization based on the reinfection threshold.
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Affiliation(s)
- Kento Okuwa
- Graduate School of Mathematical Sciences, The University of Tokyo, 3-8-1 Komaba Meguro-ku Tokyo 153-8914 Japan
| | - Hisashi Inaba
- Graduate School of Mathematical Sciences, The University of Tokyo, 3-8-1 Komaba Meguro-ku Tokyo 153-8914 Japan
| | - Toshikazu Kuniya
- Graduate School of System Informatics, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501 Japan
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46
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Lutz W, Crespo Cuaresma J, Kebede E, Prskawetz A, Sanderson WC, Striessnig E. Education rather than age structure brings demographic dividend. Proc Natl Acad Sci U S A 2019; 116:12798-803. [PMID: 31182606 DOI: 10.1073/pnas.1820362116] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The relationship between population changes and economic growth has been debated since Malthus. Initially focusing on population growth, the notion of demographic dividend has shifted the attention to changes in age structures with an assumed window of opportunity that opens when falling birth rates lead to a relatively higher proportion of the working-age population. This has become the dominant paradigm in the field of population and development, and an advocacy tool for highlighting the benefits of family planning and fertility decline. While this view acknowledges that the dividend can only be realized if associated with investments in human capital, its causal trigger is still seen in exogenous fertility decline. In contrast, unified growth theory has established human capital as a trigger of both demographic transition and economic growth. We assess the relative importance of changing age structure and increasing human capital for economic growth for a panel of 165 countries during the time period of 1980-2015. The results show a clear dominance of improving education over age structure and give evidence that the demographic dividend is driven by human capital. Declining youth dependency ratios even show negative impacts on income growth when combined with low education. Based on a multidimensional understanding of demography that considers education in addition to age, and with a view to the additional effects of education on health and general resilience, we conclude that the true demographic dividend is a human capital dividend. Global population policies should thus focus on strengthening the human resource base for sustainable development.
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Abstract
Motivated by an age-structured population model over two patches that assumes constant dispersal rates, we derive a modified model that allows density-dependent dispersal, which contains both nonlinear dispersal terms and delayed non-local birth terms resulted from the mobility of the immature individuals between the patches. A biologically meaningful assumption that the dispersal rate during the immature period depends only on the mature population enables us investigate the model theoretically. Well-posedness is confirmed, criteria for existence of a positive equilibrium are obtained, threshold for extinction/persistence is established. Also addressed are a positive invariant set and global convergence of solutions under certain conditions. Although the levels of the density- dependent dispersals play no role in determining extinction/persistence, our numerical results show that they can affect, when the population is persistent, the long term dynamics including the temporal- spatial patterns and the final population sizes.
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Affiliation(s)
- Chang-Yuan Cheng
- Department of Applied Mathematics, National Pingtung University, Pingtung, ROC 90003, Taiwan
| | - Shyan-Shiou Chen
- Department of Mathematics, National Taiwan Normal University, Taipei, ROC11677, Taiwan
| | - Xing Fu Zou
- Department of Applied Mathematics, University of Western Ontario, London, ON, N6A 5B7, Canada
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48
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Ben-Ami F. Host Age Effects in Invertebrates: Epidemiological, Ecological, and Evolutionary Implications. Trends Parasitol 2019; 35:466-480. [PMID: 31003758 DOI: 10.1016/j.pt.2019.03.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 03/19/2019] [Accepted: 03/21/2019] [Indexed: 12/26/2022]
Abstract
In most species, variation in age among individuals is the strongest and most visible form of phenotypic variation. Individual-level age effects on disease traits, caused by differences in the age at exposure of the host or its parents, have been widely documented in invertebrates. They can influence diverse traits, such as host susceptibility, virulence, parasite reproduction and further transmission, and may cascade to the population level, influencing disease prevalence and within-host competition. Here, I summarize what is known about the relationship between individual-level age/stage effects and infectious disease in invertebrates. I also attempt to link age effects to the theory of aging (senescence), and highlight the importance of population age structure to disease epidemiology and evolution. I conclude by identifying gaps in our understanding of individual- and population-level age effects in invertebrates. As the age structure of populations varies across space and time, age effects have strong epidemiological, ecological, and evolutionary implications for explaining variation in infectious diseases of invertebrates.
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Affiliation(s)
- Frida Ben-Ami
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
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49
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Gianeti MD, Santana FM, Yokota L, Vasconcelos JE, Dias JF, Lessa RP. Age structure and multi-model growth estimation of longnose stingray Hypanus guttatus (Dasyatidae: Myliobatoidei) from north-east Brazil. J Fish Biol 2019; 94:481-488. [PMID: 30702144 DOI: 10.1111/jfb.13918] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 01/30/2019] [Indexed: 06/09/2023]
Abstract
We collected 729 Hypanus guttatus from the northern coast of the state of Rio Grande do Norte (RN), of which 196 were used to estimate age and growth. Ninety-five were male (12.7 to 57.0 cm disc width; WD ) and 101 were female (13.0 to 88.5 cm WD ); females were significantly larger than males. Cross sections of vertebrae showed band-pairs ranging from 0 to > 14 in females and from 0 to 9 in males. New-borns presented an opaque edge at birth in vertebrae without a birthmark. The average percentage of error (APE; %E) for the entire sample provided evidence that ages were repeatable. The mean monthly marginal increment (IM ) indicates annual band-pair formation from August to November. The annual cycle model for one band-pair deposition provided the best fit to data based on the AIC, with peaks between August and October, similar to that found in the IM analysis, suggesting an annual formation pattern. A multi-model approach that included four models based on the observed mean WD at age indicated a modified von Bertalanffy growth model as the best for describing the species growth: W0 (WD at birth) = 14.6 cm for both sexes; females W∞ = 98.61 cm (95% CI = 87.34-114.61 cm); k = 0.112 year-1 (CI = 0.086-0.148 year-1 ); males W∞ = 60.22 cm (CI = 55.66-65.35 cm); k = 0.219 year-1 (CI = 0.185-0.276 year-1 ). The age-at-maturity in males and females is 5 years and 7 years, respectively. The age composition shows that most (84%) specimens were aged 0 to 2 years. The information provided here is essential for analytical assessments of H. guttatus, which is subject to significant fishing pressure mainly on new-borns and juveniles.
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Affiliation(s)
- Michel D Gianeti
- Laboratório de Ecologia da Reprodução e do Recrutamento de Organismos Marinhos, Departamento de Oceanografia Biológica, Instituto Oceanográfico (IO), Universidade de São Paulo (USP), São Paulo, Brazil
- Laboratório de Ictiologia, Museu de Zoologia, Universidade de São Paulo (USP), São Paulo, Brazil
| | - Francisco M Santana
- Laboratório de Dinâmica de Populações Marinhas (DIMAR), Departamento de Pesca e Aquicultura (DEPAq), Universidade Federal Rural de Pernambuco (UFRPE), Recife, Brazil
- Laboratório de Dinâmica de Populações Aquáticas (DAQUA), Unidade Acadêmica de Serra Talhada (UAST), Universidade Federal Rural de Pernambuco (UFRPE), Serra Talhada, Brazil
| | - Leandro Yokota
- Departamento de Zoologia, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Rio Claro, Brazil
| | - Jonas E Vasconcelos
- Laboratório de Dinâmica de Populações Marinhas (DIMAR), Departamento de Pesca e Aquicultura (DEPAq), Universidade Federal Rural de Pernambuco (UFRPE), Recife, Brazil
| | - June F Dias
- Laboratório de Ecologia da Reprodução e do Recrutamento de Organismos Marinhos, Departamento de Oceanografia Biológica, Instituto Oceanográfico (IO), Universidade de São Paulo (USP), São Paulo, Brazil
| | - Rosangela P Lessa
- Laboratório de Dinâmica de Populações Marinhas (DIMAR), Departamento de Pesca e Aquicultura (DEPAq), Universidade Federal Rural de Pernambuco (UFRPE), Recife, Brazil
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50
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Tonkin Z, Lyon JP, Moloney P, Balcombe SR, Hackett G. Spawning-stock characteristics and migration of a lake-bound population of the endangered Macquarie perch Macquaria australasica. J Fish Biol 2018; 93:630-640. [PMID: 29956321 DOI: 10.1111/jfb.13731] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 06/14/2018] [Indexed: 06/08/2023]
Abstract
The intrapopulation variability in the size and age structure of the spawning stock and migration of the threatened Macquarie perch Macquaria australasica in Lake Dartmouth was investigated between 2008 and 2016. Sampling centred on the core reproductive period (October-December) when mature fish migrate from the lake into riverine habitat to spawn. Spawning fish were predominantly large, spanning a broad age structure, with a high proportion of fish (25%) aged 15-30 years. The overall median size of spawning fish did not change for males or females during the 9 year study period. The size of the smaller mature male fish did change in some years suggesting a small proportion of male M. australasica matured at age 1+ and 2+. Acoustic telemetry employed over 3 years showed that M. australasica were most likely to be in the spawning reach from October to mid-December, migrated to this reach annually and moved large distances throughout the lake all year, with no evidence for any spatial structuring. Mature fish sometimes occupied the spawning reach for several months after the core reproductive period, which increased their vulnerability to recreational fishing. Males tagged in the lake were seldom recorded in the spawning reach, presumably because a high proportion had not yet entered the spawning stock despite their size suggesting maturity. Maintaining a broad age and size-structure of the spawning stock of long-lived iteroparous fish species is crucial for recruitment stability and population persistence. Overexploitation of the spawning stock has probably contributed to previous population declines in the lake as well as the collapse of other M. australasica populations in south-eastern Australia.
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Affiliation(s)
- Zeb Tonkin
- Arthur Rylah Institute for Environmental Research, Department of Environment, Land Water and Planning, Heidelberg, Victoria, Australia
- Australian Rivers Institute, Griffith University, Nathan, Queensland, Australia
| | - Jarod P Lyon
- Arthur Rylah Institute for Environmental Research, Department of Environment, Land Water and Planning, Heidelberg, Victoria, Australia
| | - Paul Moloney
- Arthur Rylah Institute for Environmental Research, Department of Environment, Land Water and Planning, Heidelberg, Victoria, Australia
| | - Stephen R Balcombe
- Australian Rivers Institute, Griffith University, Nathan, Queensland, Australia
| | - Graeme Hackett
- Arthur Rylah Institute for Environmental Research, Department of Environment, Land Water and Planning, Heidelberg, Victoria, Australia
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