1
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Chen Y, Liu Y, Wang Y, Zhang Y, Xie W, Zhang H, Weng Q, Xu M. Expression of cholesterol synthesis and steroidogenic markers in females of the Chinese brown frog ( Rana dybowskii) during prespawning and prehibernation. Am J Physiol Regul Integr Comp Physiol 2023; 325:R750-R758. [PMID: 37867473 DOI: 10.1152/ajpregu.00296.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 01/13/2023] [Accepted: 01/13/2023] [Indexed: 10/24/2023]
Abstract
The oviduct of the Chinese brown frog (Rana dybowskii) expands in prehibernation rather than in prespawning, which is one of the physiological phenomena that occur in the preparation for hibernation. Steroid hormones are known to regulate oviductal development. Cholesterol synthesis and steroidogenesis may play an important role in the expansion of the oviduct before hibernation. In this study, we investigated the expression patterns of the markers that are involved in the de novo steroid synthesis pathway in the oviduct of R. dybowskii during prespawning and prehibernation. According to histological analysis, the oviduct of R. dybowskii contains epithelial cells, glandular cells, and tubule lumens. During prehibernation, oviductal pipe diameter and weight were significantly larger than during prespawning. 3-Hydroxy-3-methylglutaryl CoA reductase (HMGCR), low-density lipoprotein receptor (LDLR), steroidogenic acute regulatory protein (StAR), cytochrome P450 cholesterol side-chain cleavage enzyme (P450scc), and steroidogenic factor 1 (SF-1) were detected in epithelial cells in prehibernation and glandular cells during prespawning. HMGCR, LDLR, StAR, and P450scc protein expression levels were higher in prehibernation than during prespawning, but the SF-1 protein expression level did not significantly differ. HMGCR, LDLR, StAR, P450scc (CYP11A1), and SF-1 (NR5A1) mRNA expression levels were significantly higher in prehibernation compared with prespawning. The transcriptome results showed that the steroid synthesis pathway was highly expressed during prehibernation. Existing results indicate that the oviduct is able to synthesize steroid hormones using cholesterol, and that steroid hormones may affect the oviductal functions of R. dybowskii.
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Affiliation(s)
- Yuan Chen
- Laboratory of Animal Physiology, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, People's Republic of China
- Beijing Key Laboratory of Food Processing and Safety in Forestry, Beijing Forestry University, Beijing, People's Republic of China
| | - Yuning Liu
- Laboratory of Animal Physiology, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, People's Republic of China
| | - Yankun Wang
- Laboratory of Animal Physiology, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, People's Republic of China
- Beijing Key Laboratory of Food Processing and Safety in Forestry, Beijing Forestry University, Beijing, People's Republic of China
| | - Yue Zhang
- Laboratory of Animal Physiology, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, People's Republic of China
- Beijing Key Laboratory of Food Processing and Safety in Forestry, Beijing Forestry University, Beijing, People's Republic of China
| | - Wenqian Xie
- Laboratory of Animal Physiology, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, People's Republic of China
| | - Haolin Zhang
- Laboratory of Animal Physiology, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, People's Republic of China
| | - Qiang Weng
- Laboratory of Animal Physiology, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, People's Republic of China
| | - Meiyu Xu
- Laboratory of Animal Physiology, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, People's Republic of China
- Beijing Key Laboratory of Food Processing and Safety in Forestry, Beijing Forestry University, Beijing, People's Republic of China
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2
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Layton‐Matthews K, Reiertsen TK, Erikstad K, Anker‐Nilssen T, Daunt F, Wanless S, Barrett RT, Newell MA, Harris MP. Consequences of cross-season demographic correlations for population viability. Ecol Evol 2023; 13:e10312. [PMID: 37456077 PMCID: PMC10338798 DOI: 10.1002/ece3.10312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 04/20/2023] [Accepted: 07/02/2023] [Indexed: 07/18/2023] Open
Abstract
Demographic correlations are pervasive in wildlife populations and can represent important secondary drivers of population growth. Empirical evidence suggests that correlations are in general positive for long-lived species, but little is known about the degree of variation among spatially segregated populations of the same species in relation to environmental conditions. We assessed the relative importance of two cross-season correlations in survival and productivity, for three Atlantic puffin (Fratercula arctica) populations with contrasting population trajectories and non-overlapping year-round distributions. The two correlations reflected either a relationship between adult survival prior to breeding on productivity, or a relationship between productivity and adult survival the subsequent year. Demographic rates and their correlations were estimated with an integrated population model, and their respective contributions to variation in population growth were calculated using a transient-life table response experiment. For all three populations, demographic correlations were positive at both time lags, although their strength differed. Given the different year-round distributions of these populations, this variation in the strength population-level demographic correlations points to environmental conditions as an important driver of demographic variation through life-history constraints. Consequently, the contributions of variances and correlations in demographic rates to population growth rates differed among puffin populations, which has implications for-particularly small-populations' viability under environmental change as positive correlations tend to reduce the stochastic population growth rate.
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Affiliation(s)
| | | | - Kjell‐Einar Erikstad
- Norwegian Institute for Nature ResearchFRAM CentreTromsøNorway
- Centre for Biodiversity Dynamics CBDNorwegian University of Science and TechnologyTrondheimNorway
| | | | - Francis Daunt
- UK Centre for Ecology & Hydrology, Bush EstatePenicuikUK
| | - Sarah Wanless
- UK Centre for Ecology & Hydrology, Bush EstatePenicuikUK
| | | | - Mark A. Newell
- UK Centre for Ecology & Hydrology, Bush EstatePenicuikUK
| | - Mike P. Harris
- UK Centre for Ecology & Hydrology, Bush EstatePenicuikUK
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3
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Amorim F, Pita R, Mata VA, Beja P, Rebelo H. Crowding after sudden habitat loss affects demography and social structure in a bat population. J Anim Ecol 2022; 91:668-680. [PMID: 34990018 DOI: 10.1111/1365-2656.13659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 12/21/2021] [Indexed: 11/28/2022]
Abstract
The sudden loss of habitats due to natural or anthropogenic disturbances causes displacement of mobile animals from affected areas to refuge habitats, where large but often transitory concentrations of individuals may occur. While these local density increases have been previously described, the hypothesis that crowding disrupts demographic processes remains largely untested. Here we used the sudden flooding of a river valley by a hydroelectric reservoir as a quasi-experiment to investigate the consequences of crowding on demography, fecundity, and social structure in the European free-tailed bat (Tadarida teniotis). We monitored bat populations at roosts near and far from the flooded area, before (2013-2014), during (2015) and after (2016) habitat flooding. We assessed population demographic parameters using Capture-Mark-Recapture (CMR) models (3821 PIT-tagged individuals), and used genetic relatedness among individuals (1407 individuals genotyped for 14 microsatellite markers) to infer changes in social structure. Habitat loss through flooding was associated with significant but transitory increases in the number of bats using nearby roosts. This may be related to the higher probability of individuals arriving at those roosts during flooding, together with increases in individual local residency through time, particularly among males. Individual apparent survival was highest during flooding and lowest in the following year, while the probability of leaving a roost safe from flooding was higher near the impact area than farther away. Crowding did not negatively affect fecundity, but the arrival of new individuals led to changes in social structure as revealed by lower genetic relatedness between individuals after disturbance at roosts near the flooding area, but not in those farther afield. Our study documents a clear example of crowding effects, suggesting that bats losing roosts due to a hydroelectric reservoir moved to alternative roosts, where local increases in population size and the arrival of new individuals reduced genetic relatedness and apparent survival, but not fecundity. These results support the hypothesis that crowding after habitat loss can disrupt population processes, even though effects may be subtle and short-lived. Also, they point out the need to duly consider crowding effects when assessing and mitigating anthropogenic impacts on animal populations.
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Affiliation(s)
- Francisco Amorim
- CIBIO-InBIO, Research Center in Biodiversity and Genetic Resources, University of Porto, Vairão, Portugal.,Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal.,BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal
| | - Ricardo Pita
- MED - Mediterranean Institute for Agriculture, Environment and Development, Unidade de Biologia da Conservação, Universidade de Évora
| | - Vanessa A Mata
- CIBIO-InBIO, Research Center in Biodiversity and Genetic Resources, University of Porto, Vairão, Portugal.,BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal
| | - Pedro Beja
- CIBIO-InBIO, Research Center in Biodiversity and Genetic Resources, University of Porto, Vairão, Portugal.,BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal.,CIBIO-InBIO, Research Center in Biodiversity and Genetic Resources, Institute of Agronomy, University of Lisbon, Lisbon, Portugal
| | - Hugo Rebelo
- CIBIO-InBIO, Research Center in Biodiversity and Genetic Resources, University of Porto, Vairão, Portugal.,BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal.,CIBIO-InBIO, Research Center in Biodiversity and Genetic Resources, Institute of Agronomy, University of Lisbon, Lisbon, Portugal
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4
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Bawa SA, Gregg PC, Del Soccoro AP, Miller C, Andrew NR. Estimating the differences in critical thermal maximum and metabolic rate of Helicoverpa punctigera (Wallengren) (Lepidoptera: Noctuidae) across life stages. PeerJ 2021; 9:e12479. [PMID: 34820201 PMCID: PMC8605760 DOI: 10.7717/peerj.12479] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 10/21/2021] [Indexed: 11/22/2022] Open
Abstract
Temperature is a crucial driver of insect activity and physiological processes throughout their life-history, and heat stress may impact life stages (larvae, pupae and adult) in different ways. Using thermolimit respirometry, we assessed the critical thermal maxima (CTmax-temperature at which an organism loses neuromuscular control), CO2 emission rate (V́CO2) and Q10 (a measure of V́CO2 temperature sensitivity) of three different life stages of Helicoverpa punctigera (Wallengren) by increasing their temperature exposure from 25 °C to 55 °C at a rate of 0.25 °C min−1. We found that the CTmax of larvae (49.1 °C ± 0.3 °C) was higher than pupae (47.4 °C ± 0.2 °C) and adults (46.9 °C ± 0.2 °C). The mean mass-specific CO2 emission rate (ml V́CO2 h−1) of larvae (0.26 ± 0.03 ml V́CO2 h−1) was also higher than adults (0.24 ± 0.04 ml V́CO2 h−1) and pupae (0.06 ± 0.02 ml V́CO2 h−1). The Q10: 25–35 °C for adults (2.01 ± 0.22) was significantly higher compared to larvae (1.40 ± 0.06) and Q10: 35–45 °C for adults (3.42 ± 0.24) was significantly higher compared to larvae (1.95 ± 0.08) and pupae (1.42 ± 0.98) respectively. We have established the upper thermal tolerance of H. punctigera, which will lead to a better understanding of the thermal physiology of this species both in its native range, and as a pest species in agricultural systems.
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Affiliation(s)
- Samuel A Bawa
- Zoology, Insect Ecology Laboratory, University of New England, Armidale, NSW, Australia.,Asuansi Agric. Station, Cape Coast, Central Region, Ghana
| | - Peter C Gregg
- Agronomy and Soil Science, University of New England, Armidale, NSW, Australia
| | - Alice P Del Soccoro
- Agronomy and Soil Science, University of New England, Armidale, NSW, Australia
| | - Cara Miller
- Science and Technology, University of New England, Armidale, NSW, Australia
| | - Nigel R Andrew
- Zoology, Insect Ecology Laboratory, University of New England, Armidale, NSW, Australia
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5
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Burant JB, Park C, Betini GS, Norris DR. Early warning indicators of population collapse in a seasonal environment. J Anim Ecol 2021; 90:1538-1549. [PMID: 33713444 DOI: 10.1111/1365-2656.13474] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 02/26/2021] [Indexed: 01/03/2023]
Abstract
Recent studies have demonstrated that generic statistical signals derived from time series of population abundance and fitness-related traits of individuals can provide reliable indicators of impending shifts in population dynamics. However, how the seasonal timing of environmental stressors influences these early warning indicators is not well understood. The goal of this study was to experimentally assess whether the timing of stressors influences the production, detection and sensitivity of abundance- and trait-based early warning indicators derived from declining populations. In a multi-generation, season-specific habitat loss experiment, we exposed replicate populations of Drosophila melanogaster to one of two rates of chronic habitat loss (10% or 20% per generation) in either the breeding or the non-breeding period. We counted population abundance at the beginning of each season, and measured body mass and activity levels in a sample of individuals at the end of each generation. When habitat was lost during the breeding period, declining populations produced signals consistent with those documented in previous studies. Inclusion of trait-based indicators generally improved the detection of impending population collapse. However, when habitat was lost during the non-breeding period, the predictive capacity of these indicators was comparatively diminished. Our results have important implications for interpreting signals in the wild because they suggest that the production and detection of early warning indicators depends on the season in which stressors occur, and that this is likely related to the capacity of populations to respond numerically the following season.
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Affiliation(s)
- Joseph B Burant
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada
| | - Candace Park
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada
| | - Gustavo S Betini
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada
| | - D Ryan Norris
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada.,Nature Conservancy of Canada, Toronto, ON, Canada
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6
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Sutton AO, Strickland D, Freeman NE, Norris DR. Climate-driven carry-over effects negatively influence population growth rate in a food-caching boreal passerine. GLOBAL CHANGE BIOLOGY 2020; 27:983-992. [PMID: 33347694 DOI: 10.1111/gcb.15445] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 10/19/2020] [Accepted: 10/28/2020] [Indexed: 06/12/2023]
Abstract
Understanding how events throughout the annual cycle are linked is important for predicting variation in individual fitness, but whether and how carry-over effects scale up to influence population dynamics is poorly understood. Using 38 years of demographic data from Algonquin Provincial Park, Ontario, and a full annual cycle integrated population model, we examined the influence of environmental conditions and density on the population growth rate of Canada jays (Perisoreus canadensis), a resident boreal passerine that relies on perishable cached food for over-winter survival and late-winter breeding. Our results demonstrate that fall environmental variables, most notably the number of freeze-thaw events, carried over to influence late-winter fecundity, which, in turn, was the main vital rate driving population growth. These results are consistent with the hypothesis that warmer and more variable fall conditions accelerate the degradation of perishable stored food that is relied upon for successful reproduction. Future warming during the fall and winter may compromise the viability of cached food that requires consistent subzero temperatures for effective preservation, potentially exacerbating climate-driven carry-over effects that impact long-term population dynamics.
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Affiliation(s)
- Alex O Sutton
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada
| | | | - Nikole E Freeman
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada
| | - D Ryan Norris
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada
- Nature Conservancy of Canada, Toronto, ON, Canada
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7
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White ER, Hastings A. Seasonality in ecology: Progress and prospects in theory. ECOLOGICAL COMPLEXITY 2020. [DOI: 10.1016/j.ecocom.2020.100867] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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8
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Burant JB, Griffin A, Betini GS, Norris DR. An experimental test of the ecological mechanisms driving density-mediated carry-over effects in a seasonal population. CAN J ZOOL 2020. [DOI: 10.1139/cjz-2019-0271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Carry-over effects occur when past experience influences current individual performance. Although variation in conspecific density in one season has been shown to carry over to influence dynamics in the following season, the proximate ecological mechanisms driving these effects are unknown. One hypothesis is that high density decreases food availability, resulting in poor physiological condition, which in turn compromises performance the next season. Alternatively, high conspecific density could also lead to a high degree of antagonistic interactions, decreasing the amount of time individuals spend foraging. To investigate these hypotheses, we applied a factorial design where both conspecific density and per capita food availability during the non-breeding period were independently manipulated in seasonal populations of common fruit flies (Drosophila melanogaster Meigen, 1830). Individual condition at the beginning of the breeding period was influenced by per capita food availability but not density during the previous non-breeding period. In contrast, reproductive output was most strongly influenced by the interaction between per capita food availability and density in the previous non-breeding period, such that populations that experienced high non-breeding densities and low food availability had the lowest reproductive output. However, the strength of this effect was relatively weak. Our results demonstrate how environmental and social conditions in one part of the annual cycle can carry over to influence individual performance in subsequent periods.
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Affiliation(s)
- Joseph B. Burant
- Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
| | - Aidan Griffin
- Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
| | - Gustavo S. Betini
- Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
| | - D. Ryan Norris
- Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
- Nature Conservancy of Canada, 245 Eglinton Avenue East, Suite 410, Toronto, ON M4P 3J1, Canada
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9
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Birnie-Gauvin K, Lennox RJ, Guglielmo CG, Teffer AK, Crossin GT, Norris DR, Aarestrup K, Cooke SJ. The Value of Experimental Approaches in Migration Biology. Physiol Biochem Zool 2020; 93:210-226. [DOI: 10.1086/708455] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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10
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Vallejos MAV, Padial AA, Vitule JRS, Monteiro-Filho ELDA. Effects of crowding due to habitat loss on species assemblage patterns. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2020; 34:405-415. [PMID: 31773785 DOI: 10.1111/cobi.13443] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 08/08/2019] [Accepted: 08/30/2019] [Indexed: 06/10/2023]
Abstract
Terrestrial animals are negatively affected by habitat loss, which is assessed on a landscape scale, whereas secondary effects of habitat loss, such as crowding, are usually disregarded. Such impacts are inherently hard to address and poorly understood, and there is a growing concern that they could have dire consequences. We sampled birds throughout a deforestation process to assess crowding stress in an adjacent habitat remnant in the southern Brazilian Atlantic Forest. Crowding is expected of highly mobile taxa, especially given the microhabitat heterogeneity of Neotropical forests, and we hypothesized that the arrival of new individuals or species in refuges shifts assemblage patterns. We used point counts to obtain bird abundances in a before-after-control-impact design sampling of a deforestation event. Temporal changes in taxonomic and functional diversity were examined with metrics used to assess alpha and beta diversity, turnover of taxonomic and functional similarity, and taxonomic and functional composition. Over time increased abundance of some species altered the Simpson index and affected the abundance-distribution of traits in the habitat remnant. Taxonomic composition and functional composition changed in the remnant, and thus bird assemblages changed over time. Taxonomic and functional metrics indicated that fugitives affected resident assemblages in refuges, and effects endured >2 years after the deforestation processes had ceased. Dissimilarity of taxonomic composition between pre- and postdeforestation assemblages increased, whereas functional composition reverted to preimpact conditions. We found that ecological disruptions resulted from crowding and escalated into disruptions of species' assemblages and potentially compromising ecosystem functioning. It is important to consider crowding effects of highly mobile taxa during impact assessments, especially in large-scale infrastructure projects that may affect larger areas than is assumed.
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Affiliation(s)
| | - André Andrian Padial
- Laboratório de Análise e Síntese em Biodiversidade, Departamento de Botânica. Programa de Pós-Graduação em Ecologia e Conservação, Setor de Ciências Biológicas, Universidade Federal do Paraná, Av. Coronel Francisco Heráclito dos Santos, 100, CEP: 81530-000, Curitiba, Paraná, Brazil
| | - Jean Ricardo Simões Vitule
- Laboratório de Ecologia e Conservação, Departamento de Engenharia Ambiental, Setor de Tecnologia, Universidade Federal do Paraná, Av. Coronel Francisco Heráclito dos Santos, 100, CEP, 81530-000, Curitiba, Paraná, Brazil
| | - Emygdio Leite de Araujo Monteiro-Filho
- Laboratório de Biologia e Ecologia de Vertebrados, Departamento de Zoologia, Setor de Ciências Biológicas, Universidade Federal do Paraná, Av. Coronel Francisco Heráclito dos Santos, 100, CEP, 81530-000, Curitiba, Paraná, Brazil
- Instituto de Pesquisas Cananéia, Av. Nina, 523, CEP, 11990-000, Cananéia, São Paulo, Brazil
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11
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Pequeno PACL, Franklin E, Norton RA. Determinants of intra‐annual population dynamics in a tropical soil arthropod. Biotropica 2019. [DOI: 10.1111/btp.12731] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Pedro Aurélio Costa Lima Pequeno
- Natural Resources Program Federal University of Roraima Boa Vista Brazil
- Laboratory of Systematics and Ecology of Terrestrial Arthropods National Institute for Amazonia Research Manaus Brazil
| | - Elizabeth Franklin
- Laboratory of Systematics and Ecology of Terrestrial Arthropods National Institute for Amazonia Research Manaus Brazil
| | - Roy A. Norton
- College of Environmental Science and Forestry State University of New York Syracuse NY USA
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12
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Burant JB, Betini GS, Norris DR. Simple signals indicate which period of the annual cycle drives declines in seasonal populations. Ecol Lett 2019; 22:2141-2150. [PMID: 31631468 DOI: 10.1111/ele.13393] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 09/06/2019] [Indexed: 12/27/2022]
Abstract
For declining wild populations, a critical aspect of effective conservation is understanding when and where the causes of decline occur. The primary drivers of decline in migratory and seasonal populations can often be attributed to a specific period of the year. However, generic, broadly applicable indicators of these season-specific drivers of population decline remain elusive. We used a multi-generation experiment to investigate whether habitat loss in either the breeding or non-breeding period generated distinct signatures of population decline. When breeding habitat was reduced, population size remained relatively stable for several generations, before declining precipitously. When non-breeding habitat was reduced, between-season variation in population counts increased relative to control populations, and non-breeding population size declined steadily. Changes in seasonal vital rates and other indicators were predicted by the season in which habitat loss treatment occurred. Per capita reproductive output increased when non-breeding habitat was reduced and decreased with breeding habitat reduction, whereas per capita non-breeding survival showed the opposite trends. Our results reveal how simple signals inherent in counts and demographics of declining populations can indicate which period of the annual cycle is driving declines.
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Affiliation(s)
- Joseph B Burant
- Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph, Ontario, N1G 2W1, Canada
| | - Gustavo S Betini
- Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph, Ontario, N1G 2W1, Canada
| | - D Ryan Norris
- Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph, Ontario, N1G 2W1, Canada.,Nature Conservancy of Canada, 245 Eglinton Avenue East - Suite 410, Toronto, Ontario, M4P 3J1, Canada
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13
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Kilgour RJ, Norris DR, McAdam AG. Carry-over effects of resource competition and social environment on aggression. Behav Ecol 2019. [DOI: 10.1093/beheco/arz170] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Abstract
Aggressive behavior is common in many species and is often adaptive because it enables individuals to gain access to limited resources. However, aggression is also highly plastic and the degree of plasticity could be influenced by factors such as resource limitation and the social environment. In this study, we examined how the effects of social experience and resource limitation could persist to affect future aggressive interactions. Using naturally inbred strains of Drosophila melanogaster that differ in aggressiveness, we manipulated the level of available resources by varying fly density (two treatments: high and low per capita resources) and group composition by varying strain frequency (five treatments: homogeneous strains, or mixed at 1:3, 1:1 or 3:1 ratios of the more aggressive to less-aggressive strain). For each treatment group, we measured aggression before and after flies were placed through a 4-day period of fixed resources. There was no consistent effect of resource competition on aggression. Instead, changes in aggression depended on resource availability in combination with group composition. In homogeneous groups made up of only one strain, all males became more aggressive following the fixed-resource period, regardless of fly density. In mixed-strain treatments at high density, we observed plastic shifts in aggression of males from both strains, but the direction of plastic responses depended on social composition. Our results show that aggression may not only be influenced by the intensity of previous competitive experiences caused by resource limitation, but also through social effects caused by the composition of the group.
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Affiliation(s)
- R J Kilgour
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - D R Norris
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - A G McAdam
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
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14
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Gow EA, Knight SM, Bradley DW, Clark RG, Winkler DW, Bélisle M, Berzins LL, Blake T, Bridge ES, Burke L, Dawson RD, Dunn PO, Garant D, Holroyd G, Horn AG, Hussell DJT, Lansdorp O, Laughlin AJ, Leonard ML, Pelletier F, Shutler D, Siefferman L, Taylor CM, Trefry H, Vleck CM, Vleck D, Whittingham LA, Norris DR. Effects of Spring Migration Distance on Tree Swallow Reproductive Success Within and Among Flyways. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00380] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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15
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Kilgour RJ, McAdam AG, Betini GS, Norris DR. Experimental evidence that density mediates negative frequency-dependent selection on aggression. J Anim Ecol 2018; 87:1091-1101. [PMID: 29446094 DOI: 10.1111/1365-2656.12813] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 01/25/2018] [Indexed: 11/28/2022]
Abstract
Aggression can be beneficial in competitive environments if aggressive individuals are more likely to access resources than non-aggressive individuals. However, variation in aggressive behaviour persists within populations, suggesting that high levels of aggression might not always be favoured. The goal of this study was to experimentally assess the effects of population density and phenotypic frequency on selection on aggression in a competitive environment. We compared survival of two strains of Drosophila melanogaster that differ in aggression across three density treatments and five frequency treatments (single strain groups, equal numbers of each strain and strains mixed at 3:1 and 1:3 ratios) during a period of limited resources. While there was no difference in survival across single-strain treatments, survival was strongly density dependent, with declining survival as density increased. Furthermore, at medium and high densities, there was evidence of negative frequency-dependent selection, where rare strains experienced greater survival than common strains. However, there was no evidence of negative frequency-dependent selection at low density. Our results indicate that the benefits of aggression during periods of limited resources can depend on the interaction between the phenotypic composition of populations and population density, both of which are mechanisms that could maintain variation in aggressive behaviours within natural populations.
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Affiliation(s)
- R Julia Kilgour
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada
| | - Andrew G McAdam
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada
| | - Gustavo S Betini
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada
| | - D Ryan Norris
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada
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16
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Elliott KH, Betini GS, Norris DR. Fear creates an Allee effect: experimental evidence from seasonal populations. Proc Biol Sci 2017; 284:rspb.2017.0878. [PMID: 28659452 DOI: 10.1098/rspb.2017.0878] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 05/26/2017] [Indexed: 11/12/2022] Open
Abstract
Allee effects driven by predation can play a strong role in the decline of small populations but are conventionally thought to occur when generalist predators target specific prey (i.e. type II functional response). However, aside from direct consumption, fear of predators could also increase vigilance and reduce time spent foraging as population size decreases, as has been observed in wild mammals living in social groups. To investigate the role of fear on fitness in relation to population density in a species with limited sociality, we exposed varying densities of Drosophila melanogaster to mantid predators either during an experimental breeding season or non-breeding season. The presence of mantids in either season decreased the reproductive performance of individuals but only at low breeding densities, providing evidence for an Allee effect. We then used our experimental results to parametrize a mathematical model to examine the population consequences of fear at low densities. Fear tended to destabilize population dynamics and increase the risk of extinction up to sevenfold. Our study provides unique experimental evidence that the indirect effects of the presence of predators can cause an Allee effect and has important consequences for our understanding of the dynamics of small populations.
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Affiliation(s)
- Kyle H Elliott
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1 .,Department of Natural Resource Sciences, McGill University, Ste Anne-de-Bellevue, Quebec, Canada H9X 3V9
| | - Gustavo S Betini
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - D Ryan Norris
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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17
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Sample C, Fryxell JM, Bieri JA, Federico P, Earl JE, Wiederholt R, Mattsson BJ, Flockhart DTT, Nicol S, Diffendorfer JE, Thogmartin WE, Erickson RA, Norris DR. A general modeling framework for describing spatially structured population dynamics. Ecol Evol 2017; 8:493-508. [PMID: 29321888 PMCID: PMC5756893 DOI: 10.1002/ece3.3685] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 09/27/2017] [Accepted: 11/08/2017] [Indexed: 11/06/2022] Open
Abstract
Variation in movement across time and space fundamentally shapes the abundance and distribution of populations. Although a variety of approaches model structured population dynamics, they are limited to specific types of spatially structured populations and lack a unifying framework. Here, we propose a unified network-based framework sufficiently novel in its flexibility to capture a wide variety of spatiotemporal processes including metapopulations and a range of migratory patterns. It can accommodate different kinds of age structures, forms of population growth, dispersal, nomadism and migration, and alternative life-history strategies. Our objective was to link three general elements common to all spatially structured populations (space, time and movement) under a single mathematical framework. To do this, we adopt a network modeling approach. The spatial structure of a population is represented by a weighted and directed network. Each node and each edge has a set of attributes which vary through time. The dynamics of our network-based population is modeled with discrete time steps. Using both theoretical and real-world examples, we show how common elements recur across species with disparate movement strategies and how they can be combined under a unified mathematical framework. We illustrate how metapopulations, various migratory patterns, and nomadism can be represented with this modeling approach. We also apply our network-based framework to four organisms spanning a wide range of life histories, movement patterns, and carrying capacities. General computer code to implement our framework is provided, which can be applied to almost any spatially structured population. This framework contributes to our theoretical understanding of population dynamics and has practical management applications, including understanding the impact of perturbations on population size, distribution, and movement patterns. By working within a common framework, there is less chance that comparative analyses are colored by model details rather than general principles.
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Affiliation(s)
| | - John M Fryxell
- Department of Integrative Biology University of Guelph Guelph ON Canada
| | - Joanna A Bieri
- Department of Mathematics University of Redlands Redlands CA USA
| | - Paula Federico
- Department of Mathematics, Computer Science and Physics Capital University Columbus OH USA
| | - Julia E Earl
- School of Biological Sciences Louisiana Tech University Ruston LA USA
| | | | - Brady J Mattsson
- Institute of Silviculture University of Natural Resources and Life Sciences Vienna Austria.,Present address: Institute of Wildlife Biology & Game Management University of Natural Resources & Life Sciences (BOKU) Vienna Austria
| | | | - Sam Nicol
- CSIRO Land and Water, EcoSciences Precinct Dutton Park Qld Australia
| | - Jay E Diffendorfer
- U.S. Geological Survey, Geosciences and Environmental Change Science Center Denver CO USA
| | - Wayne E Thogmartin
- U.S. Geological Survey Upper Midwest Environmental Sciences Center La Crosse WI USA
| | - Richard A Erickson
- U.S. Geological Survey Upper Midwest Environmental Sciences Center La Crosse WI USA
| | - D Ryan Norris
- Department of Integrative Biology University of Guelph Guelph ON Canada
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18
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Elliott KH, Norris DR, Betini GS, Dworkin I. Scared fitless: Context-dependent response of fear to loss of predators over evolutionary time in Drosophila melanogaster. Facets (Ott) 2017. [DOI: 10.1139/facets-2016-0075] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Fear of predation can disappear rapidly in the absence of predators, as bolder individuals outcompete vigilant individuals for food and mates. To examine the evolution of fear in a seasonal environment, we exposed Drosophila melanogaster to mantid predators during the breeding season and the non-breeding season, and compared these with a control. We compared three Drosophila lineages that were maintained in captivity for (1) ∼45 years without mantid predators, (2) ∼5 years without mantid predators, and (3) ∼5 years with mantid predators (predator-evolved). The presence of a predator during the non-breeding season caused reduced fecundity in the following breeding season, independent of the evolutionary lineage. However, the presence of a predator during reproduction caused offspring to emerge earlier, and this effect was more pronounced in the predator-evolved lineage. Thus, the fear response was related to evolutionary lineage only during the larval life stage, which is when foraging competition, and hence the cost of fear, may be highest. We present one of the first experimental demonstrations that emotion (fear) can evolve in response to environmental context.
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Affiliation(s)
- Kyle H. Elliott
- Department of Natural Resource Sciences, McGill University, Ste-Anne-de-Bellevue, QC H9X 3V9, Canada
- Department of Integrative Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - D. Ryan Norris
- Department of Integrative Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Gustavo S. Betini
- Department of Integrative Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Ian Dworkin
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
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19
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Ruiz-Herrera A. Carry-over effects: population abundance, ecological shifts, and the (dis-)appearance of oscillations. Ecol Modell 2017. [DOI: 10.1016/j.ecolmodel.2017.01.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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20
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Albon SD, Irvine RJ, Halvorsen O, Langvatn R, Loe LE, Ropstad E, Veiberg V, van der Wal R, Bjørkvoll EM, Duff EI, Hansen BB, Lee AM, Tveraa T, Stien A. Contrasting effects of summer and winter warming on body mass explain population dynamics in a food-limited Arctic herbivore. GLOBAL CHANGE BIOLOGY 2017; 23:1374-1389. [PMID: 27426229 DOI: 10.1111/gcb.13435] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 07/05/2016] [Indexed: 05/27/2023]
Abstract
The cumulative effects of climate warming on herbivore vital rates and population dynamics are hard to predict, given that the expected effects differ between seasons. In the Arctic, warmer summers enhance plant growth which should lead to heavier and more fertile individuals in the autumn. Conversely, warm spells in winter with rainfall (rain-on-snow) can cause 'icing', restricting access to forage, resulting in starvation, lower survival and fecundity. As body condition is a 'barometer' of energy demands relative to energy intake, we explored the causes and consequences of variation in body mass of wild female Svalbard reindeer (Rangifer tarandus platyrhynchus) from 1994 to 2015, a period of marked climate warming. Late winter (April) body mass explained 88% of the between-year variation in population growth rate, because it strongly influenced reproductive loss, and hence subsequent fecundity (92%), as well as survival (94%) and recruitment (93%). Autumn (October) body mass affected ovulation rates but did not affect fecundity. April body mass showed no long-term trend (coefficient of variation, CV = 8.8%) and was higher following warm autumn (October) weather, reflecting delays in winter onset, but most strongly, and negatively, related to 'rain-on-snow' events. October body mass (CV = 2.5%) increased over the study due to higher plant productivity in the increasingly warm summers. Density-dependent mass change suggested competition for resources in both winter and summer but was less pronounced in recent years, despite an increasing population size. While continued climate warming is expected to increase the carrying capacity of the high Arctic tundra, it is also likely to cause more frequent icing events. Our analyses suggest that these contrasting effects may cause larger seasonal fluctuations in body mass and vital rates. Overall our findings provide an important 'missing' mechanistic link in the current understanding of the population biology of a keystone species in a rapidly warming Arctic.
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Affiliation(s)
| | | | - Odd Halvorsen
- Natural History Museum, University of Oslo, Box 1172 Blindern, NO-0318, Oslo, Norway
| | - Rolf Langvatn
- University Courses in Svalbard (UNIS), P.O. Box 156, NO-9171, Longyearbyen, Norway
- Norwegian Institute for Nature Research (NINA), P.O. Box 5685 Sluppen, NO-7485, Trondheim, Norway
| | - Leif E Loe
- Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432, Aas, Norway
| | - Erik Ropstad
- Norwegian University of Life Sciences, P.O. Box 8146, NO-0033, Oslo, Norway
| | - Vebjørn Veiberg
- Norwegian Institute for Nature Research (NINA), P.O. Box 5685 Sluppen, NO-7485, Trondheim, Norway
| | - René van der Wal
- Aberdeen Centre for Environmental Sustainability (ACES), School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 3UU, UK
| | - Eirin M Bjørkvoll
- Centre for Biodiversity Dynamics (CBD), Department of Biology, Norwegian University of Science & Technology (NTNU), N-7491, Trondheim, Norway
| | - Elizabeth I Duff
- Biomathematics & Statistics Scotland (BioSS), Aberdeen, AB15 8QH, UK
| | - Brage B Hansen
- Centre for Biodiversity Dynamics (CBD), Department of Biology, Norwegian University of Science & Technology (NTNU), N-7491, Trondheim, Norway
| | - Aline M Lee
- Centre for Biodiversity Dynamics (CBD), Department of Biology, Norwegian University of Science & Technology (NTNU), N-7491, Trondheim, Norway
| | - Torkild Tveraa
- Norwegian Institute for Nature Research (NINA), Fram Centre, NO-9296, Tromsø, Norway
| | - Audun Stien
- Norwegian Institute for Nature Research (NINA), Fram Centre, NO-9296, Tromsø, Norway
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21
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Betini GS, McAdam AG, Griswold CK, Norris DR. A fitness trade-off between seasons causes multigenerational cycles in phenotype and population size. eLife 2017; 6:e18770. [PMID: 28164780 PMCID: PMC5340529 DOI: 10.7554/elife.18770] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 02/06/2017] [Indexed: 11/17/2022] Open
Abstract
Although seasonality is widespread and can cause fluctuations in the intensity and direction of natural selection, we have little information about the consequences of seasonal fitness trade-offs for population dynamics. Here we exposed populations of Drosophila melanogaster to repeated seasonal changes in resources across 58 generations and used experimental and mathematical approaches to investigate how viability selection on body size in the non-breeding season could affect demography. We show that opposing seasonal episodes of natural selection on body size interacted with both direct and delayed density dependence to cause populations to undergo predictable multigenerational density cycles. Our results provide evidence that seasonality can set the conditions for life-history trade-offs and density dependence, which can, in turn, interact to cause multigenerational population cycles.
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Affiliation(s)
- Gustavo S Betini
- Department of Integrative Biology, University of Guelph, Guelph, Canada
| | - Andrew G McAdam
- Department of Integrative Biology, University of Guelph, Guelph, Canada
| | | | - D Ryan Norris
- Department of Integrative Biology, University of Guelph, Guelph, Canada
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22
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Robinson OJ, McGowan CP, Devers PK. Disentangling density-dependent dynamics using full annual cycle models and Bayesian model weight updating. J Appl Ecol 2016. [DOI: 10.1111/1365-2664.12761] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Orin J. Robinson
- School of Forestry and Wildlife Sciences; Auburn University; Auburn AL 36849 USA
| | - Conor P. McGowan
- U.S. Geological Survey Alabama Cooperative Fish and Wildlife Research Unit; Auburn AL 36849 USA
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23
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Seasonal dynamics with compensatory effects regulate populations of tropical forest marsupials: a 16-year study. Oecologia 2016; 182:1095-1106. [DOI: 10.1007/s00442-016-3735-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Accepted: 09/14/2016] [Indexed: 10/20/2022]
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24
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Senner NR, Conklin JR, Piersma T. An ontogenetic perspective on individual differences. Proc Biol Sci 2016; 282:rspb.2015.1050. [PMID: 26336173 DOI: 10.1098/rspb.2015.1050] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Phenotypic differences among individuals can arise during any stage of life. Although several distinct processes underlying individual differences have been defined and studied (e.g. parental effects, senescence), we lack an explicit, unified perspective for understanding how these processes contribute separately and synergistically to observed variation in functional traits. We propose a conceptual framework based on a developmental view of life-history variation, linking each ontogenetic stage with the types of individual differences originating during that period. In our view, the salient differences among these types are encapsulated by three key criteria: timing of onset, when fitness consequences are realized, and potential for reversibility. To fill a critical gap in this framework, we formulate a new term to refer to individual differences generated during adulthood-reversible state effects. We define these as 'reversible changes in a functional trait resulting from life-history trade-offs during adulthood that affect fitness', highlighting how the adult phenotype can be repeatedly altered in response to environmental variation. Defining individual differences in terms of trade-offs allows explicit predictions regarding when and where fitness consequences should be expected. Moreover, viewing individual differences in a developmental context highlights how different processes can work in concert to shape phenotype and fitness, and lays a foundation for research linking individual differences to ecological and evolutionary theory.
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Affiliation(s)
- Nathan R Senner
- Conservation Ecology Group, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, PO Box 11103, Groningen 9700 CC, The Netherlands
| | - Jesse R Conklin
- Conservation Ecology Group, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, PO Box 11103, Groningen 9700 CC, The Netherlands
| | - Theunis Piersma
- Conservation Ecology Group, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, PO Box 11103, Groningen 9700 CC, The Netherlands Department of Marine Ecology, NIOZ Royal Netherlands Institute for Sea Research, PO Box 59, Den Burg, Texel, 1790 AB, The Netherlands
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25
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Potential Impact of Carry-Over Effects in the Dynamics and Management of Seasonal Populations. PLoS One 2016; 11:e0155579. [PMID: 27171267 PMCID: PMC4865231 DOI: 10.1371/journal.pone.0155579] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 05/01/2016] [Indexed: 11/19/2022] Open
Abstract
For many species living in changing environments, processes during one season influence vital rates in a subsequent season in the same annual cycle. The interplay between these carry-over effects between seasons and other density-dependent events can have a strong influence on population size and variability. We carry out a theoretical study of a discrete semelparous population model with an annual cycle divided into a breeding and a non-breeding season; the model assumes carry-over effects coming from the non-breeding period and affecting breeding performance through a density-dependent adjustment of the growth rate parameter. We analyze the influence of carry-over effects on population size, focusing on two important aspects: compensatory mortality and population variability. To understand the potential consequences of carry-over effects for management, we have introduced constant effort harvesting in the model. Our results show that carry-over effects may induce dramatic changes in population stability as harvesting pressure is increased, but these changes strongly depend on whether harvesting occurs prior to reproduction or after it.
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26
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Marra PP, Studds CE, Wilson S, Sillett TS, Sherry TW, Holmes RT. Non-breeding season habitat quality mediates the strength of density-dependence for a migratory bird. Proc Biol Sci 2016; 282:rspb.2015.0624. [PMID: 26136445 DOI: 10.1098/rspb.2015.0624] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Our understanding of when natural populations are regulated during their annual cycle is limited, particularly for migratory species. This information is needed for parametrizing models that can inform management and conservation. Here, we use 14 years of data on colour-marked birds to investigate how conspecific density and habitat quality during the tropical non-breeding period interact to affect body condition and apparent annual survival of a long-distance migratory songbird, the American redstart (Setophagaruticilla). Body condition and survival of birds in high-quality mangrove habitat declined as density increased. By contrast, body condition improved and survival did not vary as density increased in adjacent, lower quality scrub habitat, although mean condition and survival were almost always lower than in mangrove. High rainfall enhanced body condition in scrub but not in mangrove, suggesting factors such as food availability outweighed consequences of crowding in lower quality habitat. Thus, survival of overwintering redstarts in mangrove habitat, disproportionately males,appears to be regulated by a crowding mechanism based on density-dependent resource competition. Survival of individuals in scrub, mostly females, appears to be limited by density-independent environmental factors but not regulated by crowding. The contrasting effects of density and food limitation on individuals overwintering in adjacent habitats illustrate the complexity of processes operating during the non-breeding period for migratory animals, and emphasize the need for long-term studies of animals in multiple habitats and throughout their annual cycles.
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27
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Elliott KH, Betini GS, Dworkin I, Norris DR. Experimental evidence for within- and cross-seasonal effects of fear on survival and reproduction. J Anim Ecol 2016; 85:507-15. [PMID: 26713420 DOI: 10.1111/1365-2656.12487] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Accepted: 11/20/2015] [Indexed: 10/22/2022]
Abstract
Fear of predation can have non-lethal effects on individuals within a season but whether, and to what extent, these effects carry over into subsequent seasons is not known. Using a replicated seasonal population of the common fruit fly, Drosophila melanogaster, we examined both within- and cross-seasonal effects of fear on survival and reproductive output. Compared to controls, flies exposed to the scent of mantid (Tenodera sinensis) predators in the non-breeding season had 64% higher mortality, and lost 60% more mass by the end of the non-breeding season and, in the subsequent breeding season, produced 20% fewer offspring that weighed 9% less at maturity. Flies exposed to the scent of mantids in the breeding season did not produce fewer offspring, but their offspring developed faster and weighed less as adults compared to the controls. Our results demonstrate how effects of fear can be manifested both within and across seasons and emphasize the importance of understanding how events throughout the annual cycle influence individual success of animals living in seasonal environments.
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Affiliation(s)
- Kyle H Elliott
- Department of Integrative Biology, University of Guelph, Guelph, Canada, N1G 2W1.,Department of Natural Resource Sciences, McGill University, Ste Anne-de-Bellevue, Canada, H9X 3V9
| | - Gustavo S Betini
- Department of Integrative Biology, University of Guelph, Guelph, Canada, N1G 2W1
| | - Ian Dworkin
- Department of Biology, McMaster University, Hamilton, Canada, L8S 4K1
| | - D Ryan Norris
- Department of Integrative Biology, University of Guelph, Guelph, Canada, N1G 2W1
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28
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Betini GS, Pardy A, Griswold CK, Norris DR. The role of seasonality and non-lethal carry-over effects on density-dependent dispersal. Ecosphere 2015. [DOI: 10.1890/es15-00257.1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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29
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Betini GS, Fitzpatrick MJ, Norris DR. Experimental evidence for the effect of habitat loss on the dynamics of migratory networks. Ecol Lett 2015; 18:526-34. [DOI: 10.1111/ele.12432] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 12/04/2014] [Accepted: 03/02/2015] [Indexed: 11/26/2022]
Affiliation(s)
- Gustavo S. Betini
- Department of Integrative Biology; University of Guelph; Guelph ON N1G 2W1 Canada
| | - Mark J. Fitzpatrick
- Department of Biological Sciences; University of Toronto Scarborough; Toronto ON M1C 1A4 Canada
| | - D. Ryan Norris
- Department of Integrative Biology; University of Guelph; Guelph ON N1G 2W1 Canada
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30
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Wolkovich EM, Cook BI, McLauchlan KK, Davies TJ. Temporal ecology in the Anthropocene. Ecol Lett 2014; 17:1365-79. [DOI: 10.1111/ele.12353] [Citation(s) in RCA: 194] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 05/22/2014] [Accepted: 08/06/2014] [Indexed: 12/25/2022]
Affiliation(s)
- E. M. Wolkovich
- Arnold Arboretum; Boston Massachusetts USA
- Organismic & Evolutionary Biology; Cambridge Massachusetts USA
- Biodiversity Research Centre; University of British Columbia; Vancouver BC Canada
| | - B. I. Cook
- NASA Goddard Institute for Space Studies; New York New York USA
- Ocean and Climate Physics; Lamont-Doherty Earth Observatory; Palisades New York USA
| | - K. K. McLauchlan
- Department of Geography; Kansas State University; Manhattan Kansas USA
- University of Oxford; Merton College; Oxford UK
| | - T. J. Davies
- Department of Biology; McGill University; Montreal Quebec Canada
- African Centre for DNA Barcoding; University of Johannesburg; Johannesburg South Africa
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31
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Ouyang F, Hui C, Ge S, Men XY, Zhao ZH, Shi PJ, Zhang YS, Li BL. Weakening density dependence from climate change and agricultural intensification triggers pest outbreaks: a 37-year observation of cotton bollworms. Ecol Evol 2014; 4:3362-74. [PMID: 25535553 PMCID: PMC4228611 DOI: 10.1002/ece3.1190] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 07/12/2014] [Accepted: 07/21/2014] [Indexed: 11/28/2022] Open
Abstract
Understanding drivers of population fluctuation, especially for agricultural pests, is central to the provision of agro-ecosystem services. Here, we examine the role of endogenous density dependence and exogenous factors of climate and human activity in regulating the 37-year population dynamics of an important agricultural insect pest, the cotton bollworm (Helicoverpa armigera), in North China from 1975 to 2011. Quantitative time-series analysis provided strong evidence explaining long-term population dynamics of the cotton bollworm and its driving factors. Rising temperature and declining rainfall exacerbated the effect of agricultural intensification on continuously weakening the negative density dependence in regulating the population dynamics of cotton bollworms. Consequently, ongoing climate change and agricultural intensification unleashed the tightly regulated pest population and triggered the regional outbreak of H. armigera in 1992. Although the negative density dependence can effectively regulate the population change rate to fluctuate around zero at stable equilibrium levels before and after outbreak in the 1992, the population equilibrium jumped to a higher density level with apparently larger amplitudes after the outbreak. The results highlight the possibility for exogenous factors to induce pest outbreaks and alter the population regulating mechanism of negative density dependence and, thus, the stable equilibrium of the pest population, often to a higher level, posing considerable risks to the provision of agro-ecosystem services and regional food security. Efficient and timely measures of pest management in the era of Anthropocene should target the strengthening and revival of weakening density dependence caused by climate change and human activities.
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Affiliation(s)
- Fang Ouyang
- State Key Laboratory of Integrated Management of Pest and Rodents, Institute of Zoology, Chinese Academy of Sciences Beijing, 100101, China
| | - Cang Hui
- Department of Botany and Zoology, Centre for Invasion Biology, Stellenbosch University Matieland, 7602, South Africa
| | - Saiying Ge
- Fisher College of Business, Ohio State University Columbus, Ohio, 43210
| | - Xin-Yuan Men
- Institute of Plant Protection, Shandong Academy of Agricultural Sciences Jinan, 250100, China
| | - Zi-Hua Zhao
- Department of Entomology, China Agricultural University Beijing, 100193, China
| | - Pei-Jian Shi
- Institute of Bamboo, Nanjing Forestry University Nanjing, 210037, China
| | - Yong-Sheng Zhang
- State Key Laboratory of Integrated Management of Pest and Rodents, Institute of Zoology, Chinese Academy of Sciences Beijing, 100101, China ; College of Plant Protection, Hunan Agricultural University Changsha, 410128, China
| | - Bai-Lian Li
- Department of Botany and Plant Sciences, Ecological Complexity and Modeling Laboratory, University of California Riverside, California, 92521-0124
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Daunt F, Reed TE, Newell M, Burthe S, Phillips RA, Lewis S, Wanless S. Longitudinal bio-logging reveals interplay between extrinsic and intrinsic carry-over effects in a long-lived vertebrate. Ecology 2014; 95:2077-83. [DOI: 10.1890/13-1797.1] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Betini GS, Griswold CK, Prodan L, Norris DR. Body size, carry-over effects and survival in a seasonal environment: consequences for population dynamics. J Anim Ecol 2014; 83:1313-21. [DOI: 10.1111/1365-2656.12225] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Accepted: 03/21/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Gustavo S. Betini
- Department of Integrative Biology; University of Guelph; Guelph ON N1G 2W1 Canada
| | - Cortland K. Griswold
- Department of Integrative Biology; University of Guelph; Guelph ON N1G 2W1 Canada
| | - Livia Prodan
- Department of Integrative Biology; University of Guelph; Guelph ON N1G 2W1 Canada
| | - D. Ryan Norris
- Department of Integrative Biology; University of Guelph; Guelph ON N1G 2W1 Canada
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van Oudenhove L, Gauthier G, Lebreton JD. Year-round effects of climate on demographic parameters of an arctic-nesting goose species. J Anim Ecol 2014; 83:1322-33. [PMID: 24724860 DOI: 10.1111/1365-2656.12230] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 04/07/2014] [Indexed: 01/22/2023]
Abstract
Understanding how climate change will affect animal population dynamics remains a major challenge, especially in long-distant migrants exposed to different climatic regimes throughout their annual cycle. We evaluated the effect of temperature throughout the annual cycle on demographic parameters (age-specific survival and recruitment, breeding propensity and fecundity) of the greater snow goose (Chen caerulescens atlantica L.), an arctic-nesting species. As this is a hunted species, we used the theory of exploited populations to estimate hunting mortality separately from natural mortality in order to evaluate climatic effects only on the latter form of mortality. Our analysis was based on a 22-year marking study (n = 27,150 females) and included live recaptures at the breeding colony and dead recoveries from hunters. We tested the effect of climatic covariates by applying a procedure that accounts for unexplained environmental variation in the demographic parameter to a multistate capture-mark-recapture recruitment model. Breeding propensity, clutch size and hatching probability all increased with high temperatures on the breeding grounds. First-year survival to natural causes of mortality increased when temperature was high at the end of the summer, whereas adult survival was not affected by temperature. On the contrary, accession to reproduction decreased with warmer climatic conditions during the non-breeding season. Survival was strongly negatively related to hunting mortality in adults, as expected, but not in first-year birds, which suggests the possibility of compensation between natural and hunting mortality in the latter group. We show that events occurring both at and away from the breeding ground can affect the demography of migratory birds, either directly or through carryover effects, and sometimes in opposite ways. This highlights the need to account for the whole life cycle of an animal when attempting to project the response of populations to future climatic changes.
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Affiliation(s)
- Louise van Oudenhove
- Département de biologie and Centre d'études nordiques, Université Laval, 1045 avenue de la Médecine, Québec City, QC, G1V 0A6, Canada.,Centre d'écologie fonctionnelle et évolutive, UMR 5175, CNRS, 1919 Route de Mende, 34293, Montpellier Cedex 5, France
| | - Gilles Gauthier
- Département de biologie and Centre d'études nordiques, Université Laval, 1045 avenue de la Médecine, Québec City, QC, G1V 0A6, Canada
| | - Jean-Dominique Lebreton
- Centre d'écologie fonctionnelle et évolutive, UMR 5175, CNRS, 1919 Route de Mende, 34293, Montpellier Cedex 5, France
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Betini GS, Griswold CK, Norris DR. Density-mediated carry-over effects explain variation in breeding output across time in a seasonal population. Biol Lett 2013; 9:20130582. [PMID: 23925837 PMCID: PMC3971703 DOI: 10.1098/rsbl.2013.0582] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 07/15/2013] [Indexed: 11/12/2022] Open
Abstract
In seasonal environments, where density dependence can operate throughout the annual cycle, vital rates are typically considered to be a function of the number of individuals at the beginning of each season. However, variation in density in the previous season could also cause surviving individuals to be in poor physiological condition, which could carry over to influence individual success in the following season. We examine this hypothesis using replicated populations of Drosophila melanogaster, the common fruitfly, over 23 non-overlapping generations with distinct breeding and non-breeding seasons. We found that the density at the beginning of the non-breeding season negatively affected the fresh weight of individuals that survived the non-breeding season and resulted in a 25% decrease in per capita breeding output among those that survived to the next season to breed. At the population level, per capita breeding output was best explained by a model that incorporated density at the beginning of the previous non-breeding season (carry-over effect, COE) and density at the beginning of the breeding season. Our results support the idea that density-mediated COEs are critical for understanding population dynamics in seasonal environments.
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Affiliation(s)
- Gustavo S Betini
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada.
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Environmental conditions during breeding modify the strength of mass-dependent carry-over effects in a migratory bird. PLoS One 2013; 8:e77783. [PMID: 24143258 PMCID: PMC3797109 DOI: 10.1371/journal.pone.0077783] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 09/12/2013] [Indexed: 11/19/2022] Open
Abstract
In many animals, processes occurring in one season carry over to influence reproductive success and survival in future seasons. The strength of such carry-over effects is unlikely to be uniform across years, yet our understanding of the processes that are capable of modifying their strength remains limited. Here we show that female light-bellied Brent geese with higher body mass prior to spring migration successfully reared more offspring during breeding, but only in years where environmental conditions during breeding were favourable. In years of bad weather during breeding, all birds suffered reduced reproductive output irrespective of pre-migration mass. Our results suggest that the magnitude of reproductive benefits gained by maximising body stores to fuel breeding fluctuates markedly among years in concert with conditions during the breeding season, as does the degree to which carry-over effects are capable of driving variance in reproductive success among individuals. Therefore while carry-over effects have considerable power to drive fitness asymmetries among individuals, our ability to interpret these effects in terms of their implications for population dynamics is dependent on knowledge of fitness determinants occurring in subsequent seasons.
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