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Keevil MG, Noble N, Boyle SP, Lesbarrères D, Brooks RJ, Litzgus JD. Lost reproductive value reveals a high burden of juvenile road mortality in a long-lived species. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2023; 33:e2789. [PMID: 36482023 DOI: 10.1002/eap.2789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 07/23/2022] [Accepted: 08/25/2022] [Indexed: 06/17/2023]
Abstract
Adult mortality is often the most sensitive vital rate affecting at-risk wildlife populations. Therefore, road ecology studies often focus on adult mortality despite the possibility for roads to be hazardous to juvenile individuals during natal dispersal. Failure to quantify concurrent variation in mortality risk and population sensitivity across demographic states can mislead the efforts to understand and mitigate the effects of population threats. To compare relative population impacts from road mortality among demographic classes, we weighted mortality observations by applying reproductive value analysis to quantify expected stage-specific contributions to population growth. We demonstrate this approach for snapping turtles (Chelydra serpentina) observed on roads at two focal sites in Ontario, Canada, where we collected data for both live and dead individuals observed on roads. We estimated reproductive values using stage-classified matrix models to compare relative population-level impacts of adult and juvenile mortality. Reproductive value analysis is a tractable approach to assessing demographically variable effects for applications covering large spatial scales, nondiscrete populations, or where abundance data are lacking. For one site with long-term life-history data, we compared demographic frequency on roads to expected general population frequencies predicted by the matrix model. Our application of reproductive value is sex specific but, as juvenile snapping turtles lack external secondary sex characters, we estimated the sex ratio of road-crossing juveniles after dissecting and sexing carcasses collected on roads at five sites across central Ontario, Canada. Juveniles were more abundant on roads than expected, suggesting a substantial dispersal contribution, and the road-killed juvenile sex ratio approached 1:1. A higher proportion of juveniles were also found dead compared with adults, and cumulative juvenile mortality had similar population-level importance as adult mortality. This suggests that the impact of roads needs to be considered across all life stages, even in wildlife species with slow life histories, such as snapping turtles, that are particularly sensitive to adult mortality.
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Affiliation(s)
- Matthew G Keevil
- School of Natural Sciences, Laurentian University, Sudbury, Ontario, Canada
| | - Natasha Noble
- School of Natural Sciences, Laurentian University, Sudbury, Ontario, Canada
| | - Sean P Boyle
- School of Natural Sciences, Laurentian University, Sudbury, Ontario, Canada
| | - David Lesbarrères
- School of Natural Sciences, Laurentian University, Sudbury, Ontario, Canada
| | - Ronald J Brooks
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
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Leivesley JA, Nancekivell EG, Brooks RJ, Litzgus JD, Rollinson N. Long-term resilience of primary sex ratios in a species with temperature-dependent sex determination after decades of climate warming. Am Nat 2022; 200:532-543. [DOI: 10.1086/720621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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3
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Brown GP, Shine R. Do Microbiota in the Soil Affect Embryonic Development and Immunocompetence in Hatchling Reptiles? Front Ecol Evol 2022. [DOI: 10.3389/fevo.2021.780456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Reptile eggs develop in intimate association with microbiota in the soil, raising the possibility that embryogenesis may be affected by shifts in soil microbiota caused by anthropogenic disturbance, translocation of eggs for conservation purposes, or laboratory incubation in sterile media. To test this idea we incubated eggs of keelback snakes (Tropidonophis mairii, Colubridae) in untreated versus autoclaved soil, and injected lipopolysaccharide (LPS) into the egg to induce an immune response in the embryo. Neither treatment modified hatching success, water uptake, incubation period, or white-blood-cell profiles, but both treatments affected hatchling size. Eggs incubated on autoclaved soil produced smaller hatchlings than did eggs on untreated soil, suggesting that heat and/or pressure treatment decrease the soil’s suitability for incubation. Injection of LPS reduced hatchling size, suggesting that the presence of pathogen cues disrupts embryogenesis, possibly by initiating immune reactions unassociated with white-blood-cell profiles. Smaller neonates had higher ratios of heterophils to leucocytes, consistent with higher stress in smaller snakes, or body-size effects on investment into different types of immune cells. Microbiota in the incubation medium thus can affect viability-relevant phenotypic traits of hatchling reptiles. We need further studies to explore the complex mechanisms and impacts of environmental conditions on reptilian embryogenesis.
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Noble DWA, Senior AM, Uller T, Schwanz LE. Heightened among-individual variation in life history but not morphology is related to developmental temperature in reptiles. J Evol Biol 2021; 34:1793-1802. [PMID: 34543488 DOI: 10.1111/jeb.13938] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 09/07/2021] [Accepted: 09/14/2021] [Indexed: 01/08/2023]
Abstract
Increases in phenotypic variation under extreme (e.g. novel or stressful) environmental conditions are emerging as a crucial process through which evolutionary adaptation can occur. Lack of prior stabilizing selection, as well as potential instability of developmental processes in these environments, may lead to a release of phenotypic variation that can have important evolutionary consequences. Although such patterns have been shown in model study organisms, we know little about the generality of trait variance across environments for non-model organisms. Here, we test whether extreme developmental temperatures increase the phenotypic variation across diverse reptile taxa. We find that the among-individual variation in a key life-history trait (post-hatching growth) increases at extreme cold and hot temperatures. However, variations in two measures of hatchling morphology and in hatchling performance were not related to developmental temperature. Although extreme developmental temperatures may increase the variation in growth, our results suggest that plastic responses to stressful incubation conditions do not generally make more extreme phenotypes available to selection. We discuss the reasons for the general lack of increased variability at extreme incubation temperatures and the implications this has for local adaptation in hatchling morphology and physiology.
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Affiliation(s)
- Daniel W A Noble
- Division of Ecology and Evolution, Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Alistair M Senior
- Charles Perkins Centre, School of Life and Environmental Sciences, Sydney University, Sydney, NSW, Australia
| | - Tobias Uller
- Department of Biology, Lund University, Lund, Skåne, Sweden
| | - Lisa E Schwanz
- Evolution & Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, Australia
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5
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Hatchling turtles ingest natural and artificial incubation substrates at high frequency. Behav Ecol Sociobiol 2020. [DOI: 10.1007/s00265-020-02913-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Snake conservation in anthropized landscapes: considering artificial habitats and questioning management of semi-natural habitats. EUR J WILDLIFE RES 2020. [DOI: 10.1007/s10344-020-01373-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Kontopoulos D‐G, van Sebille E, Lange M, Yvon‐Durocher G, Barraclough TG, Pawar S. Phytoplankton thermal responses adapt in the absence of hard thermodynamic constraints. Evolution 2020; 74:775-790. [PMID: 32118294 PMCID: PMC7384082 DOI: 10.1111/evo.13946] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 01/25/2020] [Accepted: 01/29/2020] [Indexed: 12/16/2022]
Abstract
To better predict how populations and communities respond to climatic temperature variation, it is necessary to understand how the shape of the response of fitness-related rates to temperature evolves (the thermal performance curve). Currently, there is disagreement about the extent to which the evolution of thermal performance curves is constrained. One school of thought has argued for the prevalence of thermodynamic constraints through enzyme kinetics, whereas another argues that adaptation can-at least partly-overcome such constraints. To shed further light on this debate, we perform a phylogenetic meta-analysis of the thermal performance curves of growth rate of phytoplankton-a globally important functional group-controlling for environmental effects (habitat type and thermal regime). We find that thermodynamic constraints have a minor influence on the shape of the curve. In particular, we detect a very weak increase of maximum performance with the temperature at which the curve peaks, suggesting a weak "hotter-is-better" constraint. Also, instead of a constant thermal sensitivity of growth across species, as might be expected from strong constraints, we find that all aspects of the thermal performance curve evolve along the phylogeny. Our results suggest that phytoplankton thermal performance curves adapt to thermal environments largely in the absence of hard thermodynamic constraints.
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Affiliation(s)
- Dimitrios ‐ Georgios Kontopoulos
- Science and Solutions for a Changing Planet DTPImperial College LondonLondonSW7 2AZUK
- Department of Life SciencesImperial College LondonSilwood ParkAscotBerkshireSL5 7PYUK
| | - Erik van Sebille
- Grantham InstituteImperial College LondonLondonSW7 2AZUK
- Institute for Marine and Atmospheric Research UtrechtUtrecht UniversityUtrecht3584 CCthe Netherlands
| | - Michael Lange
- Department of Earth Science and EngineeringImperial College LondonLondonSW7 2AZUK
| | - Gabriel Yvon‐Durocher
- Environment and Sustainability InstituteUniversity of ExeterPenrynCornwallTR10 9EZUK
| | | | - Samraat Pawar
- Department of Life SciencesImperial College LondonSilwood ParkAscotBerkshireSL5 7PYUK
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Du WG, Shine R, Ma L, Sun BJ. Adaptive responses of the embryos of birds and reptiles to spatial and temporal variations in nest temperatures. Proc Biol Sci 2019; 286:20192078. [PMID: 31744441 DOI: 10.1098/rspb.2019.2078] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Natural nests of egg-laying birds and reptiles exhibit substantial thermal variation, at a range of spatial and temporal scales. Rates and trajectories of embryonic development are highly sensitive to temperature, favouring an ability of embryos to respond adaptively (i.e. match their developmental biology to local thermal regimes). Spatially, thermal variation can be significant within a single nest (top to bottom), among adjacent nests (as a function of shading, nest depth etc.), across populations that inhabit areas with different weather conditions, and across species that differ in climates occupied and/or nest characteristics. Thermal regimes also vary temporally, in ways that generate differences among nests within a single population (e.g. due to seasonal timing of laying), among populations and across species. Anthropogenic activities (e.g. habitat clearing, climate change) add to this spatial and temporal diversity in thermal regimes. We review published literature on embryonic adaptations to spatio-temporal heterogeneity in nest temperatures. Although relatively few taxa have been studied in detail, and proximate mechanisms remain unclear, our review identifies many cases in which natural selection appears to have fine-tuned embryogenesis to match local thermal regimes. Developmental rates have been reported to differ between uppermost versus lower eggs within a single nest, between eggs laid early versus late in the season, and between populations from cooler versus warmer climates. We identify gaps in our understanding of thermal adaptations of early (embryonic) phases of the life history, and suggest fruitful opportunities for future research.
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Affiliation(s)
- Wei-Guo Du
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China.,Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, People's Republic of China
| | - Richard Shine
- Department of Biological Sciences, Macquarie University, North Ryde, New South Wales 2109, Australia
| | - Liang Ma
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China
| | - Bao-Jun Sun
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China
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Bowne DR, Cosentino BJ, Anderson LJ, Cooke S, Dosch JJ, Garneau D, Fredericksen TS, Kolozsvary MB, Lindquist ES, March JG, Urban RA, Zimmermann CR. A broader approach to understanding urbanization effects on freshwater turtles: reply to Lambert and Steen 2019. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2019; 33:1197-1199. [PMID: 31404480 DOI: 10.1111/cobi.13398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 06/14/2019] [Accepted: 07/15/2019] [Indexed: 06/10/2023]
Affiliation(s)
- David R Bowne
- Department of Biology, Elizabethtown College, One Alpha Drive, Elizabethtown, PA, 17022, U.S.A
| | - Bradley J Cosentino
- Department of Biology, Hobart and William Smith Colleges, 113 Eaton Hall, Geneva, NY, 14456, U.S.A
| | - Laurel J Anderson
- Department of Botany & Microbiology, Ohio Wesleyan University, 61 S. Sandusky Street, Delaware, OH, 43015, U.S.A
| | - Sandra Cooke
- Department of Biology, High Point University, One University Parkway, High Point, NC, 27268, U.S.A
| | - Jerald J Dosch
- Department of Biology, Macalester College, 1600 Grand Avenue, Saint Paul, MN, 55105, U.S.A
| | - Danielle Garneau
- Center for Earth and Environmental Science, State University of New York, Plattsburgh, 101 Broad Street, Plattsburgh, NY, 12901, U.S.A
| | - Todd S Fredericksen
- School of Natural Sciences and Mathematics, Ferrum College, P.O. Box 100, Ferrum, VA, 24088, U.S.A
| | - Mary Beth Kolozsvary
- Department of Environmental Studies and Sciences, Siena College, 515 Loudon Road, Loudonville, NY, 12211, U.S.A
| | - Erin S Lindquist
- Department of Biological Sciences, Meredith College, 3800 Hillsborough Street, Raleigh, NC, 27607, U.S.A
| | - James G March
- Biology Department, Washington & Jefferson College, 60 S Lincoln Street, Washington, PA, 15301, U.S.A
| | - Rebecca A Urban
- Biology Department, Lebanon Valley College, 101 N. College Avenue, Annville, PA, 17033, U.S.A
| | - Craig R Zimmermann
- Department of Biology, Rogers State University, 1701 W. Will Rogers Boulevard, Claremore, OK, 74017, U.S.A
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Assessing the Impacts of Urbanization on Sex Ratios of Painted Turtles (Chrysemys picta). DIVERSITY 2019. [DOI: 10.3390/d11050072] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Turtles are particularly susceptible to the negative impacts of urbanization due to low mobility and a life history strategy emphasizing long generation times and high adult survival. In addition to declines directly through habitat loss, urbanization has been hypothesized to limit populations of aquatic turtles through changes in population structure, as adult females are disproportionally killed on and near roads, leading to male-biased populations, which can lead to population declines or local extirpations. The purpose of this study was to better understand how urbanization impacts the sex ratios of painted turtles (Chrysemys picta) in an urban ecosystem, as empirical results linking male-biased turtle populations to roads and urbanization are mixed. Using eight years of trapping data from a long-term monitoring program in a suburb of Chicago, IL, USA, we report one of the most male-biased populations ( x ¯ = 75% male) of turtles in the USA, consistent with prevailing road mortality hypotheses. However, we found no evidence that male-biased populations were related to road density or the amount of protected area around a sampling location and found that impervious surface (a metric of urbanization) was weakly related to less male-biased populations. Our results highlight the importance of replicating ecological studies across space and time and the difficulty in assessing population structure in aquatic turtles. We suggest that active conservation measures may be warranted for the continued persistence of urban turtle populations.
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