1
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PVA-based assessment of resiliency, redundancy, and representation in an imperiled freshwater turtle. Glob Ecol Conserv 2023. [DOI: 10.1016/j.gecco.2023.e02419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023] Open
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2
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Terrell VCK, Maerz JC, Engbrecht NJ, Stiles RM, Crawford BA, Lannoo MJ. Breeding Population Dynamics of Threatened Crawfish Frogs Inform Targets for Habitat Management. ICHTHYOLOGY & HERPETOLOGY 2023. [DOI: 10.1643/h2022031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Affiliation(s)
| | - John C. Maerz
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia 30602
| | - Nathan J. Engbrecht
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Terre Haute, Indiana 47809
| | - Rochelle M. Stiles
- Department of Biology, Indiana State University, Terre Haute, Indiana 47809
| | - Brian A. Crawford
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia 30602
| | - Michael J. Lannoo
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Terre Haute, Indiana 47809
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3
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Giaimo S. On two conjectures about perturbations of the stochastic growth rate. AUST NZ J STAT 2023. [DOI: 10.1111/anzs.12382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Affiliation(s)
- Stefano Giaimo
- Department of Evolutionary Theory Max Planck Institute for Evolutionary Biology August‐Thienemann‐Straße 2 24306Plön Germany
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4
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Evaluation of alternative conservation strategies for the blue-billed curassow Crax alberti in the Middle Magdalena Valley, Colombia. ORYX 2023. [DOI: 10.1017/s0030605322000060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Abstract
The blue-billed curassow Crax alberti is an endemic Colombian species categorized as Critically Endangered on the IUCN Red List because of the effects of hunting and habitat loss. Conservation and management actions are required to ensure its persistence in the forest remnants across its range. We conducted a population viability analysis for a population in the municipality of Yondó, Antioquia, based on data collected in the field and available information on the reproductive ecology of the species. We evaluate seven realistic conservation scenarios by comparing the effects that changes in mortality from hunting, carrying capacity and initial population size have on the survival probability of the population. Our results indicate that: (1) the studied population is not viable over a 100-year period under current conditions; (2) mortality as a result of hunting and the size of the initial population have the greatest impacts on the mean time to extinction; (3) a strategy based on eliminating hunting in the two sites with the largest forest remnants in the landscape could ensure the viability of the population over a 100-year period; and (4) other strategies (i.e. population supplementation with captive-bred individuals, reduction of deforestation in the landscape) do not guarantee the viability of the population if mortality from hunting remains constant, even at low levels. These results confirm the susceptibility of the blue-billed curassow to the threats it faces in this landscape, particularly hunting, and provide information on the conservation actions that could allow this remaining population to prevail in the long term.
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5
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Gibson D, Riecke TV, Catlin DH, Hunt KL, Weithman CE, Koons DN, Karpanty SM, Fraser JD. Climate change and commercial fishing practices codetermine survival of a long-lived seabird. GLOBAL CHANGE BIOLOGY 2023; 29:324-340. [PMID: 36229037 PMCID: PMC10092490 DOI: 10.1111/gcb.16482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 09/26/2022] [Accepted: 10/05/2022] [Indexed: 06/16/2023]
Abstract
Understanding the environmental mechanisms that govern population change is a fundamental objective in ecology. Although the determination of how top-down and bottom-up drivers affect demography is important, it is often equally critical to understand the extent to which, environmental conditions that underpin these drivers fluctuate across time. For example, associations between climate and both food availability and predation risk may suggest the presence of trophic interactions that may influence inferences made from patterns in ecological data. Analytical tools have been developed to account for these correlations, while providing opportunities to ask novel questions regarding how populations change across space and time. Here, we combine two modeling disciplines-path analysis and mark-recapture-recovery models-to explore whether shifts in sea-surface temperatures (SSTs) influenced top-down (entanglement in fishing equipment) or bottom-up (forage fish production) population constraints over 60 years, and the extent to which these covarying processes shaped the survival of a long-lived seabird, the Royal tern. We found that hemispheric trends in SST were associated with variation in the amount of fish harvested along the Atlantic coast of North America and in the Caribbean, whereas reductions in forage fish production were mostly driven by shifts in the amount of fish harvested by commercial fisheries throughout the North Atlantic the year prior. Although the indirect (i.e., stock depletion) and direct (i.e., entanglement) impacts of commercial fishing on Royal tern mortality has declined over the last 60 years, increased SSTs during this time period has resulted in a comparable increase in mortality risk, which disproportionately impacted the survival of the youngest age-classes of Royal terns. Given climate projections for the North Atlantic, our results indicate that threats to Royal tern population persistence in the Mid-Atlantic will most likely be driven by failures to recruit juveniles into the breeding population.
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Affiliation(s)
- Daniel Gibson
- Graduate Degree Program in Ecology, Department of Fish, Wildlife, and Conservation BiologyColorado State UniversityFort CollinsColoradoUSA
- Department of Fish and Wildlife ConservationVirginia TechBlacksburgVirginiaUSA
| | | | - Daniel H. Catlin
- Department of Fish and Wildlife ConservationVirginia TechBlacksburgVirginiaUSA
| | - Kelsi L. Hunt
- Department of Fish and Wildlife ConservationVirginia TechBlacksburgVirginiaUSA
| | - Chelsea E. Weithman
- Department of Fish and Wildlife ConservationVirginia TechBlacksburgVirginiaUSA
| | - David N. Koons
- Graduate Degree Program in Ecology, Department of Fish, Wildlife, and Conservation BiologyColorado State UniversityFort CollinsColoradoUSA
| | - Sarah M. Karpanty
- Department of Fish and Wildlife ConservationVirginia TechBlacksburgVirginiaUSA
| | - James D. Fraser
- Department of Fish and Wildlife ConservationVirginia TechBlacksburgVirginiaUSA
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6
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Manlik O, Lacy RC, Sherwin WB, Finn H, Loneragan NR, Allen SJ. A stochastic model for estimating sustainable limits to wildlife mortality in a changing world. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2022; 36:e13897. [PMID: 35122329 PMCID: PMC9542519 DOI: 10.1111/cobi.13897] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 12/22/2021] [Accepted: 01/24/2022] [Indexed: 05/27/2023]
Abstract
Human-caused mortality of wildlife is a pervasive threat to biodiversity. Assessing the population-level impact of fisheries bycatch and other human-caused mortality of wildlife has typically relied upon deterministic methods. However, population declines are often accelerated by stochastic factors that are not accounted for in such conventional methods. Building on the widely applied potential biological removal (PBR) equation, we devised a new population modeling approach for estimating sustainable limits to human-caused mortality and applied it in a case study of bottlenose dolphins affected by capture in an Australian demersal otter trawl fishery. Our approach, termed sustainable anthropogenic mortality in stochastic environments (SAMSE), incorporates environmental and demographic stochasticity, including the dependency of offspring on their mothers. The SAMSE limit is the maximum number of individuals that can be removed without causing negative stochastic population growth. We calculated a PBR of 16.2 dolphins per year based on the best abundance estimate available. In contrast, the SAMSE model indicated that only 2.3-8.0 dolphins could be removed annually without causing a population decline in a stochastic environment. These results suggest that reported bycatch rates are unsustainable in the long term, unless reproductive rates are consistently higher than average. The difference between the deterministic PBR calculation and the SAMSE limits showed that deterministic approaches may underestimate the true impact of human-caused mortality of wildlife. This highlights the importance of integrating stochasticity when evaluating the impact of bycatch or other human-caused mortality on wildlife, such as hunting, lethal control measures, and wind turbine collisions. Although population viability analysis (PVA) has been used to evaluate the impact of human-caused mortality, SAMSE represents a novel PVA framework that incorporates stochasticity for estimating acceptable levels of human-caused mortality. It offers a broadly applicable, stochastic addition to the demographic toolbox to evaluate the impact of human-caused mortality on wildlife.
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Affiliation(s)
- Oliver Manlik
- Biology Department, College of ScienceUnited Arab Emirates UniversityAbu DhabiUnited Arab Emirates
- Evolution and Ecology Research Centre, School of Biological Earth and Environmental ScienceUniversity of New South WalesSydneyNew South WalesAustralia
| | - Robert C. Lacy
- Species Conservation Toolkit InitiativeChicago Zoological SocietyBrookfieldIllinoisUSA
| | - William B. Sherwin
- Evolution and Ecology Research Centre, School of Biological Earth and Environmental ScienceUniversity of New South WalesSydneyNew South WalesAustralia
| | - Hugh Finn
- Curtin Law School, Faculty of Business and LawCurtin UniversityBentleyWestern AustraliaAustralia
| | - Neil R. Loneragan
- Environmental and Conservation Sciences, College of Science, Health, Engineering and Education and Centre for Sustainable Aquatic Ecosystems, Harry Butler InstituteMurdoch UniversityMurdochWestern AustraliaAustralia
| | - Simon J. Allen
- School of Biological SciencesUniversity of BristolBristolUK
- Department of AnthropologyUniversity of ZurichZurichSwitzerland
- School of Biological SciencesUniversity of Western AustraliaPerthWestern AustraliaAustralia
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7
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Allen AM, Jongejans E, van de Pol M, Ens BJ, Frauendorf M, van der Sluijs M, de Kroon H. The demographic causes of population change vary across four decades in a long-lived shorebird. Ecology 2021; 103:e3615. [PMID: 34921394 PMCID: PMC9286424 DOI: 10.1002/ecy.3615] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 07/29/2021] [Accepted: 09/24/2021] [Indexed: 11/07/2022]
Abstract
Understanding which factors cause populations to decline begins with identifying which parts of the life cycle, and which vital rates, have changed over time. However, in a world where humans are altering the environment both rapidly and in different ways, the demographic causes of decline likely vary over time. Identifying temporal variation in demographic causes of decline is crucial to assure that conservation actions target current and not past threats. However, this has rarely been studied as it requires long time series. Here we investigate how the demography of a long‐lived shorebird (the Eurasian Oystercatcher Haematopus ostralegus) has changed in the past four decades, resulting in a shift from stable dynamics to strong declines (−9% per year), and recently back to a modest decline. Since individuals of this species are likely to respond differently to environmental change, we captured individual heterogeneity through three state variables: age, breeding status, and lay date (using integral projection models). Timing of egg‐laying explained significant levels of variation in reproduction, with a parabolic relationship of maximal productivity near the average lay date. Reproduction explained most variation in population growth rates, largely due to poor nest success and hatchling survival. However, the demographic causes of decline have also been in flux over the last three decades: hatchling survival was low in the 2000s but improved in the 2010s, while adult survival declined in the 2000s and remains low today. Overall, the joint action of several key demographic variables explain the decline of the oystercatcher, and improvements in a single vital rate cannot halt the decline. Conservations actions will thus need to address threats occurring at different stages of the oystercatcher's life cycle. The dynamic nature of the threat landscape is further supported by the finding that the average individual no longer has the highest performance in the population, and emphasizes how individual heterogeneity in vital rates can play an important role in modulating population growth rates. Our results indicate that understanding population decline in the current era requires disentangling demographic mechanisms, individual variability, and their changes over time.
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Affiliation(s)
- Andrew M. Allen
- Department of Animal EcologyNetherlands Institute for Ecology (NIOO‐KNAW)WageningenThe Netherlands
- Department of Animal Ecology and PhysiologyRadboud UniversityNijmegenThe Netherlands
- Centre for Avian Population StudiesWageningenThe Netherlands
| | - Eelke Jongejans
- Department of Animal EcologyNetherlands Institute for Ecology (NIOO‐KNAW)WageningenThe Netherlands
- Department of Animal Ecology and PhysiologyRadboud UniversityNijmegenThe Netherlands
- Centre for Avian Population StudiesWageningenThe Netherlands
| | - Martijn van de Pol
- Department of Animal EcologyNetherlands Institute for Ecology (NIOO‐KNAW)WageningenThe Netherlands
- Centre for Avian Population StudiesWageningenThe Netherlands
- College of Science and EngineeringJames Cook UniversityTownsvilleQueenslandAustralia
| | - Bruno J. Ens
- Centre for Avian Population StudiesWageningenThe Netherlands
- Sovon Dutch Centre for Field OrnithologySovon‐TexelTexelThe Netherlands
| | - Magali Frauendorf
- Department of Animal EcologyNetherlands Institute for Ecology (NIOO‐KNAW)WageningenThe Netherlands
- Centre for Avian Population StudiesWageningenThe Netherlands
| | - Martijn van der Sluijs
- Department of Animal EcologyNetherlands Institute for Ecology (NIOO‐KNAW)WageningenThe Netherlands
- Centre for Avian Population StudiesWageningenThe Netherlands
| | - Hans de Kroon
- Centre for Avian Population StudiesWageningenThe Netherlands
- Department of Experimental Plant EcologyRadboud UniversityNijmegenThe Netherlands
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8
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Geographical variation in pace-of-life in a long-distance migratory bird: implications for population management. Oecologia 2021; 197:167-178. [PMID: 34459984 DOI: 10.1007/s00442-021-05012-8] [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: 05/06/2020] [Accepted: 08/03/2021] [Indexed: 10/20/2022]
Abstract
Life-history theory predicts that animals should develop adaptive trade-offs between survival and reproduction to maximize their fitness. This results in a continuum of life-history strategies among species, ranging from slow to fast paces-of-life. The optimal pace-of-life has been shown to vary within environmental gradients, with a commonly observed pattern of a slow-to-fast continuum from the tropics to the poles. Within species, pace-of-life variability has however received much less attention. In this study, we investigated whether or not the pace-of-life of populations within a species follows the expected slow-fast continuum associated with latitude. We analysed the variability of life-history strategies among populations of the European roller Coracias garrulus, a long-distance migratory species, comparing breeding parameters and adult survival between populations across a latitudinal gradient. The findings showed a negative correlation between survival and clutch size in roller populations, with a slower pace-of-life in the northern populations and a faster pace-of-life in the southern populations: a reverse gradient to what might be expected from inter-specific studies. These results suggest that northern populations would benefit from measures enhancing adult survival probability, such as reduction in harvesting rates, while southern populations would respond better to actions favouring reproductive success, such as nesting site provisioning. This study highlights that life-history traits can vary substantially between populations of a single species with a large latitudinal breeding range, and pinpoint how knowledge about this variability may be key in anticipating different populations' responses to threats as well as to conservation strategies.
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9
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Synodinos AD, Haegeman B, Sentis A, Montoya JM. Theory of temperature-dependent consumer-resource interactions. Ecol Lett 2021; 24:1539-1555. [PMID: 34120390 PMCID: PMC7614043 DOI: 10.1111/ele.13780] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 12/09/2020] [Accepted: 04/19/2021] [Indexed: 01/16/2023]
Abstract
Changes in temperature affect consumer-resource interactions, which underpin the functioning of ecosystems. However, existing studies report contrasting predictions regarding the impacts of warming on biological rates and community dynamics. To improve prediction accuracy and comparability, we develop an approach that combines sensitivity analysis and aggregate parameters. The former determines which biological parameters impact the community most strongly. The use of aggregate parameters (i.e., maximal energetic efficiency, ρ, and interaction strength, κ), that combine multiple biological parameters, increases explanatory power and reduces the complexity of theoretical analyses. We illustrate the approach using empirically derived thermal dependence curves of biological rates and applying it to consumer-resource biomass ratio and community stability. Based on our analyses, we generate four predictions: (1) resource growth rate regulates biomass distributions at mild temperatures, (2) interaction strength alone determines the thermal boundaries of the community, (3) warming destabilises dynamics at low and mild temperatures only and (4) interactions strength must decrease faster than maximal energetic efficiency for warming to stabilise dynamics. We argue for the potential benefits of directly working with the aggregate parameters to increase the accuracy of predictions on warming impacts on food webs and promote cross-system comparisons.
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Affiliation(s)
| | - Bart Haegeman
- Theoretical and Experimental Ecology Station, CNRS, Moulis, France
| | - Arnaud Sentis
- INRAE, Aix Marseille University, UMR RECOVER, Aix-en-Provence, France
| | - José M. Montoya
- Theoretical and Experimental Ecology Station, CNRS, Moulis, France
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10
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Dȩbicki IT, Mittell EA, Kristjánsson BK, Leblanc CA, Morrissey MB, Terzić K. Re-identification of individuals from images using spot constellations: a case study in Arctic charr ( Salvelinus alpinus). ROYAL SOCIETY OPEN SCIENCE 2021; 8:201768. [PMID: 34295512 PMCID: PMC8292754 DOI: 10.1098/rsos.201768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 06/22/2021] [Indexed: 06/13/2023]
Abstract
The ability to re-identify individuals is fundamental to the individual-based studies that are required to estimate many important ecological and evolutionary parameters in wild populations. Traditional methods of marking individuals and tracking them through time can be invasive and imperfect, which can affect these estimates and create uncertainties for population management. Here we present a photographic re-identification method that uses spot constellations in images to match specimens through time. Photographs of Arctic charr (Salvelinus alpinus) were used as a case study. Classical computer vision techniques were compared with new deep-learning techniques for masks and spot extraction. We found that a U-Net approach trained on a small set of human-annotated photographs performed substantially better than a baseline feature engineering approach. For matching the spot constellations, two algorithms were adapted, and, depending on whether a fully or semi-automated set-up is preferred, we show how either one or a combination of these algorithms can be implemented. Within our case study, our pipeline both successfully identified unmarked individuals from photographs alone and re-identified individuals that had lost tags, resulting in an approximately 4% increase in our estimate of survival rate. Overall, our multi-step pipeline involves little human supervision and could be applied to many organisms.
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Affiliation(s)
- Ignacy T. Dȩbicki
- School of Computer Science, University of St Andrews, St Andrews, UK
| | - Elizabeth A. Mittell
- School of Biology, University of St Andrews, St Andrews, UK
- Department of Aquaculture and Fish Biology, Hólar University, Sauðárkrókur, Iceland
| | | | - Camille A. Leblanc
- Department of Aquaculture and Fish Biology, Hólar University, Sauðárkrókur, Iceland
| | | | - Kasim Terzić
- School of Computer Science, University of St Andrews, St Andrews, UK
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11
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Hecht L. The importance of considering age when quantifying wild animals' welfare. Biol Rev Camb Philos Soc 2021; 96:2602-2616. [PMID: 34155749 DOI: 10.1111/brv.12769] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 01/18/2023]
Abstract
Wild animals experience different challenges and opportunities as they mature, and this variety of experiences can lead to different levels of welfare characterizing the day-to-day lives of individuals of different ages. At the same time, most wild animals who are born do not survive to adulthood. Individuals who die as juveniles do not simply experience a homogeneous fraction of the lifetimes of older members of their species; rather, their truncated lives may be characterized by very different levels of welfare. Here, I propose the concept of welfare expectancy as a framework for quantifying wild animal welfare at a population level, given individual-level data on average welfare with respect to age. This concept fits conveniently alongside methods of analysis already used in population ecology, such as demographic sensitivity analysis, and is applicable to evaluating the welfare consequences of human interventions and natural pressures that disproportionately affect individuals of different ages. In order to understand better and improve the state of wild animal welfare, more attention should be directed towards young animals and the particular challenges they face.
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Affiliation(s)
- Luke Hecht
- Wild Animal Initiative, 115 Elm Street, Suite I, PMB 2321, Farmington, MN, 55024, U.S.A.,Department of Biosciences, Durham University, Stockton Road, Durham, DH1 3LE, U.K
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12
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Thompson D, Glowacki G, Ludwig D, Reklau R, Kuhns AR, Golba CK, King R. Benefits of Head‐starting for Blanding's Turtle Size Distributions and Recruitment. WILDLIFE SOC B 2020. [DOI: 10.1002/wsb.1054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Daniel Thompson
- Forest Preserve District of DuPage County Naperville IL 60563 USA
| | - Gary Glowacki
- Lake County Forest Preserve DistrictLibertyville IL 60048 USA
| | - Daniel Ludwig
- Forest Preserve District of DuPage County Naperville IL 60563 USA
| | - Rachel Reklau
- Forest Preserve District of DuPage County Naperville IL 60563 USA
| | - Andrew R. Kuhns
- Illinois Natural History Survey, Prairie Research Institute, University of IllinoisChampaign IL 61820 USA
| | - Callie Klatt Golba
- Department of Biological SciencesNorthern Illinois UniversityDeKalb IL 60115 USA
| | - Richard King
- Department of Biological Sciences and Institute for the Study of the Environment, Sustainability, and EnergyNorthern Illinois University DeKalb IL 60115 USA
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13
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Hepp GR, Gitzen RA, Kennamer RA. Relative Importance of Vital Rates to Population Dynamics of Wood Ducks. J Wildl Manage 2020. [DOI: 10.1002/jwmg.21792] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Gary R. Hepp
- School of Forestry and Wildlife Sciences Auburn University Auburn AL 36849 USA
| | - Robert A. Gitzen
- School of Forestry and Wildlife Sciences Auburn University Auburn AL 36849 USA
| | - Robert A. Kennamer
- University of Georgia, Savannah River Ecology Laboratory P.O. Drawer E Aiken SC 29802 USA
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14
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Couet P, Gally F, Canonne C, Besnard A. Joint estimation of survival and breeding probability in female dolphins and calves with uncertainty in state assignment. Ecol Evol 2019; 9:13043-13055. [PMID: 31871628 PMCID: PMC6912916 DOI: 10.1002/ece3.5693] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 08/06/2019] [Accepted: 09/06/2019] [Indexed: 12/01/2022] Open
Abstract
While the population growth rate in long-lived species is highly sensitive to adult survival, reproduction can also significantly drive population dynamics. Reproductive parameters can be challenging to estimate as breeders and nonbreeders may vary in resighting probability and reproductive status may be difficult to assess. We extended capture-recapture (CR) models previously fitted for data on other long-lived marine mammals to estimate demographic parameters while accounting for detection heterogeneity between individuals and state uncertainty regarding reproductive status. We applied this model to data on 106 adult female bottlenose dolphins observed over 13 years. The detection probability differed depending on breeding status. Concerning state uncertainty, offspring were not always sighted with their mother, and older calves were easier to detect than young-of-the-year (YOY), respectively, 0.79 (95% CI 0.59-0.90) and 0.58 (95% CI 0.46-0.68). This possibly led to inaccurate reproductive status assignment of females. Adult female survival probability was high (0.97 CI 95% 0.96-0.98) and did not differ according to breeding status. Young-of-the-year and 1-year-old calves had a significantly higher survival rate than 2-year-old (respectively, 0.66 CI 95% 0.50-0.78 and 0.45 CI 95% 0.29-0.61). This reduced survival is probably related to weaning, a period during which young are exposed to more risks since they lose protection and feeding from the mother. The probability of having a new YOY was high for breeding females that had raised a calf to the age of 3 or lost a 2-year-old calf (0.71, CI 95% 0.45-0.88). Yet, this probability was much lower for nonbreeding females and breeding females that had lost a YOY or a 1-year-old calf (0.33, 95% CI 0.26-0.42). The multievent CR framework we used is highly flexible and could be easily modified for other study questions or taxa (marine or terrestrial) aimed at modeling reproductive parameters.
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Affiliation(s)
- Pauline Couet
- CNRSUMSupAgroIRDINRAUMR 5175 CEFEEPHEPSL Research UniversityMontpellierFrance
- Groupe d'Etude des Cétacés du CotentinCherbourg‐OctevilleFrance
| | - François Gally
- Groupe d'Etude des Cétacés du CotentinCherbourg‐OctevilleFrance
| | - Coline Canonne
- CNRSUMSupAgroIRDINRAUMR 5175 CEFEEPHEPSL Research UniversityMontpellierFrance
- Direction Recherche et ExpertiseONCFSSaint‐BenoitAuffargisFrance
| | - Aurélien Besnard
- CNRSUMSupAgroIRDINRAUMR 5175 CEFEEPHEPSL Research UniversityMontpellierFrance
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15
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Manlik O. The Importance of Reproduction for the Conservation of Slow-Growing Animal Populations. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1200:13-39. [PMID: 31471793 DOI: 10.1007/978-3-030-23633-5_2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Both survival and reproduction are important fitness components, and thus critical to the viability of wildlife populations. Preventing one death (survival) or contributing one newborn (reproduction), has arguably the same effect on population dynamics-in each instance the population grows or is maintained by one additional member. However, for the conservation of slow-growing animal populations, the importance of reproduction is sometimes overlooked when evaluating wildlife management options. This has to do with the use of demographic sensitivity analyses, which quantify the relative contribution of vital rates to population growth. For slow-growing populations, the results of such analyses typically show that growth rates are more sensitive to changes in survival than to equal proportional changes in reproduction. Consequently, for slow-growing taxa, survival has been labelled a better fitness surrogate than reproduction. However, such a generalization, derived from conventional sensitivity analyses, is based on flawed approaches, such as omitting appropriate scaling of vital rates, and sometimes misinterpretations. In this chapter, I make the case that for the conservation of slow-growing species the role of reproduction is considerably greater than conventional sensitivity analyses would suggest. This is illustrated by case studies on wildlife populations that underscore the importance of reproduction for the conservation of slow-growing birds, ungulates, carnivores, and cetaceans.
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Affiliation(s)
- Oliver Manlik
- Biology Department, College of Science, United Arab Emirates University, Al Ain, United Arab Emirates. .,Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, Australia.
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16
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Paquet M, Arlt D, Knape J, Low M, Forslund P, Pärt T. Quantifying the links between land use and population growth rate in a declining farmland bird. Ecol Evol 2019; 9:868-879. [PMID: 30766676 PMCID: PMC6362438 DOI: 10.1002/ece3.4766] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Revised: 11/13/2018] [Accepted: 11/05/2018] [Indexed: 11/17/2022] Open
Abstract
Land use is likely to be a key driver of population dynamics of species inhabiting anthropogenic landscapes, such as farmlands. Understanding the relationships between land use and variation in population growth rates is therefore critical for the management of many farmland species. Using 24 years of data of a declining farmland bird in an integrated population model, we examined how spatiotemporal variation in land use (defined as habitats with "Short" and "Tall" ground vegetation during the breeding season) and habitat-specific demographic parameters relates to variation in population growth taking into account individual movements between habitats. We also evaluated contributions to population growth using transient life table response experiments which gives information on contribution of past variation of parameters and real-time elasticities which suggests future scenarios to change growth rates. LTRE analyses revealed a clear contribution of Short habitats to the annual variation in population growth rate that was mostly due to fledgling recruitment, whereas there was no evidence for a contribution of Tall habitats. Only 18% of the variation in population growth was explained by the modeled local demography, the remaining variation being explained by apparent immigration (i.e., the residual variation). We discuss potential biological and methodological reasons for high contributions of apparent immigration in open populations. In line with LTRE analysis, real-time elasticity analysis revealed that demographic parameters linked to Short habitats had a stronger potential to influence population growth rate than those of Tall habitats. Most particularly, an increase of the proportion of Short sites occupied by Old breeders could have a distinct positive impact on population growth. High-quality Short habitats such as grazed pastures have been declining in southern Sweden. Converting low-quality to high-quality habitats could therefore change the present negative population trend of this, and other species with similar habitat requirements.
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Affiliation(s)
- Matthieu Paquet
- Department of EcologySwedish University of Agricultural SciencesUppsalaSweden
| | - Debora Arlt
- Department of EcologySwedish University of Agricultural SciencesUppsalaSweden
| | - Jonas Knape
- Department of EcologySwedish University of Agricultural SciencesUppsalaSweden
| | - Matthew Low
- Department of EcologySwedish University of Agricultural SciencesUppsalaSweden
| | - Pär Forslund
- Department of EcologySwedish University of Agricultural SciencesUppsalaSweden
| | - Tomas Pärt
- Department of EcologySwedish University of Agricultural SciencesUppsalaSweden
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Lacy RC. Lessons from 30 years of population viability analysis of wildlife populations. Zoo Biol 2018; 38:67-77. [PMID: 30585658 DOI: 10.1002/zoo.21468] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 11/14/2018] [Accepted: 12/04/2018] [Indexed: 12/16/2022]
Abstract
Population viability analysis (PVA) has been used for three decades to assess threats and evaluate conservation options for wildlife populations. What has been learned from PVA on in situ populations are valuable lessons also for assessing and managing viability and sustainability of ex situ populations. The dynamics of individual populations are unpredictable, due to limited knowledge about important factors, variability in the environment, and the probabilistic nature of demographic events. PVA considers such uncertainty within simulations that generate the distribution of likely fates for a population; management of ex situ populations should also take into consideration the uncertainty in our data and in the trajectories of populations. The processes affecting wildlife populations interact, with feedbacks often leading to amplified threats to viability; projections of ex situ populations should include such feedbacks to allow for management that foresees and responds to the cumulative and synergistic threats. PVA is useful for evaluating conservation options only if the goals for each population and measures of success are first clearly identified; similarly, for ex situ populations to contribute maximally to species conservation, the purposes for the population and definitions of sustainability in terms of acceptable risk must be documented. PVA requires a lot of data, knowledge of many processes affecting the populations, modeling expertize, and understanding of management goals and constraints. Therefore, to be useful in guiding conservation it must be a collaborative, trans-disciplinary, and social process. PVA can help integrate management of in situ and ex situ populations within comprehensive species conservation plans.
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Bradke DR, Bailey RL, Bartman JF, Campa H, Hileman ET, Krueger C, Kudla N, Lee YM, Thacker AJ, Moore JA. Sensitivity Analysis Using Site-Specific Demographic Parameters to Guide Research and Management of Threatened Eastern Massasaugas. COPEIA 2018. [DOI: 10.1643/ot-18-059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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van Rees CB, Reed JM. Predicted effects of landscape change, sea level rise, and habitat management on the extirpation risk of the Hawaiian common gallinule ( Gallinula galeata sandvicensis) on the island of O'ahu. PeerJ 2018; 6:e4990. [PMID: 29942683 PMCID: PMC6016525 DOI: 10.7717/peerj.4990] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 05/27/2018] [Indexed: 11/28/2022] Open
Abstract
We conducted a spatially explicit, stochastic, individually based population viability analysis for the Hawaiian common gallinule (Gallinula galeata sandvicensis), an endangered subspecies of waterbird endemic to fragmented coastal wetlands in Hawai'i. This subspecies persists on two islands, with no apparent movement between them. We assessed extirpation risk for birds on O'ahu, where the resident gallinule population is made up of several fragmented subpopulations. Data on genetic differentiation were used to delineate subpopulations and estimate dispersal rates between them. We used sensitivity analyses to gauge the impact of current uncertainty of vital rate parameters on population projections, to ascertain the relative importance of gallinule vital rates to population persistence, and to compare the efficacy of potential management strategies. We used available sea level rise projections to examine the relative vulnerability of O'ahu's gallinule population to habitat loss arising from this threat. Our model predicted persistence of the island's gallinule population at 160 years (∼40 generations), but with high probabilities of extirpation for small subpopulations. Sensitivity analyses highlighted the importance of juvenile and adult mortality to population persistence in Hawaiian gallinules, justifying current predator control efforts and suggesting the need for additional research on chick and fledgling survival. Subpopulation connectivity from dispersal had little effect on the persistence of the island-wide population, but strong effects on the persistence of smaller subpopulations. Our model also predicted island-wide population persistence under predicted sea level rise scenarios, but with O'ahu's largest gallinule populations losing >40% of current carrying capacity.
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Affiliation(s)
- Charles B. van Rees
- Department of Biology, Tufts University, Medford, MA, United States of America
| | - J. Michael Reed
- Department of Biology, Tufts University, Medford, MA, United States of America
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