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Shkalim Zemer V, Manor I, Weizman A, Cohen HA, Hoshen M, Menkes Caspi N, Cohen S, Faraone SV, Shahar N. The influence of COVID-19 on attention-deficit/hyperactivity disorder diagnosis and treatment rates across age, gender, and socioeconomic status: A 20-year national cohort study. Psychiatry Res 2024; 339:116077. [PMID: 39053214 DOI: 10.1016/j.psychres.2024.116077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Revised: 06/27/2024] [Accepted: 06/30/2024] [Indexed: 07/27/2024]
Abstract
Infection and lockdowns resulting from COVID-19 have been suggested to increase the prevalence and treatment rates of Attention Deficit/Hyperactivity Disorder (ADHD). To accurately estimate the pandemic's effects, pre-pandemic data can be used to estimate diagnosis and treatment rates during the COVID-19 years as if the COVID-19 pandemic did not occur. However, accurate predictions require a broad dataset, both in terms of the number of cases and the pre-pandemic timeframe. In the current study, we modeled monthly ADHD diagnosis and treatment rates over the 18 years preceding the COVID-19 pandemic. The dataset included ∼3 million cases for individuals aged 6 to 18 from the Clalit Health Services' electronic database. Using a trained model, we projected monthly rates for post-lockdown and post-infection periods, enabling us to estimate the expected diagnosis and treatment rates without the COVID-19 pandemic. We then compared these predictions to observed data, stratified by age groups, gender, and socioeconomic status. Our findings suggest no influence of the COVID-19 pandemic on ADHD diagnosis or treatment rates. We show that a narrower timeframe for pre-COVID-19 data points can lead to incorrect conclusions that COVID-19 affected ADHD diagnosis rates. Findings are discussed, given the assumed impact of the COVID-19 pandemic on ADHD.
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Affiliation(s)
- Vered Shkalim Zemer
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Dan-Petach-Tikva District, Clalit Health Services, Israel.
| | - Iris Manor
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Dan-Petach-Tikva District, Clalit Health Services, Israel; Geha Mental Health Center, Petah Tikva, Israel
| | - Abraham Weizman
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Dan-Petach-Tikva District, Clalit Health Services, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Herman Avner Cohen
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Pediatric Ambulatory Community Clinic, Petach Tikva, Israel
| | - Moshe Hoshen
- Dan-Petach-Tikva District, Clalit Health Services, Israel; Bioinformatics Department, Jerusalem College of Technology, Jerusalem, Israel
| | | | - Shira Cohen
- Geha Mental Health Center, Petah Tikva, Israel
| | - Stephen V Faraone
- Departments of Psychiatry and Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Nitzan Shahar
- The School of Psychological Sciences, Tel Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
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2
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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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3
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Bradshaw CJA, Herrando‐Pérez S. Logistic-growth models measuring density feedback are sensitive to population declines, but not fluctuating carrying capacity. Ecol Evol 2023; 13:e10010. [PMID: 37122772 PMCID: PMC10131297 DOI: 10.1002/ece3.10010] [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: 01/17/2023] [Revised: 03/27/2023] [Accepted: 03/31/2023] [Indexed: 05/02/2023] Open
Abstract
Analysis of long-term trends in abundance of animal populations provides insights into population dynamics. Population growth rates are the emergent interplay of inter alia fertility, survival, and dispersal. However, the density feedbacks operating on some vital rates ("component feedback") can be decoupled from density feedbacks on population growth rates estimated using abundance time series ("ensemble feedback"). Many of the mechanisms responsible for this decoupling are poorly understood, thereby questioning the validity of using logistic-growth models versus vital rates to infer long-term population trends. To examine which conditions lead to decoupling, we simulated age-structured populations of long-lived vertebrates experiencing component density feedbacks on survival. We then quantified how imposed stochasticity in survival rates, density-independent mortality (catastrophes, harvest-like removal of individuals) and variation in carrying capacity modified the ensemble feedback in abundance time series simulated from age-structured populations. The statistical detection of ensemble density feedback from census data was largely unaffected by density-independent processes. Long-term population decline caused from density-independent mortality was the main mechanism decoupling the strength of component versus ensemble density feedbacks. Our study supports the use of simple logistic-growth models to capture long-term population trends, mediated by changes in population abundance, when survival rates are stochastic, carrying capacity fluctuates, and populations experience moderate catastrophic mortality over time.
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Affiliation(s)
- Corey J. A. Bradshaw
- Global Ecology, College of Science and EngineeringFlinders UniversityAdelaideSouth AustraliaAustralia
- Australian Research Council Centre of Excellence for Australian Biodiversity and HeritageWollongongNew South WalesAustralia
| | - Salvador Herrando‐Pérez
- Department of Biogeography and Global ChangeMuseo Nacional de Ciencias Naturales, Spanish National Research Council (CSIC)MadridSpain
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4
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Rullens V, Stephenson F, Hewitt JE, Clark DE, Pilditch CA, Thrush SF, Ellis JI. The impact of cumulative stressor effects on uncertainty and ecological risk. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 842:156877. [PMID: 35752242 DOI: 10.1016/j.scitotenv.2022.156877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 05/29/2022] [Accepted: 06/18/2022] [Indexed: 06/15/2023]
Abstract
To enable environmental management actions to be more effectively prioritized, cumulative effects between multiple stressors need to be accounted for in risk-assessment frameworks. Ecological risk and uncertainty are generally high when multiple stressors occur. In the face of high uncertainty, transparent communication is essential to inform decision-making. The impact of stressor interactions on risk and uncertainty was assessed using generalized linear models for additive and multiplicative effect of six anthropogenic stressors on the abundance of estuarine macrofauna across New Zealand. Models that accounted for multiplicative stressor interactions demonstrated that non-additive effects dominated, had increased explanatory power (6 to 73 % relative increase between models), and thereby reduced the risk of unexpected ecological responses to stress. Secondly, 3D-plots provide important insights in the direction, magnitude and gradients of change, and aid transparency and communication of complex stressor effects. Notably, small changes in a stressor can cause a disproportionally steep gradient of change for a synergistic effect where the tolerance to stressors are lost, and would invoke precautionary management. 3D-plots were able to clearly identify directional shifts where the nature of the interaction changed from antagonistic to synergistic along increasing stressor gradients. For example, increased nitrogen load and exposure caused a shift from positive to negative effect on the abundance of a deposit-feeding polychaete (Magelona). Assessments relying on model coefficient estimates, which provide one effect term, could not capture the complexities observed in 3D-plots and are at risk of mis-identifying interaction types. Finally, visualising model uncertainty demonstrated that although error terms were higher for multiplicative models, they better captured the uncertainty caused by data availability. Together, the steep gradients of change identified in 3D-plots and the higher uncertainty in model predictions in multiplicative models urges more conservative limits to be set for management that account for risk and uncertainty in multiple stressor effects.
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Affiliation(s)
- Vera Rullens
- School of Science, University of Waikato, Hamilton, New Zealand.
| | - Fabrice Stephenson
- School of Science, University of Waikato, Hamilton, New Zealand; National Institute for Water and Atmospheric research, Hamilton, New Zealand
| | - Judi E Hewitt
- National Institute for Water and Atmospheric research, Hamilton, New Zealand; Department of Statistics, University of Auckland, Auckland, New Zealand
| | | | | | - Simon F Thrush
- Institute of Marine Science, University of Auckland, Auckland, New Zealand
| | - Joanne I Ellis
- School of Science, University of Waikato, Tauranga, New Zealand
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5
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Bahlai CA, White ER, Perrone JD, Cusser S, Stack Whitney K. The broken window: An algorithm for quantifying and characterizing misleading trajectories in ecological processes. ECOL INFORM 2021. [DOI: 10.1016/j.ecoinf.2021.101336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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6
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Vallecillo D, Gauthier‐Clerc M, Guillemain M, Vittecoq M, Vandewalle P, Roche B, Champagnon J. Reliability of animal counts and implications for the interpretation of trends. Ecol Evol 2021; 11:2249-2260. [PMID: 33717452 PMCID: PMC7920765 DOI: 10.1002/ece3.7191] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 11/17/2020] [Accepted: 12/18/2020] [Indexed: 11/24/2022] Open
Abstract
Population time series analysis is an integral part of conservation biology in the current context of global changes. To quantify changes in population size, wildlife counts only provide estimates because of various sources of error. When unaccounted for, such errors can obscure important ecological patterns and reduce confidence in the derived trend. In the case of highly gregarious species, which are common in the animal kingdom, the estimation of group size is an important potential bias, which is characterized by high variance among observers. In this context, it is crucial to quantify the impact of observer changes, inherent to population monitoring, on i) the minimum length of population time series required to detect significant trends and ii) the accuracy (bias and precision) of the trend estimate.We acquired group size estimation error data by an experimental protocol where 24 experienced observers conducted counting simulation tests on group sizes. We used this empirical data to simulate observations over 25 years of a declining population distributed over 100 sites. Five scenarios of changes in observer identity over time and sites were tested for each of three simulated trends (true population size evolving according to deterministic models parameterized with declines of 1.1%, 3.9% or 7.4% per year that justify respectively a "declining," "vulnerable" or "endangered" population under IUCN criteria).We found that under realistic field conditions observers detected the accurate value of the population trend in only 1.3% of the cases. Our results also show that trend estimates are similar if many observers are spatially distributed among the different sites, or if one single observer counts all sites. However, successive changes in observer identity over time lead to a clear decrease in the ability to reliably estimate a given population trend, and an increase in the number of years of monitoring required to adequately detect the trend.Minimizing temporal changes of observers improve the quality of count data and help taking appropriate management decisions and setting conservation priorities. The same occurs when increasing the number of observers spread over 100 sites. If the population surveyed is composed of few sites, then it is preferable to perform the survey by one observer. In this context, it is important to reconsider how we use estimated population trend values and potentially to scale our decisions according to the direction and duration of estimated trends, instead of setting too precise threshold values before action.
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Affiliation(s)
- David Vallecillo
- Tour du ValatResearch institute for the conservation of Mediterranean wetlandsArlesFrance
- OFBUnité Avifaune migratriceLa Tour du ValatArlesFrance
| | | | | | - Marion Vittecoq
- Tour du ValatResearch institute for the conservation of Mediterranean wetlandsArlesFrance
| | | | - Benjamin Roche
- IRDSorbonne UniversitéUMMISCOBondyFrance
- MIVEGEC, IRDCNRSUniversité MontpellierMontpellierFrance
- Departamento de EtologíaFauna Silvestre y Animales de LaboratorioFacultad de Medicina Veterinaria y ZootecniaUniversidad Nacional Autónoma de México (UNAM)Ciudad de MéxicoMéxico
| | - Jocelyn Champagnon
- Tour du ValatResearch institute for the conservation of Mediterranean wetlandsArlesFrance
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7
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Awkerman J, Raimondo S, Schmolke A, Galic N, Rueda-Cediel P, Kapo K, Accolla C, Vaugeois M, Forbes V. Guidance for Developing Amphibian Population Models for Ecological Risk Assessment. INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2020; 16:223-233. [PMID: 31538699 PMCID: PMC8425957 DOI: 10.1002/ieam.4215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 07/22/2019] [Accepted: 09/10/2019] [Indexed: 05/05/2023]
Abstract
Despite widespread acceptance of the utility of population modeling and advocacy of this approach for a more ecologically relevant perspective, it is not routinely incorporated in ecological risk assessments (ERA). A systematic framework for situation-specific model development is one of the major challenges to broadly adopting population models in ERA. As risk assessors confront the multitude of species and chemicals requiring evaluation, an adaptable stepwise guide for model parameterization would facilitate this process. Additional guidance on interpretation of model output and evaluating uncertainty would further contribute to establishing consensus on good modeling practices. We build on previous work that created a framework and decision guide for developing population models for ERA by focusing on data types, model structure, and extrinsic stressors relevant to anuran amphibians. Anurans have a unique life cycle with varying habitat requirements and high phenotypic plasticity. These species belong to the amphibian class, which is facing global population decline in large part due to anthropogenic stressors, including chemicals. We synthesize information from databases and literature relevant to amphibian risks to identify traits that influence exposure likelihood, inherent sensitivity, population vulnerability, and environmental constraints. We link these concerns with relevant population modeling methods and structure in order to evaluate pesticide effects with appropriate scale and parameterization. A standardized population modeling approach, with additional guidance for anuran ERA, offers an example method for quantifying population risks and evaluating long-term impacts of chemical stressors to populations. Integr Environ Assess Manag 2020;16:223-233. © 2019 SETAC.
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Affiliation(s)
- Jill Awkerman
- Gulf Ecology Division, US Environmental Protection Agency, Gulf Breeze, Florida
| | - Sandy Raimondo
- Gulf Ecology Division, US Environmental Protection Agency, Gulf Breeze, Florida
| | | | - Nika Galic
- Syngenta Crop Protection, LLC, Greensboro, North Carolina, USA
| | - Pamela Rueda-Cediel
- College of Biological Sciences, University of Minnesota, St Paul, Minnesota, USA
| | | | - Chiara Accolla
- College of Biological Sciences, University of Minnesota, St Paul, Minnesota, USA
| | - Maxime Vaugeois
- College of Biological Sciences, University of Minnesota, St Paul, Minnesota, USA
| | - Valery Forbes
- College of Biological Sciences, University of Minnesota, St Paul, Minnesota, USA
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8
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Wauchope HS, Amano T, Sutherland WJ, Johnston A. When can we trust population trends? A method for quantifying the effects of sampling interval and duration. Methods Ecol Evol 2019. [DOI: 10.1111/2041-210x.13302] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hannah S. Wauchope
- Conservation Science Group Department of Zoology University of Cambridge Cambridge UK
| | - Tatsuya Amano
- Conservation Science Group Department of Zoology University of Cambridge Cambridge UK
- Centre for the Study of Existential Risk University of Cambridge Cambridge UK
- School of Biological Sciences The University of Queensland Brisbane Australia
| | - William J. Sutherland
- Conservation Science Group Department of Zoology University of Cambridge Cambridge UK
| | - Alison Johnston
- Conservation Science Group Department of Zoology University of Cambridge Cambridge UK
- Cornell Lab of Ornithology Cornell University Ithaca NY USA
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9
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10
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White ER. Minimum Time Required to Detect Population Trends: The Need for Long-Term Monitoring Programs. Bioscience 2018. [DOI: 10.1093/biosci/biy144] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Easton R White
- Center for Population Biology at the University of California, Davis
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11
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Thomas FM, Vesk PA, Hauser CE. A field ecologist's adventures in the virtual world: using simulations to design data collection for complex models. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2018; 28:2130-2141. [PMID: 30276923 DOI: 10.1002/eap.1801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 07/01/2018] [Accepted: 08/20/2018] [Indexed: 06/08/2023]
Abstract
Field data collection can be expensive, time consuming, and difficult; insightful research requires statistical analyses supported by sufficient data. Pilot studies and power analysis provide guidance on sampling design but can be challenging to perform, as ecologists increasingly collect multiple types of data over different scales. Despite a growing simulation literature, it remains unclear how to appropriately design data collection for many complex projects. Approaches that seek to achieve realism in decision-making contexts, such as management strategy evaluation and virtual ecologist simulations, can help. For a relatively complex analysis, we develop and demonstrate a flexible simulation approach that informs what data are needed and how long those data will take to collect, under realistic fieldwork constraints. We simulated data collection and analysis under different constraint scenarios that varied in deterministic (field trip length, travel, and measurement times) and stochastic (species detection and occupancy rates and inclement weather) features. In our case study, we fit plant height data to a multispecies, three-parameter, nonlinear growth model. We tested how the simulated data sets, based on the varying constraint scenarios, affected the model fit (parameter bias, uncertainty, and capture rate). Species prevalence in the field exerted a stronger influence on the data sets and downstream model performance than deterministic aspects such as travel times. When species detection and occupancy were not considered, the field time needed to collect an adequate data set was underestimated by 40%. Simulations can assist in refining fieldwork design, estimating field costs, and incorporating uncertainties into project planning. We argue that combining data collection, analysis, and decision-making processes in a flexible virtual setting can help address many of the decisions that field ecologists face when designing field-based research.
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Affiliation(s)
- Freya M Thomas
- School of BioSciences, ARC Centre of Excellence for Environmental Decisions, The University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Peter A Vesk
- School of BioSciences, ARC Centre of Excellence for Environmental Decisions, The University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Cindy E Hauser
- School of BioSciences, ARC Centre of Excellence for Environmental Decisions, The University of Melbourne, Melbourne, Victoria, 3010, Australia
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12
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Goodwin CED, Hodgson DJ, Al-Fulaij N, Bailey S, Langton S, Mcdonald RA. Voluntary recording scheme reveals ongoing decline in the United Kingdom hazel dormouse Muscardinus avellanarius
population. Mamm Rev 2017. [DOI: 10.1111/mam.12091] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Cecily E. D. Goodwin
- Environment and Sustainability Institute; University of Exeter; Penryn Campus; Penryn TR10 9FE Cornwall UK
| | - David J. Hodgson
- Centre for Ecology and Conservation; University of Exeter; Penryn Campus; Penryn TR10 9FE Cornwall UK
| | - Nida Al-Fulaij
- People's Trust for Endangered Species; 3 Cloisters House 8 Battersea Park Road London SW8 4BG UK
| | - Sallie Bailey
- Forest Enterprise Scotland; Dumfries & Borders Forest District; Ae Village, Parkgate Dumfries DG1 1QB UK
| | - Steve Langton
- Hallgarth; Leavening Malton YO17 9SA North Yorkshire UK
| | - Robbie A. Mcdonald
- Environment and Sustainability Institute; University of Exeter; Penryn Campus; Penryn TR10 9FE Cornwall UK
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13
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Regan HM, Bohórquez CI, Keith DA, Regan TJ, Anderson KE. Implications of different population model structures for management of threatened plants. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2017; 31:459-468. [PMID: 27596063 DOI: 10.1111/cobi.12831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 05/23/2016] [Accepted: 07/19/2016] [Indexed: 06/06/2023]
Abstract
Population viability analysis (PVA) is a reliable tool for ranking management options for a range of species despite parameter uncertainty. No one has yet investigated whether this holds true for model uncertainty for species with complex life histories and for responses to multiple threats. We tested whether a range of model structures yielded similar rankings of management and threat scenarios for 2 plant species with complex postfire responses. We examined 2 contrasting species from different plant functional types: an obligate seeding shrub and a facultative resprouting shrub. We exposed each to altered fire regimes and an additional, species-specific threat. Long-term demographic data sets were used to construct an individual-based model (IBM), a complex stage-based model, and a simple matrix model that subsumes all life stages into 2 or 3 stages. Agreement across models was good under some scenarios and poor under others. Results from the simple and complex matrix models were more similar to each other than to the IBM. Results were robust across models when dominant threats are considered but were less so for smaller effects. Robustness also broke down as the scenarios deviated from baseline conditions, likely the result of a number of factors related to the complexity of the species' life history and how it was represented in a model. Although PVA can be an invaluable tool for integrating data and understanding species' responses to threats and management strategies, this is best achieved in the context of decision support for adaptive management alongside multiple lines of evidence and expert critique of model construction and output.
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Affiliation(s)
- Helen M Regan
- Biology Department, University of California Riverside, 900 University Avenue, Riverside, CA, 92521, U.S.A
| | - Clara I Bohórquez
- Biology Department, University of California Riverside, 900 University Avenue, Riverside, CA, 92521, U.S.A
- Biology Department, Universidad Nacional de Colombia, Carrera 45 #26-85, Edif. Uriel Gutiérrez, Bogotá D.C., Colombia
| | - David A Keith
- Centre for Ecosystem Science, School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia
- New South Wales Office of Environment & Heritage, P.O. Box A290, Sydney South, NSW, 1232, Australia
| | - Tracey J Regan
- Arthur Rylah Institute for Environmental Research, The Department of Environment, Land, Water and Planning, 123 Brown Street, Heidelberg, VIC, 3084, Australia
- School of Biosciences, University of Melbourne, Parkville Campus, VIC, 3010, Australia
| | - Kurt E Anderson
- Biology Department, University of California Riverside, 900 University Avenue, Riverside, CA, 92521, U.S.A
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14
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Tolimieri N, Holmes EE, Williams GD, Pacunski R, Lowry D. Population assessment using multivariate time-series analysis: A case study of rockfishes in Puget Sound. Ecol Evol 2017; 7:2846-2860. [PMID: 28428874 PMCID: PMC5395462 DOI: 10.1002/ece3.2901] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 02/13/2017] [Accepted: 02/21/2017] [Indexed: 11/06/2022] Open
Abstract
Estimating a population's growth rate and year-to-year variance is a key component of population viability analysis (PVA). However, standard PVA methods require time series of counts obtained using consistent survey methods over many years. In addition, it can be difficult to separate observation and process variance, which is critical for PVA. Time-series analysis performed with multivariate autoregressive state-space (MARSS) models is a flexible statistical framework that allows one to address many of these limitations. MARSS models allow one to combine surveys with different gears and across different sites for estimation of PVA parameters, and to implement replication, which reduces the variance-separation problem and maximizes informational input for mean trend estimation. Even data that are fragmented with unknown error levels can be accommodated. We present a practical case study that illustrates MARSS analysis steps: data choice, model set-up, model selection, and parameter estimation. Our case study is an analysis of the long-term trends of rockfish in Puget Sound, Washington, based on citizen science scuba surveys, a fishery-independent trawl survey, and recreational fishery surveys affected by bag-limit reductions. The best-supported models indicated that the recreational and trawl surveys tracked different, temporally independent assemblages that declined at similar rates (an average of -3.8% to -3.9% per year). The scuba survey tracked a separate increasing and temporally independent assemblage (an average of 4.1% per year). Three rockfishes (bocaccio, canary, and yelloweye) are listed in Puget Sound under the US Endangered Species Act (ESA). These species are associated with deep water, which the recreational and trawl surveys sample better than the scuba survey. All three ESA-listed rockfishes declined as a proportion of recreational catch between the 1970s and 2010s, suggesting that they experienced similar or more severe reductions in abundance than the 3.8-3.9% per year declines that were estimated for rockfish populations sampled by the recreational and trawl surveys.
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Affiliation(s)
- Nick Tolimieri
- Conservation Biology DivisionNorthwest Fisheries Science CenterNational Marine Fisheries ServiceNational Oceanic and Atmospheric AdministrationSeattleWAUSA
| | - Elizabeth E. Holmes
- Conservation Biology DivisionNorthwest Fisheries Science CenterNational Marine Fisheries ServiceNational Oceanic and Atmospheric AdministrationSeattleWAUSA
| | - Gregory D. Williams
- Pacific States Marine Fisheries Commission, Under Contract to Northwest Fisheries Science CenterNational Marine Fisheries ServiceNational Oceanic and Atmospheric AdministrationSeattleWAUSA
| | - Robert Pacunski
- Marine Fish Science UnitFish Management DivisionWashington Department of Fish and WildlifeMill CreekWAUSA
| | - Dayv Lowry
- Marine Fish Science UnitFish Management DivisionWashington Department of Fish and WildlifeOlympiaWAUSA
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15
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Riofrío-Lazo M, Arreguín-Sánchez F, Páez-Rosas D. Population Abundance of the Endangered Galapagos Sea Lion Zalophus wollebaeki in the Southeastern Galapagos Archipelago. PLoS One 2017; 12:e0168829. [PMID: 28052081 PMCID: PMC5215494 DOI: 10.1371/journal.pone.0168829] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Accepted: 12/07/2016] [Indexed: 11/22/2022] Open
Abstract
There is great concern regarding the population status of the endangered Galapagos sea lion (GSL) because it has drastically decreased over the last 30 years. We determined the population size and growth trend of the GSL in the Galapagos southeastern region (SER) at three population levels based on the available census data: 1) SER (2011-2015), including 13 rookeries on the four islands San Cristóbal (SC), Española, Floreana, and Santa Fe, comprising 58% of the archipelago's population; 2) SC (2011-2015), including five rookeries, comprising 52% of the SER population; and 3) El Malecón (2005-2015), the largest rookery on SC and in the SER (43% of the population on SC and 22% in the SER). We also analyzed the influence of environmental variability on pup abundance in these rookeries. The current GSL population size in the SER, after applying correction factors to the counts, is estimated at approximately 2300-4100 individuals and has declined at an average annual rate (ʎ) of 8.7% over the last five years. A similar trend was determined for SC but at ʎ = 1.4% during the same period. For El Malecón, a count-based population viability analysis using a diffusion approximation approach showed that the population increased from 2005 to 2015 at ʎ = 2%. The interannual variability in pup abundance was associated with anomalies in sea surface temperature linked to oceanographic-atmospheric events, which impact the abundance and availability of prey, and ultimately may determine the population's reproductive success. Since rookeries in the SER had different population trends, management actions should be implemented based on their specific conditions, giving priority to rookeries such as El Malecón, which, despite showing a slightly increasing population trend, still faces a high risk of extinction due to anthropogenic disturbances and environmental variability that may affect its growth and survival.
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Affiliation(s)
- Marjorie Riofrío-Lazo
- Universidad San Francisco de Quito, Galapagos Science Center, San Cristóbal Island, Galápagos, Ecuador
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, La Paz, Baja California Sur, México
| | - Francisco Arreguín-Sánchez
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, La Paz, Baja California Sur, México
| | - Diego Páez-Rosas
- Universidad San Francisco de Quito, Galapagos Science Center, San Cristóbal Island, Galápagos, Ecuador
- Dirección Parque Nacional Galápagos, Unidad Técnica Operativa San Cristóbal, San Cristóbal Island, Galápagos, Ecuador
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