151
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Delabouglise A, Choisy M, Phan TD, Antoine-Moussiaux N, Peyre M, Vu TD, Pfeiffer DU, Fournié G. Economic factors influencing zoonotic disease dynamics: demand for poultry meat and seasonal transmission of avian influenza in Vietnam. Sci Rep 2017; 7:5905. [PMID: 28724978 PMCID: PMC5517570 DOI: 10.1038/s41598-017-06244-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 06/12/2017] [Indexed: 11/08/2022] Open
Abstract
While climate is often presented as a key factor influencing the seasonality of diseases, the importance of anthropogenic factors is less commonly evaluated. Using a combination of methods - wavelet analysis, economic analysis, statistical and disease transmission modelling - we aimed to explore the influence of climatic and economic factors on the seasonality of H5N1 Highly Pathogenic Avian Influenza in the domestic poultry population of Vietnam. We found that while climatic variables are associated with seasonal variation in the incidence of avian influenza outbreaks in the North of the country, this is not the case in the Centre and the South. In contrast, temporal patterns of H5N1 incidence are similar across these 3 regions: periods of high H5N1 incidence coincide with Lunar New Year festival, occurring in January-February, in the 3 climatic regions for 5 out of the 8 study years. Yet, daily poultry meat consumption drastically increases during Lunar New Year festival throughout the country. To meet this rise in demand, poultry production and trade are expected to peak around the festival period, promoting viral spread, which we demonstrated using a stochastic disease transmission model. This study illustrates the way in which economic factors may influence the dynamics of livestock pathogens.
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Affiliation(s)
- Alexis Delabouglise
- Veterinary Epidemiology, Economics and Public Health Group, Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hawkshead Lane, Hatfield, Hertfordshire, AL97TA, United Kingdom.
- AGIRs-Animal and Integrated Risk Management Research Unit, CIRAD-Agricultural Research Center for International Development, Campus International de Baillarguet, Montpellier Cedex 5, 34398, Montpellier, France.
| | - Marc Choisy
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, 78 Giai Phong, Dong Da, Hanoi, Vietnam
- MIVEGEC, University of Montpellier, CNRS 5290, IRD 224, 911 Avenue Agropolis, 64501, Montpellier cedex 5, 34394, France
| | - Thang D Phan
- Center for Interdisciplinary Research on Rural Development, Vietnam National University of Agriculture, Ngo Xuan Quang Street, Trau Quy, Gia Lam, Hanoi, Vietnam
| | - Nicolas Antoine-Moussiaux
- FARAH-Fundamental and Applied Research for Animals & Health, University of Liège, Avenue de Cureghem 7A-7D, Liège, 4000, Belgium
| | - Marisa Peyre
- AGIRs-Animal and Integrated Risk Management Research Unit, CIRAD-Agricultural Research Center for International Development, Campus International de Baillarguet, Montpellier Cedex 5, 34398, Montpellier, France
| | - Ton D Vu
- Center for Interdisciplinary Research on Rural Development, Vietnam National University of Agriculture, Ngo Xuan Quang Street, Trau Quy, Gia Lam, Hanoi, Vietnam
| | - Dirk U Pfeiffer
- Veterinary Epidemiology, Economics and Public Health Group, Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hawkshead Lane, Hatfield, Hertfordshire, AL97TA, United Kingdom
- School of Veterinary Medicine, City University of Hong Kong, 31 To Yuen Street, Kowloon, Hong Kong
| | - Guillaume Fournié
- Veterinary Epidemiology, Economics and Public Health Group, Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hawkshead Lane, Hatfield, Hertfordshire, AL97TA, United Kingdom
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152
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Benincà E, van Boven M, Hagenaars T, van der Hoek W. Space-time analysis of pneumonia hospitalisations in the Netherlands. PLoS One 2017; 12:e0180797. [PMID: 28704495 PMCID: PMC5509219 DOI: 10.1371/journal.pone.0180797] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 06/21/2017] [Indexed: 11/21/2022] Open
Abstract
Community acquired pneumonia is a major global public health problem. In the Netherlands there are 40,000-50,000 hospital admissions for pneumonia per year. In the large majority of these hospital admissions the etiologic agent is not determined and a real-time surveillance system is lacking. Localised and temporal increases in hospital admissions for pneumonia are therefore only detected retrospectively and the etiologic agents remain unknown. Here, we perform spatio-temporal analyses of pneumonia hospital admission data in the Netherlands. To this end, we scanned for spatial clusters on yearly and seasonal basis, and applied wavelet cluster analysis on the time series of five main regions. The pneumonia hospital admissions show strong clustering in space and time superimposed on a regular yearly cycle with high incidence in winter and low incidence in summer. Cluster analysis reveals a heterogeneous pattern, with most significant clusters occurring in the western, highly urbanised, and in the eastern, intensively farmed, part of the Netherlands. Quantitatively, the relative risk (RR) of the significant clusters for the age-standardised incidence varies from a minimum of 1.2 to a maximum of 2.2. We discuss possible underlying causes for the patterns observed, such as variations in air pollution.
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Affiliation(s)
- Elisa Benincà
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
- Department of Bacteriology and Epidemiology, Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | - Michiel van Boven
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
| | - Thomas Hagenaars
- Department of Bacteriology and Epidemiology, Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | - Wim van der Hoek
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
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153
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Abstract
Human trade and travel are breaking-down biogeographic barriers, resulting in shifts in the geographical distribution of organisms, yet it remains largely unknown whether different alien species generally follow similar spatiotemporal colonization patterns and how such patterns are driven by trends in global trade. Here, we analyse the global distribution of 241 alien ant species and show that these species comprise four distinct groups that inherently differ in their worldwide distribution from that of native species. The global spread of these four distinct species groups has been greatly, but differentially, influenced by major events in recent human history, in particular historical waves of globalization (approximately 1850-1914, and 1960-present), world wars and global recessions. Species in these four groups also differ in six important morphological and life-history traits and their degree of invasiveness. Combining spatiotemporal distribution data with life-history trait information provides valuable insight into the processes driving biological invasions and facilitates identification of species most likely to become invasive in the future.
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154
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Barraquand F, Louca S, Abbott KC, Cobbold CA, Cordoleani F, DeAngelis DL, Elderd BD, Fox JW, Greenwood P, Hilker FM, Murray DL, Stieha CR, Taylor RA, Vitense K, Wolkowicz GS, Tyson RC. Moving forward in circles: challenges and opportunities in modelling population cycles. Ecol Lett 2017. [DOI: 10.1111/ele.12789] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Frédéric Barraquand
- Department of Arctic and Marine Biology University of Tromsø Tromsø Norway
- Integrative and Theoretical Ecology Chair, LabEx COTE University of Bordeaux Pessac France
| | - Stilianos Louca
- Institute of Applied Mathematics University of British Columbia Vancouver BC Canada
| | - Karen C. Abbott
- Department of Biology Case Western Reserve University Cleveland OH USA
| | | | - Flora Cordoleani
- Institute of Marine Science University of California Santa Cruz Santa Cruz CA USA
- Southwest Fisheries Science Center Santa Cruz CA USA
| | | | - Bret D. Elderd
- Department of Biological Sciences Lousiana State University Baton Rouge LA USA
| | - Jeremy W. Fox
- Department of Biological Sciences University of Calgary Calgary ABCanada
| | | | - Frank M. Hilker
- Institute of Environmental Systems Research, School of Mathematics/Computer Science Osnabrück University Osnabrück Germany
| | - Dennis L. Murray
- Integrative Wildlife Conservation Lab Trent University Peterborough ONCanada
| | - Christopher R. Stieha
- Department of Biology Case Western Reserve University Cleveland OH USA
- Department of Entomology Cornell University Ithaca NY USA
| | - Rachel A. Taylor
- Department of Integrative Biology University of South Florida Tampa FLUSA
| | - Kelsey Vitense
- Department of Fisheries, Wildlife, and Conservation Biology University of Minnesota Saint Paul MN USA
| | - Gail S.K. Wolkowicz
- Department of Mathematics and Statistics McMaster University Hamilton ON Canada
| | - Rebecca C. Tyson
- Department of Mathematics and Statistics University of British Columbia Okanagan Kelowna BC Canada
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155
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Cui W, Chui TFM. Temporal variations in water quality in a brackish tidal pond: Implications for governing processes and management strategies. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2017; 193:108-117. [PMID: 28192738 DOI: 10.1016/j.jenvman.2017.01.073] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 01/24/2017] [Accepted: 01/28/2017] [Indexed: 06/06/2023]
Abstract
Brackish tidal ponds have been constructed along coastal areas in many parts of the world for aquaculture, including some Ramsar Sites. Such ponds are considered a sustainable, wise use of wetlands if managed properly, but they can also pose serious environmental problems if mismanaged. To understand the governing processes and to promote sustainable management strategies, this study examines the different temporal variations in water quality parameters in a brackish tidal pond located within the wetland complex of the Mai Po Ramsar Site in Hong Kong, China. The variations are compared with those of the receiving bay, and the water channel that connects the pond and the bay. Equations are then developed to link the dissolved oxygen (DO) concentrations in the pond with the governing processes, and to analyze their relative contributions to DO levels. Field data show seasonal patterns in water temperature and salinity in response to the seasonal variations in solar radiation and rainfall. For the pond and the channel, DO, chlorophyll and pH exhibit fortnightly variations due to the bi-weekly water exchange between the pond and the bay. There were also diurnal variations in water temperature and DO in response to changes in solar radiation for both locations, and the tidal flushing for the water channel. Analysis of the findings indicates that water exchange influences the DO concentration more strongly than solar radiation. The DO equation links pond water quality with the time of day, and the time in a water exchange cycle, and thus provides some guidance for determining water exchange and water sampling schedules. The study sheds light on the governing processes and management strategies related to the sustainable management of a brackish tidal pond. The results are thus beneficial in elucidating and promoting the sustainable management and wise use of wetlands in other locations.
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Affiliation(s)
- Wenhui Cui
- Department of Civil Engineering, The University of Hong Kong, Pokfulam, Hong Kong
| | - Ting Fong May Chui
- Department of Civil Engineering, The University of Hong Kong, Pokfulam, Hong Kong.
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156
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Viehman HA, Zydlewski GB. Multi-scale temporal patterns in fish presence in a high-velocity tidal channel. PLoS One 2017; 12:e0176405. [PMID: 28493894 PMCID: PMC5426631 DOI: 10.1371/journal.pone.0176405] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 04/09/2017] [Indexed: 11/30/2022] Open
Abstract
The natural variation of fish presence in high-velocity tidal channels is not well understood. A better understanding of fish use of these areas would aid in predicting fish interactions with marine hydrokinetic (MHK) devices, the effects of which are uncertain but of high concern. To characterize the patterns in fish presence at a tidal energy site in Cobscook Bay, Maine, we examined two years of hydroacoustic data continuously collected at the proposed depth of an MHK turbine with a bottom-mounted, side-looking echosounder. The maximum number of fish counted per hour ranged from hundreds in the early spring to over 1,000 in the fall. Counts varied greatly with tidal and diel cycles in a seasonally changing relationship, likely linked to the seasonally changing fish community of the bay. In the winter and spring, higher hourly counts were generally confined to ebb tides and low slack tides near sunrise and sunset. In summer and fall of each year, the highest fish counts shifted to night and occurred during ebb, low slack, and flood tides. Fish counts were not linked to current speed, and did not decrease as current speed increased, contrary to observations at other tidal power sites. As fish counts may be proportional to the encounter rate of fish with an MHK turbine at the same depth, highly variable counts indicate that the risk to fish is similarly variable. The links between fish presence and environmental cycles at this site will likely be present at other locations with similar environmental forcing, making these observations useful in predicting potential fish interactions at tidal energy sites worldwide.
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Affiliation(s)
- Haley A. Viehman
- School of Marine Sciences, University of Maine, Orono, Maine, United States of America
| | - Gayle Barbin Zydlewski
- School of Marine Sciences, University of Maine, Orono, Maine, United States of America
- * E-mail:
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157
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Zhang J, Hull V, Ouyang Z, He L, Connor T, Yang H, Huang J, Zhou S, Zhang Z, Zhou C, Zhang H, Liu J. Modeling activity patterns of wildlife using time-series analysis. Ecol Evol 2017; 7:2575-2584. [PMID: 28428848 PMCID: PMC5395454 DOI: 10.1002/ece3.2873] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 02/09/2017] [Accepted: 02/10/2017] [Indexed: 11/17/2022] Open
Abstract
The study of wildlife activity patterns is an effective approach to understanding fundamental ecological and evolutionary processes. However, traditional statistical approaches used to conduct quantitative analysis have thus far had limited success in revealing underlying mechanisms driving activity patterns. Here, we combine wavelet analysis, a type of frequency‐based time‐series analysis, with high‐resolution activity data from accelerometers embedded in GPS collars to explore the effects of internal states (e.g., pregnancy) and external factors (e.g., seasonal dynamics of resources and weather) on activity patterns of the endangered giant panda (Ailuropoda melanoleuca). Giant pandas exhibited higher frequency cycles during the winter when resources (e.g., water and forage) were relatively poor, as well as during spring, which includes the giant panda's mating season. During the summer and autumn when resources were abundant, pandas exhibited a regular activity pattern with activity peaks every 24 hr. A pregnant individual showed distinct differences in her activity pattern from other giant pandas for several months following parturition. These results indicate that animals adjust activity cycles to adapt to seasonal variation of the resources and unique physiological periods. Wavelet coherency analysis also verified the synchronization of giant panda activity level with air temperature and solar radiation at the 24‐hr band. Our study also shows that wavelet analysis is an effective tool for analyzing high‐resolution activity pattern data and its relationship to internal and external states, an approach that has the potential to inform wildlife conservation and management across species.
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Affiliation(s)
- Jindong Zhang
- Key Laboratory of Southwest China Wildlife Resources ConservationChina West Normal UniversityMinistry of EducationNanchong, Sichuan 637009China
- Center for Systems Integration and SustainabilityDepartment of Fisheries and WildlifeMichigan State UniversityEast LansingMI 48823USA
| | - Vanessa Hull
- Center for Systems Integration and SustainabilityDepartment of Fisheries and WildlifeMichigan State UniversityEast LansingMI 48823USA
- Department of Wildlife Ecology and ConservationUniversity of FloridaGainesvilleFL 32611USA
| | - Zhiyun Ouyang
- State Key Laboratory of Urban and Regional EcologyResearch Center for Eco–environmental SciencesChinese Academy of SciencesBeijing 100085China
| | - Liang He
- National Meteorological CenterBeijing 100081China
| | - Thomas Connor
- Center for Systems Integration and SustainabilityDepartment of Fisheries and WildlifeMichigan State UniversityEast LansingMI 48823USA
| | - Hongbo Yang
- Center for Systems Integration and SustainabilityDepartment of Fisheries and WildlifeMichigan State UniversityEast LansingMI 48823USA
| | - Jinyan Huang
- Conservation and Research Center for the Giant Panda (CCRCGP)Wolong Nature ReserveSichuan 623006China
| | - Shiqiang Zhou
- Conservation and Research Center for the Giant Panda (CCRCGP)Wolong Nature ReserveSichuan 623006China
| | - Zejun Zhang
- Key Laboratory of Southwest China Wildlife Resources ConservationChina West Normal UniversityMinistry of EducationNanchong, Sichuan 637009China
| | - Caiquan Zhou
- Key Laboratory of Southwest China Wildlife Resources ConservationChina West Normal UniversityMinistry of EducationNanchong, Sichuan 637009China
| | - Hemin Zhang
- Conservation and Research Center for the Giant Panda (CCRCGP)Wolong Nature ReserveSichuan 623006China
| | - Jianguo Liu
- Center for Systems Integration and SustainabilityDepartment of Fisheries and WildlifeMichigan State UniversityEast LansingMI 48823USA
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158
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Rochlin I, Morris JT. Regulation of salt marsh mosquito populations by the 18.6-yr lunar-nodal cycle. Ecology 2017; 98:2059-2068. [PMID: 28418218 DOI: 10.1002/ecy.1861] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 03/10/2017] [Accepted: 04/05/2017] [Indexed: 11/07/2022]
Abstract
The 18.6-yr lunar-nodal cycle drives changes in tidal amplitude globally, affecting coastal habitat formation, species and communities inhabiting rocky shores, and salt marsh vegetation. However, the cycle's influence on salt marsh fauna lacked sufficient long-term data for testing its effect. We circumvented this problem by using salt marsh mosquito records obtained over a period of over four decades in two estuaries in the northeastern USA. Salt marsh mosquito habitat is near the highest tide level where the impact of the nodal cycle on flood frequency is greatest. Wavelet spectral and cross-correlation analyses revealed periodicity in salt marsh mosquito abundance that was negatively correlated with tidal amplitude. Tidal amplitude was a significant predictor of salt marsh mosquito abundance with the cycle maxima coinciding with lower mosquito populations, possibly due to access by predatory fish. However, these effects were detected only at the location with extensive salt marsh habitat and astronomical tides and were weakened or lacked significance at the location with small microtidal salt marshes and wind-driven tides. Mosquitoes can serve as proxy indicators for numerous invertebrate species on the salt marsh. These predictable cycles and their effects need to be taken into consideration when investigating, restoring, or managing intertidal communities that are also facing sea-level rise.
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Affiliation(s)
- Ilia Rochlin
- Suffolk County Vector Control, 335 Yaphank Ave, Yaphank, New York, 11980, USA
- Center for Vector Biology, Rutgers University, New Brunswick, New Jersey, 08901, USA
| | - James T Morris
- Belle Baruch Institute for Marine & Coastal Sciences, University of South Carolina, Columbia, South Carolina, 29208, USA
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159
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Tonkin JD, Bogan MT, Bonada N, Rios‐Touma B, Lytle DA. Seasonality and predictability shape temporal species diversity. Ecology 2017; 98:1201-1216. [DOI: 10.1002/ecy.1761] [Citation(s) in RCA: 176] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 01/23/2017] [Accepted: 01/24/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Jonathan D. Tonkin
- Department of Integrative Biology Oregon State University Corvallis Oregon 97331 USA
| | - Michael T. Bogan
- School of Natural Resources and the Environment University of Arizona Tucson Arizona 85721 USA
| | - Núria Bonada
- Grup de Recerca Freshwater Ecology and Management (FEM) Departament d'Ecologia Facultat de Biologia Institut de Recerca de la Biodiversitat (IRBio) Universitat de Barcelona Diagonal 643 08028 Barcelona Catalonia Spain
| | - Blanca Rios‐Touma
- Facultad de Ingenierías y Ciencias Agropecuarias, Ingeniería Ambiental Unidad de Biotecnología y Medio Ambiente (BIOMA) Campus Queri, Calle José Queri y Av, Granados, Edificio #8 PB Quito Ecuador
- Universidad de las Américas Quito Ecuador
| | - David A. Lytle
- Department of Integrative Biology Oregon State University Corvallis Oregon 97331 USA
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160
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Lebar N, Danna J, Moré S, Mouchnino L, Blouin J. On the neural basis of sensory weighting: Alpha, beta and gamma modulations during complex movements. Neuroimage 2017; 150:200-212. [DOI: 10.1016/j.neuroimage.2017.02.043] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 01/26/2017] [Accepted: 02/15/2017] [Indexed: 10/20/2022] Open
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161
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Marques SC, Pardal MÂ, Primo AL, Martinho F, Falcão J, Azeiteiro U, Molinero JC. Evidence for Changes in Estuarine Zooplankton Fostered by Increased Climate Variance. Ecosystems 2017. [DOI: 10.1007/s10021-017-0134-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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162
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Soleymani A, Pennekamp F, Dodge S, Weibel R. Characterizing change points and continuous transitions in movement behaviours using wavelet decomposition. Methods Ecol Evol 2017. [DOI: 10.1111/2041-210x.12755] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ali Soleymani
- Department of Geography University of Zurich Zurich Switzerland
| | - Frank Pennekamp
- Institute of Evolutionary Biology and Environmental Studies University of Zurich Zurich Switzerland
| | - Somayeh Dodge
- Department of Geography, Environment, and Society University of Minnesota Twin Cities MN USA
| | - Robert Weibel
- Department of Geography University of Zurich Zurich Switzerland
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163
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Bush ER, Abernethy KA, Jeffery K, Tutin C, White L, Dimoto E, Dikangadissi J, Jump AS, Bunnefeld N. Fourier analysis to detect phenological cycles using long‐term tropical field data and simulations. Methods Ecol Evol 2016. [DOI: 10.1111/2041-210x.12704] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Emma R. Bush
- Biological and Environmental Sciences Faculty of Natural Sciences University of Stirling Stirling FK9 4LA UK
| | - Katharine A. Abernethy
- Biological and Environmental Sciences Faculty of Natural Sciences University of Stirling Stirling FK9 4LA UK
- Institut de Recherche en Écologie Tropicale CENAREST BP 842 Libreville Gabon
| | - Kathryn Jeffery
- Biological and Environmental Sciences Faculty of Natural Sciences University of Stirling Stirling FK9 4LA UK
- Agence Nationale des Parcs Nationaux (ANPN) B.P. 20379 Libreville Gabon
| | - Caroline Tutin
- Biological and Environmental Sciences Faculty of Natural Sciences University of Stirling Stirling FK9 4LA UK
| | - Lee White
- Biological and Environmental Sciences Faculty of Natural Sciences University of Stirling Stirling FK9 4LA UK
- Institut de Recherche en Écologie Tropicale CENAREST BP 842 Libreville Gabon
- Agence Nationale des Parcs Nationaux (ANPN) B.P. 20379 Libreville Gabon
| | - Edmond Dimoto
- Agence Nationale des Parcs Nationaux (ANPN) B.P. 20379 Libreville Gabon
| | | | - Alistair S. Jump
- Biological and Environmental Sciences Faculty of Natural Sciences University of Stirling Stirling FK9 4LA UK
| | - Nils Bunnefeld
- Biological and Environmental Sciences Faculty of Natural Sciences University of Stirling Stirling FK9 4LA UK
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164
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165
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Time-series analyses of water temperature and dissolved oxygen concentration in Lake Valkea-Kotinen (Finland) during ice season. ECOL INFORM 2016. [DOI: 10.1016/j.ecoinf.2015.06.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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166
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Early-life sexual segregation: ontogeny of isotopic niche differentiation in the Antarctic fur seal. Sci Rep 2016; 6:33211. [PMID: 27620663 PMCID: PMC5020412 DOI: 10.1038/srep33211] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 08/15/2016] [Indexed: 11/08/2022] Open
Abstract
Investigating the ontogeny of niche differentiation enables to determine at which life-stages sexual segregation arises, providing insights into the main factors driving resource partitioning. We investigated the ontogeny of foraging ecology in Antarctic fur seals (Arctocephalus gazella), a highly dimorphic species with contrasting breeding strategies between sexes. Sequential δ(13)C and δ(15)N values of whiskers provided a longitudinal proxy of the foraging niche throughout the whole life of seals, from weaning, when size dimorphism is minimal to the age of 5. Females exhibited an early-life ontogenetic shift, from a total segregation during their first year at-sea, to a similar isotopic niche as breeding females as early as age 2. In contrast, males showed a progressive change in isotopic niche throughout their development such that 5-year-old males did not share the same niche as territorial bulls. Interestingly, males and females segregated straight after weaning with males appearing to feed in more southerly habitats than females. This spatial segregation was of similar amplitude as observed in breeding adults and was maintained throughout development. Such early-life niche differentiation is an unusual pattern and indicates size dimorphism and breeding constraints do not directly drive sexual segregation contrary to what has been assumed in otariid seals.
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167
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D'Ambrosio M, Molinero JC, Azeiteiro UM, Pardal MA, Primo AL, Nyitrai D, Marques SC. Interannual abundance changes of gelatinous carnivore zooplankton unveil climate-driven hydrographic variations in the Iberian Peninsula, Portugal. MARINE ENVIRONMENTAL RESEARCH 2016; 120:103-110. [PMID: 27494188 DOI: 10.1016/j.marenvres.2016.07.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 07/15/2016] [Accepted: 07/25/2016] [Indexed: 06/06/2023]
Abstract
The persistent massive blooms of gelatinous zooplankton recorded during recent decades may be indicative of marine ecosystem changes. In this study, we investigated the potential influence of the North Atlantic climate (NAO) variability on decadal abundance changes of gelatinous carnivore zooplankton in the Mondego estuary, Portugal, over the period 2003-2013. During the 11-year study, the community of gelatinous carnivores encompassed a larger diversity of hydromedusae than siphonophores; the former dominated by Obelia spp., Lizzia blondina, Clythia hemisphaerica, Liriope tetraphylla and Solmaris corona, while the latter dominated by Muggiaea atlantica. Gelatinous carnivore zooplankton displayed marked interannual variability and mounting species richness over the period examined. Their pattern of abundance shifted towards larger abundances ca. 2007 and significant phenological changes. The latter included a shift in the mean annual pattern (from unimodal to bimodal peak, prior and after 2007 respectively) and an earlier timing of the first annual peak concurrent with enhanced temperatures. These changes were concurrent with the climate-driven environmental variability mainly controlled by the NAO, which displayed larger variance after 2007 along with an enhanced upwelling activity. Structural equation modelling allowed depicting cascading effects derived from the NAO influence on regional climate and upwelling variability further shaping water temperature. Such cascading effect percolated the structure and dynamics of the community of gelatinous carnivore zooplankton in the Mondego estuary.
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Affiliation(s)
- Mariaelena D'Ambrosio
- Centre for Functional Ecology (CFE), Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal.
| | - Juan C Molinero
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Marine Ecology/Food Webs, Duesternbrooker Weg 20, D-24105 Kiel, Germany
| | - Ulisses M Azeiteiro
- Centre for Functional Ecology (CFE), Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal; Department of Science and Technology, University Aberta, 4200-055 Porto, Portugal
| | - Miguel A Pardal
- Centre for Functional Ecology (CFE), Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal
| | - Ana L Primo
- Centre for Functional Ecology (CFE), Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal
| | - Daniel Nyitrai
- Centre for Functional Ecology (CFE), Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal
| | - Sónia C Marques
- Centre for Functional Ecology (CFE), Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal; IPMA - Portuguese Sea and Atmosphere Institute, Lisbon, Portugal; MARE - Marine and Environmental Sciences Centre, Escola Superior de Turismo e Tecnologia do Mar - Instituto Politécnico de Leiria, Leiria, Portugal
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Edeline E, Groth A, Cazelles B, Claessen D, Winfield IJ, Ohlberger J, Asbjørn Vøllestad L, Stenseth NC, Ghil M. Pathogens trigger top-down climate forcing on ecosystem dynamics. Oecologia 2016; 181:519-32. [DOI: 10.1007/s00442-016-3575-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 01/24/2016] [Indexed: 11/24/2022]
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169
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Cronin JT, Reeve JD, Xu D, Xiao M, Stevens HN. Variable prey development time suppresses predator–prey cycles and enhances stability. Ecol Lett 2016; 19:318-27. [DOI: 10.1111/ele.12571] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 12/02/2015] [Accepted: 12/20/2015] [Indexed: 11/29/2022]
Affiliation(s)
- James T. Cronin
- Department of Biological Sciences Louisiana State University Baton Rouge Louisiana 70803 USA
| | - John D. Reeve
- Department of Zoology Southern Illinois University Carbondale Illinois 62901 USA
| | - Dashun Xu
- Department of Mathematics Southern Illinois University Carbondale Illinois 62901 USA
| | - Mingqing Xiao
- Department of Mathematics Southern Illinois University Carbondale Illinois 62901 USA
| | - Heidi N. Stevens
- Department of Mathematics Southern Illinois University Carbondale Illinois 62901 USA
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170
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Region-wide synchrony and traveling waves of dengue across eight countries in Southeast Asia. Proc Natl Acad Sci U S A 2015; 112:13069-74. [PMID: 26438851 DOI: 10.1073/pnas.1501375112] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Dengue is a mosquito-transmitted virus infection that causes epidemics of febrile illness and hemorrhagic fever across the tropics and subtropics worldwide. Annual epidemics are commonly observed, but there is substantial spatiotemporal heterogeneity in intensity. A better understanding of this heterogeneity in dengue transmission could lead to improved epidemic prediction and disease control. Time series decomposition methods enable the isolation and study of temporal epidemic dynamics with a specific periodicity (e.g., annual cycles related to climatic drivers and multiannual cycles caused by dynamics in population immunity). We collected and analyzed up to 18 y of monthly dengue surveillance reports on a total of 3.5 million reported dengue cases from 273 provinces in eight countries in Southeast Asia, covering ∼ 10(7) km(2). We detected strong patterns of synchronous dengue transmission across the entire region, most markedly during a period of high incidence in 1997-1998, which was followed by a period of extremely low incidence in 2001-2002. This synchrony in dengue incidence coincided with elevated temperatures throughout the region in 1997-1998 and the strongest El Niño episode of the century. Multiannual dengue cycles (2-5 y) were highly coherent with the Oceanic Niño Index, and synchrony of these cycles increased with temperature. We also detected localized traveling waves of multiannual dengue epidemic cycles in Thailand, Laos, and the Philippines that were dependent on temperature. This study reveals forcing mechanisms that drive synchronization of dengue epidemics on a continental scale across Southeast Asia.
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171
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Thai PQ, Choisy M, Duong TN, Thiem VD, Yen NT, Hien NT, Weiss DJ, Boni MF, Horby P. Seasonality of absolute humidity explains seasonality of influenza-like illness in Vietnam. Epidemics 2015; 13:65-73. [PMID: 26616043 DOI: 10.1016/j.epidem.2015.06.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 06/30/2015] [Accepted: 06/30/2015] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Experimental and ecological studies have shown the role of climatic factors in driving the epidemiology of influenza. In particular, low absolute humidity (AH) has been shown to increase influenza virus transmissibility and has been identified to explain the onset of epidemics in temperate regions. Here, we aim to study the potential climatic drivers of influenza-like illness (ILI) epidemiology in Vietnam, a tropical country characterized by a high diversity of climates. We specifically focus on quantifying and explaining the seasonality of ILI. METHODS We used 18 years (1993-2010) of monthly ILI notifications aggregated by province (52) and monthly climatic variables (minimum, mean, maximum temperatures, absolute and relative humidities, rainfall and hours of sunshine) from 67 weather stations across Vietnam. Seasonalities were quantified from global wavelet spectra, using the value of the power at the period of 1 year as a measure of the intensity of seasonality. The 7 climatic time series were characterized by 534 summary statistics which were entered into a regression tree to identify factors associated with the seasonality of AH. Results were extrapolated to the global scale using simulated climatic times series from the NCEP/NCAR project. RESULTS The intensity of ILI seasonality in Vietnam is best explained by the intensity of AH seasonality. We find that ILI seasonality is weak in provinces experiencing weak seasonal fluctuations in AH (annual power <17.6), whereas ILI seasonality is strongest in provinces with pronounced AH seasonality (power >17.6). In Vietnam, AH and ILI are positively correlated. CONCLUSIONS Our results identify a role for AH in driving the epidemiology of ILI in a tropical setting. However, in contrast to temperate regions, high rather than low AH is associated with increased ILI activity. Fluctuation in AH may be the climate factor that underlies and unifies the seasonality of ILI in both temperate and tropical regions. Alternatively, the mechanism of action of AH on disease transmission may be different in cold-dry versus hot-humid settings.
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Affiliation(s)
- Pham Quang Thai
- National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam; Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Hanoi, Viet Nam.
| | - Marc Choisy
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Hanoi, Viet Nam; MIVEGEC, University of Montpellier, CNRS 5290, IRD 224, Montpellier, France
| | - Tran Nhu Duong
- National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam
| | - Vu Dinh Thiem
- National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam
| | - Nguyen Thu Yen
- National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam
| | | | - Daniel J Weiss
- Spatial Ecology & Epidemiology Group, Department of Zoology, University of Oxford, Oxford, UK
| | - Maciej F Boni
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK; Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Peter Horby
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Hanoi, Viet Nam; Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
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172
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Kernaléguen L, Cherel Y, Knox TC, Baylis AMM, Arnould JPY. Sexual Niche Segregation and Gender-Specific Individual Specialisation in a Highly Dimorphic Marine Mammal. PLoS One 2015; 10:e0133018. [PMID: 26244371 PMCID: PMC4526469 DOI: 10.1371/journal.pone.0133018] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 06/22/2015] [Indexed: 11/18/2022] Open
Abstract
While sexual segregation is expected in highly dimorphic species, the local environment is a major factor driving the degree of resource partitioning within a population. Sexual and individual niche segregation was investigated in the Australian fur seal (Arctocephalus pusillus doriferus), which is a benthic foraging species restricted to the shallow continental shelf region of south-eastern Australia. Tracking data and the isotopic values of plasma, red blood cells and whiskers were combined to document spatial and dietary niche segregation throughout the year. Tracking data indicated that, in winter, males and females overlapped in their foraging habitat. All individuals stayed within central Bass Strait, relatively close (< 220 km) to the breeding colony. Accordingly, both genders exhibited similar plasma and red cell δ13C values. However, males exhibited greater δ13C intra-individual variation along the length of their whisker than females. This suggests that males exploited a greater diversity of foraging habitats throughout the year than their female counterparts, which are restricted in their foraging grounds by the need to regularly return to the breeding colony to suckle their pup. The degree of dietary sexual segregation was also surprisingly low, both sexes exhibiting a great overlap in their δ15N values. Yet, males displayed higher δ15N values than females, suggesting they fed upon a higher proportion of higher trophic level prey. Given that males and females exploit different resources (mainly foraging habitats), the degree of individual specialisation might differ between the sexes. Higher degrees of individual specialisation would be expected in males which exploit a greater range of resources. However, comparable levels of inter-individual variation in δ15N whisker values were found in the sampled males and females, and, surprisingly, all males exhibited similar seasonal and inter-annual variation in their δ13C whisker values, suggesting they all followed the same general dispersion pattern throughout the year.
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Affiliation(s)
- Laëtitia Kernaléguen
- School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia
- * E-mail:
| | - Yves Cherel
- Centre d'Etudes Biologiques de Chizé, UMR 7372 du CNRS-Université de La Rochelle, Villiers-en-Bois, France
| | - Travis C. Knox
- School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia
| | - Alastair M. M. Baylis
- School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia
- South Atlantic Environmental Research Institute, Stanley, FIQQ1ZZ, Falkland Islands
| | - John P. Y. Arnould
- School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia
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173
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Kernaléguen L, Dorville N, Ierodiaconou D, Hoskins AJ, Baylis AMM, Hindell MA, Semmens J, Abernathy K, Marshall GJ, Cherel Y, Arnould JPY. From video recordings to whisker stable isotopes: a critical evaluation of timescale in assessing individual foraging specialisation in Australian fur seals. Oecologia 2015; 180:657-70. [DOI: 10.1007/s00442-015-3407-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 07/16/2015] [Indexed: 11/29/2022]
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174
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Lee HF, Pei Q, Zhang DD, Choi KPK. Quantifying the Intra-Regional Precipitation Variability in Northwestern China over the Past 1,400 Years. PLoS One 2015; 10:e0131693. [PMID: 26154711 PMCID: PMC4495927 DOI: 10.1371/journal.pone.0131693] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 06/04/2015] [Indexed: 11/18/2022] Open
Abstract
There has been a surge of paleo-climatic/environmental studies of Northwestern China (NW China), a region characterized by a diverse assortment of hydro-climatic systems. Their common approach, however, focuses on "deducing regional resemblance" rather than "exploring regional variance." To date, efforts to produce a quantitative assessment of long-term intra-regional precipitation variability (IRPV) in NW China has been inadequate. In the present study, we base on historical flood/drought records to compile a decadal IRPV index for NW China spanned AD580-1979 and to find its major determinants via wavelet analysis. Results show that our IRPV index captures the footprints of internal hydro-climatic disparity in NW China. In addition, we find distinct ~120-200 year periodicities in the IRPV index over the Little Ice Age, which are attributable to the change of hydro-climatic influence of ocean-atmospheric modes during the period. Also, we offer statistical evidence of El Niño Southern Oscillation (Indo-Pacific warm pool sea surface temperature and China-wide land surface temperature) as the prominent multi-decadal to centennial (centennial to multi-centennial) determinant of the IRPV in NW China. The present study contributes to the quantitative validation of the long-term IRPV in NW China and its driving forces, covering the periods with and without instrumental records. It may help to comprehend the complex hydro-climatic regimes in the region.
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Affiliation(s)
- Harry F. Lee
- Department of Geography, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
- International Centre of China Development Studies, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
- * E-mail:
| | - Qing Pei
- Department of Geography, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
- International Centre of China Development Studies, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - David D. Zhang
- Department of Geography, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
- International Centre of China Development Studies, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Kan P. K. Choi
- Department of Geography, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
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175
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Wang C, Liang S, Li Y, Li K, Wang X. The spatial distribution of dissolved and particulate heavy metals and their response to land-based inputs and tides in a semi-enclosed industrial embayment: Jiaozhou Bay, China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:10480-10495. [PMID: 25728204 DOI: 10.1007/s11356-015-4259-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 02/18/2015] [Indexed: 06/04/2023]
Abstract
In order to evaluate heavy metal contamination in surface waters in the Jiaozhou Bay (JZB), a typical semi-enclosed bay in the north of China, and to identify the response of heavy metal distribution to terrigenous sources and tides, the land-based discharge flux of dissolved Cu, Pb, Zn and Cd and their particulates, as well as their concentrations, were synchronously surveyed in JZB in flood season and normal season respectively. The survey results showed that the amount of dissolved Cu clearly increased from the estuaries to the offshore waters during the flood season, especially from the Dagu estuary to the mouth of JZB. The same trend was observed for Pb. The isopleths of dissolved Zn during the flood season presented a different pattern in which a clear decrease was observed from the Lianwan, Moshui and Dagu estuaries to the offshore waters. However, the particulate Cu isopleths during the flood season, which had the same pattern as those of particulate Pb, Zn and Cd, showed a clear decrease from the Dagu estuary to the mouth of JZB. The isopleths for dissolved and particulate Cu during the normal season showed a clear decrease from the northeast to the entrance of JZB, and the same trend was observed for Pb, Zn and Cd. Observations based on synchronous investigations of the fluvial fluxes of the selected metals and their average concentrations in JZB showed that these patterns were controlled by the strong external fluvial inputs, especially from the Dagu River. The diurnal change in the Cu, Pb, Zn and Cd concentrations showed a periodicity with a cycle length of approximately 12 h in JZB, which indicates the noticeable impact of the semi-diurnal tide. The weighed average concentration from freshwater inputs calculated for dissolved Cu, Pb, Zn and Cd were higher than their average concentrations in JZB. This indicated that JZB had been contaminated with these metals, whose concentrations were also higher than those found in uncontaminated waters.
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Affiliation(s)
- Changyou Wang
- School of Marine Sciences, Nanjing University of Information Science and Technology, Nanjing, 210044, People's Republic of China
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176
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Pei Q, Zhang DD, Li G, Lee HF. Climate change and the macroeconomic structure in pre-industrial europe: new evidence from wavelet analysis. PLoS One 2015; 10:e0126480. [PMID: 26039087 PMCID: PMC4454689 DOI: 10.1371/journal.pone.0126480] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Accepted: 04/02/2015] [Indexed: 11/19/2022] Open
Abstract
The relationship between climate change and the macroeconomy in pre-industrial Europe has attracted considerable attention in recent years. This study follows the combined paradigms of evolutionary economics and ecological economics, in which wavelet analysis (spectrum analysis and coherence analysis) is applied as the first attempt to examine the relationship between climate change and the macroeconomic structure in pre-industrial Europe in the frequency domain. Aside from confirming previous results, this study aims to further substantiate the association between climate change and macroeconomy by presenting new evidence obtained from the wavelet analysis. Our spectrum analysis shows a consistent and continuous frequency band of 60–80 years in the temperature, grain yield ratio, grain price, consumer price index, and real wage throughout the study period. Besides, coherence analysis shows that the macroeconomic structure is shaped more by climate change than population change. In addition, temperature is proven as a key climatic factor that influences the macroeconomic structure. The analysis reveals a unique frequency band of about 20 years (15–35 years) in the temperature in AD1600-1700, which could have contributed to the widespread economic crisis in pre-industrial Europe. Our findings may have indications in re-examining the Malthusian theory.
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Affiliation(s)
- Qing Pei
- Department of Geography and International Centre for China Development Study, University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
- Department of Statistics and Actuarial Science, University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
- * E-mail:
| | - David D. Zhang
- Department of Geography and International Centre for China Development Study, University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Guodong Li
- Department of Statistics and Actuarial Science, University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Harry F. Lee
- Department of Geography and International Centre for China Development Study, University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
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177
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Hempel K, Earn DJD. A century of transitions in New York City's measles dynamics. J R Soc Interface 2015; 12:20150024. [PMID: 25833244 PMCID: PMC4424677 DOI: 10.1098/rsif.2015.0024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 03/10/2015] [Indexed: 12/16/2022] Open
Abstract
Infectious diseases spreading in a human population occasionally exhibit sudden transitions in their qualitative dynamics. Previous work has successfully predicted such transitions in New York City's historical measles incidence using the seasonally forced susceptible-infectious-recovered (SIR) model. This work relied on a dataset spanning 45 years (1928-1973), which we have extended to 93 years (1891-1984). We identify additional dynamical transitions in the longer dataset and successfully explain them by analysing attractors and transients of the same mechanistic epidemiological model.
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Affiliation(s)
- Karsten Hempel
- Department of Mathematics and Statistics, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1
| | - David J D Earn
- Department of Mathematics and Statistics, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1
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178
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179
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Rivest EB, Gouhier TC. Complex environmental forcing across the biogeographical range of coral populations. PLoS One 2015; 10:e0121742. [PMID: 25799322 PMCID: PMC4370630 DOI: 10.1371/journal.pone.0121742] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 02/15/2015] [Indexed: 01/07/2023] Open
Abstract
Although there is a substantial body of work on how temperature shapes coastal marine ecosystems, the spatiotemporal variability of seawater pH and corresponding in situ biological responses remain largely unknown across biogeographic ranges of tropical coral species. Environmental variability is important to characterize because it can amplify or dampen the biological consequences of global change, depending on the functional relationship between mean temperature or pH and organismal traits. Here, we characterize the spatiotemporal variability of pH, temperature, and salinity at fringing reefs in Moorea, French Polynesia and Nanwan Bay, Taiwan using advanced time series analysis, including wavelet analysis, and infer their potential impact on the persistence and stability of coral populations. Our results demonstrate that both the mean and variance of pH and temperature differed significantly between sites in Moorea and Taiwan. Seawater temperature at the Moorea site passed the local bleaching threshold several times within the ~45 day deployment while aragonite saturation state at the Taiwan site was often below commonly observed levels for coral reefs. Our results showcase how a better understanding of the differences in environmental conditions between sites can (1) provide an important frame of reference for designing laboratory experiments to study the effects of environmental variability, (2) identify the proximity of current environmental conditions to predicted biological thresholds for the coral reef, and (3) help predict when the temporal variability and mean of environmental conditions will interact synergistically or antagonistically to alter the abundance and stability of marine populations experiencing climate change.
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Affiliation(s)
- Emily B. Rivest
- Bodega Marine Laboratory, University of California Davis, Bodega Bay, California, United States of America
| | - Tarik C. Gouhier
- Marine Science Center, Northeastern University, Nahant, Massachusetts, United States of America
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180
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Kernaléguen L, Arnould JPY, Guinet C, Cherel Y. Determinants of individual foraging specialization in large marine vertebrates, the Antarctic and subantarctic fur seals. J Anim Ecol 2015; 84:1081-91. [PMID: 25649011 DOI: 10.1111/1365-2656.12347] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 01/23/2015] [Indexed: 11/29/2022]
Abstract
The degree of individual specialization in resource use differs widely among wild populations where individuals range from fully generalized to highly specialized. This interindividual variation has profound implications in many ecological and evolutionary processes. A recent review proposed four main ecological causes of individual specialization: interspecific and intraspecific competition, ecological opportunity and predation. Using the isotopic signature of subsampled whiskers, we investigated to what degree three of these factors (interspecific and intraspecific competition and ecological opportunity) affect the population niche width and the level of individual foraging specialization in two fur seal species, the Antarctic and subantarctic fur seals (Arctocephalus gazella and Arctocephalus tropicalis), over several years. Population niche width was greater when the two seal species bred in allopatry (low interspecific competition) than in sympatry or when seals bred in high-density stabilized colonies (high intraspecific competition). In agreement with the niche variation hypothesis (NVH), higher population niche width was associated with higher interindividual niche variation. However, in contrast to the NVH, all Antarctic females increased their niche width during the interbreeding period when they had potential access to a wider diversity of foraging grounds and associated prey (high ecological opportunities), suggesting they all dispersed to a similar productive area. The degree of individual specialization varied among populations and within the annual cycle. Highest levels of interindividual variation were found in a context of lower interspecific or higher intraspecific competition. Contrasted results were found concerning the effect of ecological opportunity. Depending on seal species, females exhibited either a greater or lower degree of individual specialization during the interbreeding period, reflecting species-specific biological constraints during that period. These results suggest a significant impact of ecological interactions on the population niche width and degree of individual specialization. Such variation at the individual level may be an important factor in the species plasticity with significant consequences on how it may respond to environmental variability.
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Affiliation(s)
- Laëtitia Kernaléguen
- School of Life and Environmental Sciences, Deakin University, 221 Burwood Highway, 3125 Burwood, Vic., Australia.,Centre d'Etudes Biologiques de Chizé, UMR 7372 du CNRS-Université de La Rochelle, BP 14, 79360, Villiers-en-Bois, France
| | - John P Y Arnould
- School of Life and Environmental Sciences, Deakin University, 221 Burwood Highway, 3125 Burwood, Vic., Australia
| | - Christophe Guinet
- Centre d'Etudes Biologiques de Chizé, UMR 7372 du CNRS-Université de La Rochelle, BP 14, 79360, Villiers-en-Bois, France
| | - Yves Cherel
- Centre d'Etudes Biologiques de Chizé, UMR 7372 du CNRS-Université de La Rochelle, BP 14, 79360, Villiers-en-Bois, France
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181
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Moore JW, Beakes MP, Nesbitt HK, Yeakel JD, Patterson DA, Thompson LA, Phillis CC, Braun DC, Favaro C, Scott D, Carr-Harris C, Atlas WI. Emergent stability in a large, free-flowing watershed. Ecology 2015; 96:340-7. [DOI: 10.1890/14-0326.1] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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182
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Characteristics of Lake Chad level variability and links to ENSO, precipitation, and river discharge. ScientificWorldJournal 2014; 2014:145893. [PMID: 25538946 PMCID: PMC4265694 DOI: 10.1155/2014/145893] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 09/15/2014] [Accepted: 09/28/2014] [Indexed: 11/18/2022] Open
Abstract
This study used trend, correlation, and wavelet analysis to characterize Lake Chad (LC) level fluctuations, river discharge, El Niño Southern Oscillation (ENSO), and precipitation regimes and their interrelationships. Linear correlation results indicate a negative association between ENSO and LC level, river discharge and precipitation. Trend analysis shows increasing precipitation in the Lake Chad Basin (LCB) but decreasing LC level. The mode of interannual variability in LC level, rainfall, and ENSO analyzed using wavelet analysis is dominated by 3-4-year periods. Results show that variability in ENSO could explain only 31% and 13% of variations in LC level at Kindjeria and precipitation in the northern LCB, respectively. The wavelet transform coherency (WTC) between LC level of the southern pool at Kalom and ENSO is statistically significant at the 95% confidence level and phase-locked, implying a cause-and-effect association. These strong coherencies coincide with the La Niña years with the exception of 1997-1998 El Niño events. The WTC shows strong covariance between increasing precipitation and LC level in the northern pool at a 2- to 4-year band and 3- to 4-year band localized from 1996 to 2010. Implications for water resource planning and management are discussed.
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183
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Aharon-Rotman Y, Soloviev M, Minton C, Tomkovich P, Hassell C, Klaassen M. Loss of periodicity in breeding success of waders links to changes in lemming cycles in Arctic ecosystems. OIKOS 2014. [DOI: 10.1111/oik.01730] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Yaara Aharon-Rotman
- Centre for Integrative Ecology, School of life and Environmental Science, Deakin Univ.; Geelong Australia
| | - Mikhail Soloviev
- Dept of Vertebrate Zoology; Lomonosov Moscow State Univ.; Moscow Russia
| | - Clive Minton
- Australian Wader Studies Group; Victoria Australia
| | - Pavel Tomkovich
- Zoological Museum, Lomonosov Moscow State Univ.; Moscow Russia
| | | | - Marcel Klaassen
- Centre for Integrative Ecology, School of life and Environmental Science, Deakin Univ.; Geelong Australia
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184
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Cutaneous leishmaniasis and sand fly fluctuations are associated with el niño in panamá. PLoS Negl Trop Dis 2014; 8:e3210. [PMID: 25275503 PMCID: PMC4183471 DOI: 10.1371/journal.pntd.0003210] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 08/23/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Cutaneous Leishmaniasis (CL) is a neglected tropical vector-borne disease. Sand fly vectors (SF) and Leishmania spp parasites are sensitive to changes in weather conditions, rendering disease transmission susceptible to changes in local and global scale climatic patterns. Nevertheless, it is unclear how SF abundance is impacted by El Niño Southern Oscillation (ENSO) and how these changes might relate to changes in CL transmission. METHODOLOGY AND FINDINGS We studied association patterns between monthly time series, from January 2000 to December 2010, of: CL cases, rainfall and temperature from Panamá, and an ENSO index. We employed autoregressive models and cross wavelet coherence, to quantify the seasonal and interannual impact of local climate and ENSO on CL dynamics. We employed Poisson Rate Generalized Linear Mixed Models to study SF abundance patterns across ENSO phases, seasons and eco-epidemiological settings, employing records from 640 night-trap sampling collections spanning 2000-2011. We found that ENSO, rainfall and temperature were associated with CL cycles at interannual scales, while seasonal patterns were mainly associated with rainfall and temperature. Sand fly (SF) vector abundance, on average, decreased during the hot and cold ENSO phases, when compared with the normal ENSO phase, yet variability in vector abundance was largest during the cold ENSO phase. Our results showed a three month lagged association between SF vector abundance and CL cases. CONCLUSION Association patterns of CL with ENSO and local climatic factors in Panamá indicate that interannual CL cycles might be driven by ENSO, while the CL seasonality was mainly associated with temperature and rainfall variability. CL cases and SF abundance were associated in a fashion suggesting that sudden extraordinary changes in vector abundance might increase the potential for CL epidemic outbreaks, given that CL epidemics occur during the cold ENSO phase, a time when SF abundance shows its highest fluctuations.
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185
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Kreppel KS, Caminade C, Telfer S, Rajerison M, Rahalison L, Morse A, Baylis M. A non-stationary relationship between global climate phenomena and human plague incidence in Madagascar. PLoS Negl Trop Dis 2014; 8:e3155. [PMID: 25299064 PMCID: PMC4191945 DOI: 10.1371/journal.pntd.0003155] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 07/31/2014] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Plague, a zoonosis caused by Yersinia pestis, is found in Asia and the Americas, but predominantly in Africa, with the island of Madagascar reporting almost one third of human cases worldwide. Plague's occurrence is affected by local climate factors which in turn are influenced by large-scale climate phenomena such as the El Niño Southern Oscillation (ENSO). The effects of ENSO on regional climate are often enhanced or reduced by a second large-scale climate phenomenon, the Indian Ocean Dipole (IOD). It is known that ENSO and the IOD interact as drivers of disease. Yet the impacts of these phenomena in driving plague dynamics via their effect on regional climate, and specifically contributing to the foci of transmission on Madagascar, are unknown. Here we present the first analysis of the effects of ENSO and IOD on plague in Madagascar. METHODOLOGY/PRINCIPAL FINDINGS We use a forty-eight year monthly time-series of reported human plague cases from 1960 to 2008. Using wavelet analysis, we show that over the last fifty years there have been complex non-stationary associations between ENSO/IOD and the dynamics of plague in Madagascar. We demonstrate that ENSO and IOD influence temperature in Madagascar and that temperature and plague cycles are associated. The effects on plague appear to be mediated more by temperature, but precipitation also undoubtedly influences plague in Madagascar. Our results confirm a relationship between plague anomalies and an increase in the intensity of ENSO events and precipitation. CONCLUSIONS/SIGNIFICANCE This work widens the understanding of how climate factors acting over different temporal scales can combine to drive local disease dynamics. Given the association of increasing ENSO strength and plague anomalies in Madagascar it may in future be possible to forecast plague outbreaks in Madagascar. The study gives insight into the complex and changing relationship between climate factors and plague in Madagascar.
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Affiliation(s)
- Katharina S. Kreppel
- LUCINDA group, Institute of Infection and Global Health, Department of Epidemiology and Population Health, University of Liverpool, Neston, United Kingdom
| | - Cyril Caminade
- LUCINDA group, Institute of Infection and Global Health, Department of Epidemiology and Population Health, University of Liverpool, Neston, United Kingdom
- Department of Geography and Planning, School of Environmental Sciences, University of Liverpool, Liverpool, Merseyside, United Kingdom
| | - Sandra Telfer
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | | | - Lila Rahalison
- Centers for Disease Control and Prevention, Division of Bacterial Diseases, Atlanta, Georgia, United States of America
| | - Andy Morse
- Department of Geography and Planning, School of Environmental Sciences, University of Liverpool, Liverpool, Merseyside, United Kingdom
| | - Matthew Baylis
- LUCINDA group, Institute of Infection and Global Health, Department of Epidemiology and Population Health, University of Liverpool, Neston, United Kingdom
- Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, Neston, United Kingdom
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186
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Flores-Moreno H, García-Treviño ES, Letten AD, Moles AT. In the beginning: phenotypic change in three invasive species through their first two centuries since introduction. Biol Invasions 2014. [DOI: 10.1007/s10530-014-0789-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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187
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Lepeigneul O, Ballouard JM, Bonnet X, Beck E, Barbier M, Ekori A, Buisson E, Caron S. Immediate response to translocation without acclimation from captivity to the wild in Hermann’s tortoise. EUR J WILDLIFE RES 2014. [DOI: 10.1007/s10344-014-0857-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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188
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Disentangling the confounding effects of PAR and air temperature on net ecosystem exchange at multiple time scales. ECOLOGICAL COMPLEXITY 2014. [DOI: 10.1016/j.ecocom.2014.04.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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189
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Complex temporal climate signals drive the emergence of human water-borne disease. Emerg Microbes Infect 2014; 3:e56. [PMID: 26038751 PMCID: PMC4150285 DOI: 10.1038/emi.2014.56] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 06/03/2014] [Accepted: 06/16/2014] [Indexed: 12/18/2022]
Abstract
Predominantly occurring in developing parts of the world, Buruli ulcer is a severely disabling mycobacterium infection which often leads to extensive necrosis of the skin. While the exact route of transmission remains uncertain, like many tropical diseases, associations with climate have been previously observed and could help identify the causative agent's ecological niche. In this paper, links between changes in rainfall and outbreaks of Buruli ulcer in French Guiana, an ultraperipheral European territory in the northeast of South America, were identified using a combination of statistical tests based on singular spectrum analysis, empirical mode decomposition and cross-wavelet coherence analysis. From this, it was possible to postulate for the first time that outbreaks of Buruli ulcer can be triggered by combinations of rainfall patterns occurring on a long (i.e., several years) and short (i.e., seasonal) temporal scale, in addition to stochastic events driven by the El Niño-Southern Oscillation that may disrupt or interact with these patterns. Long-term forecasting of rainfall trends further suggests the possibility of an upcoming outbreak of Buruli ulcer in French Guiana.
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190
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Wavelet analysis of time-lags in the response of cyanobacteria growth to water quality conditions in Lake Taihu, China. ECOL INFORM 2014. [DOI: 10.1016/j.ecoinf.2014.05.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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191
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Kerr KA, Christy JH, Joly-Lopez Z, Luque J, Collin R, Guichard F. Reproducing on time when temperature varies: shifts in the timing of courtship by fiddler crabs. PLoS One 2014; 9:e97593. [PMID: 24832079 PMCID: PMC4022618 DOI: 10.1371/journal.pone.0097593] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 04/21/2014] [Indexed: 11/19/2022] Open
Abstract
Many species reproduce when conditions are most favorable for the survival of young. Numerous intertidal fish and invertebrates release eggs or larvae during semilunar, large amplitude, nocturnal tides when these early life stages are best able to escape predation by fish that feed near the shore during the day. Remarkably, some species, including the fiddler crabs Uca terpsichores and Uca deichmanni, maintain this timing throughout the year as temperature, and thus the rate of embryonic development, vary. The mechanisms that allow such precision in the timing of the production of young are poorly known. A preliminary study suggested that when temperature decreases, U. terpsichores mate earlier in the tidal amplitude cycle such that larvae are released at the appropriate time. We tested this idea by studying the timing of courtship in U. terpsichores and U. deichmanni as temperature varied annually during two years, at 5 locations that differed in the temperature of the sediment where females incubate their eggs. Uca terpsichores courted earlier at locations where sediment temperature declined seasonally but not where sediment temperature remained elevated throughout the year. In contrast, clear shifts in courtship timing were not observed for U. deichmanni despite variation in sediment temperature. We discuss other mechanisms by which this species may maintain reproductive timing. These two species are likely to be affected differently by changes in the frequency and intensity of cold periods that are expected to accompany climate change.
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Affiliation(s)
- Kecia A. Kerr
- Department of Biology, McGill University, Montréal, Québec, Canada
- Smithsonian Tropical Research Institute, Balboa, Ancon, Panama, Panama
- McGill-STRI Neotropical Environment Option (NEO), McGill University, Montréal, Québec, Canada
- * E-mail:
| | - John H. Christy
- Smithsonian Tropical Research Institute, Balboa, Ancon, Panama, Panama
| | - Zoé Joly-Lopez
- Department of Biology, McGill University, Montréal, Québec, Canada
| | - Javier Luque
- Smithsonian Tropical Research Institute, Balboa, Ancon, Panama, Panama
- University of Alberta, Department of Biological Sciences, Edmonton, Alberta, Canada
| | - Rachel Collin
- Smithsonian Tropical Research Institute, Balboa, Ancon, Panama, Panama
- McGill-STRI Neotropical Environment Option (NEO), McGill University, Montréal, Québec, Canada
| | - Frédéric Guichard
- Department of Biology, McGill University, Montréal, Québec, Canada
- McGill-STRI Neotropical Environment Option (NEO), McGill University, Montréal, Québec, Canada
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193
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Evrendilek F, Karakaya N. Monitoring diel dissolved oxygen dynamics through integrating wavelet denoising and temporal neural networks. ENVIRONMENTAL MONITORING AND ASSESSMENT 2014; 186:1583-1591. [PMID: 24100799 DOI: 10.1007/s10661-013-3476-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2013] [Accepted: 10/01/2013] [Indexed: 06/02/2023]
Abstract
Diel dissolved oxygen (DO) time series measured continuously using proximal sensors in situ for a temperate lake were denoised using discrete wavelet transform (DWT) with the orthogonal wavelet families of coiflet, daubechies, and symmlet with order of 10. Diel DO time series denoised were modeled using nine temporal artificial neural networks (ANNs) as a function of water level, water temperature, electrical conductivity, pH, day of year, and hour. Our results showed that time-lag recurrent network (TLRN) using denoised data emulated diel DO dynamics better than the best-performing TLRN using the original data, time-delay neural network (TDNN), and recurrent network (RNN). Daubechies basis dealt with diel DO data slightly better than the other bases given its coefficient of determination (r (2) = 87.1 %), while symmlet performed slightly better than the other bases in terms of root mean square error (RMSE = 1.2 ppm) and mean absolute error (MAE = 0.9 ppm).
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Affiliation(s)
- Fatih Evrendilek
- Department of Environmental Engineering, Abant Izzet Baysal University, Bolu, Turkey,
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194
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Wood TE, Detto M, Silver WL. Sensitivity of soil respiration to variability in soil moisture and temperature in a humid tropical forest. PLoS One 2013; 8:e80965. [PMID: 24312508 PMCID: PMC3846571 DOI: 10.1371/journal.pone.0080965] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 10/08/2013] [Indexed: 12/04/2022] Open
Abstract
Precipitation and temperature are important drivers of soil respiration. The role of moisture and temperature are generally explored at seasonal or inter-annual timescales; however, significant variability also occurs on hourly to daily time-scales. We used small (1.54 m2), throughfall exclusion shelters to evaluate the role soil moisture and temperature as temporal controls on soil CO2 efflux from a humid tropical forest in Puerto Rico. We measured hourly soil CO2 efflux, temperature and moisture in control and exclusion plots (n = 6) for 6-months. The variance of each time series was analyzed using orthonormal wavelet transformation and Haar-wavelet coherence. We found strong negative coherence between soil moisture and soil respiration in control plots corresponding to a two-day periodicity. Across all plots, there was a significant parabolic relationship between soil moisture and soil CO2 efflux with peak soil respiration occurring at volumetric soil moisture of approximately 0.375 m3/m3. We additionally found a weak positive coherence between CO2 and temperature at longer time-scales and a significant positive relationship between soil temperature and CO2 efflux when the analysis was limited to the control plots. The coherence between CO2 and both temperature and soil moisture were reduced in exclusion plots. The reduced CO2 response to temperature in exclusion plots suggests that the positive effect of temperature on CO2 is constrained by soil moisture availability.
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Affiliation(s)
- Tana E. Wood
- International Institute of Tropical Forestry, USDA Forest Service, Río Piedras, Puerto Rico, United States of America
- Fundación Puertorriqueña de Conservación, San Juan, Puerto Rico, United States of America
- * E-mail:
| | - Matteo Detto
- Smithsonian Tropical Research Institute, Apartado Balboa, Republic of Panama
| | - Whendee L. Silver
- Department of Environmental Science, Policy and Management, University of California, Berkeley, California, United States of America
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195
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Cazelles B, Cazelles K, Chavez M. Wavelet analysis in ecology and epidemiology: impact of statistical tests. J R Soc Interface 2013; 11:20130585. [PMID: 24284892 DOI: 10.1098/rsif.2013.0585] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Wavelet analysis is now frequently used to extract information from ecological and epidemiological time series. Statistical hypothesis tests are conducted on associated wavelet quantities to assess the likelihood that they are due to a random process. Such random processes represent null models and are generally based on synthetic data that share some statistical characteristics with the original time series. This allows the comparison of null statistics with those obtained from original time series. When creating synthetic datasets, different techniques of resampling result in different characteristics shared by the synthetic time series. Therefore, it becomes crucial to consider the impact of the resampling method on the results. We have addressed this point by comparing seven different statistical testing methods applied with different real and simulated data. Our results show that statistical assessment of periodic patterns is strongly affected by the choice of the resampling method, so two different resampling techniques could lead to two different conclusions about the same time series. Moreover, our results clearly show the inadequacy of resampling series generated by white noise and red noise that are nevertheless the methods currently used in the wide majority of wavelets applications. Our results highlight that the characteristics of a time series, namely its Fourier spectrum and autocorrelation, are important to consider when choosing the resampling technique. Results suggest that data-driven resampling methods should be used such as the hidden Markov model algorithm and the 'beta-surrogate' method.
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Affiliation(s)
- Bernard Cazelles
- UMR 7625, UPMC-ENS, Ecole Normale Supérieure, , 46 rue d'Ulm, Paris Cedex 05 75230, France
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196
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Cuong HQ, Vu NT, Cazelles B, Boni MF, Thai KTD, Rabaa MA, Quang LC, Simmons CP, Huu TN, Anders KL. Spatiotemporal dynamics of dengue epidemics, southern Vietnam. Emerg Infect Dis 2013; 19:945-53. [PMID: 23735713 PMCID: PMC3713821 DOI: 10.3201/eid1906.121323] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
An improved understanding of heterogeneities in dengue virus transmission might provide insights into biological and ecologic drivers and facilitate predictions of the magnitude, timing, and location of future dengue epidemics. To investigate dengue dynamics in urban Ho Chi Minh City and neighboring rural provinces in Vietnam, we analyzed a 10-year monthly time series of dengue surveillance data from southern Vietnam. The per capita incidence of dengue was lower in Ho Chi Minh City than in most rural provinces; annual epidemics occurred 1-3 months later in Ho Chi Minh City than elsewhere. The timing and the magnitude of annual epidemics were significantly more correlated in nearby districts than in remote districts, suggesting that local biological and ecologic drivers operate at a scale of 50-100 km. Dengue incidence during the dry season accounted for 63% of variability in epidemic magnitude. These findings can aid the targeting of vector-control interventions and the planning for dengue vaccine implementation.
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Affiliation(s)
- Hoang Quoc Cuong
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
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197
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Different types of synchrony in chaotic and cyclic communities. Nat Commun 2013; 4:1359. [PMID: 23322047 DOI: 10.1038/ncomms2355] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 12/03/2012] [Indexed: 11/08/2022] Open
Abstract
Stability and persistence of populations is of great interest for management and conservation purposes. Spatial dynamics can have a crucial role in population stability via synchronization, and beneficial and detrimental effects on population persistence have been shown. Despite a theoretical understanding of synchronization, empirical data on synchrony of populations are restricted to systems that do not display the full spectrum of complex dynamics that may occur in nature (that is, chaos or quasiperiodicity). Here we show in experiments that the qualitative form of dynamic behaviour of chaotic and periodic oscillating communities did not change when unidirectionally coupled to oscillating driver communities. Driver and response populations were phase locked in cyclic communities, whereas chaotic communities showed only short periods of statistical coherencies. Our study provides the first empirical analysis of synchronization of chaotic communities and shows that the likelihood for chaos is not lowered in spatially explicit systems but that cyclic and chaotic systems differ in synchronization.
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198
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Xiao H, Tian HY, Cazelles B, Li XJ, Tong SL, Gao LD, Qin JX, Lin XL, Liu HN, Zhang XX. Atmospheric moisture variability and transmission of hemorrhagic fever with renal syndrome in Changsha City, Mainland China, 1991-2010. PLoS Negl Trop Dis 2013; 7:e2260. [PMID: 23755316 PMCID: PMC3674989 DOI: 10.1371/journal.pntd.0002260] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 04/26/2013] [Indexed: 12/04/2022] Open
Abstract
Background The transmission of hemorrhagic fever with renal syndrome (HFRS) is influenced by environmental determinants. This study aimed to explore the association between atmospheric moisture variability and the transmission of hemorrhagic fever with renal syndrome (HFRS) for the period of 1991–2010 in Changsha, China. Methods and Findings Wavelet analyses were performed by using monthly reported time series data of HFRS cases to detect and quantify the periodicity of HFRS. A generalized linear model with a Poisson distribution and a log link model were used to quantify the relationship between climate and HFRS cases, highlighting the importance of moisture conditions. There was a continuous annual oscillation mode and multi-annual cycle around 3–4 years from 1994 to 1999. There was a significant association of HFRS incidence with moisture conditions and the Multivariate El Niño–Southern Oscillation Index (MEI). Particularly, atmospheric moisture has a significant effect on the propagation of HFRS; annual incidence of HFRS was positively correlated with annual precipitation and annual mean absolute humidity. Conclusions The final model had good accuracy in forecasting the occurrence of HFRS and moisture condition can be used in disease surveillance and risk management to provide early warning of potential epidemics of this disease. Hemorrhagic fever with renal syndrome (HFRS), a rodentborne disease caused by Hantaviruses, is characterized by fever, haemorrhage, headache, back pain, abdominal pain, and acute kidney injury. At present, it is endemic in all 31 provinces, autonomous regions, and metropolitan areas in mainland China where human cases account for 90% of the total global cases. Infection rates and population dynamics of hosts are thought to be influenced by climatic factors, especially humidity. Some studies have found that hantaviruses are limited in their spread to high-humidity environments for extended ex vivo stability. Here we provide the evidence that HFRS incidence was strongly associated with moisture conditions, including seasonal variation and annual situation, in Changsha, mainland China, 1991–2010. The results most likely indicate that moisture not only influences growth of food sources that determine rodent population size, thereby affecting the HFRS transmission, but also directly influences rodent activity and hantavirus infectivity. These findings offer insights in understanding possible causes of HFRS transmission, and can be used in disease surveillance and risk management to provide early warning of potential epidemics of this disease.
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Affiliation(s)
- Hong Xiao
- College of Resources and Environment Science, Hunan Normal University, Changsha, China
- * E-mail: (HX); (HYT)
| | - Huai-Yu Tian
- College of Resources and Environment Science, Hunan Normal University, Changsha, China
- * E-mail: (HX); (HYT)
| | - Bernard Cazelles
- Ecologie & Evolution, UMR 7625, UPMC-ENS, Paris, France
- UMMISCO UMI 209 IRD - UPMC, Bondy, France
| | - Xiu-Jun Li
- School of Public Health, Shandong University, Jinan, China
| | - Shi-Lu Tong
- School of Public Health and Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Li-Dong Gao
- Hunan Provincial Center for Disease Control and Prevention, Changsha, China
| | - Jian-Xin Qin
- College of Resources and Environment Science, Hunan Normal University, Changsha, China
| | - Xiao-Ling Lin
- College of Resources and Environment Science, Hunan Normal University, Changsha, China
| | - Hai-Ning Liu
- College of Resources and Environment Science, Hunan Normal University, Changsha, China
| | - Xi-Xing Zhang
- Changsha Municipal Center for Disease Control and Prevention, Changsha , China
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Krylova O, Earn DJD. Effects of the infectious period distribution on predicted transitions in childhood disease dynamics. J R Soc Interface 2013; 10:20130098. [PMID: 23676892 DOI: 10.1098/rsif.2013.0098] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The population dynamics of infectious diseases occasionally undergo rapid qualitative changes, such as transitions from annual to biennial cycles or to irregular dynamics. Previous work, based on the standard seasonally forced 'susceptible-exposed-infectious-removed' (SEIR) model has found that transitions in the dynamics of many childhood diseases result from bifurcations induced by slow changes in birth and vaccination rates. However, the standard SEIR formulation assumes that the stage durations (latent and infectious periods) are exponentially distributed, whereas real distributions are narrower and centred around the mean. Much recent work has indicated that realistically distributed stage durations strongly affect the dynamical structure of seasonally forced epidemic models. We investigate whether inferences drawn from previous analyses of transitions in patterns of measles dynamics are robust to the shapes of the stage duration distributions. As an illustrative example, we analyse measles dynamics in New York City from 1928 to 1972. We find that with a fixed mean infectious period in the susceptible-infectious-removed (SIR) model, the dynamical structure and predicted transitions vary substantially as a function of the shape of the infectious period distribution. By contrast, with fixed mean latent and infectious periods in the SEIR model, the shapes of the stage duration distributions have a less dramatic effect on model dynamical structure and predicted transitions. All these results can be understood more easily by considering the distribution of the disease generation time as opposed to the distributions of individual disease stages. Numerical bifurcation analysis reveals that for a given mean generation time the dynamics of the SIR and SEIR models for measles are nearly equivalent and are insensitive to the shapes of the disease stage distributions.
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Affiliation(s)
- Olga Krylova
- Department of Mathematics and Statistics, McMaster University, Hamilton, Ontario, Canada
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200
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Fernández de Puelles ML, Molinero JC. Increasing zooplankton variance in the late 1990s unveils hydroclimate modifications in the Balearic Sea, Western Mediterranean. MARINE ENVIRONMENTAL RESEARCH 2013; 86:76-80. [PMID: 23433612 DOI: 10.1016/j.marenvres.2012.12.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 11/28/2012] [Accepted: 12/03/2012] [Indexed: 06/01/2023]
Abstract
We examined seasonal and interannual patterns of zooplankton functional groups in the Balearic Sea from 1994 to 2003 and revealed a conspicuous increase in zooplankton variance at community and population levels. The change occurred in 1999-2000, and paralleled modifications in the North Atlantic climate that cascaded down affecting the water column thermal gradient in the Balearic Sea. The observed modifications in both hydroclimate and ecological compartments raise the question of a potential ecological shift in the pelagic ecosystem of the Western Mediterranean in the late 1990s.
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Affiliation(s)
- Ma Luz Fernández de Puelles
- Centro Oceanográfico de Baleares, Instituto Español de Oceanografía, P.O. Box 291, 07080 Palma de Mallorca, Baleares, Spain.
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