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Eustache KB, van Loon E, Rummer JL, Planes S, Smallegange I. Spatial and temporal analysis of juvenile blacktip reef shark (Carcharhinus melanopterus) demographies identifies critical habitats. J Fish Biol 2024; 104:92-103. [PMID: 37726231 DOI: 10.1111/jfb.15569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 09/14/2023] [Accepted: 09/17/2023] [Indexed: 09/21/2023]
Abstract
Reef shark species have undergone sharp declines in recent decades, as they inhabit coastal areas, making them an easy target in fisheries (i.e., sharks are exploited globally for their fins, meat, and liver oil) and exposing them to other threats (e.g., being part of by-catch, pollution, and climate change). Reef sharks play a critical role in coral reef ecosystems, where they control populations of smaller predators and herbivorous fishes either directly via predation or indirectly via behavior, thus protecting biodiversity and preventing potential overgrazing of corals. The urgent need to conserve reef shark populations necessitates a multifaceted approach to policy at local, federal, and global levels. However, monitoring programmes to evaluate the efficiency of such policies are lacking due to the difficulty in repeatedly sampling free-ranging, wild shark populations. Over nine consecutive years, we monitored juveniles of the blacktip reef shark (Carcharhinus melanopterus) population around Moorea, French Polynesia, and within the largest shark sanctuary globally, to date. We investigated the roles of spatial (i.e., sampling sites) and temporal variables (i.e., sampling year, season, and month), water temperature, and interspecific competition on shark density across 10 coastal nursery areas. Juvenile C. melanopterus density was found to be stable over 9 years, which may highlight the effectiveness of local and likely federal policies. Two of the 10 nursery areas exhibited higher juvenile shark densities over time, which may have been related to changes in female reproductive behavior or changes in habitat type and resources. Water temperatures did not affect juvenile shark density over time as extreme temperatures proven lethal (i.e., 33°C) in juvenile C. melanopterus might have been tempered by daily variation. The proven efficiency of time-series datasets for reef sharks to identify critical habitats (having the highest juvenile shark densities over time) should be extended to other populations to significantly contribute to the conservation of reef shark species.
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Affiliation(s)
- Kim B Eustache
- PSL Research University, EPHE-UPVD-CNRS, UAR 3278 CRIOBE, Université de Perpignan, Perpignan Cedex, France
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, Netherlands
| | - Emiel van Loon
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, Netherlands
| | - Jodie L Rummer
- Australian Research Council Centre of Excellence for Coral Reef Studies and the College of Science and Engineering James Cook University, Townsville, Queensland, Australia
| | - Serge Planes
- PSL Research University, EPHE-UPVD-CNRS, UAR 3278 CRIOBE, Université de Perpignan, Perpignan Cedex, France
- Laboratoire d'Excellence "CORAIL," EPHE, PSL Research University, UPVD, CNRS, UAR 3278 CRIOBE, Papetoai, French Polynesia
| | - Isabel Smallegange
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, UK
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Mumme S, Middleton AD, Ciucci P, De Groeve J, Corradini A, Aikens EO, Ossi F, Atwood P, Balkenhol N, Cole EK, Debeffe L, Dewey SR, Fischer C, Gude J, Heurich M, Hurley MA, Jarnemo A, Kauffman MJ, Licoppe A, van Loon E, McWhirter D, Mong TW, Pedrotti L, Morellet N, Mysterud A, Peters W, Proffitt K, Saïd S, Signer J, Sunde P, Starý M, Cagnacci F. Wherever I may roam-Human activity alters movements of red deer (Cervus elaphus) and elk (Cervus canadensis) across two continents. Glob Chang Biol 2023; 29:5788-5801. [PMID: 37306048 DOI: 10.1111/gcb.16769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 03/29/2023] [Accepted: 04/02/2023] [Indexed: 06/13/2023]
Abstract
Human activity and associated landscape modifications alter the movements of animals with consequences for populations and ecosystems worldwide. Species performing long-distance movements are thought to be particularly sensitive to human impact. Despite the increasing anthropogenic pressure, it remains challenging to understand and predict animals' responses to human activity. Here we address this knowledge gap using 1206 Global Positioning System movement trajectories of 815 individuals from 14 red deer (Cervus elaphus) and 14 elk (Cervus canadensis) populations spanning wide environmental gradients, namely the latitudinal range from the Alps to Scandinavia in Europe, and the Greater Yellowstone Ecosystem in North America. We measured individual-level movements relative to the environmental context, or movement expression, using the standardized metric Intensity of Use, reflecting both the directionality and extent of movements. We expected movement expression to be affected by resource (Normalized Difference Vegetation Index, NDVI) predictability and topography, but those factors to be superseded by human impact. Red deer and elk movement expression varied along a continuum, from highly segmented trajectories over relatively small areas (high intensity of use), to directed transitions through restricted corridors (low intensity of use). Human activity (Human Footprint Index, HFI) was the strongest driver of movement expression, with a steep increase in Intensity of Use as HFI increased, but only until a threshold was reached. After exceeding this level of impact, the Intensity of Use remained unchanged. These results indicate the overall sensitivity of Cervus movement expression to human activity and suggest a limitation of plastic responses under high human pressure, despite the species also occurring in human-dominated landscapes. Our work represents the first comparison of metric-based movement expression across widely distributed populations of a deer genus, contributing to the understanding and prediction of animals' responses to human activity.
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Affiliation(s)
- Steffen Mumme
- Department of Biology and Biotechnologies "Charles Darwin", University of Rome La Sapienza, Rome, Italy
- Animal Ecology Unit, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, Italy
- Department of Environmental Science, Policy, and Management, University of California, California, Berkeley, USA
| | - Arthur D Middleton
- Department of Environmental Science, Policy, and Management, University of California, California, Berkeley, USA
| | - Paolo Ciucci
- Department of Biology and Biotechnologies "Charles Darwin", University of Rome La Sapienza, Rome, Italy
| | - Johannes De Groeve
- Animal Ecology Unit, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, Italy
- Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, Amsterdam, The Netherlands
| | - Andrea Corradini
- Animal Ecology Unit, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, Italy
- NBFC, National Biodiversity Future Center, Palermo, Italy
- Department of Civil, Environmental and Mechanical Engineering (DICAM), University of Trento, Trento, Italy
- Stelvio National Park-Ersaf Lombardia, Bormio, Italy
| | - Ellen O Aikens
- School of Computing, University of Wyoming, Wyoming, Laramie, USA
- Haub School of Environment and Natural Resources, University of Wyoming, Wyoming, Laramie, USA
| | - Federico Ossi
- Animal Ecology Unit, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, Italy
- NBFC, National Biodiversity Future Center, Palermo, Italy
| | - Paul Atwood
- Idaho Department of Fish and Game, Idaho, Coeur d'Alene, USA
| | - Niko Balkenhol
- Wildlife Sciences, Faculty of Forest Sciences and Forest Ecology, University of Goettingen, Goettingen, Germany
| | - Eric K Cole
- US Fish and Wildlife Service, National Elk Refuge, Wyoming, Jackson, USA
| | - Lucie Debeffe
- Université de Toulouse, INRAE, CEFS, Castanet Tolosan, France
- LTSER ZA PYRénées GARonne, Auzeville Tolosane, France
| | - Sarah R Dewey
- National Park Service, Grand Teton National Park, Wyoming, Moose, USA
| | - Claude Fischer
- Department of Nature Management, University of Applied Sciences of Western Switzerland, Jussy, Switzerland
| | - Justin Gude
- Montana Department of Fish, Wildlife and Parks, Montana, Helena, USA
| | - Marco Heurich
- Department of Visitor Management and National Park Monitoring, Bavarian Forest National Park, Grafenau, Germany
- Chair of Wildlife Ecology and Management, Albert Ludwigs University Freiburg, Freiburg, Germany
- Inland Norway University of Applied Science Institute for Forest and Wildlife Management, Koppang, Norway
| | - Mark A Hurley
- Idaho Department of Fish and Game, Idaho, Boise, USA
| | - Anders Jarnemo
- School of Business, Innovation and Sustainability, Halmstad University, Halmstad, Sweden
| | - Matthew J Kauffman
- U.S. Geological Survey, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology, University of Wyoming, Wyoming, Laramie, USA
| | - Alain Licoppe
- Natural and Agricultural Environmental Studies Department, Service Public de Wallonie, Gembloux, Belgium
| | - Emiel van Loon
- Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, Amsterdam, The Netherlands
| | | | - Tony W Mong
- Wyoming Game and Fish Department, Wyoming, Cody, USA
| | - Luca Pedrotti
- Stelvio National Park-Ersaf Lombardia, Bormio, Italy
| | - Nicolas Morellet
- Université de Toulouse, INRAE, CEFS, Castanet Tolosan, France
- LTSER ZA PYRénées GARonne, Auzeville Tolosane, France
| | - Atle Mysterud
- Department of Biosciences, Centre for Ecological and Evolutionary Synthesis, University of Oslo, Oslo, Norway
| | - Wibke Peters
- Department for Conservation, Biodiversity and Wildlife Management, Bavarian State Institute of Forestry, Freising, Germany
| | - Kelly Proffitt
- Montana Department of Fish, Wildlife and Parks, Montana, Bozeman, USA
| | - Sonia Saïd
- Office Français de la Biodiversité, DRAS, "Montfort", Birieux, France
| | - Johannes Signer
- Wildlife Sciences, Faculty of Forest Sciences and Forest Ecology, University of Goettingen, Goettingen, Germany
| | - Peter Sunde
- Department of Ecoscience-Wildlife Ecology, Aarhus University, Aarhus, Denmark
| | | | - Francesca Cagnacci
- Animal Ecology Unit, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, Italy
- NBFC, National Biodiversity Future Center, Palermo, Italy
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Li Q, Larsen KS, Kopittke G, van Loon E, Tietema A. Long-term temporal patterns in ecosystem carbon flux components and overall balance in a heathland ecosystem. Sci Total Environ 2023; 875:162658. [PMID: 36894076 DOI: 10.1016/j.scitotenv.2023.162658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/27/2023] [Accepted: 03/01/2023] [Indexed: 06/18/2023]
Abstract
Terrestrial ecosystems have strong feedback to atmospheric CO2 concentration and climate change. However, the long-term whole life cycle dynamics of ecosystem carbon (C) fluxes and overall balance in some ecosystem types, such as heathland ecosystems, have not been thoroughly explored. We studied the changes in ecosystem CO2 flux components and overall C balance over a full ecosystem lifecycle in stands of Calluna vulgaris (L.) Hull by using a chronosequence of 0, 12, 19 and 28 years after vegetation cutting. Overall, the ecosystem C balance was highly nonlinear over time and exhibited a sinusoidal-like curvature of C sink/source change over the three-decade timescale. After cutting, plant-related C flux components of gross photosynthesis (PG), aboveground autotrophic respiration (Raa) and belowground autotrophic respiration (Rba) were higher at the young age (12 years) than at middle (19 years) and old (28 years) ages. The young ecosystem was a C sink (12 years: -0.374 kg C m-2 year-1) while it became a C source with aging (19 years: 0.218 kg C m-2 year-1) and when dying (28 years: 0.089 kg C m-2 year-1). The post-cutting C compensation point was observed after four years, while the cumulative C loss in the period after cutting had been compensated by an equal amount of C uptake after seven years. Annual ecosystem C payback from the ecosystem to the atmosphere started after 16 years. This information may be used directly for optimizing vegetation management practices for maximal ecosystem C uptake capacity. Our study highlights that whole life cycle observational data of changes in C fluxes and balance in ecosystems are important and the ecosystem model needs to take the successional stage and vegetation age into account when projecting component C fluxes, ecosystem C balance, and overall feedback to climate change.
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Affiliation(s)
- Qiaoyan Li
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark.
| | - Klaus Steenberg Larsen
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark
| | - Gillian Kopittke
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, the Netherlands
| | - Emiel van Loon
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, the Netherlands
| | - Albert Tietema
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, the Netherlands
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Janmaat KRL, de Guinea M, Collet J, Byrne RW, Robira B, van Loon E, Jang H, Biro D, Ramos-Fernández G, Ross C, Presotto A, Allritz M, Alavi S, Van Belle S. Using natural travel paths to infer and compare primate cognition in the wild. iScience 2021; 24:102343. [PMID: 33997670 PMCID: PMC8101046 DOI: 10.1016/j.isci.2021.102343] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Within comparative psychology, the evolution of animal cognition is typically studied either by comparing indirect measures of cognitive abilities (e.g., relative brain size) across many species or by conducting batteries of decision-making experiments among (typically) a few captive species. Here, we propose a third, complementary approach: inferring and comparing cognitive abilities through observational field records of natural information gradients and the associated variation in decision-making outcomes, using the ranging behavior of wild animals. To demonstrate the feasibility of our proposal, we present the results of a global survey assessing the availability of long-term ranging data sets from wild primates and the willingness of primatologists to share such data. We explore three ways in which such ranging data, with or without the associated behavioral and ecological data often collected by primatologists, might be used to infer and compare spatial cognition. Finally, we suggest how ecological complexity may be best incorporated into comparative analyses. Comparing animal ranging decisions in natural habitats has untapped potential How decisions vary with natural information gradients reveals wild animal cognition Ranging data on at least 164 populations of 105 wild primate species are available We present three thought analyses to compare cognition and explain its evolution
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Affiliation(s)
- Karline R L Janmaat
- Evolutionary and Population Biology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands.,Department of Cognitive Psychology, Faculty of Social Sciences, Leiden University, Leiden, the Netherlands.,ARTIS Amsterdam Royal zoo, Amsterdam, the Netherlands
| | - Miguel de Guinea
- Department of Social Sciences, Oxford Brookes University, Oxford, UK
| | - Julien Collet
- Oxford Navigation Group, Department of Zoology, Oxford University, Oxford, UK
| | - Richard W Byrne
- Centre for Social Learning and Cognitive Evolution, School of Psychology and Neuroscience, University of St Andrews, St Andrew, UK.,Scottish Primate Research Group, Scotland, UK
| | - Benjamin Robira
- Centre d'Écologie Fonctionnelle et Évolutive, Université de Montpellier, Montpellier, France.,Eco-anthropologie, Muséum National d'Histoire Naturelle, CNRS, Université de Paris, Paris, France
| | - Emiel van Loon
- Theoretical and Computational Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands
| | - Haneul Jang
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Dora Biro
- Oxford Navigation Group, Department of Zoology, Oxford University, Oxford, UK.,Department of Brain and Cognitive Sciences, University of Rochester, Rochester, USA
| | - Gabriel Ramos-Fernández
- Department of Mathematical Modelling of Social Systems, Institute for Research on Applied Mathematics and Systems, Universidad Nacional Autónoma de México, Mexico City, Mexico.,Center for Complexity Sciences, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Cody Ross
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Andrea Presotto
- Department of Geography and Geosciences, Salisbury University, Salisbury, MA, USA
| | - Matthias Allritz
- School of Psychology and Neuroscience, University of St Andrews, Scotland, UK
| | - Shauhin Alavi
- Department for the Ecology of Animal Societies, Max Planck Institute of Animal Behaviour, Konstanz, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany.,Department of Biology, University of Konstanz, Konstanz, Germany
| | - Sarie Van Belle
- Department of Anthropology, University of Austin at Texas, Austin, TX, USA
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Abcouwer K, van Loon E. Library inventory using a RFID wand: contribution of tag and book specific factors on the read rate. LHT 2020. [DOI: 10.1108/lht-06-2019-0129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PurposeLow read rates are a general problem in library inventories. The purpose of this study is to examine the factors that contribute to the success of library inventory by means of a radio-frequency identification (RFID) inventory taker. The factors investigated were tag position, tag orientation, book thickness, tag density (related to thickness of a sequence of books) and position on the shelf.Design/methodology/approachA total of 210 books were placed in eight random permutations on three fixed book shelves. For each configuration, the RFID tags were read forty times. The resulting data were analysed by means of a generalized linear model, relating the combined contribution of tag position, tag orientation, book thickness and position on the bookshelf to the read rate.FindingsThe tags positioned directly next to the spine were always read, but those near the opening of the book (far from the spine and inventory reader) were not always read. Considering only books with tags near the opening, tag orientation and position on the shelf appeared not to be related to the read rate, while book thickness, thickness over three books and spine tag density appeared to have a small positive contribution to the read rate.Practical implicationsLow read rates during a library inventory can be prevented by placing the tags near the book spine – the other book specific factors (listed in the previous paragraph) are of little influence. When not scanned during a first sweep, repeated scanning can increase the read rate with 0.15.Originality/valueThis paper is one of the first to analyse the influence of tag location and book specific factors on the read rate of RFID tags in library books. The experimental approach sets an example for future work.
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Padget O, Bond SL, Kavelaars MM, van Loon E, Bolton M, Fayet AL, Syposz M, Roberts S, Guilford T. In Situ Clock Shift Reveals that the Sun Compass Contributes to Orientation in a Pelagic Seabird. Curr Biol 2018; 28:275-279.e2. [PMID: 29337074 DOI: 10.1016/j.cub.2017.11.062] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 10/30/2017] [Accepted: 11/28/2017] [Indexed: 10/18/2022]
Abstract
Compass orientation is central to the control of animal movement from the scale of local food-caching movements around a familiar area in parids [1] and corvids [2, 3] to the first autumn vector navigation of songbirds embarking on long-distance migration [4-6]. In the study of diurnal birds, where the homing pigeon, Columba livia, has been the main model, a time-compensated sun compass [7] is central to the two-step map-and-compass process of navigation from unfamiliar places, as well as guiding movement via a representation of familiar area landmarks [8-12]. However, its use by an actively navigating wild bird is yet to be shown. By phase shifting an animal's endogenous clock, known as clock-shifting [13-15], sun-compass use can be demonstrated when the animal incorrectly consults the sun's azimuthal position while homing after experimental displacement [15-17]. By applying clock-shift techniques at the nest of a wild bird during natural incubation, we show here that an oceanic navigator-the Manx shearwater, Puffinus puffinus-incorporates information from a time-compensated sun compass during homeward guidance to the breeding colony after displacement. Consistently with homing pigeons navigating within their familiar area [8, 9, 11, 18], we find that the effect of clock shift, while statistically robust, is partial in nature, possibly indicating the incorporation of guidance from landmarks into movement decisions.
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Affiliation(s)
- Oliver Padget
- Department of Zoology, University of Oxford, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG, UK.
| | - Sarah L Bond
- Department of Zoology, University of Oxford, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG, UK
| | - Marwa M Kavelaars
- Behavioural Ecology and Ecophysiology Group, University of Antwerp, Universiteitsplein, Wilrijk, Antwerp, Belgium
| | - Emiel van Loon
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Sciencepark 904, 1098 XH Amsterdam, Netherlands
| | - Mark Bolton
- RSPB Centre for Conservation Science, The Lodge, Sandy, Bedfordshire SG19 2DL, UK
| | - Annette L Fayet
- Department of Zoology, University of Oxford, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG, UK
| | - Martyna Syposz
- Department of Zoology, University of Oxford, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG, UK
| | - Stephen Roberts
- Machine Learning Research Group, Information Engineering Building, Engineering Science, Parks Rd., University of Oxford, Oxford OX1 3PJ, UK
| | - Tim Guilford
- Department of Zoology, University of Oxford, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG, UK.
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Alexander BE, Liebrand K, Osinga R, van der Geest HG, Admiraal W, Cleutjens JPM, Schutte B, Verheyen F, Ribes M, van Loon E, de Goeij JM. Cell turnover and detritus production in marine sponges from tropical and temperate benthic ecosystems. PLoS One 2014; 9:e109486. [PMID: 25289641 PMCID: PMC4188633 DOI: 10.1371/journal.pone.0109486] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 09/01/2014] [Indexed: 02/02/2023] Open
Abstract
This study describes in vivo cell turnover (the balance between cell proliferation and cell loss) in eight marine sponge species from tropical coral reef, mangrove and temperate Mediterranean reef ecosystems. Cell proliferation was determined through the incorporation of 5-bromo-2′-deoxyuridine (BrdU) and measuring the percentage of BrdU-positive cells after 6 h of continuous labeling (10 h for Chondrosia reniformis). Apoptosis was identified using an antibody against active caspase-3. Cell loss through shedding was studied quantitatively by collecting and weighing sponge-expelled detritus and qualitatively by light microscopy of sponge tissue and detritus. All species investigated displayed substantial cell proliferation, predominantly in the choanoderm, but also in the mesohyl. The majority of coral reef species (five) showed between 16.1±15.9% and 19.0±2.0% choanocyte proliferation (mean±SD) after 6 h and the Mediterranean species, C. reniformis, showed 16.6±3.2% after 10 h BrdU-labeling. Monanchora arbuscula showed lower choanocyte proliferation (8.1±3.7%), whereas the mangrove species Mycale microsigmatosa showed relatively higher levels of choanocyte proliferation (70.5±6.6%). Choanocyte proliferation in Haliclona vansoesti was variable (2.8–73.1%). Apoptosis was negligible and not the primary mechanism of cell loss involved in cell turnover. All species investigated produced significant amounts of detritus (2.5–18% detritus bodyweight−1·d−1) and cell shedding was observed in seven out of eight species. The amount of shed cells observed in histological sections may be related to differences in residence time of detritus within canals. Detritus production could not be directly linked to cell shedding due to the degraded nature of expelled cellular debris. We have demonstrated that under steady-state conditions, cell turnover through cell proliferation and cell shedding are common processes to maintain tissue homeostasis in a variety of sponge species from different ecosystems. Cell turnover is hypothesized to be the main underlying mechanism producing sponge-derived detritus, a major trophic resource transferred through sponges in benthic ecosystems, such as coral reefs.
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Affiliation(s)
- Brittany E. Alexander
- Department of Aquatic Ecology and Ecotoxicology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
- Porifarma B.V. Poelbos 3, Ede, The Netherlands
- * E-mail: or
| | - Kevin Liebrand
- Department of Aquatic Ecology and Ecotoxicology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Harm G. van der Geest
- Department of Aquatic Ecology and Ecotoxicology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - Wim Admiraal
- Department of Aquatic Ecology and Ecotoxicology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - Jack P. M. Cleutjens
- Department of Pathology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Bert Schutte
- Department of Molecular Cell Biology, Research Institute Growth and Development, Maastricht University, Maastricht, The Netherlands
| | - Fons Verheyen
- Electron Microscopy Unit, CRISP, Maastricht, The Netherlands
| | - Marta Ribes
- Institut de Ciències del Mar-Consejo Superior de Investigaciones Científicas (ICM-CSIC), Barcelona, Spain
| | - Emiel van Loon
- Department of Computational Geo-Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - Jasper M. de Goeij
- Department of Aquatic Ecology and Ecotoxicology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
- Porifarma B.V. Poelbos 3, Ede, The Netherlands
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Shamoun-Baranes J, Leyrer J, van Loon E, Bocher P, Robin F, Meunier F, Piersma T. Stochastic atmospheric assistance and the use of emergency staging sites by migrants. Proc Biol Sci 2010; 277:1505-11. [PMID: 20071381 PMCID: PMC2871836 DOI: 10.1098/rspb.2009.2112] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Numerous animals move vast distances through media with stochastic dynamic properties. Avian migrants must cope with variable wind speeds and directions en route, which potentially jeopardize fine-tuned migration routes and itineraries. We show how unpredictable winds affect flight times and the use of an intermediate staging site by red knots (Calidris canutus canutus) migrating from west Africa to the central north Siberian breeding areas via the German Wadden Sea. A dynamic migration model incorporating wind conditions during flight shows that flight durations between Mauritania and the Wadden Sea vary between 2 and 8 days. The number of birds counted at the only known intermediate staging site on the French Atlantic coast was strongly positively correlated with simulated flight times. In addition, particularly light-weight birds occurred at this location. These independent results support the idea that stochastic wind conditions are the main driver of the use of this intermediate stopover site as an emergency staging area. Because of the ubiquity of stochastically varying media, we expect such emergency habitats to exist in many other migratory systems, both airborne and oceanic. Our model provides a tool to quantify the effect of winds and currents en route.
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Affiliation(s)
- Judy Shamoun-Baranes
- Computational Geo-ecology, Institute for Biodiversity and Ecosystem Dynamics IBED, University of Amsterdam, Nieuwe Achtergracht 166, Amsterdam, The Netherlands.
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Fillinger U, Sombroek H, Majambere S, van Loon E, Takken W, Lindsay SW. Identifying the most productive breeding sites for malaria mosquitoes in The Gambia. Malar J 2009; 8:62. [PMID: 19361337 PMCID: PMC2674466 DOI: 10.1186/1475-2875-8-62] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Accepted: 04/10/2009] [Indexed: 11/17/2022] Open
Abstract
Background Ideally larval control activities should be targeted at sites that generate the most adult vectors, thereby reducing operational costs. Despite the plethora of potential mosquito breeding sites found in the floodplains of the Gambia River, about 150 km from its mouth, during the rainy season, only a small proportion are colonized by anophelines on any day. This study aimed to determine the characteristics of larval habitats most frequently and most densely populated by anopheline larvae and to estimate the numbers of adults produced in different habitats. Methods A case-control design was used to identify characteristics of sites with or without mosquitoes. Sites were surveyed for their physical water properties and invertebrate fauna. The characteristics of 83 sites with anopheline larvae (cases) and 75 sites without (controls) were collected between June and November 2005. Weekly adult productivity was estimated with emergence traps in water-bodies commonly containing larvae. Results The presence of anopheline larvae was associated with high invertebrate diversity (Odds Ratio, OR 11.69, 95% CI 5.61–24.34, p < 0.001), the presence of emergent vegetation (OR 2.83, 95% CI 1.35–5.95, p = 0.006), and algae (at borderline significance; OR 1.87, 95% CI 0.96–3.618, p = 0.065). The density of larvae was reduced in sites that were larger than 100 m in perimeter (OR 0.151; 95% CI 0.060–0.381, p < 0.001), where water was tidal (OR 0.232; 95% CI 0.101–0.533, p = 0.001), vegetation shaded over 25% of the habitat (OR 0.352; 95% CI 0.136–0.911, p = 0.031) and water conductivity was above 2,000 μS/cm (OR 0.458; 95% CI 0.220–0.990, p = 0.048). Pools produced the highest numbers of Anopheles gambiae adults compared with rice fields, floodwater areas close to the edge of the floodplain or close to the river, and stream fringes. Pools were characterized by high water temperature and turbidity, low conductivity, increased presence of algae, and absence of tidal water. Conclusion There are few breeding sites that produce a high number of adult vectors in the middle reaches of the river in The Gambia, whereas those with low productivity are larger in area and can be found throughout the rainy season. Even though risk factors could be identified for the presence and density of larvae and productivity of habitats, the results indicate that anti-larval interventions in this area of The Gambia cannot be targeted in space or time during the rainy season.
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Affiliation(s)
- Ulrike Fillinger
- Disease Control & Vector Biology Unit, London School of Hygiene and Tropical Medicine, London, UK.
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Zaugg S, Saporta G, van Loon E, Schmaljohann H, Liechti F. Automatic identification of bird targets with radar via patterns produced by wing flapping. J R Soc Interface 2008; 5:1041-53. [PMID: 18331979 PMCID: PMC2607429 DOI: 10.1098/rsif.2007.1349] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Bird identification with radar is important for bird migration research, environmental impact assessments (e.g. wind farms), aircraft security and radar meteorology. In a study on bird migration, radar signals from birds, insects and ground clutter were recorded. Signals from birds show a typical pattern due to wing flapping. The data were labelled by experts into the four classes BIRD, INSECT, CLUTTER and UFO (unidentifiable signals). We present a classification algorithm aimed at automatic recognition of bird targets. Variables related to signal intensity and wing flapping pattern were extracted (via continuous wavelet transform). We used support vector classifiers to build predictive models. We estimated classification performance via cross validation on four datasets. When data from the same dataset were used for training and testing the classifier, the classification performance was extremely to moderately high. When data from one dataset were used for training and the three remaining datasets were used as test sets, the performance was lower but still extremely to moderately high. This shows that the method generalizes well across different locations or times. Our method provides a substantial gain of time when birds must be identified in large collections of radar signals and it represents the first substantial step in developing a real time bird identification radar system. We provide some guidelines and ideas for future research.
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Affiliation(s)
- Serge Zaugg
- Swiss Ornithological Institute, 6204 Sempach, Switzerland.
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Abstract
How flying organisms alter their air speed in response to wind is important in theories of flight energetics. Numerous studies have investigated the relationship between air and wind as a function of ground speed and air speed. This study shows that this approach can lead to erroneous results, due to spurious correlations. An alternative way to analyze air speed is proposed that overcomes the problems of one-dimensional linear models. The new model is non-linear and has two explanatory variables. Using two synthetic data sets with known properties and a data set with real observations of migratory bird tracks and wind observations, we illustrate the weaknesses of the conventional analysis as well as the strengths of the newly proposed model. This leads to the conclusion that for many studies a reanalysis of the effect of wind on air speed is desirable.
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Affiliation(s)
- Judy Shamoun-Baranes
- Computational Biogeography and Physical Geography, Institute of Biodiversity and Ecosystem Dynamics, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands.
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Abstract
During non-migratory flight, gulls (Larids) use a wide variety of flight strategies. We investigate the extent to which the energy balance of a bird explains flight strategy selection. We develop a model based on optimal foraging and aerodynamic theories, to calculate the ground speeds and airspeeds at which a gull is expected to flap or soar during foraging flight. The model results are compared with observed flight speeds, directions, and flight strategies of two species of gulls, the black-headed gull Larus ridibundus and the lesser black-backed gull Larus fuscus. The observations were made using a tracking radar over land in The Netherlands. The model suggests that, especially at combinations of low ground speed (approximately 5-10 m s(-1)), high air speed (approximately 20-25 m s(-1)) and low ground and air speed, gulls should favor soaring flight. At intermediate ground and air speeds the predicted net energy gain is similar for soaring and flapping. Hence the ratio of flapping to soaring may be higher than for other air and ground speed combinations. This range of speeds is broadest for black-headed gulls. The model results are supported by the observations. For example, flapping is more prevalent at speeds where the predicted net energy gain is similar for both strategies. Interestingly, combinations of air speed and flight speed that, according to the model, would result in a loss of net energy gain, were not observed. Additional factors that may influence flight strategy selection are also briefly discussed.
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Affiliation(s)
- Judy Shamoun-Baranes
- Computational Bio- and Physical Geography, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands.
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