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Winterl A, Richter S, Houstin A, Barracho T, Boureau M, Cornec C, Couet D, Cristofari R, Eiselt C, Fabry B, Krellenstein A, Mark C, Mainka A, Ménard D, Morinay J, Pottier S, Schloesing E, Le Bohec C, Zitterbart DP. Remote sensing of emperor penguin abundance and breeding success. Nat Commun 2024; 15:4419. [PMID: 38811565 PMCID: PMC11137044 DOI: 10.1038/s41467-024-48239-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 04/25/2024] [Indexed: 05/31/2024] Open
Abstract
Emperor penguins (Aptenodytes forsteri) are under increasing environmental pressure. Monitoring colony size and population trends of this Antarctic seabird relies primarily on satellite imagery recorded near the end of the breeding season, when light conditions levels are sufficient to capture images, but colony occupancy is highly variable. To correct population estimates for this variability, we develop a phenological model that can predict the number of breeding pairs and fledging chicks, as well as key phenological events such as arrival, hatching and foraging times, from as few as six data points from a single season. The ability to extrapolate occupancy from sparse data makes the model particularly useful for monitoring remotely sensed animal colonies where ground-based population estimates are rare or unavailable.
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Affiliation(s)
- Alexander Winterl
- Department of Physics, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany.
| | - Sebastian Richter
- Department of Physics, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Aymeric Houstin
- Department of Physics, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
- Department of Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole, USA
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000, Strasbourg, France
| | - Téo Barracho
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000, Strasbourg, France
- CEFE, Université de Montpellier, CNRS, EPHE, IRD, Montpellier, France
- University of Moncton, Canada Research Chair in Polar and Boreal Ecology and Centre d'Études Nordiques, Department of Biology, Moncton, New Brunswick, Canada
| | - Matthieu Boureau
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000, Strasbourg, France
| | - Clément Cornec
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000, Strasbourg, France
- ENES Bioacoustics Research Laboratory, CRNL, CNRS, Inserm, University of Saint-Etienne, Saint-Etienne, France
| | - Douglas Couet
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000, Strasbourg, France
| | - Robin Cristofari
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000, Strasbourg, France
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Claire Eiselt
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000, Strasbourg, France
| | - Ben Fabry
- Department of Physics, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | | | - Christoph Mark
- Department of Physics, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Astrid Mainka
- Department of Physics, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Delphine Ménard
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000, Strasbourg, France
| | - Jennifer Morinay
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000, Strasbourg, France
| | - Susie Pottier
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000, Strasbourg, France
| | - Elodie Schloesing
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000, Strasbourg, France
| | - Céline Le Bohec
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000, Strasbourg, France.
- CEFE, Université de Montpellier, CNRS, EPHE, IRD, Montpellier, France.
- Centre Scientifique de Monaco, Département de Biologie Polaire, Monaco, Principality of Monaco.
| | - Daniel P Zitterbart
- Department of Physics, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany.
- Department of Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole, USA.
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LaRue M, Iles D, Labrousse S, Fretwell P, Ortega D, Devane E, Horstmann I, Viollat L, Foster-Dyer R, Le Bohec C, Zitterbart D, Houstin A, Richter S, Winterl A, Wienecke B, Salas L, Nixon M, Barbraud C, Kooyman G, Ponganis P, Ainley D, Trathan P, Jenouvrier S. Advances in remote sensing of emperor penguins: first multi-year time series documenting trends in the global population. Proc Biol Sci 2024; 291:20232067. [PMID: 38471550 PMCID: PMC10932703 DOI: 10.1098/rspb.2023.2067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 02/15/2024] [Indexed: 03/14/2024] Open
Abstract
Like many polar animals, emperor penguin populations are challenging to monitor because of the species' life history and remoteness. Consequently, it has been difficult to establish its global status, a subject important to resolve as polar environments change. To advance our understanding of emperor penguins, we combined remote sensing, validation surveys and using Bayesian modelling, we estimated a comprehensive population trajectory over a recent 10-year period, encompassing the entirety of the species' range. Reported as indices of abundance, our study indicates with 81% probability that there were fewer adult emperor penguins in 2018 than in 2009, with a posterior median decrease of 9.6% (95% credible interval (CI) -26.4% to +9.4%). The global population trend was -1.3% per year over this period (95% CI = -3.3% to +1.0%) and declines probably occurred in four of eight fast ice regions, irrespective of habitat conditions. Thus far, explanations have yet to be identified regarding trends, especially as we observed an apparent population uptick toward the end of time series. Our work potentially establishes a framework for monitoring other Antarctic coastal species detectable by satellite, while promoting a need for research to better understand factors driving biotic changes in the Southern Ocean ecosystem.
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Affiliation(s)
- Michelle LaRue
- Department of Earth and Environmental Science, University of Minnesota, Minneapolis, MN, USA
- School of Earth and Environment, University of Canterbury, Christchurch, New Zealand
| | - David Iles
- Canadian Wildlife Service, Environment and Climate Change Canada, Ottawa, Canada
- Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Sara Labrousse
- Department of Earth and Environmental Science, University of Minnesota, Minneapolis, MN, USA
- Woods Hole Oceanographic Institution, Woods Hole, MA, USA
- Sorbonne Université, LOCEAN-IPSL, UMR 7159, 75005, Paris, France
| | | | - David Ortega
- Department of Earth and Environmental Science, University of Minnesota, Minneapolis, MN, USA
| | - Eileen Devane
- Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | | | - Lise Viollat
- Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Rose Foster-Dyer
- School of Earth and Environment, University of Canterbury, Christchurch, New Zealand
| | - Céline Le Bohec
- Centre National de la Recherche Scientifique, Université de Strasbourg, IPHC UMR 7178, Strasbourg, France
- Département de Biologie Polaire, Centre Scientifique de Monaco, Monaco City, Monaco
| | - Daniel Zitterbart
- Woods Hole Oceanographic Institution, Woods Hole, MA, USA
- Department of Physics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Aymeric Houstin
- Centre National de la Recherche Scientifique, Université de Strasbourg, IPHC UMR 7178, Strasbourg, France
- Département de Biologie Polaire, Centre Scientifique de Monaco, Monaco City, Monaco
- Department of Physics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Sebastian Richter
- Department of Physics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Alexander Winterl
- Department of Physics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Barbara Wienecke
- Department of Climate Change, Energy, the Environment and Water, Australian Antarctic Division, Hobart, Australia
| | - Leo Salas
- Point Blue Conservation Science, Petaluma, CA, USA
| | - Monique Nixon
- School of Earth and Environment, University of Canterbury, Christchurch, New Zealand
| | - Christophe Barbraud
- Centre d'Etudes Biologiques de Chizé, UMR7372 Centre National de la Recherche Scientifique – La Rochelle Université, 79360 Villiers en Bois, France
| | | | - Paul Ponganis
- Scripps Institution of Oceanography, La Jolla, CA, USA
| | | | - Philip Trathan
- British Antarctic Survey, Cambridge, UK
- Ocean and Earth Science, National Oceanography Centre, University of Southampton, University Road, Southampton SO17 1BJ, UK
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Houstin A, Zitterbart DP, Winterl A, Richter S, Planas-Bielsa V, Chevallier D, Ancel A, Fournier J, Fabry B, Le Bohec C. Biologging of emperor penguins-Attachment techniques and associated deployment performance. PLoS One 2022; 17:e0265849. [PMID: 35925903 PMCID: PMC9352057 DOI: 10.1371/journal.pone.0265849] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 03/08/2022] [Indexed: 11/18/2022] Open
Abstract
An increasing number of marine animals are equipped with biologgers, to study their physiology, behaviour and ecology, often for conservation purposes. To minimise the impacts of biologgers on the animals’ welfare, the Refinement principle from the Three Rs framework (Replacement, Reduction, Refinement) urges to continuously test and evaluate new and updated biologging protocols. Here, we propose alternative and promising techniques for emperor penguin (Aptenodytes forsteri) capture and on-site logger deployment that aim to mitigate the potential negative impacts of logger deployment on these birds. We equipped adult emperor penguins for short-term (GPS, Time-Depth Recorder (TDR)) and long-term (i.e. planned for one year) deployments (ARGOS platforms, TDR), as well as juvenile emperor penguins for long-term deployments (ARGOS platforms) in the Weddell Sea area where they had not yet been studied. We describe and qualitatively evaluate our protocols for the attachment of biologgers on-site at the colony, the capture of the animals and the recovery of the devices after deployment. We report unprecedented recaptures of long-term equipped adult emperor penguins (50% of equipped individuals recaptured after 290 days). Our data demonstrate that the traditional technique of long-term attachment by gluing the biologgers directly to the back feathers causes excessive feather breakage and the loss of the devices after a few months. We therefore propose an alternative method of attachment for back-mounted devices. This technique led to successful year-round deployments on 37.5% of the equipped juveniles. Finally, we also disclose the first deployments of leg-bracelet mounted TDRs on emperor penguins. Our findings highlight the importance of monitoring potential impacts of biologger deployments on the animals and the need to continue to improve methods to minimize disturbance and enhance performance and results.
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Affiliation(s)
- Aymeric Houstin
- Département de Biologie Polaire, Centre Scientifique de Monaco, Monaco, Principality of Monaco
- CNRS UMR 7178, IPHC, Université de Strasbourg, Strasbourg, France
- Department of Physics, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
- * E-mail: (AH); (CLB)
| | - Daniel P. Zitterbart
- Department of Physics, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
- Applied Ocean Physics and Engineering Woods Hole, Woods Hole Oceanographic Institution, Woods Hole, MA, United States of America
- International Research Organization for Advanced Science and Technology (IROAST), Kumamoto University, Kumamoto, Japan
| | - Alexander Winterl
- Department of Physics, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
- Applied Ocean Physics and Engineering Woods Hole, Woods Hole Oceanographic Institution, Woods Hole, MA, United States of America
| | - Sebastian Richter
- Department of Physics, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
- Applied Ocean Physics and Engineering Woods Hole, Woods Hole Oceanographic Institution, Woods Hole, MA, United States of America
| | - Víctor Planas-Bielsa
- Département de Biologie Polaire, Centre Scientifique de Monaco, Monaco, Principality of Monaco
| | | | - André Ancel
- CNRS UMR 7178, IPHC, Université de Strasbourg, Strasbourg, France
| | - Jérôme Fournier
- CNRS UMR 7204 CESCO, Station de Biologie Marine, Muséum National d’Histoire Naturelle, Concarneau, France
- Centre de Recherches sur la Biologie des Populations d’Oiseaux, Muséum National d’Histoire Naturelle, Paris, France
| | - Ben Fabry
- Department of Physics, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Céline Le Bohec
- Département de Biologie Polaire, Centre Scientifique de Monaco, Monaco, Principality of Monaco
- CNRS UMR 7178, IPHC, Université de Strasbourg, Strasbourg, France
- * E-mail: (AH); (CLB)
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Winterl A, Richter S, Houstin A, Nesterova AP, Bonadonna F, Schneider W, Fabry B, Le Bohec C, Zitterbart DP. micrObs - A customizable time-lapse camera for ecological studies. HARDWAREX 2020; 8:e00134. [PMID: 35498253 PMCID: PMC9041239 DOI: 10.1016/j.ohx.2020.e00134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 08/13/2020] [Accepted: 08/15/2020] [Indexed: 06/14/2023]
Abstract
Camera traps for motion-triggered or continuous time-lapse recordings are readily available on the market. For demanding applications in ecology and environmental sciences, however, commercial systems often lack flexibility to freely adjust recording time intervals, suffer from mechanical component wear, and can be difficult to combine with auxiliary sensors such as GPS, weather stations, or light sensors. We present a robust time-lapse camera system that has been operating continuously since 2013 under the harsh climatic conditions of the Antarctic and Subantarctic regions. Thus far, we have recorded over one million images with individual cameras. The system consumes 122 mW of power in standby mode and captures up to 200,000 high-resolution (16 MPix) images without maintenance such as battery or image memory replacement. It offers time-lapse intervals between 2 s and 1 h, low-light or night-time power saving, and data logging capabilities for additional inputs such as GPS and weather data.
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Affiliation(s)
- Alexander Winterl
- Department of Physics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
- Department of Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole, USA
| | - Sebastian Richter
- Department of Physics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
- Department of Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole, USA
| | - Aymeric Houstin
- Centre Scientifique de Monaco, Département de Biologie Polaire, Monaco, Monaco
- Université de Strasbourg, CNRS, IPHC, UMR 7178, Strasbourg, France
| | - Anna P. Nesterova
- INRAE, CNRS, Université de Tours, PRC, UMR 7247, Nouzilly, France
- CEFE, Univ Montpellier, CNRS, Univ Paul Valéry Montpellier 3, EPHE, IRD, Montpellier, France
| | - Francesco Bonadonna
- CEFE, Univ Montpellier, CNRS, Univ Paul Valéry Montpellier 3, EPHE, IRD, Montpellier, France
| | - Werner Schneider
- Department of Physics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Ben Fabry
- Department of Physics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Céline Le Bohec
- Centre Scientifique de Monaco, Département de Biologie Polaire, Monaco, Monaco
- Université de Strasbourg, CNRS, IPHC, UMR 7178, Strasbourg, France
| | - Daniel P. Zitterbart
- Department of Physics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
- Department of Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole, USA
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Gerum RC, Richter S, Winterl A, Mark C, Fabry B, Bohec CL, Zitterbart DP. CameraTransform: A Python package for perspective corrections and image mapping. SOFTWAREX 2019; 10:100333. [PMID: 32864407 PMCID: PMC7453838 DOI: 10.1016/j.softx.2019.100333] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Camera images and video recordings are simple and non-invasive tools to investigate animals in their natural habitat. Quantitative evaluations, however, often require an exact reconstruction of object positions, sizes, and distances in the image. Here, we provide an open source software package to perform such calculations. Our approach allows the user to correct for perspective distortion, transform images to "bird's-eye" view projections, or transform image-coordinates to real-world coordinates and vice versa. The extrinsic camera parameters that are necessary to perform such image corrections and transformations (elevation, tilt/roll angle, and heading of the camera) are obtained from the image using contextual information such as a visible horizon, GPS coordinates of landmarks, known object sizes, or images of the same object obtained from different viewing angles. All mathematical operations are implemented in the Python package CameraTransform. The performance of the implementation is evaluated using computer-generated synthetic images with known camera parameters. Moreover, we test our algorithm on images of emperor penguin colonies, and demonstrate that the camera tilt and roll angles can be estimated with an error of less than one degree, and the camera elevation with an error of less than 5%. The CameraTransform software package simplifies camera matrix-based image transformations and the extraction of quantitative image information. An extensive documentation and usage examples in an ecological context are provided at http://cameratransform.readthedocs.io.
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Affiliation(s)
- Richard C. Gerum
- Biophysics Group, Department of Physics, University of Erlangen-Nürnberg, Germany
| | - Sebastian Richter
- Biophysics Group, Department of Physics, University of Erlangen-Nürnberg, Germany
- Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Alexander Winterl
- Biophysics Group, Department of Physics, University of Erlangen-Nürnberg, Germany
- Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Christoph Mark
- Biophysics Group, Department of Physics, University of Erlangen-Nürnberg, Germany
| | - Ben Fabry
- Biophysics Group, Department of Physics, University of Erlangen-Nürnberg, Germany
| | - Céline Le Bohec
- Centre Scientifique de Monaco, Département de Biologie Polaire, Principality of Monaco, Monaco
- Université de Strasbourg, CNRS, IPHC, UMR 7178, Strasbourg, France
| | - Daniel P. Zitterbart
- Biophysics Group, Department of Physics, University of Erlangen-Nürnberg, Germany
- Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
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Richter S, Gerum R, Winterl A, Houstin A, Seifert M, Peschel J, Fabry B, Le Bohec C, Zitterbart DP. Phase transitions in huddling emperor penguins. JOURNAL OF PHYSICS D: APPLIED PHYSICS 2018; 51:214002. [PMID: 30416209 PMCID: PMC6221190 DOI: 10.1088/1361-6463/aabb8e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Emperor penguins (Aptenodytes forsteri) are highly adapted to the harsh conditions of the Antarctic winter: they are able to fast for up to 134 days during breeding. To conserve energy, emperor penguins form tight groups (huddles), which is key for their reproductive success. The effect of different meteorological factors on the huddling behaviour, however, is not well understood. Using time-lapse image recordings of an emperor penguin colony, we show that huddling can be described as a phase transition from a fluid to a solid state. We use the colony density as order parameter, and an apparent temperature that is perceived by the penguins as the thermodynamic variable. We approximate the apparent temperature as a linear combination of four meteorological parameters: ambient temperature, wind speed, global radiation and relative humidity. We find a wind chill factor of -2.9 °C/(ms -1), a humidity chill factor of -0.5°C/% rel. humidity, and a solar radiation heating factor of 0.3 °C//(Wm 2). In the absence of wind, humidity and solar radiation, the phase transition temperature (50% huddling probability) is -48.2°C for the investigated time period (May 2014). We propose that higher phase transition temperatures indicate a shrinking thermal insulation and thus can serve as a proxy for lower energy reserves of the colony, integrating pre-breeding foraging success at sea and energy expenditure at land due to environmental conditions. As current global change is predicted to have strong detrimental effects on emperor penguins within the next decades, our approach may thus contribute towards an urgently needed long-term monitoring system for assessing colony health.
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Affiliation(s)
- S Richter
- Biophysics Group, Friedrich-Alexander University, Erlangen, Germany
| | - R Gerum
- Biophysics Group, Friedrich-Alexander University, Erlangen, Germany
| | - A Winterl
- Biophysics Group, Friedrich-Alexander University, Erlangen, Germany
| | - A Houstin
- Centre Scientifique de Monaco, Département de Biologie Polaire, Monaco, Principality of Monaco
- Université de Strasbourg, CNRS, IPHC, UMR 7178, Strasbourg, France
| | - M Seifert
- Biophysics Group, Friedrich-Alexander University, Erlangen, Germany
| | - J Peschel
- Biophysics Group, Friedrich-Alexander University, Erlangen, Germany
| | - B Fabry
- Biophysics Group, Friedrich-Alexander University, Erlangen, Germany
| | - C Le Bohec
- Centre Scientifique de Monaco, Département de Biologie Polaire, Monaco, Principality of Monaco
- Université de Strasbourg, CNRS, IPHC, UMR 7178, Strasbourg, France
| | - D P Zitterbart
- Biophysics Group, Friedrich-Alexander University, Erlangen, Germany
- Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole, USA
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