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230 results on '"Lunn, Nicholas J."'

3. Characterising menotactic behaviours in movement data using hidden Markov models

Author

Togunov, Ron R., Derocher, Andrew E., Lunn, Nicholas J., and Auger-Méthé, Marie

Subjects
Quantitative Biology - Quantitative Methods
Abstract

1. Movement is the primary means by which animals obtain resources and avoid hazards. Most movement exhibits directional bias that is related to environmental features (taxis), such as the location of food patches, predators, ocean currents, or wind. Numerous behaviours with directional bias can be characterized by maintaining orientation at an angle relative to the environmental stimuli (menotaxis), including navigation relative to sunlight or magnetic fields and energy-conserving flight across wind. However, no statistical methods exist to flexibly classify and characterise such directional bias. 2. We propose a biased correlated random walk model that can identify menotactic behaviours by predicting turning angle as a trade-off between directional persistence and directional bias relative to environmental stimuli without making a priori assumptions about the angle of bias. We apply the model within the framework of a multi-state hidden Markov model (HMM) and describe methods to remedy information loss associated with coarse environmental data to improve the classification and parameterization of directional bias. 3. Using simulation studies, we illustrate how our method more accurately classifies behavioural states compared to conventional correlated random walk HMMs that do not incorporate directional bias. We illustrate the application of these methods by identifying cross wind olfactory foraging and drifting behaviour mediated by wind-driven sea ice drift in polar bears (Ursus maritimus) from movement data collected by satellite telemetry. 4. The extensions we propose can be readily applied to movement data to identify and characterize behaviours with directional bias toward any angle, and open up new avenues to investigate more mechanistic relationships between animal movement and the environment.

Published
2021
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4. Widespread Exposure to Mosquitoborne California Serogroup Viruses in Caribou, Arctic Fox, Red Fox, and Polar Bears, Canada

Author

Buhler, Kayla J., Dibernardo, Antonia, Pilfold, Nicholas W., Harms, N. Jane, Fenton, Heather, Carriere, Suzanne, Kelly, Allicia, Schwantje, Helen, Aguilar, Xavier Fernandez, Leclerc, Lisa-Marie, Gouin, Geraldine G., Lunn, Nicholas J., Richardson, Evan S., McGeachy, David, Bouchard, Emilie, Ortiz, Adrian Hernandez, Samelius, Gustaf, Lindsay, L. Robbin, Drebot, Michael A., Gaffney, Patricia, Leighton, Patrick, Alisauskas, Ray, and Jenkins, Emily

Subjects
Red fox -- Health aspects, Reindeer -- Health aspects, Polar bear -- Health aspects, Arboviruses -- Identification and classification -- Distribution, Caribou -- Health aspects, Arctic fox -- Health aspects, Vector-borne diseases -- Risk factors, Company distribution practices, Health
Abstract

Annual temperatures in the circumpolar Arctic are rising at 2-3 times the global average, reducing ecologic barriers for arthropod reproduction and fueling shifts in insect diversity and distribution (2,2). The [...]

Published
2023
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10. Assessing the risk of climate maladaptation for Canadian polar bears.

Author

Rivkin, L. Ruth, Richardson, Evan S., Miller, Joshua M., Atwood, Todd C., Baryluk, Steven, Born, Erik W., Davis, Corey, Dyck, Markus, de Greef, Evelien, Laidre, Kristin L., Lunn, Nicholas J., McCarthy, Sara, Obbard, Martyn E., Owen, Megan A., Pilfold, Nicholas W., Roberto‐Charron, Amelie, Wiig, Øystein, Wilder, Aryn P., and Garroway, Colin J.

Subjects
POLAR bear, GLOBAL warming, ANTARCTIC ice, GENE flow, GENETIC variation
Abstract

The Arctic is warming four times faster than the rest of the world, threatening the persistence of many Arctic species. It is uncertain if Arctic wildlife will have sufficient time to adapt to such rapidly warming environments. We used genetic forecasting to measure the risk of maladaptation to warming temperatures and sea ice loss in polar bears (Ursus maritimus) sampled across the Canadian Arctic. We found evidence for local adaptation to sea ice conditions and temperature. Forecasting of genome‐environment mismatches for predicted climate scenarios suggested that polar bears in the Canadian high Arctic had the greatest risk of becoming maladapted to climate warming. While Canadian high Arctic bears may be the most likely to become maladapted, all polar bears face potentially negative outcomes to climate change. Given the importance of the sea ice habitat to polar bears, we expect that maladaptation to future warming is already widespread across Canada. [ABSTRACT FROM AUTHOR]

Published
2024
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12. Abundance and species diversity hotspots of tracked marine predators across the North American Arctic

Author

Yurkowski, David J., Auger-Méthé, Marie, Mallory, Mark L., Wong, Sarah N. P., Gilchrist, Grant, Derocher, Andrew E., Richardson, Evan, Lunn, Nicholas J., Hussey, Nigel E., Marcoux, Marianne, Togunov, Ron R., Fisk, Aaron T., Harwood, Lois A., Dietz, Rune, Rosing-Asvid, Aqqalu, Born, Erik W., Mosbech, Anders, Fort, Jérôme, Grémillet, David, Loseto, Lisa, Richard, Pierre R., Iacozza, John, Jean-Gagnon, Frankie, Brown, Tanya M., Westdal, Kristin H., Orr, Jack, LeBlanc, Bernard, Hedges, Kevin J., Treble, Margaret A., Kessel, Steven T., Blanchfield, Paul J., Davis, Shanti, Maftei, Mark, Spencer, Nora, McFarlane-Tranquilla, Laura, Montevecchi, William A., Bartzen, Blake, Dickson, Lynne, Anderson, Christine, and Ferguson, Steven H.

Published
2019

28. The Role of Satellite Telemetry Data in 21st Century Conservation of Polar Bears (Ursus maritimus)

Author

Laidre, Kristin L., Durner, George M., Lunn, Nicholas J., Regehr, Eric V., Atwood, Todd C., Rode, Karyn D., Aars, Jon, Routti, Heli, Wiig, Øystein, Dyck, Markus, Richardson, Evan S., Atkinson, Stephen, Belikov, Stanislav, and Stirling, Ian

Subjects
Global and Planetary Change, Ocean Engineering, Aquatic Science, Oceanography, Water Science and Technology
Abstract

Satellite telemetry (ST) has played a critical role in the management and conservation of polar bears (Ursus maritimus) over the last 50 years. ST data provide biological information relevant to subpopulation delineation, movements, habitat use, maternal denning, health, human-bear interactions, and accurate estimates of vital rates and abundance. Given that polar bears are distributed at low densities over vast and remote habitats, much of the information provided by ST data cannot be collected by other means. Obtaining ST data for polar bears requires chemical immobilization and application of a tracking device. Although immobilization has not been found to have negative effects beyond a several-day reduction in activity, over the last few decades opposition to immobilization and deployment of satellite-linked radio collars has resulted in a lack of current ST data in many of the 19 recognized polar bear subpopulations. Here, we review the uses of ST data for polar bears and evaluate its role in addressing 21st century conservation and management challenges, which include estimation of sustainable harvest rates, understanding the impacts of climate warming, delineating critical habitat, and assessing potential anthropogenic impacts from tourism, resource development and extraction. We found that in subpopulations where ST data have been consistently collected, information was available to estimate vital rates and subpopulation density, document the effects of sea-ice loss, and inform management related to subsistence harvest and regulatory requirements. In contrast, a lack of ST data in some subpopulations resulted in increased bias and uncertainty in ecological and demographic parameters, which has a range of negative consequences. As sea-ice loss due to climate warming continues, there is a greater need to monitor polar bear distribution, habitat use, abundance, and subpopulation connectivity. We conclude that continued collection of ST data will be critically important for polar bear management and conservation in the 21st century and that the benefits of immobilizing small numbers of individual polar bears in order to deploy ST devices significantly outweigh the risks.

Published
2022

32. Additional file 1 of Drivers of polar bear behavior and the possible effects of prey availability on foraging strategy

Author

Togunov, Ron R., Derocher, Andrew E., Lunn, Nicholas J., and Auger-Méthé, Marie

Abstract

Additional file 1. Contains supplementary figures, tables, methods, and results. The file contains hypotheses and predictions associated with each covariate used in modelling (Table A1), description of all data sources used in analysis (Table A2), methods and results for t correction and tidal integration (Section B), methods and results for satellite-ice-drift-based sea ice drift correction (Section C), methods and results of HMM without drift correction (Section D.1), HMM using wind and tidal integration (Section D.2), HMM using satellite-based drift correction (Section D.3), and HMM using wind-based drift correction and tidal integration (Section D.4), comparison of different drift correction and integration approaches and discussion of results (Sections D.5 and D.6), structure of pseudo-design matrices used to formulate HMM emission probabilities (Section E), effect of hour and month on state frequency (Figure F1), and distribution and frequency of predicted states in Hudson Bay (Figure G1).

Published
2022
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33. A body composition model with multiple storage compartments for polar bears (Ursus maritimus).

Author

Penk, Stephanie R, Sadana, Pranav, Archer, Louise C, Pagano, Anthony M, Cattet, Marc R L, Lunn, Nicholas J, Thiemann, Gregory W, and Molnár, Péter K

Abstract

Climate warming is rapidly altering Arctic ecosystems. Polar bears (Ursus maritimus) need sea ice as a platform from which to hunt seals, but increased sea-ice loss is lengthening periods when bears are without access to primary hunting habitat. During periods of food scarcity, survival depends on the energy that a bear has stored in body reserves, termed storage energy, making this a key metric in predictive models assessing climate change impacts on polar bears. Here, we developed a body composition model for polar bears that estimates storage energy while accounting for changes in storage tissue composition. We used data of dissected polar bears (n =  31) to link routinely collected field measures of total body mass and straight-line body length to the body composition of individual bears, described in terms of structural mass and two storage compartments, adipose and muscle. We then estimated the masses of metabolizable proteins and lipids within these storage compartments, giving total storage energy. We tested this multi-storage model by using it to predict changes in the lipid stores from an independent dataset of wild polar bears (n  = 36) that were recaptured 8–200 days later. Using length and mass measurements, our model successfully predicted direct measurements of lipid changes via isotopic dilutions (root mean squared error of 14.5 kg). Separating storage into two compartments, and allowing the molecular composition of storage to vary, provides new avenues for quantifying energy stores of individuals across their life cycle. The multi-storage body composition model thus provides a basis for further exploring energetic costs of physiological processes that contribute to individual survival and reproductive success. Given bioenergetic models are increasingly used as a tool to predict individual fitness and population dynamics, our approach for estimating individual energy stores could be applicable to a wide range of species. [ABSTRACT FROM AUTHOR]

Published
2023
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35. Letters to the Editor

Author

Kingsley, Michael C. S., Stirling, Ian, Lunn, Nicholas J., and Iacozza, John

Published
2000

39. Long‐term increases in pathogen seroprevalence in polar bears ( Ursus maritimus ) influenced by climate change

Author

Pilfold, Nicholas W., primary, Richardson, Evan S., additional, Ellis, John, additional, Jenkins, Emily, additional, Scandrett, W. Brad, additional, Hernández‐Ortiz, Adrián, additional, Buhler, Kayla, additional, McGeachy, David, additional, Al‐Adhami, Batol, additional, Konecsni, Kelly, additional, Lobanov, Vladislav A., additional, Owen, Megan A., additional, Rideout, Bruce, additional, and Lunn, Nicholas J., additional

Published
2021
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44. Range contraction and increasing isolation of a polar bear subpopulation in an era of sea‐ice loss

Author

Laidre, K.L., Born, Erik W., Atkinson, Stephen N., Wiig, Øystein, Andersen, Liselotte W., Lunn, Nicholas J., Dyck, Markus, Regehr, E.V., McGovern, R., Heagerty, Patrick, and Heagerty, P.

Subjects
0106 biological sciences, animal movements, 010504 meteorology & atmospheric sciences, Ursus maritimus, Range (biology), URSUS-MARITIMUS, BEAUFORT SEA, Zoology, 010603 evolutionary biology, 01 natural sciences, HOME-RANGE, Latitude, Arctic, biology.animal, Sea ice, POPULATION-STRUCTURE, 14. Life underwater, HABITAT, QH540-549.5, Ecology, Evolution, Behavior and Systematics, Original Research, 0105 earth and related environmental sciences, Nature and Landscape Conservation, polar bear, geography, CLIMATE-CHANGE, MOVEMENTS, Habitat fragmentation, geography.geographical_feature_category, Ecology, biology, contraction, 15. Life on land, GREENLAND, sea ice, HUDSON-BAY, 13. Climate action, range, Biological dispersal, SPACE-USE, isolation, Bay
Abstract

Climate change is expected to result in range shifts and habitat fragmentation for many species. In the Arctic, loss of sea ice will reduce barriers to dispersal or eliminate movement corridors, resulting in increased connectivity or geographic isolation with sweeping implications for conservation. We used satellite telemetry, data from individually marked animals (research and harvest), and microsatellite genetic data to examine changes in geographic range, emigration, and interpopulation connectivity of the Baffin Bay (BB) polar bear (Ursus maritimus) subpopulation over a 25-year period of sea-ice loss. Satellite telemetry collected from n = 43 (1991-1995) and 38 (2009-2015) adult females revealed a significant contraction in subpopulation range size (95% bivariate normal kernel range) in most months and seasons, with the most marked reduction being a 70% decline in summer from 716,000 km(2) (SE 58,000) to 211,000 km(2) (SE 23,000) (p

Published
2018

49. The stress of Arctic warming on polar bears

Author

Boonstra, Rudy, primary, Bodner, Korryn, additional, Bosson, Curtis, additional, Delehanty, Brendan, additional, Richardson, Evan S., additional, Lunn, Nicholas J., additional, Derocher, Andrew E., additional, and Molnár, Péter K., additional

Published
2020
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