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Seascapes of fear and competition shape regional seabird movement ecology. Commun Biol 2022; 5:208. [PMID: 35246607 PMCID: PMC8897475 DOI: 10.1038/s42003-022-03151-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 02/08/2022] [Indexed: 11/17/2022] Open
Abstract
Fear effects of predators on prey distributions are seldom considered in marine environments, especially over large spatial scales and in conservation contexts. To fill these major gaps, we tested the Seascape of Fear Hypothesis in the Benguela marine ecosystem off South Africa. Using electronic tracking data, we showed that Cape gannets and their predator, the Cape fur seal, co-occurred in daytime and competed with fisheries within coastal areas. At night, gannets are particularly vulnerable to seals, and 28% of the birds returned to the safety of their breeding colony. The remaining 72% slept at the sea surface, but shifted to offshore areas with lower seal attendance, reducing predation risk by 25%. Overall, our integrative study demonstrates how fear and competition shape the seascape of threatened Cape gannets within a marine environment perturbed by climate change and overfishing. Such knowledge has strong implications for the design of marine protected areas. Fear effects of predators on prey distributions are seldom considered in marine environments, even though they have strong implications for the design of marine protected areas. This work demonstrates such ‘Seascape of Fear’ for Cape gannets off South Africa, as they adjusted their at-sea movements relative to those of predatory Cape fur seals.
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Drivers of concentrated predation in an Antarctic marginal-ice-zone food web. Sci Rep 2020; 10:7282. [PMID: 32350362 PMCID: PMC7190673 DOI: 10.1038/s41598-020-63875-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 04/03/2020] [Indexed: 02/05/2023] Open
Abstract
Predators impact preyscapes (3-D distribution of forage species) by consuming prey according to their abilities or by altering prey behavior as they avoid being consumed. We elucidate prey (Antarctic silverfish[Pleuragramma antarctica] and crystal krill[Euphausia chrystallorophias]) responses to predation associated with the marginal ice zone (MIZ) of the McMurdo Sound, Antarctica, polynya. Prey abundance and habitat was sampled across a 30 × 15 km area by remotely-operated vehicle, and included locations that were accessible (ice edge) or inaccessible (solid fast ice) to air-breathing predators. Prey and habitat sampling coincided with bio-logging of Adélie penguins and observations of other air-breathing predators (penguins, seals, and whales), all of which were competing for the same prey. Adélie penguins dived deeper, and more frequently, near the ice edge. Lowered abundance of krill at the ice edge indicated they were depleted or were responding to increased predation and/or higher light levels along the ice edge. Penguin diet shifted increasingly to silverfish from krill during sampling, and was correlated with the arrival of krill-eating whales. Behaviorally-mediated, high trophic transfer characterizes the McMurdo Sound MIZ, and likely other MIZs, warranting more specific consideration in food web models and conservation efforts.
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Lescroël A, Ballard G, Massaro M, Dugger K, Jennings S, Pollard A, Porzig E, Schmidt A, Varsani A, Grémillet D, Ainley D. Evidence of age-related improvement in the foraging efficiency of Adélie penguins. Sci Rep 2019; 9:3375. [PMID: 30833598 PMCID: PMC6399253 DOI: 10.1038/s41598-019-39814-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 01/30/2019] [Indexed: 11/21/2022] Open
Abstract
Age variation in reproductive performance is well-documented but the mechanisms underlying this variation remain unclear. Foraging efficiency is likely to be a key source of demographic variation as it determines the amount of energy that can be invested in fitness-related activities. Evidence of age-related changes in the foraging efficiency of adult seabirds is scarce and inconsistent. We investigated the effects of age on the foraging efficiency of breeding Adélie penguins, a relatively short-lived seabird species, in order to gain a broader perspective on the processes driving variation in ageing rates. We found support for a positive effect of age, either linear or levelling off at old ages, on both our proxies for daily catch rate and catch per unit effort. Across all age classes, males were more performant foragers than females. We found no strong evidence for differing ageing patterns between sexes or individual quality levels, and no evidence for senescence. We infer that continuous individual improvement could be responsible for a larger amount of the variation in foraging efficiency with age at our study site, compared with selective disappearance of underperforming phenotypes. The different results reported by other studies highlight the need to conduct longitudinal studies across a range of species in different environments.
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Affiliation(s)
- Amélie Lescroël
- Point Blue Conservation Science, Petaluma, CA, 94954, USA. .,Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175, CNRS - Université de Montpellier - Université Paul-Valéry Montpellier - EPHE, Montpellier, France.
| | - Grant Ballard
- Point Blue Conservation Science, Petaluma, CA, 94954, USA
| | - Melanie Massaro
- School of Environmental Sciences, Institute for Land, Water and Society, Charles Sturt University, Albury, NSW, 2640, Australia
| | - Katie Dugger
- U.S. Geological Survey, Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oregon, USA
| | - Scott Jennings
- Point Blue Conservation Science, Petaluma, CA, 94954, USA.,U.S. Geological Survey, Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oregon, USA
| | - Annie Pollard
- Point Blue Conservation Science, Petaluma, CA, 94954, USA
| | | | - Annie Schmidt
- Point Blue Conservation Science, Petaluma, CA, 94954, USA
| | - Arvind Varsani
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine, School of Life sciences, Arizona State University, Tempe, Arizona, USA.,Structural Biology Research Unit, Department of Clinical Laboratory Sciences, University of Cape Town, Observatory, Cape Town, South Africa
| | - David Grémillet
- Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175, CNRS - Université de Montpellier - Université Paul-Valéry Montpellier - EPHE, Montpellier, France.,FitzPatrick Institute, DST/NRF centre of excellence at the University of Cape Town, Rondebosch, 7701, South Africa
| | - David Ainley
- H.T. Harvey & Associates, Los Gatos, California, USA
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Habitat preferences of Adélie Pygoscelis adeliae and Chinstrap Penguins Pygoscelis antarctica during pre-moult in the Weddell Sea (Southern Ocean). Polar Biol 2019. [DOI: 10.1007/s00300-019-02465-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Time-lapse imagery of Adélie penguins reveals differential winter strategies and breeding site occupation. PLoS One 2018; 13:e0193532. [PMID: 29561876 PMCID: PMC5862443 DOI: 10.1371/journal.pone.0193532] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 02/13/2018] [Indexed: 11/19/2022] Open
Abstract
Polar seabirds adopt different over-wintering strategies to survive and build condition during the critical winter period. Penguin species either reside at the colony during the winter months or migrate long distances. Tracking studies and survey methods have revealed differences in winter migration routes among penguin species and colonies, dependent on both biotic and abiotic factors present. However, scan sampling methods are rarely used to reveal non-breeding behaviors during winter and little is known about presence at the colony site over this period. Here we show that Adélie penguins on the Yalour Islands in the Western Antarctic Peninsula (WAP) are present year-round at the colony and undergo a mid-winter peak in abundance during winter. We found a negative relationship between daylight hours and penguin abundance when either open water or compact ice conditions were present, suggesting that penguins return to the breeding colony when visibility is lowest for at-sea foraging and when either extreme low or high levels of sea ice exist offshore. In contrast, Adélie penguins breeding in East Antarctica were not observed at the colonies during winter, suggesting that Adélie penguins undergo differential winter strategies in the marginal ice zone on the WAP compared to those in East Antarctica. These results demonstrate that cameras can successfully monitor wildlife year-round in areas that are largely inaccessible during winter.
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Kooyman GL, van Dam RP, Hückstädt LA. Night diving by some emperor penguins during the winter breeding period at Cape Washington. ACTA ACUST UNITED AC 2018; 221:221/1/jeb170795. [PMID: 29317482 DOI: 10.1242/jeb.170795] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 11/06/2017] [Indexed: 11/20/2022]
Abstract
All through the bird literature and feature films, there is much ado about dedicated emperor penguin males fasting for 115 days while they do all the incubation of the single egg. Sometimes, they may not fast for so long. Based on a winter visit to Cape Washington, we obtained evidence that some birds may feed before the egg is laid, and if they do, and some are males, then their fast is much less than 115 days. The consequence of a shorter fast for the male is a better chance of completing the 65 day incubation fast and success in fledging the chick. For those in northern colonies that may migrate south, there will be closer access to open water, but there will be the need to dive in the dark.
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Affiliation(s)
- Gerald L Kooyman
- Scripps Institution of Oceanography, Scholander Hall, University of California, San Diego, La Jolla, CA 92093, USA
| | - Robert P van Dam
- Scripps Institution of Oceanography, Scholander Hall, University of California, San Diego, La Jolla, CA 92093, USA
| | - Luis A Hückstädt
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA
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Lee WY, Kokubun N, Jung JW, Chung H, Kim JH. Diel diving behavior of breeding gentoo penguins on King George Island in Antarctica. Anim Cells Syst (Seoul) 2015. [DOI: 10.1080/19768354.2015.1074107] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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Dugger KM, Ballard G, Ainley DG, Lyver PO, Schine C. Adélie penguins coping with environmental change: results from a natural experiment at the edge of their breeding range. Front Ecol Evol 2014. [DOI: 10.3389/fevo.2014.00068] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Lescroël A, Ballard G, Grémillet D, Authier M, Ainley DG. Antarctic climate change: extreme events disrupt plastic phenotypic response in Adélie penguins. PLoS One 2014; 9:e85291. [PMID: 24489657 PMCID: PMC3906005 DOI: 10.1371/journal.pone.0085291] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Accepted: 12/04/2013] [Indexed: 02/01/2023] Open
Abstract
In the context of predicted alteration of sea ice cover and increased frequency of extreme events, it is especially timely to investigate plasticity within Antarctic species responding to a key environmental aspect of their ecology: sea ice variability. Using 13 years of longitudinal data, we investigated the effect of sea ice concentration (SIC) on the foraging efficiency of Adélie penguins (Pygoscelis adeliae) breeding in the Ross Sea. A 'natural experiment' brought by the exceptional presence of giant icebergs during 5 consecutive years provided unprecedented habitat variation for testing the effects of extreme events on the relationship between SIC and foraging efficiency in this sea-ice dependent species. Significant levels of phenotypic plasticity were evident in response to changes in SIC in normal environmental conditions. Maximum foraging efficiency occurred at relatively low SIC, peaking at 6.1% and decreasing with higher SIC. The 'natural experiment' uncoupled efficiency levels from SIC variations. Our study suggests that lower summer SIC than currently observed would benefit the foraging performance of Adélie penguins in their southernmost breeding area. Importantly, it also provides evidence that extreme climatic events can disrupt response plasticity in a wild seabird population. This questions the predictive power of relationships built on past observations, when not only the average climatic conditions are changing but the frequency of extreme climatic anomalies is also on the rise.
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Affiliation(s)
- Amélie Lescroël
- Biodiversité et gestion des territoires, URU 420, Université de Rennes 1, Rennes, France
- Centre d'Ecologie Fonctionnelle et Evolutive, CNRS, UMR 5175, Montpellier, France
| | - Grant Ballard
- Point Blue Conservation Science, Petaluma, California, United States of America
| | - David Grémillet
- Centre d'Ecologie Fonctionnelle et Evolutive, CNRS, UMR 5175, Montpellier, France
- Percy FitzPatrick Institute and DST/NRF Excellence Centre, University of Cape Town, Rondebosch, South Africa
| | - Matthieu Authier
- Centre d'Ecologie Fonctionnelle et Evolutive, CNRS, UMR 5175, Montpellier, France
| | - David G. Ainley
- H.T. Harvey & Associates, Los Gatos, California, United States of America
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Abstract
We developed an automated method using depth and one axis of body acceleration data recorded by animal-borne data loggers to identify activities of penguins over long-term deployments. Using this technique, we evaluated the activity time budget of emperor penguins (n = 10) both in water and on sea ice during foraging trips in chick-rearing season. During the foraging trips, emperor penguins alternated dive bouts (4.8 ± 4.5 h) and rest periods on sea ice (2.5 ± 2.3 h). After recorder deployment and release near the colony, the birds spent 17.9 ± 8.4% of their time traveling until they reached the ice edge. Once at the ice edge, they stayed there more than 4 hours before the first dive. After the first dive, the mean proportions of time spent on the ice and in water were 30.8 ± 7.4% and 69.2 ± 7.4%, respectively. When in the water, they spent 67.9 ± 3.1% of time making dives deeper than 5 m. Dive activity had no typical diurnal pattern for individual birds. While in the water between dives, the birds had short resting periods (1.2 ± 1.7 min) and periods of swimming at depths shallower than 5 m (0.25 ± 0.38 min). When the birds were on the ice, they primarily used time for resting (90.3 ± 4.1% of time) and spent only 9.7 ± 4.1% of time traveling. Thus, it appears that, during foraging trips at sea, emperor penguins traveled during dives >5 m depth, and that sea ice was primarily used for resting. Sea ice probably provides refuge from natural predators such as leopard seals. We also suggest that 24 hours of sunlight and the cycling of dive bouts with short rest periods on sea ice allow emperor penguins to dive continuously throughout the day during foraging trips to sea.
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Affiliation(s)
- Shinichi Watanabe
- Faculty of Life Science and Biotechnology, Fukuyama University, Fukuyama, Hiroshima, Japan.
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