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Dreyer S, Marcu D, Keyser S, Bennett M, Maree L, Koeppel K, Abernethy D, Petrik L. Factors in the decline of the African penguin: Are contaminants of emerging concern (CECs) a potential new age stressor? MARINE POLLUTION BULLETIN 2024; 206:116688. [PMID: 39029148 DOI: 10.1016/j.marpolbul.2024.116688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Revised: 07/01/2024] [Accepted: 07/03/2024] [Indexed: 07/21/2024]
Abstract
The African penguin is currently experiencing a significant decline, with just over 10,000 breeding pairs left. A substantial body of research reflects the impacts of contaminants of emerging concern (CECs) on the marine environment, with wastewater treatment plants reported as one of the main sources of CEC release. In South Africa, CECs were identified contaminating the marine environment and bioaccumulating in several marine species. Approximately 70 % of all African penguin colonies breed in close proximity to cities and/or harbors in South Africa. Currently, the impact of CECs as a stressor upon the viability of African penguin populations is unknown. Based on the search results there was a clear lack of information on CECs' bioaccumulation and impact on the African penguin. This narrative review will thus focus on the prevalent sources and types of CECs and examine the reported consequences of constant exposure in seabirds, particularly African penguins.
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Affiliation(s)
- Stephanie Dreyer
- Animal Production Studies, Faculty of Veterinary Sciences, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa.
| | - Daniel Marcu
- School of Biological Sciences, University of East Anglia, NR4 7TJ, United Kingdom
| | - Shannen Keyser
- Comparative Spermatology Laboratory, Department of Medical Bioscience, University of the Western Cape, Private Bag X17, Bellville 7535, South Africa
| | - Monique Bennett
- Comparative Spermatology Laboratory, Department of Medical Bioscience, University of the Western Cape, Private Bag X17, Bellville 7535, South Africa
| | - Liana Maree
- Comparative Spermatology Laboratory, Department of Medical Bioscience, University of the Western Cape, Private Bag X17, Bellville 7535, South Africa
| | - Katja Koeppel
- Animal Production Studies, Faculty of Veterinary Sciences, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - Darrell Abernethy
- Aberystwyth School of Veterinary Science, Aberystwyth University, Ceredigion SY23 3FL, United Kingdom
| | - Leslie Petrik
- Environmental and Nano Sciences Group, Department of Chemistry, University of the Western Cape, Private Bag X17, Bellville 7535, South Africa
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2
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Votier S. Marine ecology: Increased fishing subsidy for seabirds. Curr Biol 2023; 33:R1240-R1242. [PMID: 38052176 DOI: 10.1016/j.cub.2023.10.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Innovative use of light loggers reveals increased nocturnal foraging activity at fishing vessels by pelagic seabirds, illuminating the complex ways in which fisheries and biodiversity interact.
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3
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Mason C, Hobday AJ, Lea M, Alderman R. Individual consistency in the localised foraging behaviour of shy albatross ( Thalassarche cauta). Ecol Evol 2023; 13:e10644. [PMID: 37881226 PMCID: PMC10594074 DOI: 10.1002/ece3.10644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 09/28/2023] [Accepted: 10/09/2023] [Indexed: 10/27/2023] Open
Abstract
Quantifying the intra- and interindividual variation that exists within a population can provide meaningful insights into a population's vulnerability and response to rapid environmental change. We characterise the foraging behaviour of 308 trips taken by 96 shy albatross (Thalassarche cauta) from Albatross Island across seven consecutive years. At a population level, incubating shy albatross exploited a consistent area within ca. 500 km radius of their breeding colony. During half of the trips, individuals utilised the closest shelf break to the west of the colony, where upwelling events have been reported. The other half of the trips were exclusively within the neritic zone, utilising a variety of locations within the Bass Strait. Furthermore, we found evidence of individual consistency to geographic locations, with subsequent trips by an individual more similar than random trips from all individuals in our data, both within and between years (G-test, p < .05). Between-individual variation in foraging behaviour was not meaningfully explained by age (linear regression, p > .05) or sex (t-test, p > .05) for any metric, suggesting that other intrinsic individual factors are accounting for between-individual variation in foraging trips. A localised foraging distribution is unusual for albatross, which, combined with high variation in space use between individuals demonstrated here, suggests that this species is accessing adequate resources near the colony. Overall, these findings suggest that incubating shy albatross from Albatross Island exhibit tendencies of a generalist population comprised of uniquely specialised individuals. These results suggest that this species is operating below its biological capacity in this fast-warming area and provide a baseline from which to assess future change.
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Affiliation(s)
- Claire Mason
- Institute for Marine and Antarctic StudiesUniversity of TasmaniaBattery PointTasmaniaAustralia
- CSIRO EnvironmentBattery PointTasmaniaAustralia
| | | | - Mary‐Anne Lea
- Institute for Marine and Antarctic StudiesUniversity of TasmaniaBattery PointTasmaniaAustralia
| | - Rachael Alderman
- Department of Natural Resources and EnvironmentTasmanian GovernmentTasmaniaHobartAustralia
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4
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Vanstreels RET, Parsons NJ, Sherley RB, Stander N, Strauss V, Kemper J, Waller L, Barham BJ, Ludynia K. Factors determining the number of seabirds impacted by oil spills and the success of their rehabilitation: Lessons learned from Namibia and South Africa. MARINE POLLUTION BULLETIN 2023; 188:114708. [PMID: 36773585 DOI: 10.1016/j.marpolbul.2023.114708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 02/01/2023] [Accepted: 02/03/2023] [Indexed: 06/18/2023]
Abstract
The coastal waters of Namibia and South Africa have an extensive history of oil spills, with 71 recorded up to 2021. Thirty-nine spills reportedly affected 83,224 seabirds, with African penguins (Spheniscus demersus; 91.0 %) and Cape gannets (Morus capensis; 8.5 %) most affected. Spills affecting seabirds were caused by unknown sources (46 %), bulk/cargo carriers (43 %), tankers (38 %) and ship-to-ship transfers (14 %). The number of penguins oiled was predicted by the breeding population size within 25 to 75 km, but not the volume of oiled spilled, the month or the year. Rehabilitation records from penguins oiled in spills since 2001 reveal that the day of admission (relative to the start of the spill) was predictive of packed cell volume, body mass, and plasma total solids, with the latter two being predictive of rehabilitation success. Our results highlight the importance of rapid monitoring at colonies to locate oiled birds in the event of spills.
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Affiliation(s)
- Ralph E T Vanstreels
- Institute of Research and Rehabilitation of Marine Animals (IPRAM), Vila Velha, Brazil.
| | - Nola J Parsons
- Southern African Foundation for the Conservation of Coastal Birds (SANCCOB), Cape Town, South Africa
| | - Richard B Sherley
- Environment and Sustainability Institute, University of Exeter, Penryn, United Kingdom; FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Cape Town, South Africa; African Penguin Conservation Project, Lüderitz, Namibia
| | - Nicky Stander
- Southern African Foundation for the Conservation of Coastal Birds (SANCCOB), Cape Town, South Africa
| | - Venessa Strauss
- Southern African Foundation for the Conservation of Coastal Birds (SANCCOB), Cape Town, South Africa
| | | | - Lauren Waller
- Southern African Foundation for the Conservation of Coastal Birds (SANCCOB), Cape Town, South Africa
| | | | - Katrin Ludynia
- Southern African Foundation for the Conservation of Coastal Birds (SANCCOB), Cape Town, South Africa; Department of Biological Sciences, University of Cape Town, Cape Town, South Africa
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5
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Important marine areas for endangered African penguins before and after the crucial stage of moulting. Sci Rep 2022; 12:9489. [PMID: 35676286 PMCID: PMC9177839 DOI: 10.1038/s41598-022-12969-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 05/19/2022] [Indexed: 11/09/2022] Open
Abstract
The population of the Endangered African penguin Spheniscus demersus has decreased by > 65% in the last 20 years. A major driver of this decrease has been the reduced availability of their principal prey, sardine Sardinops sagax and anchovy Engraulis encrasicolus. To date, conservation efforts to improve prey availability have focused on spatial management strategies to reduce resource competition with purse-seine fisheries during the breeding season. However, penguins also undergo an annual catastrophic moult when they are unable to feed for several weeks. Before moulting they must accumulate sufficient energy stores to survive this critical life-history stage. Using GPS tracking data collected between 2012 and 2019, we identify important foraging areas for pre- and post-moult African penguins at three of their major colonies in South Africa: Dassen Island and Stony Point (Western Cape) and Bird Island (Eastern Cape). The foraging ranges of pre- and post-moult adult African penguins (c. 600 km from colony) was far greater than that previously observed for breeding penguins (c. 50 km from colony) and varied considerably between sites, years and pre- and post-moult stages. Despite their more extensive range during the non-breeding season, waters within 20 and 50 km of their breeding colonies were used intensively and represent important foraging areas to pre- and post-moult penguins. Furthermore, penguins in the Western Cape travelled significantly further than those in the Eastern Cape which is likely a reflection of the poor prey availability along the west coast of South Africa. Our findings identify important marine areas for pre- and post-moult African penguins and support for the expansion of fisheries-related spatio-temporal management strategies to help conserve African penguins outside the breeding season.
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6
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Oosthuizen WC, Pistorius PA, Korczak‐Abshire M, Hinke JT, Santos M, Lowther AD. The foraging behavior of nonbreeding Adélie penguins in the western Antarctic Peninsula during the breeding season. Ecosphere 2022. [DOI: 10.1002/ecs2.4090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- W. Chris Oosthuizen
- Marine Apex Predator Research Unit, Institute for Coastal and Marine Research and Department of Zoology Nelson Mandela University Port Elizabeth South Africa
- Centre for Statistics in Ecology, Environment and Conservation, Department of Statistical Sciences University of Cape Town Cape Town South Africa
| | - Pierre A. Pistorius
- Marine Apex Predator Research Unit, Institute for Coastal and Marine Research and Department of Zoology Nelson Mandela University Port Elizabeth South Africa
| | | | - Jefferson T. Hinke
- Antarctic Ecosystem Research Division, Southwest Fisheries Science Center National Marine Fisheries Service, National Oceanic and Atmospheric Administration La Jolla California USA
| | - Mercedes Santos
- Departamento Biología de Predadores Tope Instituto Antártico Argentino Buenos Aires Argentina
- Laboratorios Anexos Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata Buenos Aires Argentina
| | - Andrew D. Lowther
- Norwegian Polar Institute, Research Department Fram Centre Tromsø Norway
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7
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Frankish CK, Manica A, Clay TA, Wood AG, Phillips RA. Ontogeny of movement patterns and habitat selection in juvenile albatrosses. OIKOS 2022. [DOI: 10.1111/oik.09057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Caitlin K. Frankish
- British Antarctic Survey, Natural Environment Research Council Cambridge UK
- Dept of Zoology, Univ. of Cambridge Cambridge UK
| | | | - Thomas A. Clay
- School of Environmental Sciences, Univ. of Liverpool Liverpool UK
- Inst. of Marine Sciences, Univ. of California Santa Cruz Santa Cruz CA USA
| | - Andrew G. Wood
- British Antarctic Survey, Natural Environment Research Council Cambridge UK
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8
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Nunes GT, Efe MA, Barreto CT, Gaiotto JV, Silva AB, Vilela F, Roy A, Bertrand S, Costa PG, Bianchini A, Bugoni L. Ecological trap for seabirds due to the contamination caused by the Fundão dam collapse, Brazil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 807:151486. [PMID: 34742806 DOI: 10.1016/j.scitotenv.2021.151486] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 10/28/2021] [Accepted: 11/02/2021] [Indexed: 06/13/2023]
Abstract
Human-induced rapid environmental changes can disrupt habitat quality in the short term. A decrease in quality of habitats associated with preference for these over other available higher quality is referred as ecological trap. In 2015, the Fundão dam containing iron mining tailings, eastern Brazil, collapsed and released about 50 million cubic meters of metal-rich mud composed by Fe, As, Cd, Hg, Pb in three rivers and the adjacent continental shelf. The area is a foraging site for dozens of seabird and shorebird species. In this study, we used a dataset from before and after Fundão dam collapse containing information on at-sea distribution during foraging activities (biologging), dietary aspects (stable isotopes), and trace elements concentration in feathers and blood from three seabird species known to use the area as foraging site: Phaethon aethereus, Sula leucogaster, and Pterodroma arminjoniana. In general, a substantial change in foraging strategies was not detected, as seabirds remain using areas and food resources similar to those used before the dam collapse. However, concentration of non-essential elements increased (e.g., Cd and As) while essential elements decreased (e.g., Mn and Zn), suggesting that the prey are contaminated by trace elements from tailings. This scenario represents evidence of an ecological trap as seabirds did not change habitat use, even though it had its quality reduced by contamination. The sinking-resuspension dynamics of tailings deposited on the continental shelf can temporally increase seabird exposure to contaminants, which can promote deleterious effects on populations using the region as foraging sites in medium and long terms.
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Affiliation(s)
- Guilherme Tavares Nunes
- Centro de Estudos Costeiros, Limnológicos e Marinhos, Universidade Federal do Rio Grande do Sul, 95625-000 Imbé, RS, Brazil; Programa de Monitoramento da Biodiversidade Aquática, Rede Rio Doce Mar, Brazil.
| | - Márcio Amorim Efe
- Laboratório de Bioecologia e Conservação de Aves Neotropicais, Universidade Federal de Alagoas, 57072-900 Maceió, AL, Brazil; Programa de Monitoramento da Biodiversidade Aquática, Rede Rio Doce Mar, Brazil
| | - Cindy Tavares Barreto
- Laboratório de Aves Aquáticas e Tartarugas Marinhas, Universidade Federal do Rio Grande, 96203-900 Rio Grande, RS, Brazil; Programa de Monitoramento da Biodiversidade Aquática, Rede Rio Doce Mar, Brazil
| | - Juliana Vallim Gaiotto
- Laboratório de Aves Aquáticas e Tartarugas Marinhas, Universidade Federal do Rio Grande, 96203-900 Rio Grande, RS, Brazil; Programa de Monitoramento da Biodiversidade Aquática, Rede Rio Doce Mar, Brazil
| | - Aline Barbosa Silva
- Laboratório de Aves Aquáticas e Tartarugas Marinhas, Universidade Federal do Rio Grande, 96203-900 Rio Grande, RS, Brazil; Programa de Monitoramento da Biodiversidade Aquática, Rede Rio Doce Mar, Brazil
| | - Fiorella Vilela
- Centro de Estudos Costeiros, Limnológicos e Marinhos, Universidade Federal do Rio Grande do Sul, 95625-000 Imbé, RS, Brazil
| | - Amédée Roy
- IRD, MARBEC (Univ. Montpellier, Ifremer, CNRS, IRD), Centre de Recherche Halieutique Méditerranéenne et Tropicale, BP 171, 34203 Sète Cedex, France
| | - Sophie Bertrand
- IRD, MARBEC (Univ. Montpellier, Ifremer, CNRS, IRD), Centre de Recherche Halieutique Méditerranéenne et Tropicale, BP 171, 34203 Sète Cedex, France
| | - Patrícia Gomes Costa
- Laboratório de Determinações 2, Universidade Federal do Rio Grande, 96203-900 Rio Grande, RS, Brazil; Programa de Monitoramento da Biodiversidade Aquática, Rede Rio Doce Mar, Brazil
| | - Adalto Bianchini
- Laboratório de Determinações 2, Universidade Federal do Rio Grande, 96203-900 Rio Grande, RS, Brazil; Programa de Monitoramento da Biodiversidade Aquática, Rede Rio Doce Mar, Brazil
| | - Leandro Bugoni
- Laboratório de Aves Aquáticas e Tartarugas Marinhas, Universidade Federal do Rio Grande, 96203-900 Rio Grande, RS, Brazil; Programa de Monitoramento da Biodiversidade Aquática, Rede Rio Doce Mar, Brazil
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9
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Kapuka A, Hlásny T. Climate change impacts on ecosystems and adaptation options in nine countries in southern Africa: What do we know? Ecosphere 2021. [DOI: 10.1002/ecs2.3860] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Alpo Kapuka
- Czech University of Life Sciences Prague, Faculty of Forestry and Wood Sciences Kamýcká 129 Prague 6 ‐ Suchdol 165 00 Czech Republic
| | - Tomáš Hlásny
- Czech University of Life Sciences Prague, Faculty of Forestry and Wood Sciences Kamýcká 129 Prague 6 ‐ Suchdol 165 00 Czech Republic
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11
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Scheun J, Miller RJ, Ganswindt A, Waller LJ, Pichegru L, Sherley RB, Maneveldt GW. Urofaecal glucocorticoid metabolite concentrations in African penguin ( Spheniscus demersus) chick populations experiencing different levels of human disturbance. CONSERVATION PHYSIOLOGY 2021; 9:coab078. [PMID: 34532057 PMCID: PMC8439262 DOI: 10.1093/conphys/coab078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 07/02/2021] [Accepted: 08/18/2021] [Indexed: 06/13/2023]
Abstract
Despite the importance of ecotourism in species conservation, little is known about the industry's effects on wildlife. In South Africa, some African penguin (Spheniscus demersus) colonies have become tourist attractions. The species is globally endangered, with population sizes decreasing over the past 40 years. As African penguin chicks are altricial and unable to move away from anthropogenic stressors, it is important to evaluate the effect of tourist activities on baseline glucocorticoid levels as a measure of potential disturbance. Chicks at three study sites within two breeding colonies (Robben Island, Stony Point), with varying levels of exposure to tourism (low/moderate/high) were monitored. Urofaecal samples were collected to determine urofaecal glucocorticoid metabolite (ufGCM) concentrations as an indication of baseline stress physiology. Morphometric measurements were taken to compare body condition between sites. Penguin chicks experiencing low, infrequent human presence had significantly higher mean (± standard deviation) ufGCM levels [1.34 ± 1.70 μg/g dry weight (DW)] compared to chicks experiencing both medium (0.50 ± 0.40 μg/g DW, P = 0.001) and high levels of human presence (0.57 ± 0.47 μg/g DW, P = 0.003). There was no difference in chick body condition across sites. These results suggest that exposure to frequent human activity may induce habituation/desensitization in African penguin chicks. Acute, infrequent human presence was likely an important driver for comparatively higher ufGCM levels in chicks, though several other environmental stressors may also play an important role in driving adrenocortical activity. Nevertheless, as unhabituated chicks experiencing infrequent anthropogenic presence showed significantly higher ufGCM levels, managers and legislation should attempt to minimize all forms of activity around important breeding colonies that are not already exposed to regular tourism. Although the results of this study are crucial for developing enhanced conservation and management protocols, additional research on the long-term effect of anthropogenic activities on African penguin physiology is required.
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Affiliation(s)
- Juan Scheun
- Department of Life and Consumer Sciences, University of South Africa, Roodepoort, 1724, South Africa
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, 0081, South Africa
- National Zoological Garden, South African National Biodiversity Institute, Pretoria, 0002, South Africa
| | - Rebecca J Miller
- Department of Biodiversity and Conservation Biology, University of the Western Cape, Bellville, 7535, South Africa
| | - Andre Ganswindt
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, 0081, South Africa
| | - Lauren J Waller
- Department of Biodiversity and Conservation Biology, University of the Western Cape, Bellville, 7535, South Africa
- Southern African Foundation for the Conservation of Coastal Birds (SANCCOB), Table View, 7441, South Africa
| | - Lorien Pichegru
- DST-NRF Centre of Excellence at the Percy FitzPatrick Institute of African Ornithology and Institute for Coastal and Marine Research at the Nelson Mandela University, Port Elizabeth, 6031, South Africa
| | - Richard B Sherley
- Centre for Ecology and Conservation, University of Exeter, Penry Campus, Penryn, Cornwall, TR10 9FE, UK
| | - Gavin W Maneveldt
- Department of Biodiversity and Conservation Biology, University of the Western Cape, Bellville, 7535, South Africa
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12
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Carroll G, Brodie S, Whitlock R, Ganong J, Bograd SJ, Hazen E, Block BA. Flexible use of a dynamic energy landscape buffers a marine predator against extreme climate variability. Proc Biol Sci 2021; 288:20210671. [PMID: 34344182 PMCID: PMC8334847 DOI: 10.1098/rspb.2021.0671] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Animal migrations track predictable seasonal patterns of resource availability and suitable thermal habitat. As climate change alters this ‘energy landscape’, some migratory species may struggle to adapt. We examined how climate variability influences movements, thermal habitat selection and energy intake by juvenile Pacific bluefin tuna (Thunnus orientalis) during seasonal foraging migrations in the California Current. We tracked 242 tuna across 15 years (2002–2016) with high-resolution archival tags, estimating their daily energy intake via abdominal warming associated with digestion (the ‘heat increment of feeding’). The poleward extent of foraging migrations was flexible in response to climate variability, allowing tuna to track poleward displacements of thermal habitat where their standard metabolic rates were minimized. During a marine heatwave that saw temperature anomalies of up to +2.5°C in the California Current, spatially explicit energy intake by tuna was approximately 15% lower than average. However, by shifting their mean seasonal migration approximately 900 km poleward, tuna remained in waters within their optimal temperature range and increased their energy intake. Our findings illustrate how tradeoffs between physiology and prey availability structure migration in a highly mobile vertebrate, and suggest that flexible migration strategies can buffer animals against energetic costs associated with climate variability and change.
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Affiliation(s)
- Gemma Carroll
- Institute of Marine Science, University of California Santa Cruz, Santa Cruz, CA, USA.,Environmental Research Division, NOAA Southwest Fisheries Science Center, Monterey, CA, USA.,School of Aquatic and Fisheries Science, University of Washington, Seattle, WA, USA.,Environmental Defense Fund, San Francisco, CA, USA
| | - Stephanie Brodie
- Institute of Marine Science, University of California Santa Cruz, Santa Cruz, CA, USA.,Environmental Research Division, NOAA Southwest Fisheries Science Center, Monterey, CA, USA
| | - Rebecca Whitlock
- Department of Aquatic Resources, Swedish University of Agricultural Sciences, Drottningholm, Sweden
| | - James Ganong
- Hopkins Marine Station, Stanford University, Monterey, CA, USA
| | - Steven J Bograd
- Institute of Marine Science, University of California Santa Cruz, Santa Cruz, CA, USA.,Environmental Research Division, NOAA Southwest Fisheries Science Center, Monterey, CA, USA
| | - Elliott Hazen
- Institute of Marine Science, University of California Santa Cruz, Santa Cruz, CA, USA.,Environmental Research Division, NOAA Southwest Fisheries Science Center, Monterey, CA, USA.,Hopkins Marine Station, Stanford University, Monterey, CA, USA
| | - Barbara A Block
- Hopkins Marine Station, Stanford University, Monterey, CA, USA
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13
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Krams R, Krama T, Brūmelis G, Elferts D, Strode L, Dauškane I, Luoto S, Šmits A, Krams IA. Ecological traps: evidence of a fitness cost in a cavity-nesting bird. Oecologia 2021; 196:735-745. [PMID: 34155528 PMCID: PMC8292250 DOI: 10.1007/s00442-021-04969-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 06/10/2021] [Indexed: 11/26/2022]
Abstract
Habitat quality has direct effects on the evolutionary fitness of breeding organisms, which is why it is believed that animals tend to have an evolved preference for the best possible habitats. However, some animals may mistakenly choose to reproduce in habitats that decrease their fitness, resulting in 'ecological traps'. In this study, we tested whether great tits (Parus major) attracted to areas affected by outbreaks of the great web-spinning sawfly (Acantholyda posticalis) had fitness detriments characteristic of ecological traps. Sawfly larvae consume pine needles, which decreases resource availability for birds co-habiting the forest. Using artificial nesting sites, we found that great tits inhabiting areas of sawfly outbreaks had similar clutch sizes as tits breeding in healthy forest patches; however, the fledgling number was significantly lower, and fledgling condition was worse in the damaged forests. While moth larvae are the most important food for bird nestlings, the forest patches damaged by sawflies had lower larval biomass. Although most ecological traps occur in environments altered by humans, this study shows that pest insects can lower habitat quality, forming ecological traps. Our results indicate that attracting cavity-nesting birds should be done with caution because it may negatively impact birds' nutritional status and reproductive fitness.
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Affiliation(s)
- Ronalds Krams
- Department of Biotechnology, Daugavpils University, Daugavpils, 5401, Latvia
- Chair of Plant Health, Estonian University of Life Sciences, 51006, Tartu, Estonia
| | - Tatjana Krama
- Department of Biotechnology, Daugavpils University, Daugavpils, 5401, Latvia
- Chair of Plant Health, Estonian University of Life Sciences, 51006, Tartu, Estonia
| | - Guntis Brūmelis
- Department of Botany and Ecology, Faculty of Biology, University of Latvia, Riga, 1004, Latvia
| | - Didzis Elferts
- Department of Botany and Ecology, Faculty of Biology, University of Latvia, Riga, 1004, Latvia
| | - Linda Strode
- Department of Botany and Ecology, Faculty of Biology, University of Latvia, Riga, 1004, Latvia
| | - Iluta Dauškane
- Department of Botany and Ecology, Faculty of Biology, University of Latvia, Riga, 1004, Latvia
| | - Severi Luoto
- English, Drama and Writing Studies, University of Auckland, Auckland, 1010, New Zealand
- School of Psychology, University of Auckland, Auckland, 1010, New Zealand
| | - Agnis Šmits
- Latvian State Forest Research Institute "Silava", Salaspils, 2169, Latvia
| | - Indrikis A Krams
- Department of Biotechnology, Daugavpils University, Daugavpils, 5401, Latvia.
- Department of Zoology and Animal Ecology, Faculty of Biology, University of Latvia, Riga, 1004, Latvia.
- Institute of Ecology and Earth Science, University of Tartu, Vanemuise 46, 51014, Tartu, Estonia.
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14
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Combining Regional Habitat Selection Models for Large-Scale Prediction: Circumpolar Habitat Selection of Southern Ocean Humpback Whales. REMOTE SENSING 2021. [DOI: 10.3390/rs13112074] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Machine learning algorithms are often used to model and predict animal habitat selection—the relationships between animal occurrences and habitat characteristics. For broadly distributed species, habitat selection often varies among populations and regions; thus, it would seem preferable to fit region- or population-specific models of habitat selection for more accurate inference and prediction, rather than fitting large-scale models using pooled data. However, where the aim is to make range-wide predictions, including areas for which there are no existing data or models of habitat selection, how can regional models best be combined? We propose that ensemble approaches commonly used to combine different algorithms for a single region can be reframed, treating regional habitat selection models as the candidate models. By doing so, we can incorporate regional variation when fitting predictive models of animal habitat selection across large ranges. We test this approach using satellite telemetry data from 168 humpback whales across five geographic regions in the Southern Ocean. Using random forests, we fitted a large-scale model relating humpback whale locations, versus background locations, to 10 environmental covariates, and made a circumpolar prediction of humpback whale habitat selection. We also fitted five regional models, the predictions of which we used as input features for four ensemble approaches: an unweighted ensemble, an ensemble weighted by environmental similarity in each cell, stacked generalization, and a hybrid approach wherein the environmental covariates and regional predictions were used as input features in a new model. We tested the predictive performance of these approaches on an independent validation dataset of humpback whale sightings and whaling catches. These multiregional ensemble approaches resulted in models with higher predictive performance than the circumpolar naive model. These approaches can be used to incorporate regional variation in animal habitat selection when fitting range-wide predictive models using machine learning algorithms. This can yield more accurate predictions across regions or populations of animals that may show variation in habitat selection.
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Omeyer LCM, Stokes KL, Beton D, Çiçek BA, Davey S, Fuller WJ, Godley BJ, Sherley RB, Snape RTE, Broderick AC. Investigating differences in population recovery rates of two sympatrically nesting sea turtle species. Anim Conserv 2021. [DOI: 10.1111/acv.12689] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- L. C. M. Omeyer
- Centre for Ecology and Conservation College of Life and Environmental Sciences University of Exeter Penryn UK
| | - K. L. Stokes
- Centre for Ecology and Conservation College of Life and Environmental Sciences University of Exeter Penryn UK
- Department of Biosciences Swansea University Singleton Park Swansea UK
| | - D. Beton
- Society for the Protection of Turtles Gönyeli North Cyprus
| | - B. A. Çiçek
- Faculty of Arts and Sciences Eastern Mediterranean University Famagusta North Cyprus
| | - S. Davey
- Society for the Protection of Turtles Gönyeli North Cyprus
| | - W. J. Fuller
- Society for the Protection of Turtles Gönyeli North Cyprus
- Faculty of Veterinary Medicine Near East University Nicosia North Cyprus
| | - B. J. Godley
- Centre for Ecology and Conservation College of Life and Environmental Sciences University of Exeter Penryn UK
| | - R. B. Sherley
- Centre for Ecology and Conservation College of Life and Environmental Sciences University of Exeter Penryn UK
| | - R. T. E. Snape
- Centre for Ecology and Conservation College of Life and Environmental Sciences University of Exeter Penryn UK
- Society for the Protection of Turtles Gönyeli North Cyprus
| | - A. C. Broderick
- Centre for Ecology and Conservation College of Life and Environmental Sciences University of Exeter Penryn UK
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16
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Collet J, Weimerskirch H. Albatrosses can memorize locations of predictable fishing boats but favour natural foraging. Proc Biol Sci 2020; 287:20200958. [PMID: 32752984 DOI: 10.1098/rspb.2020.0958] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Human activities generate food attracting many animals worldwide, causing major conservation issues. The spatio-temporal predictability of anthropogenic resources could reduce search costs for animals and mediate their attractiveness. We investigated this through GPS tracking in breeding black-browed albatrosses attracted to fishing boats. We tested for answers to the following questions. (i) Can future boat locations be anticipated from cues available to birds? (ii) Are birds able to appropriately use these cues to increase encounters? (iii) How frequently do birds use these cues? Boats were spatially persistent: birds searching in the direction where they previously attended boats would encounter twice as many boats compared with following a random direction strategy. A large proportion of birds did not use this cue: across pairs of consecutive trips (n = 85), 51% of birds switched their foraging direction irrespective of previous boat encounters. Still, 15 birds (27%) were observed to closely approach (approx. 0.1-1 km) where they previously attended a boat while boats were no longer there. This is less than the distance expected by chance (approx. 10-100 km), based on permutation control procedures accounting for individual-specific spatial consistency, suggesting individuals could memorize where they encountered boats across consecutive trips. We conclude albatrosses were able to exploit predictive cues from recent boat encounters but most favoured alternative resources.
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Affiliation(s)
- Julien Collet
- Centre d'Etudes Biologiques de Chizé, UMR 7372 CNRS-Université de la Rochelle, 79360 Villiers-en-Bois, France.,Department of Zoology, University of Oxford, 10a Mansfield Road, OX1 3QT, Oxford, UK
| | - Henri Weimerskirch
- Centre d'Etudes Biologiques de Chizé, UMR 7372 CNRS-Université de la Rochelle, 79360 Villiers-en-Bois, France
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17
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Sherley RB, Crawford RJM, de Blocq AD, Dyer BM, Geldenhuys D, Hagen C, Kemper J, Makhado AB, Pichegru L, Tom D, Upfold L, Visagie J, Waller LJ, Winker H. The conservation status and population decline of the African penguin deconstructed in space and time. Ecol Evol 2020; 10:8506-8516. [PMID: 32788996 PMCID: PMC7417240 DOI: 10.1002/ece3.6554] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/05/2020] [Accepted: 06/10/2020] [Indexed: 12/19/2022] Open
Abstract
Understanding changes in abundance is crucial for conservation, but population growth rates often vary over space and time. We use 40 years of count data (1979-2019) and Bayesian state-space models to assess the African penguin Spheniscus demersus population under IUCN Red List Criterion A. We deconstruct the overall decline in time and space to identify where urgent conservation action is needed. The global African penguin population met the threshold for Endangered with a high probability (97%), having declined by almost 65% since 1989. An historical low of ~17,700 pairs bred in 2019. Annual changes were faster in the South African population (-4.2%, highest posterior density interval, HPDI: -7.8 to -0.6%) than the Namibian one (-0.3%, HPDI: -3.3 to +2.6%), and since 1999 were almost -10% at South African colonies north of Cape Town. Over the 40-year period, the Eastern Cape colonies went from holding ~25% of the total penguin population to ~40% as numbers decreased more rapidly elsewhere. These changes coincided with an altered abundance and availability of the main prey of African penguins. Our results underline the dynamic nature of population declines in space as well as time and highlight which penguin colonies require urgent conservation attention.
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Affiliation(s)
- Richard B. Sherley
- Centre for Ecology and ConservationCollege of Life and Environmental SciencesUniversity of ExeterPenrynUK
- FitzPatrick Institute of African OrnithologyDST‐NRF Centre of ExcellenceUniversity of Cape TownCape TownSouth Africa
| | | | - Andrew D. de Blocq
- Seabird Conservation ProgrammeBirdLife South AfricaCape TownSouth Africa
| | - Bruce M. Dyer
- Department of Environment, Forestry and Fisheries (DEFF)Cape TownSouth Africa
| | | | - Christina Hagen
- Seabird Conservation ProgrammeBirdLife South AfricaCape TownSouth Africa
| | | | - Azwianewi B. Makhado
- FitzPatrick Institute of African OrnithologyDST‐NRF Centre of ExcellenceUniversity of Cape TownCape TownSouth Africa
- Department of Environment, Forestry and Fisheries (DEFF)Cape TownSouth Africa
| | - Lorien Pichegru
- DST/NRF Centre of Excellence at the FitzPatrick Institute of African OrnithologyInstitute for Coastal and Marine Research and Department of ZoologyNelson Mandela UniversityPort ElizabethSouth Africa
| | - Desmond Tom
- Ministry of Fisheries and Marine ResourcesLüderitzNamibia
| | - Leshia Upfold
- Department of Environment, Forestry and Fisheries (DEFF)Cape TownSouth Africa
| | - Johan Visagie
- CapeNaturePGWC Shared Services CentreBridgetownSouth Africa
| | - Lauren J. Waller
- Southern African Foundation for the Conservation of Coastal Birds (SANCCOB)Cape TownSouth Africa
- Department of Biodiversity and Conservation BiologyUniversity of the Western CapeBellvilleSouth Africa
| | - Henning Winker
- Joint Research Centre of the European CommissionIspraItaly
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18
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Vander Vorste R, Obedzinski M, Nossaman Pierce S, Carlson SM, Grantham TE. Refuges and ecological traps: Extreme drought threatens persistence of an endangered fish in intermittent streams. GLOBAL CHANGE BIOLOGY 2020; 26:3834-3845. [PMID: 32293095 PMCID: PMC7384119 DOI: 10.1111/gcb.15116] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 03/13/2020] [Accepted: 03/27/2020] [Indexed: 05/26/2023]
Abstract
Recent droughts raise global concern over potential biodiversity loss and mitigating impacts to vulnerable species has become a management priority. However, drought impacts on populations are difficult to predict, in part, because habitat refuges can buffer organisms from harsh environmental conditions. In a global change context, more extreme droughts may turn previously suitable habitats into ecological traps, where vulnerable species can no longer persist. Here, we explore the impacts of California's recent record-breaking drought on endangered juvenile Coho salmon. We estimated the variability of cumulative salmon survival using mark-recapture of nearly 20,000 tagged fish in intermittent stream pools during a 7-year period encompassing drought and non-drought conditions. We then determined the relative importance of physical habitat, streamflow, precipitation, landscape, and biological characteristics that may limit survival during drought. Our most striking result was an increase in the number of pools with reduced or zero survival during drought years and a coincident increase in spatial variability in survival among study reaches. In nearly half of the stream pools, salmon survival during drought was similar to mean survival of pools assessed during non-drought years, indicating some pools had remarkable resistance (ability to withstand disturbance) to extreme drought. Lower survival was most attributable to longer duration of disconnection between upstream and downstream habitats, a consequence of increasing drought severity. Our results not only suggest that many pools sustain juvenile salmon in non-drought years transition into ecological traps during drought but also highlight that some pools serve as refuges even under extreme drought conditions. Projected increases in drought severity that lead to longer droughts and greater habitat fragmentation could transform an increasing proportion of suitable habitats into ecological traps. Predicting future impacts of drought on Coho salmon and other sensitive species will require identification and protection of drought refuges and management strategies that prevent further habitat fragmentation.
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Affiliation(s)
- Ross Vander Vorste
- Department of Environmental Science, Policy, & ManagementUniversity of California BerkeleyBerkeleyCAUSA
- Present address:
Department of BiologyUniversity of Wisconsin La CrosseLa CrosseWIUSA
| | | | | | - Stephanie M. Carlson
- Department of Environmental Science, Policy, & ManagementUniversity of California BerkeleyBerkeleyCAUSA
| | - Theodore E. Grantham
- Department of Environmental Science, Policy, & ManagementUniversity of California BerkeleyBerkeleyCAUSA
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19
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Rodríguez-Malagón MA, Camprasse ECM, Angel LP, Arnould JPY. Geographical, temporal and individual factors influencing foraging behaviour and consistency in Australasian gannets. ROYAL SOCIETY OPEN SCIENCE 2020; 7:181423. [PMID: 32537184 PMCID: PMC7277272 DOI: 10.1098/rsos.181423] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 05/01/2020] [Indexed: 06/11/2023]
Abstract
Foraging is a behaviour that can be influenced by multiple factors and is highly plastic. Recent studies have shown consistency in individual foraging behaviour has serious ecological and evolutionary implications within species and populations. Such information is crucial to understand how species select habitats, and how such selection might allow them to adapt to the environmental changes they face. Five foraging metrics (maximum distance from the colony, bearing from the colony to the most distal point, tortuosity index, total number of dives and mean vectorial dynamic body acceleration were obtained using GPS tracking and accelerometry data in adult Australasian gannets (Morus serrator) from two colonies in southeastern Australia. Individuals were instrumented over two breeding seasons to obtain data to assess factors influencing foraging behaviour and behavioural consistency over multiple timescales (consecutive trips, breeding stages and years) and habitats (pelagic, mixed pelagic and inshore, and inshore). Colony, breeding stage and year were the factors which had the greatest influence on foraging behaviour, followed by sex. Behavioural consistency, measured as the contribution of the individual to the observed variance, was low to moderate for all foraging metrics (0.0-27.05%), with the higher values occurring over shorter timescales. In addition, behavioural consistency was driven by spatio-temporal factors rather than intrinsic characteristics. Behavioural consistency was higher in individuals foraging in inshore than pelagic habitats or mixed pelagic/inshore strategy, supporting suggestions that consistency is favoured in stable environments.
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20
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Collet J, Prudor A, Corbeau A, Mendez L, Weimerskirch H. First explorations: ontogeny of central place foraging directions in two tropical seabirds. Behav Ecol 2020. [DOI: 10.1093/beheco/araa028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Abstract
A widespread hypothesis for the ontogeny of behavior and decision-making is the early-exploration-later-canalization hypothesis. It postulates that juveniles are more exploratory and adults more consistent in their behavior. In addition, it is often assumed that naïve juveniles could overcome the costs of individual experience building by copying more the decisions of others than adults (early-conformism-later-self-defining hypothesis). Here, we compare the central place foraging movements of adults and postfledging juveniles in their first flights around the colony before dispersal and migration in two sympatric species of tropical seabirds: red-footed boobies and great frigatebirds. Using GPS records of individual movements, we analyzed the foraging directions of seabirds from the colony across successive trips. Juveniles of both species showed significant within-individual consistency in foraging direction but at lower levels than adults. Juveniles leaving the colony within the same time window showed significant but low between-individual resemblance in foraging direction at levels similar to adults. In both species, homing efficiency was lower in juveniles than in adults. Juvenile foraging directions were initially influenced by wind conditions, particularly in low wing loading frigatebirds. Wind conditions progressively lost influence on juvenile foraging directions during their first weeks of flights. In contrast, within-individual consistency, between-individual resemblance, and homing efficiency did not show signs of progression in juveniles. Our results support the early-exploration-later-canalization hypothesis but not the early-conformism-later-self-defining hypothesis. Relaxed constraints on self-feeding efficiency could favor high variability in postfledging tropical seabirds. Our simple approach could be applied to further test these hypotheses by comparing strategies across a wide range of central place foragers.
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Affiliation(s)
- Julien Collet
- Centre d’Etudes Biologiques de Chizé, UMR 7372 CNRS—Université de la Rochelle, France
- Department of Zoology, University of Oxford, Oxford OX1, UK
| | - Aurélien Prudor
- Centre d’Etudes Biologiques de Chizé, UMR 7372 CNRS—Université de la Rochelle, France
| | - Alexandre Corbeau
- Centre d’Etudes Biologiques de Chizé, UMR 7372 CNRS—Université de la Rochelle, France
| | - Loriane Mendez
- Centre d’Etudes Biologiques de Chizé, UMR 7372 CNRS—Université de la Rochelle, France
- CIESM—Mediterranean Science Commission, Monaco
| | - Henri Weimerskirch
- Centre d’Etudes Biologiques de Chizé, UMR 7372 CNRS—Université de la Rochelle, France
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21
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Pagano AM, Atwood TC, Durner GM, Williams TM. The seasonal energetic landscape of an apex marine carnivore, the polar bear. Ecology 2020; 101:e02959. [DOI: 10.1002/ecy.2959] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 10/22/2019] [Accepted: 11/12/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Anthony M. Pagano
- U.S. Geological SurveyAlaska Science Center4210 University Drive Anchorage Alaska99508USA
- Department of Ecology & Evolutionary Biology University of California Santa Cruz 130 McAllister Way Santa Cruz California95060USA
| | - Todd C. Atwood
- U.S. Geological SurveyAlaska Science Center4210 University Drive Anchorage Alaska99508USA
| | - George M. Durner
- U.S. Geological SurveyAlaska Science Center4210 University Drive Anchorage Alaska99508USA
| | - Terrie M. Williams
- Department of Ecology & Evolutionary Biology University of California Santa Cruz 130 McAllister Way Santa Cruz California95060USA
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22
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Boersma P, Borboroglu PG, Gownaris N, Bost C, Chiaradia A, Ellis S, Schneider T, Seddon P, Simeone A, Trathan P, Waller L, Wienecke B. Applying science to pressing conservation needs for penguins. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2020; 34:103-112. [PMID: 31257646 PMCID: PMC7027562 DOI: 10.1111/cobi.13378] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 06/25/2019] [Accepted: 06/25/2019] [Indexed: 05/29/2023]
Abstract
More than half of the world's 18 penguin species are declining. We, the Steering Committee of the International Union for Conservation of Nature Species Survival Commission Penguin Specialist Group, determined that the penguin species in most critical need of conservation action are African penguin (Spheniscus demersus), Galápagos penguin (Spheniscus mendiculus), and Yellow-eyed penguin (Megadyptes antipodes). Due to small or rapidly declining populations, these species require immediate scientific collaboration and policy intervention. We also used a pairwise-ranking approach to prioritize research and conservation needs for all penguins. Among the 12 cross-taxa research areas we identified, we ranked quantifying population trends, estimating demographic rates, forecasting environmental patterns of change, and improving the knowledge of fisheries interactions as the highest priorities. The highest ranked conservation needs were to enhance marine spatial planning, improve stakeholder engagement, and develop disaster-management and species-specific action plans. We concurred that, to improve the translation of science into effective conservation for penguins, the scientific community and funding bodies must recognize the importance of and support long-term research; research on and conservation of penguins must expand its focus to include the nonbreeding season and juvenile stage; marine reserves must be designed at ecologically appropriate spatial and temporal scales; and communication between scientists and decision makers must be improved with the help of individual scientists and interdisciplinary working groups.
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Affiliation(s)
- P.D. Boersma
- Center for Ecosystem Sentinels and Department of BiologyUniversity of WashingtonSeattleWA98103U.S.A.
- Global Penguin SocietyPuerto Madryn9120Argentina
| | - P. García Borboroglu
- Center for Ecosystem Sentinels and Department of BiologyUniversity of WashingtonSeattleWA98103U.S.A.
- Global Penguin SocietyPuerto Madryn9120Argentina
- CESIMAR CCT Cenpat‐CONICET9120Puerto MadrynChubutArgentina
| | - N.J. Gownaris
- Center for Ecosystem Sentinels and Department of BiologyUniversity of WashingtonSeattleWA98103U.S.A.
| | - C.A. Bost
- Centre d'Etudes Biologiques de Chizé79360Villiers‐en‐BoisFrance
| | - A. Chiaradia
- Conservation DepartmentPhillip Island Nature ParksCowesVIC3922Australia
| | - S. Ellis
- International Rhino FoundationStrasburgVA22657U.S.A.
| | - T. Schneider
- Detroit Zoological SocietyRoyal OakMI48067U.S.A.
| | - P.J. Seddon
- Department of ZoologyUniversity of OtagoDunedin9016New Zealand
| | - A. Simeone
- Facultad de Ciencias de la VidaUniversidad Andres BelloSantiago8370146Chile
| | | | - L.J. Waller
- Southern African Foundation for the Conservation of Coastal Birds (SANCCOB)Cape Town7441South Africa
- Department of Biodiversity and Conservation BiologyUniversity of the Western CapeBellvilleCape Town7535South Africa
| | - B. Wienecke
- Australian Antarctic DivisionKingstonTAS7050Australia
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23
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Robertson BA, Blumstein DT. How to disarm an evolutionary trap. CONSERVATION SCIENCE AND PRACTICE 2019. [DOI: 10.1111/csp2.116] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- Bruce A. Robertson
- Division of Science, Mathematics, and Computing Bard College Annandale‐on‐Hudson New York
| | - Daniel T. Blumstein
- Department of Ecology and Evolutionary Biology University of California Los Angeles California
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24
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Simpson M, Morris RL, Harasti D, Coleman RA. The endangered White's seahorse Hippocampus whitei chooses artificial over natural habitats. JOURNAL OF FISH BIOLOGY 2019; 95:555-561. [PMID: 31073989 DOI: 10.1111/jfb.14002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 05/09/2019] [Indexed: 06/09/2023]
Abstract
To explore whether the endangered White's seahorse Hippocampus whitei would choose to inhabit artificial over natural habitats, 10 adult H. whitei individuals were put through a series of binary choice trials in aquaria, during which they were offered different paired combinations of natural (different types of macroalga and seagrass) and artificial habitat (panels of swimming-net material). It was found that H. whitei displayed a significant choice for swimming-net material over all other available natural habitats and chose habitats according to the following rankings: (a) Net; (b) Sargassum sp.; (c) Posidonia australis; (d) Zostera muelleri. Hippocampus whitei's choice of swimming net material over natural habitat suggests that these artificial structures could be a useful conservation measure for seahorses in areas where natural habitat is becoming less favourable due to declines in abundance or quality.
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Affiliation(s)
- Michael Simpson
- Coastal and Marine Ecosystems, School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Rebecca L Morris
- National Centre for Coasts and Climate, School of Biosciences, The University of Melbourne, Melbourne, Victoria, Australia
| | - David Harasti
- Fisheries Research, NSW Department of Primary Industries, Taylors Beach, New South Wales, Australia
| | - Ross A Coleman
- Coastal and Marine Ecosystems, School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
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Campbell KJ, Steinfurth A, Underhill LG, Coetzee JC, Dyer BM, Ludynia K, Makhado AB, Merkle D, Rademan J, Upfold L, Sherley RB. Local forage fish abundance influences foraging effort and offspring condition in an endangered marine predator. J Appl Ecol 2019. [DOI: 10.1111/1365-2664.13409] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kate J. Campbell
- Animal Demography Unit, Department of Biological Sciences University of Cape Town Cape Town South Africa
- Marine Research (MA‐RE) Institute University of Cape Town Cape Town South Africa
| | - Antje Steinfurth
- FitzPatrick Institute of African Ornithology, DST‐NRF Centre of Excellence University of Cape Town Cape Town South Africa
| | - Les G. Underhill
- Animal Demography Unit, Department of Biological Sciences University of Cape Town Cape Town South Africa
| | - Janet C. Coetzee
- Fisheries Management Branch Department of Agriculture, Forestry and Fisheries Cape Town South Africa
| | - Bruce M. Dyer
- Oceans and Coasts Branch Department of Environmental Affairs Cape Town South Africa
| | - Katrin Ludynia
- Marine Research (MA‐RE) Institute University of Cape Town Cape Town South Africa
- Southern African Foundation for the Conservation of Coastal Birds (SANCCOB) Cape Town South Africa
| | - Azwianewi B. Makhado
- FitzPatrick Institute of African Ornithology, DST‐NRF Centre of Excellence University of Cape Town Cape Town South Africa
- Oceans and Coasts Branch Department of Environmental Affairs Cape Town South Africa
| | - Dagmar Merkle
- Fisheries Management Branch Department of Agriculture, Forestry and Fisheries Cape Town South Africa
| | - Johan Rademan
- Fisheries Management Branch Department of Agriculture, Forestry and Fisheries Cape Town South Africa
| | - Leshia Upfold
- Oceans and Coasts Branch Department of Environmental Affairs Cape Town South Africa
| | - Richard B. Sherley
- Environment and Sustainability Institute University of Exeter Exeter UK
- Bristol Zoological Society Bristol UK
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26
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Imlay TL, Nickerson D, Horn AG. Temperature and breeding success for Cliff Swallows (Petrochelidon pyrrhonota) nesting on man-made structures: ecological traps? CAN J ZOOL 2019. [DOI: 10.1139/cjz-2018-0224] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
When an environmental cue that previously signaled a suitable habitat leads an animal to use an unsuitable site, individual fitness can decrease, ultimately leading to population declines. Such “ecological traps” may be particularly likely for birds that use human infrastructure for nesting. Here we tested whether high nest temperatures and the physical properties of barns are associated with lower breeding success for a declining population of Cliff Swallows (Petrochelidon pyrrhonota (Vieillot, 1817)). We monitored nests under barn eaves below wood and metal roofs to determine nestling survival and mass, and recorded temperature under barn eaves, to relate ambient temperature to eave temperature. We found that eave temperature increased with ambient temperatures and was higher at high temperatures and lower at cool temperatures under metal roofs than wood roofs. Nestling survival was lower during periods with higher ambient temperatures, and both survival and mass were lower under metal roofs. Our findings suggest that barn eaves, especially those with metal roofs, may be an ecological trap for Cliff Swallows, where a seemingly suitable nesting site early in the breeding season results in low breeding success. Furthermore, warming temperatures may lead to ecological traps for other bird species, particularly those nesting in man-made structures.
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Affiliation(s)
- Tara L. Imlay
- Department of Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
- Department of Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Donavon Nickerson
- Department of Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
- Department of Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Andrew G. Horn
- Department of Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
- Department of Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
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27
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Sherley RB, Barham BJ, Barham PJ, Campbell KJ, Crawford RJM, Grigg J, Horswill C, McInnes A, Morris TL, Pichegru L, Steinfurth A, Weller F, Winker H, Votier SC. Bayesian inference reveals positive but subtle effects of experimental fishery closures on marine predator demographics. Proc Biol Sci 2019; 285:rspb.2017.2443. [PMID: 29343602 PMCID: PMC5805942 DOI: 10.1098/rspb.2017.2443] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 12/11/2017] [Indexed: 11/22/2022] Open
Abstract
Global forage-fish landings are increasing, with potentially grave consequences for marine ecosystems. Predators of forage fish may be influenced by this harvest, but the nature of these effects is contentious. Experimental fishery manipulations offer the best solution to quantify population-level impacts, but are rare. We used Bayesian inference to examine changes in chick survival, body condition and population growth rate of endangered African penguins Spheniscus demersus in response to 8 years of alternating time–area closures around two pairs of colonies. Our results demonstrate that fishing closures improved chick survival and condition, after controlling for changing prey availability. However, this effect was inconsistent across sites and years, highlighting the difficultly of assessing management interventions in marine ecosystems. Nevertheless, modelled increases in population growth rates exceeded 1% at one colony; i.e. the threshold considered biologically meaningful by fisheries management in South Africa. Fishing closures evidently can improve the population trend of a forage-fish-dependent predator—we therefore recommend they continue in South Africa and support their application elsewhere. However, detecting demographic gains for mobile marine predators from small no-take zones requires experimental time frames and scales that will often exceed those desired by decision makers.
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Affiliation(s)
- Richard B Sherley
- Environment and Sustainability Institute, University of Exeter, Penryn Campus, Penryn, Cornwall TR10 9FE, UK .,FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, Cape Town 7701, South Africa
| | - Barbara J Barham
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Peter J Barham
- H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK.,Animal Demography Unit, Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
| | - Kate J Campbell
- Animal Demography Unit, Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa.,Marine Research Institute, Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
| | - Robert J M Crawford
- Animal Demography Unit, Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa.,Department of Environmental Affairs (DEA), PO Box 52126, Cape Town 8000, South Africa
| | - Jennifer Grigg
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Cat Horswill
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | - Alistair McInnes
- DST/NRF Centre of Excellence at the FitzPatrick Institute of African Ornithology, Institute for Coastal and Marine Research and Department of Zoology, Nelson Mandela University, Port Elizabeth, South Africa
| | - Taryn L Morris
- Seabird Conservation Programme, BirdLife South Africa, PO Box 7119, Roggebaai, 8012 Cape Town, South Africa
| | - Lorien Pichegru
- DST/NRF Centre of Excellence at the FitzPatrick Institute of African Ornithology, Institute for Coastal and Marine Research and Department of Zoology, Nelson Mandela University, Port Elizabeth, South Africa
| | - Antje Steinfurth
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, Cape Town 7701, South Africa.,RSPB Centre for Conservation Science, Royal Society for the Protection of Birds, David Attenborough Building, Pembroke Street, Cambridge, Cambridgeshire CB2 3QZ, UK
| | - Florian Weller
- Marine Research Institute, Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
| | - Henning Winker
- Department of Agriculture, Forestry and Fisheries (DAFF), Private Bag X2, Roggebaai, 8012 Cape Town, South Africa
| | - Stephen C Votier
- Environment and Sustainability Institute, University of Exeter, Penryn Campus, Penryn, Cornwall TR10 9FE, UK
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Orgeret F, Péron C, Enstipp MR, Delord K, Weimerskirch H, Bost CA. Exploration during early life: distribution, habitat and orientation preferences in juvenile king penguins. MOVEMENT ECOLOGY 2019; 7:29. [PMID: 31660153 PMCID: PMC6805568 DOI: 10.1186/s40462-019-0175-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 09/24/2019] [Indexed: 05/21/2023]
Abstract
BACKGROUND The early life of marine apex predators is poorly known, particularly for diving species. The orientation and foraging skills are presumably less developed in juveniles than in adults, especially during their first year at sea when juveniles might disperse further than adults. METHODS Over two years of monitoring, we tracked the movements of 17 juvenile king penguins (Aptenodytes patagonicus, ~ 1 year old) using satellite relay tags from Crozet Archipelago (Southern Indian Ocean), starting when birds left their natal colony for the first time. For comparison we also tagged 6 non-breeding adults, which at that stage, similar to juveniles, are unhampered by reproductive constraints and might roam further than breeders. We used a combination of cluster analysis and habitat modelling to investigate and compare the movement patterns and habitat use of experienced (non-breeding adults) and non-experienced (juveniles) individuals. RESULTS While juvenile penguins and non-breeding adults followed similar routes, the movements by adults started later in the season and ranged over a considerably smaller area than juveniles. Net squared displacement analysis revealed that both groups did not move to a specific wintering area. Changes in direction of juveniles in respect to their departure island were similar and synchronous for both years. Habitat models revealed that foraging behaviour was affected by environmental variables such as wind or current speeds, sea surface temperature, or oceanic productivity, for both stages. Analysis of tracks revealed that birds moved predominately perpendicular or against the main direction of the Antarctic Circumpolar Current and the prevailing wind during austral summer (juveniles only) and autumn (juveniles and non-breeding adults). However, both juveniles and adults were more likely to move against the prevailing winds if productivity increased along their trajectories. CONCLUSIONS The exceptional duration of our tracking study provided unprecedented insights into the distribution, habitat preferences and orientation of two poorly known life history stages of an expert avian diver. Our study suggests that juveniles might use both innate and learnt skills to reach profitable foraging areas during their first year at sea, which is critical in long-lived species.
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Affiliation(s)
- F. Orgeret
- Centre d’Etudes Biologiques de Chizé, CNRS, UMR 7372, 79360 Villiers en Bois, France
| | - C. Péron
- Laboratoire de Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), MNHN, CNRS, IRD, SU, UCN, UA. CP 26, 43 rue Cuvier, 75231 Paris Cedex 05, France
| | - M. R. Enstipp
- Département Ecologie, Physiologie et Ethologie, Université de Strasbourg, CNRS, IPHC, UMR 7178, F-67000 Strasbourg, France
| | - K. Delord
- Centre d’Etudes Biologiques de Chizé, CNRS, UMR 7372, 79360 Villiers en Bois, France
| | - H. Weimerskirch
- Centre d’Etudes Biologiques de Chizé, CNRS, UMR 7372, 79360 Villiers en Bois, France
| | - C. A. Bost
- Centre d’Etudes Biologiques de Chizé, CNRS, UMR 7372, 79360 Villiers en Bois, France
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Gownaris NJ, Boersma PD. Sex-biased survival contributes to population decline in a long-lived seabird, the Magellanic Penguin. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2019; 29:e01826. [PMID: 30601594 PMCID: PMC6849821 DOI: 10.1002/eap.1826] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 09/12/2018] [Accepted: 10/16/2018] [Indexed: 05/29/2023]
Abstract
We developed a Hidden Markov mark-recapture model (R package marked) to examine sex-specific demography in Magellanic Penguins (Spheniscus magellanicus). Our model was based on 33 yr of resightings at Punta Tombo, Argentina, where we banded ~44,000 chicks from 1983 to 2010. Because we sexed only 57% of individuals over their lifetime, we treated sex as an uncertain state in our model. Our goals were to provide insight into the population dynamics of this declining colony, to inform conservation of this species, and to highlight the importance of considering sex-specific vital rates in demographic seabird studies. Like many other seabirds, Magellanic Penguins are long-lived, serially monogamous, and exhibit obligate biparental care. We found that the non-breeding-season survival of females was lower than that of males and that the magnitude of this bias was highest for juveniles. Biases in survival accumulated as cohorts aged, leading to increasingly skewed sex ratios. The survival bias was greatest in years when overall survival was low, that is, females fared disproportionality worse when conditions were unfavorable. Our model-estimated survival patterns are consistent with independent data on carcasses from the species' non-breeding grounds, showing that mortality is higher for juveniles than for adults and higher for females than for males. Juveniles may be less efficient foragers than adults are and, because of their smaller size, females may show less resilience to food scarcity than males. We used perturbation analysis of a population matrix model to determine the impact of sex-biased survival on adult sex ratio and population growth rate at Punta Tombo. We found that adult sex ratio and population growth rate have the greatest proportional response, that is, elasticity, to female pre-breeder and adult survival. Sex bias in juvenile survival (i.e., lower survival of females) made the greatest contribution to population declines from 1990 to 2009. Because starvation is a leading cause of morality in juveniles and adults, precautionary fisheries and spatial management in the region could help to slow population decline. Our data add to growing evidence that knowledge of sex-specific demography and sex ratios are necessary for accurate assessment of seabird population trends.
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Affiliation(s)
- N. J. Gownaris
- Department of Biology and Center for Ecosystem SentinelsUniversity of WashingtonSeattleWashington98103USA
| | - P. D. Boersma
- Department of Biology and Center for Ecosystem SentinelsUniversity of WashingtonSeattleWashington98103USA
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Managing fishery development in sensitive ecosystems: identifying penguin habitat use to direct management in Antarctica. Ecosphere 2018. [DOI: 10.1002/ecs2.2392] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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Warwick-Evans V, Ratcliffe N, Lowther AD, Manco F, Ireland L, Clewlow HL, Trathan PN. Using habitat models for chinstrap penguinsPygoscelis antarcticato advise krill fisheries management during the penguin breeding season. DIVERS DISTRIB 2018. [DOI: 10.1111/ddi.12817] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
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A non-invasive approach to estimate the energetic requirements of an increasing seabird population in a perturbed marine ecosystem. Sci Rep 2018; 8:8343. [PMID: 29844530 PMCID: PMC5974355 DOI: 10.1038/s41598-018-26647-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 04/20/2018] [Indexed: 12/03/2022] Open
Abstract
There is a growing desire to integrate the food requirements of predators living in marine ecosystems impacted by humans into sustainable fisheries management. We used non-invasive video-recording, photography and focal observations to build time-energy budget models and to directly estimate the fish mass delivered to chicks by adult greater crested terns Thalasseus bergii breeding in the Benguela ecosystem. Mean modelled adult daily food intake increased from 140.9 g·d−1 of anchovy Engraulis capensis during incubation to 171.7 g·d−1 and 189.2 g·d−1 when provisioning small and large chicks, respectively. Modelled prey intake expected to be returned to chicks was 58.3 g·d−1 (95% credible intervals: 44.9–75.8 g·d−1) over the entire growth period. Based on our observations, chicks were fed 19.9 g·d−1 (17.2–23.0 g·d−1) to 45.1 g·d−1 (34.6–58.7 g·d−1) of anchovy during early and late provisioning, respectively. Greater crested terns have lower energetic requirements at the individual (range: 15–34%) and population level (range: 1–7%) than the other Benguela endemic seabirds that feed on forage fish. These modest requirements – based on a small body size and low flight costs – coupled with foraging plasticity have allowed greater crested terns to cope with changing prey availability, unlike the other seabirds species using the same exploited prey base.
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Plasticity in the foraging behavior of male Southern Rockhopper Penguins (Eudyptes chrysocome) during incubation in the Falkland/Malvinas Islands. Polar Biol 2018. [DOI: 10.1007/s00300-018-2320-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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35
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Faldyn MJ, Hunter MD, Elderd BD. Climate change and an invasive, tropical milkweed: an ecological trap for monarch butterflies. Ecology 2018; 99:1031-1038. [PMID: 29618170 DOI: 10.1002/ecy.2198] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 02/07/2018] [Accepted: 02/15/2018] [Indexed: 11/09/2022]
Abstract
While it is well established that climate change affects species distributions and abundances, the impacts of climate change on species interactions has not been extensively studied. This is particularly important for specialists whose interactions are tightly linked, such as between the monarch butterfly (Danaus plexippus) and the plant genus Asclepias, on which it depends. We used open-top chambers (OTCs) to increase temperatures in experimental plots and placed either nonnative Asclepias curassavica or native A. incarnata in each plot along with monarch larvae. We found, under current climatic conditions, adult monarchs had higher survival and mass when feeding on A. curassavica. However, under future conditions, monarchs fared much worse on A. curassavica. The decrease in adult survival and mass was associated with increasing cardenolide concentrations under warmer temperatures. Increased temperatures alone reduced monarch forewing length. Cardenolide concentrations in A. curassavica may have transitioned from beneficial to detrimental as temperature increased. Thus, the increasing cardenolide concentrations may have pushed the larvae over a tipping point into an ecological trap; whereby past environmental cues associated with increased fitness give misleading information. Given the ubiquity of specialist plant-herbivore interactions, the potential for such ecological traps to emerge as temperatures increase may have far-reaching consequences.
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Affiliation(s)
- Matthew J Faldyn
- Department of Biological Sciences, Louisiana State University, 202 Louisiana State University Life Sciences Building, Baton Rouge, Louisiana, 70803, USA
| | - Mark D Hunter
- Department of Ecology and Evolutionary Biology and School of Natural Resources and Environment, University of Michigan, 2053 Natural Sciences Building, 830 North University, Ann Arbor, Michigan, 48109-1048, USA
| | - Bret D Elderd
- Department of Biological Sciences, Louisiana State University, 202 Louisiana State University Life Sciences Building, Baton Rouge, Louisiana, 70803, USA
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Foraging plasticity in seabirds: A non-invasive study of the diet of greater crested terns breeding in the Benguela region. PLoS One 2018; 13:e0190444. [PMID: 29385167 PMCID: PMC5791960 DOI: 10.1371/journal.pone.0190444] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 12/14/2017] [Indexed: 11/25/2022] Open
Abstract
Marine predators, such as seabirds, are useful indicators of marine ecosystem functioning. In particular, seabird diet may reflect variability in food-web composition due to natural or human-induced environmental change. Diet monitoring programmes, which sample diet non-invasively, are valuable aids to conservation and management decision-making. We investigated the diet of an increasing population of greater crested terns Thalasseus bergii in the Western Cape, South Africa, during three successive breeding seasons (2013 to 2015), when populations of other seabirds feeding on small pelagic schooling fish in the region were decreasing. Breeding greater crested terns carry prey in their bills, so we used an intensive photo-sampling method to record their diet with little disturbance. We identified 24,607 prey items from at least 47 different families, with 34 new prey species recorded. Fish dominated the diet, constituting 94% of prey by number, followed by cephalopods (3%), crustaceans (2%) and insects (1%). The terns mainly targeted surface-schooling Clupeiformes, with anchovy Engraulis encrasicolus the most abundant prey in all three breeding seasons (65% overall). Prey composition differed significantly between breeding stages and years, with anchovy most abundant at the start of the breeding season, becoming less frequent as the season progressed. The proportion of anchovy in the diet also was influenced by environmental factors; anchovy occurred more frequently with increasing wind speeds and was scarce on foggy days, presumably because terns rely in part on social facilitation to locate anchovy schools. The application of this intensive and non-invasive photo-sampling method revealed an important degree of foraging plasticity for this seabird within a context of locally reduced food availability, suggesting that, unlike species that specialise on a few high-quality prey, opportunistic seabirds may be better able to cope with reductions in the abundance of their preferred prey.
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Sherley RB, Botha P, Underhill LG, Ryan PG, van Zyl D, Cockcroft AC, Crawford RJM, Dyer BM, Cook TR. Defining ecologically relevant scales for spatial protection with long-term data on an endangered seabird and local prey availability. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2017; 31:1312-1321. [PMID: 28248436 DOI: 10.1111/cobi.12923] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Revised: 02/09/2017] [Accepted: 02/25/2017] [Indexed: 06/06/2023]
Abstract
Human activities are important drivers of marine ecosystem functioning. However, separating the synergistic effects of fishing and environmental variability on the prey base of nontarget predators is difficult, often because prey availability estimates on appropriate scales are lacking. Understanding how prey abundance at different spatial scales links to population change can help integrate the needs of nontarget predators into fisheries management by defining ecologically relevant areas for spatial protection. We investigated the local population response (number of breeders) of the Bank Cormorant (Phalacrocorax neglectus), a range-restricted endangered seabird, to the availability of its prey, the heavily fished west coast rock lobster (Jasus lalandii). Using Bayesian state-space modeled cormorant counts at 3 colonies, 22 years of fisheries-independent data on local lobster abundance, and generalized additive modeling, we determined the spatial scale pertinent to these relationships in areas with different lobster availability. Cormorant numbers responded positively to lobster availability in the regions with intermediate and high abundance but not where regime shifts and fishing pressure had depleted lobster stocks. The relationships were strongest when lobsters 20-30 km offshore of the colony were considered, a distance greater than the Bank Cormorant's foraging range when breeding, and may have been influenced by prey availability for nonbreeding birds, prey switching, or prey ecology. Our results highlight the importance of considering the scale of ecological relationships in marine spatial planning and suggest that designing spatial protection around focal species can benefit marine predators across their full life cycle. We propose the precautionary implementation of small-scale marine protected areas, followed by robust assessment and adaptive-management, to confirm population-level benefits for the cormorants, their prey, and the wider ecosystem, without negative impacts on local fisheries.
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Affiliation(s)
- Richard B Sherley
- Environment and Sustainability Institute, University of Exeter, Penryn Campus, Penryn, Cornwall TR10 9FE, U.K
- Animal Demography Unit, Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa
| | - Philna Botha
- Animal Demography Unit, Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, 7701, South Africa
| | - Les G Underhill
- Animal Demography Unit, Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa
- Marine Research Institute, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa
| | - Peter G Ryan
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, 7701, South Africa
| | - Danie van Zyl
- Department of Agriculture, Forestry and Fisheries (DAFF), Private Bag X2, Rogge Bay, 8012, Cape Town, South Africa
| | - Andrew C Cockcroft
- Department of Agriculture, Forestry and Fisheries (DAFF), Private Bag X2, Rogge Bay, 8012, Cape Town, South Africa
| | - Robert J M Crawford
- Animal Demography Unit, Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa
- Department of Environmental Affairs (DEA), P.O. Box 52126, Cape Town, 8000, South Africa
| | - Bruce M Dyer
- Department of Environmental Affairs (DEA), P.O. Box 52126, Cape Town, 8000, South Africa
| | - Timothée R Cook
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, 7701, South Africa
- Institute of Ecology and Environmental Sciences, Evolutionary Eco-physiology Team, University Pierre et Marie Curie, Bâtiment A-7ème étage, 7 quai, St Bernard, 75005, Paris, France
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Crawford R, Ellenberg U, Frere E, Hagen C, Baird K, Brewin P, Crofts S, Glass J, Mattern T, Pompert J, Ross K, Kemper J, Ludynia K, Sherley RB, Steinfurth A, Suazo CG, Yorio P, Tamini L, Mangel JC, Bugoni L, Jiménez Uzcátegui G, Simeone A, Luna-Jorquera G, Gandini P, Woehler EJ, Pütz K, Dann P, Chiaradia A, Small C. Tangled and drowned: a global review of penguin bycatch in fisheries. ENDANGER SPECIES RES 2017. [DOI: 10.3354/esr00869] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Linking extreme interannual changes in prey availability to foraging behaviour and breeding investment in a marine predator, the macaroni penguin. PLoS One 2017; 12:e0184114. [PMID: 28910405 PMCID: PMC5598940 DOI: 10.1371/journal.pone.0184114] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 08/18/2017] [Indexed: 11/25/2022] Open
Abstract
Understanding the mechanisms that link prey availability to predator behaviour and population change is central to projecting how a species may respond to future environmental pressures. We documented the behavioural responses and breeding investment of macaroni penguins Eudyptes chrysolophus across five breeding seasons where local prey density changed by five-fold; from very low to highly abundant. When prey availability was low, foraging trips were significantly longer and extended overnight. Birds also foraged farther from the colony, potentially in order to reach more distant foraging grounds and allow for increased search times. These extended foraging trips were also linked to a marked decrease in fledgling weights, most likely associated with reduced rates of provisioning. Furthermore, by comparing our results with previous work on this population, it appears that lowered first-year survival rates associated, at least partially, with fledging masses were also evident for this cohort. This study integrates a unique set of prey density, predator behaviour and predator breeding investment data to highlight a possible behavioural mechanism linking perturbations in prey availability to population demography.
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Collet J, Patrick SC, Weimerskirch H. A comparative analysis of the behavioral response to fishing boats in two albatross species. Behav Ecol 2017. [DOI: 10.1093/beheco/arx097] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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