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van Oordt F, Cuba A, Choy ES, Elliott JE, Elliott KH. Amino acid-specific isotopes reveal changing five-dimensional niche segregation in Pacific seabirds over 50 years. Sci Rep 2024; 14:7899. [PMID: 38570566 PMCID: PMC10991557 DOI: 10.1038/s41598-024-57339-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 03/18/2024] [Indexed: 04/05/2024] Open
Abstract
Hutchison's niche theory suggests that coexisting competing species occupy non-overlapping hypervolumes, which are theoretical spaces encompassing more than three dimensions, within an n-dimensional space. The analysis of multiple stable isotopes can be used to test these ideas where each isotope can be considered a dimension of niche space. These hypervolumes may change over time in response to variation in behaviour or habitat, within or among species, consequently changing the niche space itself. Here, we use isotopic values of carbon and nitrogen of ten amino acids, as well as sulphur isotopic values, to produce multi-isotope models to examine niche segregation among an assemblage of five coexisting seabird species (ancient murrelet Synthliboramphus antiquus, double-crested cormorant Phalacrocorax auritus, Leach's storm-petrel Oceanodrama leucorhoa, rhinoceros auklet Cerorhinca monocerata, pelagic cormorant Phalacrocorax pelagicus) that inhabit coastal British Columbia. When only one or two isotope dimensions were considered, the five species overlapped considerably, but segregation increased in more dimensions, but often in complex ways. Thus, each of the five species occupied their own isotopic hypervolume (niche), but that became apparent only when factoring the increased information from sulphur and amino acid specific isotope values, rather than just relying on proxies of δ15N and δ13C alone. For cormorants, there was reduction of niche size for both species consistent with a decline in their dominant prey, Pacific herring Clupea pallasii, from 1970 to 2006. Consistent with niche theory, cormorant species showed segregation across time, with the double-crested demonstrating a marked change in diet in response to prey shifts in a higher dimensional space. In brief, incorporating multiple isotopes (sulfur, PC1 of δ15N [baselines], PC2 of δ15N [trophic position], PC1 and PC2 of δ13C) metrics allowed us to infer changes and differences in food web topology that were not apparent from classic carbon-nitrogen biplots.
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Affiliation(s)
- Francis van Oordt
- Department of Natural Resources Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada.
| | | | - Emily S Choy
- Biology Department, McMaster University, Hamilton, ON, Canada
| | - John E Elliott
- Science & Technology Branch, Environment and Climate Change Canada, Delta, Canada
| | - Kyle H Elliott
- Department of Natural Resources Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
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2
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Xu X, Ye Y, Briggs E, Wang C, Qing B, Song Z, Ding C. Why do parents produce small broods of offspring that have lower body mass, survival, and lifetime reproductive success? A case study in a long-lived bird. Behav Ecol Sociobiol 2023. [DOI: 10.1007/s00265-023-03301-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
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3
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Chick Provisioning in Grey-Faced Petrel (Pterodroma gouldi) under Environmental Stress. BIRDS 2022. [DOI: 10.3390/birds3030019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Grey-faced Petrels (Pterodroma gouldi) are colonial burrowing seabirds predominantly nesting on offshore islands of the upper North Island of New Zealand. We studied their chick provisioning on Te Hāwere-a-Maki during two years of unfavourable warmer La Niña conditions in 2011 and 2013. We intensively monitored chicks in each year, weighing chicks every 12 h for 10 consecutive days to estimate meal sizes following chick provisioning and to estimate 12-hourly body mass loss as a function of time since last feeding. We found a quadratic relationship of body mass loss with time since last feeding, with rapid digestion of meals following provisioning followed by a period of fasting from five days post feeding as chicks waited an unknown and variable amount of time until their next meal. The rate of body mass loss did not depend on chick age nor body mass, and did not differ between years, but heavier chicks included in our study were more likely to successfully fledge, suggesting a legacy of adult provisioning prior to our study commencing. Our regular handling of chicks for monitoring has no discernible impact on parent provisioning compared to a set of control chicks. The mean estimates of 100-gram meal sizes and 10-day foraging trip durations are likely to be below the break-even point for this species.
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4
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Leclaire S, Pineaux M, Blanchard P, White J, Hatch SA. Microbiota composition and diversity of multiple body sites vary according to reproductive performance in a seabird. Mol Ecol 2022; 32:2115-2133. [PMID: 35152516 DOI: 10.1111/mec.16398] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 01/03/2022] [Accepted: 02/07/2022] [Indexed: 11/30/2022]
Abstract
The microbiota is suggested to be a fundamental contributor to host reproduction and survival, but associations between microbiota and fitness are rare, especially for wild animals. Here, we tested the association between microbiota and two proxies of breeding performance in multiple body sites of the black-legged kittiwake, a seabird species. First we found that, in females, nonbreeders (i.e., birds that did not lay eggs) hosted different microbiota composition to that of breeders in neck and flank feathers, in the choanae, in the outer-bill and in the cloacae, but not in preen feathers and tracheae. These differences in microbiota might reflect variations in age or individual quality between breeders and nonbreeders. Second, we found that better female breeders (i.e., with higher body condition, earlier laying date, heavier eggs, larger clutch, and higher hatching success) had lower abundance of several Corynebacteriaceae in cloaca than poorer female breeders, suggesting that these bacteria might be pathogenic. Third, in females, better breeders had different microbiota composition and lower microbiota diversity in feathers, especially in preen feathers. They had also reduced dispersion in microbiota composition across body sites. These results might suggest that good breeding females are able to control their feather microbiota-potentially through preen secretions-more tightly than poor breeding females. We did not find strong evidence for an association between reproductive outcome and microbiota in males. Our results are consistent with the hypothesis that natural variation in the microbiota is associated with differences in host fitness in wild animals, but the causal relationships remain to be investigated.
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Affiliation(s)
- Sarah Leclaire
- Laboratoire Evolution et Diversité Biologique (EDB) UMR5174 Université Toulouse 3 Paul Sabatier CNRS, IRD Toulouse France
| | - Maxime Pineaux
- Laboratoire Evolution et Diversité Biologique (EDB) UMR5174 Université Toulouse 3 Paul Sabatier CNRS, IRD Toulouse France
| | - Pierrick Blanchard
- Laboratoire Evolution et Diversité Biologique (EDB) UMR5174 Université Toulouse 3 Paul Sabatier CNRS, IRD Toulouse France
| | - Joël White
- Laboratoire Evolution et Diversité Biologique (EDB) UMR5174 Université Toulouse 3 Paul Sabatier CNRS, IRD Toulouse France
- ENSFEA Castanet‐Tolosan France
| | - Scott A Hatch
- Institute for Seabird Research and Conservation Anchorage AK 99516 USA
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5
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Free CM, Jensen OP, Hilborn R. Evaluating impacts of forage fish abundance on marine predators. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2021; 35:1540-1551. [PMID: 33899227 DOI: 10.1111/cobi.13709] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 01/22/2021] [Indexed: 06/12/2023]
Abstract
Forage fish-small, low trophic level, pelagic fish such as herrings, sardines, and anchovies-are important prey species in marine ecosystems and also support large commercial fisheries. In many parts of the world, forage fish fisheries are managed using precautionary principles that target catch limits below the maximum sustainable yield. However, there are increasing calls to further limit forage fish catch to safeguard their fish, seabird, and marine mammal predators. The effectiveness of these extra-precautionary regulations, which assume that increasing prey abundance increases predator productivity, are under debate. In this study, we used prey-linked population models to measure the influence of forage fish abundance on the population growth rates of 45 marine predator populations representing 32 fish, seabird, and mammal species from 5 regions around the world. We used simulated data to confirm the ability of the statistical model to accurately detect prey influences under varying levels of influence strength and process variability. Our results indicate that predator productivity was rarely influenced by the abundance of their forage fish prey. Only 6 predator populations (13% of the total) were positively influenced by increasing prey abundance and the model exhibited high power to detect prey influences when they existed. These results suggest that additional limitation of forage fish harvest to levels well below sustainable yields would rarely result in detectable increases in marine predator populations.
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Affiliation(s)
- Christopher M Free
- Bren School of Environmental Science and Management, University of California, Santa Barbara, Santa Barbara, California, USA
- Department of Marine and Coastal Sciences, Rutgers University, New Brunswick, New Jersey, USA
| | - Olaf P Jensen
- Department of Marine and Coastal Sciences, Rutgers University, New Brunswick, New Jersey, USA
- University of Wisconsin - Madison, Center for Limnology, 680 N Park St., Madison, WI, 53706, USA
| | - Ray Hilborn
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington, USA
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6
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Speakman CN, Hoskins AJ, Hindell MA, Costa DP, Hartog JR, Hobday AJ, Arnould JPY. Influence of environmental variation on spatial distribution and habitat-use in a benthic foraging marine predator. ROYAL SOCIETY OPEN SCIENCE 2021; 8:211052. [PMID: 34754503 PMCID: PMC8493206 DOI: 10.1098/rsos.211052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 09/13/2021] [Indexed: 06/13/2023]
Abstract
The highly dynamic nature of the marine environment can have a substantial influence on the foraging behaviour and spatial distribution of marine predators, particularly in pelagic marine systems. However, knowledge of the susceptibility of benthic marine predators to environmental variability is limited. This study investigated the influence of local-scale environmental conditions and large-scale climate indices on the spatial distribution and habitat use in the benthic foraging Australian fur seal (Arctocephalus pusillus doriferus; AUFS). Female AUFS provisioning pups were instrumented with GPS or ARGOS platform terminal transmitter tags during the austral winters of 2001-2019 at Kanowna Island, south-eastern Australia. Individuals were most susceptible to changes in the Southern Oscillation Index that measures the strength of the El Niño Southern Oscillation, with larger foraging ranges, greater distances travelled and more dispersed movement associated with 1-yr lagged La Niña-like conditions. Additionally, the total distance travelled was negatively correlated with the current year sea surface temperature and 1-yr lagged Indian Ocean Dipole, and positively correlated with 1-yr lagged chlorophyll-a concentration. These results suggest that environmental variation may influence the spatial distribution and availability of prey, even within benthic marine systems.
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Affiliation(s)
- Cassie N Speakman
- School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia
| | | | - Mark A Hindell
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia
| | - Daniel P Costa
- Ecology and Evolutionary Biology Department, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Jason R Hartog
- CSIRO Oceans and Atmosphere, Hobart, Tasmania, Australia
| | | | - John P Y Arnould
- School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia
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7
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Lei W, Masero JA, Dingle C, Liu Y, Chai Z, Zhu B, Peng H, Zhang Z, Piersma T. The value of coastal saltpans for migratory shorebirds: conservation insights from a stable isotope approach based on feeding guild and body size. Anim Conserv 2021. [DOI: 10.1111/acv.12717] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Weipan Lei
- Key Laboratory for Biodiversity Science and Ecological Engineering National Demonstration Center for Experimental Life Sciences & Biotechnology Education College of Life Sciences Beijing Normal University Beijing China
| | - Jose A. Masero
- Ecology in the Anthropocene Associated Unit CSIC‐UEX, Zoology Faculty of Sciences University of Extremadura Badajoz Spain
| | - Caroline Dingle
- Division of Ecology & Biodiversity School of Biological Sciences The University of Hong Kong Hong Kong S.A.R. China
| | - Yang Liu
- State Key Laboratory of Biocontrol School of Ecology School of Life Sciences Sun Yat‐sen University Guangzhou China
| | - Ziwen Chai
- Key Laboratory for Biodiversity Science and Ecological Engineering National Demonstration Center for Experimental Life Sciences & Biotechnology Education College of Life Sciences Beijing Normal University Beijing China
| | - Bingrun Zhu
- Key Laboratory for Biodiversity Science and Ecological Engineering National Demonstration Center for Experimental Life Sciences & Biotechnology Education College of Life Sciences Beijing Normal University Beijing China
- Conservation Ecology Group Groningen Institute for Evolutionary Life Sciences (GELIFES) University of Groningen Groningen The Netherlands
| | - Hebo Peng
- Conservation Ecology Group Groningen Institute for Evolutionary Life Sciences (GELIFES) University of Groningen Groningen The Netherlands
- Department of Coastal Systems NIOZ Royal Netherlands Institute for Sea Research Texel The Netherlands
| | - Zhengwang Zhang
- Key Laboratory for Biodiversity Science and Ecological Engineering National Demonstration Center for Experimental Life Sciences & Biotechnology Education College of Life Sciences Beijing Normal University Beijing China
| | - Theunis Piersma
- Conservation Ecology Group Groningen Institute for Evolutionary Life Sciences (GELIFES) University of Groningen Groningen The Netherlands
- Department of Coastal Systems NIOZ Royal Netherlands Institute for Sea Research Texel The Netherlands
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8
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Ramírez F, Chiaradia A, O'Leary DA, Reina RD. Making the most of the old age: Autumn breeding as an extra reproductive investment in older seabirds. Ecol Evol 2021; 11:5393-5401. [PMID: 34026015 PMCID: PMC8131812 DOI: 10.1002/ece3.7431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 02/11/2021] [Accepted: 03/01/2021] [Indexed: 02/05/2023] Open
Abstract
The extrinsic and intrinsic factors affecting differing reproductive strategies among populations are central to understanding population and evolutionary ecology. To evaluate whether individual reproductive strategies responded to annual patterns in marine productivity and age-related processes in a seabird we used a long term (2003-2013), a continuous dataset on nest occupancy and attendance at the colony by little penguins (Eudyptula minor) at Phillip Island (Victoria, Australia). We found that concurrent with a secondary annual peak of marine productivity, a secondary peak in colony attendance and nest occupancy was observed in Autumn (out of the regular breeding season in spring/summer) with individuals showing mating-like behavior. Individuals attending this autumn peak averaged 2.5 years older than those individuals that exclusively bred during spring/summer. Rather than being a naïve response by younger and inexperienced birds misreading environmental cues, our data indicate that the autumn peak attendance is an earlier attempt to breed by older and more experienced penguins. Therefore, we provide strong support for the fundamental prediction of the life-history theory of increasing investment in reproduction with age to maximize lifetime fitness as future survival prospects diminish and experience increases.
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Affiliation(s)
- Francisco Ramírez
- Department of Renewable Marine ResourcesInstitut de Ciències del Mar (ICM‐CSIC)BarcelonaSpain
| | - Andre Chiaradia
- School of Biological SciencesMonash UniversityClaytonVICAustralia
- Conservation DepartmentPhillip Island Nature ParksCowesVICAustralia
| | | | - Richard D. Reina
- School of Biological SciencesMonash UniversityClaytonVICAustralia
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9
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Romero J, Catry P, Alonso H, Granadeiro JP. Seabird diet analysis suggests sudden shift in the pelagic communities of the subtropical Northeast Atlantic. MARINE ENVIRONMENTAL RESEARCH 2021; 165:105232. [PMID: 33360626 DOI: 10.1016/j.marenvres.2020.105232] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 11/27/2020] [Accepted: 11/30/2020] [Indexed: 06/12/2023]
Abstract
The dynamics of the subtropical pelagic ecosystems of the Northeast Atlantic are still poorly known due to the high costs associated with sampling large oceanic areas. Top predators can be used as alternative low-cost samplers and indicators of the temporal variability of such systems. To study the variation in the composition of pelagic species through time in the broad Canary current region, we analysed foraging trips and regurgitations of Cory's shearwaters Calonectris borealis nesting on Selvagens islands, in 2008-2011 and 2016-2018. Fisheries data, oceanographic variables and the North Atlantic Oscillation were explored as possible explanatory variables for trends in behaviour and diet. Cory's shearwaters' diet, complemented by fisheries data, revealed marked changes in the composition of the pelagic fish communities. In 2016 there was a peak in the abundance of the Atlantic chub mackerel Scomber colias, followed by an explosive increase in the abundance of the Longspine snipefish Macroramphosus scolopax in 2017 and 2018, as deduced from the diet composition of the Cory's shearwater, and supported by fisheries data, in the broad oceanic area surrounding the Selvagens islands. Oceanographic variables did not show fluctuations correlated with these marked shifts in pelagic fish availability, the causes of which remain largely unknown. This study highlights the importance of the Atlantic chub mackerel and of the Longspine snipefish in the Madeira/Canary region and exemplifies the efficiency of avian predators in revealing rapid changes in pelagic communities of oceanic domains. Such trends and variations need to be better monitored and understood to measure the impact of ongoing global changes and to sustainably manage the marine environment and resources.
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Affiliation(s)
- Joana Romero
- CESAM, Centre for Environmental and Marine Studies, Departamento de Biologia Animal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016, Lisbon, Portugal.
| | - Paulo Catry
- MARE, Marine and Environmental Sciences Centre, ISPA-Instituto Universitário, Rua Jardim do Tabaco 34, 1149-041, Lisbon, Portugal
| | - Hany Alonso
- SPEA, Portuguese Society for the Study of Birds, Avenida Columbano Bordalo Pinheiro 87, 1070-062, Lisbon, Portugal
| | - José Pedro Granadeiro
- CESAM, Centre for Environmental and Marine Studies, Departamento de Biologia Animal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016, Lisbon, Portugal
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10
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Cerveira LR, Ramos JA, Rodrigues I, Almeida N, Araújo PM, Santos ID, Vieira C, Pereira JM, Ceia FR, Geraldes P, Melo T, Paiva VH. Inter-annual changes in oceanic conditions drives spatial and trophic consistency of a tropical marine predator. MARINE ENVIRONMENTAL RESEARCH 2020; 162:105165. [PMID: 33068920 DOI: 10.1016/j.marenvres.2020.105165] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 09/29/2020] [Accepted: 10/01/2020] [Indexed: 06/11/2023]
Abstract
Pelagic seabirds exhibit plasticity in foraging characteristics in relation to oceanographic conditions. This should be particularly relevant in tropical marine environments where food resources are naturally more unpredictable. We studied how inter-annual variations (2013-2018) in tropical oceanographic conditions (driver of oceanic productivity) can influence the spatial and trophic ecology of Cape Verde shearwater (Calonectris edwardsii) during the breeding season. During years of poor oceanographic conditions around the colony, birds engaged in longer trips to West Africa, showed higher spatial and behavioural consistency, and presented a wider isotopic niche. Opposite patterns were generally found for years of good oceanographic conditions, when birds foraged more on their colony surroundings. New foraging areas off West Africa were highlighted as relevant, especially during years of poor environmental conditions. This study highlights the need for long-term studies to assess variation in foraging areas and foraging decisions by seabird populations.
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Affiliation(s)
- L R Cerveira
- University of Coimbra, MARE - Marine and Environmental Sciences Centre, Department of Life Sciences, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal.
| | - Jaime A Ramos
- University of Coimbra, MARE - Marine and Environmental Sciences Centre, Department of Life Sciences, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Isabel Rodrigues
- Biosfera Cabo Verde, Rua de Moçambique 28, Mindelo, caixa postal 233, São Vicente, Cape Verde
| | - Nathalie Almeida
- University of Coimbra, MARE - Marine and Environmental Sciences Centre, Department of Life Sciences, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Pedro M Araújo
- University of Coimbra, MARE - Marine and Environmental Sciences Centre, Department of Life Sciences, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal; CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Universidade do Porto, 4485-661, Vairão, Portugal
| | - Ivo Dos Santos
- University of Coimbra, MARE - Marine and Environmental Sciences Centre, Department of Life Sciences, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Cristiana Vieira
- University of Coimbra, MARE - Marine and Environmental Sciences Centre, Department of Life Sciences, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Jorge M Pereira
- University of Coimbra, MARE - Marine and Environmental Sciences Centre, Department of Life Sciences, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal; Environment and Sustainability Institute, University of Exeter, Penryn Campus, Penryn, Cornwall, TR10 9FE, UK
| | - Filipe R Ceia
- University of Coimbra, MARE - Marine and Environmental Sciences Centre, Department of Life Sciences, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Pedro Geraldes
- SPEA - Sociedade Portuguesa para o Estudo das Aves, Av. Columbano Bordalo Pinheiro, 87, 3(o) andar, 1070-062, Lisboa, Portugal
| | - Tommy Melo
- Biosfera Cabo Verde, Rua de Moçambique 28, Mindelo, caixa postal 233, São Vicente, Cape Verde
| | - Vitor H Paiva
- University of Coimbra, MARE - Marine and Environmental Sciences Centre, Department of Life Sciences, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
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11
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Mestre J, Authier M, Cherel Y, Harcourt R, McMahon CR, Hindell MA, Charrassin JB, Guinet C. Decadal changes in blood δ 13C values, at-sea distribution, and weaning mass of southern elephant seals from Kerguelen Islands. Proc Biol Sci 2020; 287:20201544. [PMID: 32811318 PMCID: PMC7482287 DOI: 10.1098/rspb.2020.1544] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 07/27/2020] [Indexed: 11/12/2022] Open
Abstract
Changes in the foraging environment and at-sea distribution of southern elephant seals from Kerguelen Islands were investigated over a decade (2004-2018) using tracking, weaning mass, and blood δ13C values. Females showed either a sub-Antarctic or an Antarctic foraging strategy, and no significant shift in their at-sea distribution was detected between 2004 and 2017. The proportion of females foraging in sub-Antarctic versus Antarctic habitats did not change over the 2006-2018 period. Pup weaning mass varied according to the foraging habitat of their mothers. The weaning mass of sub-Antarctic foraging mothers' pups decreased by 11.7 kg over the study period, but they were on average 5.8 kg heavier than pups from Antarctic foraging mothers. Pup blood δ13C values decreased by 1.1‰ over the study period regardless of their sex and the presumed foraging habitat of their mothers. Together, these results suggest an ecological change is occurring within the Indian sector of the Southern Ocean with possible consequences on the foraging performance of southern elephant seals. We hypothesize that this shift in δ13C is related to a change in primary production and/or in the composition of phytoplankton communities, but this requires further multidisciplinary investigations.
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Affiliation(s)
- Julie Mestre
- Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 du CNRS-La Rochelle Université, 79360 Villiers-en-Bois, France
- Sorbonne Université, Collège Doctoral, F-75005 Paris, France
| | - Matthieu Authier
- Observatoire PELAGIS, UMS 3462 La Rochelle Université and CNRS, La Rochelle, France
- ADERA, Pessac Cedex, France
| | - Yves Cherel
- Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 du CNRS-La Rochelle Université, 79360 Villiers-en-Bois, France
| | - Rob Harcourt
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, Australia
| | - Clive R. McMahon
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, Australia
- IMOS Animal Tagging, Sydney Institute of Marine Science, Sydney, NSW, Australia
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS, Australia
| | - Mark A. Hindell
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS, Australia
| | | | - Christophe Guinet
- Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 du CNRS-La Rochelle Université, 79360 Villiers-en-Bois, France
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12
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Cavallo C, Chiaradia A, Deagle BE, Hays GC, Jarman S, McInnes JC, Ropert‐Coudert Y, Sánchez S, Reina RD. Quantifying prey availability using the foraging plasticity of a marine predator, the little penguin. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13605] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Catherine Cavallo
- School of Biological Sciences Monash University Clayton VIC Australia
| | - André Chiaradia
- School of Biological Sciences Monash University Clayton VIC Australia
- Conservation Department Phillip Island Nature Parks Cowes VIC Australia
| | - Bruce E. Deagle
- Australian Antarctic Division Kingston TAS Australia
- CSIRO National Research Collections‐Australian National Fish Collection Hobart TAS Australia
| | - Graeme C. Hays
- Centre for Integrative Ecology School of Life and Environmental Sciences Deakin University Geelong VIC Australia
| | - Simon Jarman
- School of Biological Sciences University of Western Australia Perth WA Australia
| | - Julie C. McInnes
- Australian Antarctic Division Kingston TAS Australia
- Institute for Marine and Antarctic Studies University of Tasmania Hobart TAS Australia
| | - Yan Ropert‐Coudert
- Centre d'Etudes Biologiques de Chizé UMR7372 CNRSLa Rochelle Université Villiers‐en‐Bois France
| | - Sonia Sánchez
- School of Biological Sciences Monash University Clayton VIC Australia
| | - Richard D. Reina
- School of Biological Sciences Monash University Clayton VIC Australia
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13
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Reynolds SJ, Hughes BJ, Wearn CP, Dickey RC, Brown J, Weber NL, Weber SB, Paiva VH, Ramos JA. Long-term dietary shift and population decline of a pelagic seabird-A health check on the tropical Atlantic? GLOBAL CHANGE BIOLOGY 2019; 25:1383-1394. [PMID: 30712272 DOI: 10.1111/gcb.14560] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 11/23/2018] [Indexed: 06/09/2023]
Abstract
In the face of accelerating ecological change to the world's oceans, seabirds are some of the best bio-indicators of marine ecosystem function. However, unravelling ecological changes that pre-date modern monitoring programmes remains challenging. Using stable isotope analysis of feathers and regurgitants collected from sooty terns (Onychoprion fuscatus) nesting at a major Atlantic colony, we reconstructed a long-term dietary time series from 1890 to the present day and show that a significant dietary shift occurred during the second half of the twentieth century coinciding with an apparent population collapse of approximately 84%. After correcting for the "Suess Effect," δ13 C in feathers declined by ~1.5‰ and δ15 N by ~2‰ between the 1890s and the present day, indicating that birds changed their diets markedly over the period of population decline. Isotopic niches were equally wide before and after the population collapse but isotopic mixing models suggest that birds have grown ever more reliant on nutrient-poor squid and invertebrates as teleost fish have declined in availability. Given that sooty terns rely heavily on associations with sub-surface predators such as tuna to catch fish prey, the rapid expansion of industrialized fisheries for these species over the same period seems a plausible mechanism. Our results suggest that changes to marine ecosystems over the past 60 years have had a dramatic impact on the ecology of the most abundant seabird of tropical oceans, and highlight the potentially pervasive consequences of large predatory fish depletion on marine ecosystem function.
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Affiliation(s)
- S James Reynolds
- Centre for Ornithology, School of Biosciences, College of Life & Environmental Sciences, The University of Birmingham, Edgbaston, Birmingham, UK
- The Army Ornithological Society (AOS), c/o Prince Consort Library, Aldershot, Hampshire, UK
| | - B John Hughes
- Centre for Ornithology, School of Biosciences, College of Life & Environmental Sciences, The University of Birmingham, Edgbaston, Birmingham, UK
- The Army Ornithological Society (AOS), c/o Prince Consort Library, Aldershot, Hampshire, UK
| | - Colin P Wearn
- The Royal Air Force Ornithological Society (RAFOS), High Wycombe, Buckinghamshire, UK
| | - Roger C Dickey
- The Army Ornithological Society (AOS), c/o Prince Consort Library, Aldershot, Hampshire, UK
| | - Judith Brown
- Ascension Island Government Conservation and Fisheries Department (AIGCFD), Georgetown, Ascension Island
| | - Nicola L Weber
- Ascension Island Government Conservation and Fisheries Department (AIGCFD), Georgetown, Ascension Island
- Centre for Ecology and Conservation, Biosciences, College of Life and Environmental Sciences, University of Exeter, Penryn, Cornwall, UK
| | - Sam B Weber
- Ascension Island Government Conservation and Fisheries Department (AIGCFD), Georgetown, Ascension Island
- Centre for Ecology and Conservation, Biosciences, College of Life and Environmental Sciences, University of Exeter, Penryn, Cornwall, UK
| | - Vitor H Paiva
- Department of Life Sciences, MARE, Marine and Environmental Sciences Centre, University of Coimbra, Coimbra, Portugal
| | - Jaime A Ramos
- Department of Life Sciences, MARE, Marine and Environmental Sciences Centre, University of Coimbra, Coimbra, Portugal
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14
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Rodríguez A, Ramírez F, Carrasco MN, Chiaradia A. Seabird plastic ingestion differs among collection methods: Examples from the short-tailed shearwater. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 243:1750-1757. [PMID: 30408862 DOI: 10.1016/j.envpol.2018.09.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 09/02/2018] [Accepted: 09/02/2018] [Indexed: 05/10/2023]
Abstract
Despite the increase of literature on seabird plastic ingestion in recent years, few studies have assessed how plastic loads vary according to different sampling methods. Most studies use necropsies of seabirds with a natural cause of death, e.g. beached or predated, to determine plastic loads and monitor marine debris. Sampling naturally dead seabirds may be biased as they have perished because of their intrinsic factors, e.g. poor body condition, high parasite loads, sickness or predation, affecting estimates of plastic loads. However, seabirds killed accidentally may be more representative of the population. Here, we used the short-tailed shearwater Ardenna tenuirostris to test different sampling methods: naturally beached fledglings and accidentally road-killed fledglings after being attracted and grounded by artificial lights. We compared plastic load, body condition, and feeding strategies (through using feathers' δ13C and δ15N isotope niche) between beached and road-killed fledglings. Beached birds showed higher plastic loads, poorer body condition and reduced isotopic variability, suggesting that this group is not a representative subsample of the whole cohort of the fledgling population. Our results might have implications for long-term monitoring programs of seabird plastic ingestion. Monitoring plastic debris through beached birds could overestimate plastic ingestion by the entire population. We encourage the establishment of refined monitoring programs using fledglings grounded by light pollution if available. These samples focus on known cohorts from the same population. The fledgling plastic loads are transferred from parents during parental feeding, accumulating during the chick-rearing period. Thus, these fledglings provide a higher and valuable temporal resolution, which is more useful and informative than unknown life history of beached birds.
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Affiliation(s)
- Airam Rodríguez
- Conservation Department, Phillip Island Nature Parks, P.O. Box 97, Cowes, 3922, Victoria, Australia; Department of Evolutionary Ecology, Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas, Avda. Américo Vespucio 26, 41092, Seville, Spain; Canary Islands' Ornithology and Natural History Group (GOHNIC), La Malecita s/n, 38480 Buenavista del Norte, Tenerife, Canary Islands, Spain.
| | - Francisco Ramírez
- Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Universitat de Barcelona, Facultat de Biologia, Avda. Diagonal 643, Barcelona, Spain
| | - M Nazaret Carrasco
- Canary Islands' Ornithology and Natural History Group (GOHNIC), La Malecita s/n, 38480 Buenavista del Norte, Tenerife, Canary Islands, Spain
| | - André Chiaradia
- Conservation Department, Phillip Island Nature Parks, P.O. Box 97, Cowes, 3922, Victoria, Australia
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15
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Lesser kestrel diet and agricultural intensification in the Mediterranean: An unexpected win-win solution? J Nat Conserv 2018. [DOI: 10.1016/j.jnc.2018.08.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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16
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Finger A, Lavers JL, Dann P, Kowalczyk ND, Scarpaci C, Nugegoda D, Orbell JD. Metals and metalloids in Little Penguin (Eudyptula minor) prey, blood and faeces. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 223:567-574. [PMID: 28159398 DOI: 10.1016/j.envpol.2017.01.059] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Revised: 01/11/2017] [Accepted: 01/19/2017] [Indexed: 06/06/2023]
Abstract
Piscivorous species like the Little Penguin (Eudyptula minor) are particularly at risk of being negatively impacted by pollution due to their heightened exposure through aquatic food chains. Therefore, determining the concentration of heavy metals in the fish prey of seabirds is an essential component of assessing such risk. In this study, we report on arsenic, cadmium, mercury, lead and selenium concentrations in three fish species, which are known to comprise a substantial part of the diet of Little Penguins at the urban colony of St Kilda, Melbourne, Australia. Metal concentrations in the fish sampled were generally within the expected limits, however, arsenic and mercury were higher than reported elsewhere. Anchovy (Engraulis australis) and sandy sprat (Hyperlophus vittatus) contained higher Hg concentrations than pilchard (Sardinops sagax), while sandy sprat and pilchard contained more selenium. We present these findings together with metal concentrations in Little Penguin blood and faeces, sampled within weeks of the fish collection. Mercury concentrations were highest in the blood, while faeces and fish prey species contained similar concentrations of arsenic and lead, suggesting faeces as a primary route of detoxification for these elements. We also investigated paired blood - faecal samples and found a correlation for selenium only. Preliminary data from stable isotope ratios in penguin blood indicate that changes in penguin blood mercury concentrations cannot be explained by trophic changes in their diet alone, suggesting a variation of bioavailable Hg within this semi-enclosed bay.
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Affiliation(s)
- Annett Finger
- Institute for Sustainability & Innovation, College of Engineering and Science, Victoria University, PO Box 14428, Melbourne, Victoria 8001, Australia.
| | - Jennifer L Lavers
- Institute for Marine and Antarctic Studies, 20 Castray Esplanade, Battery Point, Tasmania 7004, Australia
| | - Peter Dann
- Research Department, Phillip Island Nature Parks, PO Box 97, Cowes, Victoria 3922, Australia
| | - Nicole D Kowalczyk
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Carol Scarpaci
- Institute for Sustainability & Innovation, College of Engineering and Science, Victoria University, PO Box 14428, Melbourne, Victoria 8001, Australia
| | - Dayanthi Nugegoda
- RMIT University, School of Science, GPO Box 2476, Melbourne, Victoria, Australia
| | - John D Orbell
- Institute for Sustainability & Innovation, College of Engineering and Science, Victoria University, PO Box 14428, Melbourne, Victoria 8001, Australia
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17
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Finger A, Lavers JL, Orbell JD, Dann P, Nugegoda D, Scarpaci C. Seasonal variation and annual trends of metals and metalloids in the blood of the Little Penguin (Eudyptula minor). MARINE POLLUTION BULLETIN 2016; 110:261-273. [PMID: 27329818 DOI: 10.1016/j.marpolbul.2016.06.055] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 06/09/2016] [Accepted: 06/13/2016] [Indexed: 06/06/2023]
Abstract
Little Penguins (Eudyptula minor) are high-trophic coastal feeders and are effective indicators of bioavailable pollutants in their foraging zones. Here, we present concentrations of metals and metalloids in blood of 157 Little Penguins, collected over three years and during three distinct seasons (breeding, moulting and non-breeding) at two locations: the urban St Kilda colony and the semi-rural colony at Phillip Island, Victoria, Australia. Penguin metal concentrations were foremostly influenced by location (St Kilda>Phillip Island for non-essential elements) and differed among years and seasons at both locations, reflecting differences in seasonal metal bioaccumulation or seasonal exposure through prey. Mean blood mercury concentrations showed an increasing annual trend and a negative correlation with flipper length at St Kilda. Notably, this study is the first to report on blood metal concentrations during the different stages of moult, showing the mechanism of non-essential metal mobilisation and detoxification.
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Affiliation(s)
- Annett Finger
- Institute for Sustainability & Innovation, College of Engineering & Science, Victoria University, Hoppers Crossing, Werribee, Victoria 3030, Australia.
| | - Jennifer L Lavers
- Institute for Marine and Antarctic Studies, 20 Castray Esplanade, Battery Point, Tasmania 7004, Australia
| | - John D Orbell
- Institute for Sustainability & Innovation, College of Engineering & Science, Victoria University, Hoppers Crossing, Werribee, Victoria 3030, Australia
| | - Peter Dann
- Research Department, Phillip Island Nature Parks, PO Box 97, Cowes, Victoria 3922, Australia
| | - Dayanthi Nugegoda
- RMIT University, School of Applied Science, GPO Box 2476, Melbourne, Victoria, Australia
| | - Carol Scarpaci
- Institute for Sustainability & Innovation, College of Engineering & Science, Victoria University, Hoppers Crossing, Werribee, Victoria 3030, Australia
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18
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Dehnhard N, Eens M, Sturaro N, Lepoint G, Demongin L, Quillfeldt P, Poisbleau M. Is individual consistency in body mass and reproductive decisions linked to individual specialization in foraging behavior in a long-lived seabird? Ecol Evol 2016; 6:4488-501. [PMID: 27386091 PMCID: PMC4930996 DOI: 10.1002/ece3.2213] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 04/25/2016] [Accepted: 05/11/2016] [Indexed: 01/02/2023] Open
Abstract
Individual specialization in diet or foraging behavior within apparently generalist populations has been described for many species, especially in polar and temperate marine environments, where resource distribution is relatively predictable. It is unclear, however, whether and how increased environmental variability – and thus reduced predictability of resources – due to global climate change will affect individual specialization. We determined the within‐ and among‐individual components of the trophic niche and the within‐individual repeatability of δ13C and δ15N in feathers and red blood cells of individual female southern rockhopper penguins (Eudyptes chrysocome) across 7 years. We also investigated the effect of environmental variables (Southern Annular Mode, Southern Oscillation Index, and local sea surface temperature anomaly) on the isotopic values, as well as the link between stable isotopes and female body mass, clutch initiation dates, and total clutch mass. We observed consistent red blood cell δ13C and δ15N values within individuals among years, suggesting a moderate degree of within‐individual specialization in C and N during the prebreeding period. However, the total niche width was reduced and individual specialization not present during the premolt period. Despite significant interannual differences in isotope values of C and N and environmental conditions, none of the environmental variables were linked to stable isotope values and thus able to explain phenotypic plasticity. Furthermore, neither the within‐individual nor among‐individual effects of stable isotopes were found to be related to female body mass, clutch initiation date, or total clutch mass. In conclusion, our results emphasize that the degree of specialization within generalist populations can vary over the course of 1 year, even when being consistent within the same season across years. We were unable to confirm that environmental variability counteracts individual specialization in foraging behavior, as phenotypic plasticity in δ13C and δ15N was not linked to any of the environmental variables studied.
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Affiliation(s)
- Nina Dehnhard
- Department Biology - Behavioural Ecology & Ecophysiology Group University of Antwerp Campus Drie Eiken, Universiteitsplein 12610 Antwerp (Wilrijk) Belgium; Department of Migration and Immuno-Ecology Max Planck Institute for Ornithology Am Obstberg 178315 Radolfzell Germany; Department of Biology University of Konstanz 78457 Konstanz Germany
| | - Marcel Eens
- Department Biology - Behavioural Ecology & Ecophysiology Group University of Antwerp Campus Drie Eiken, Universiteitsplein 1 2610 Antwerp (Wilrijk) Belgium
| | - Nicolas Sturaro
- Laboratory of Oceanology MARE Centre University of Liège B6C, Sart Tilman 4000 Liège Belgium
| | - Gilles Lepoint
- Laboratory of Oceanology MARE Centre University of Liège B6C, Sart Tilman 4000 Liège Belgium
| | - Laurent Demongin
- Department Biology - Behavioural Ecology & Ecophysiology Group University of Antwerp Campus Drie Eiken, Universiteitsplein 12610 Antwerp (Wilrijk) Belgium; Department of Migration and Immuno-Ecology Max Planck Institute for Ornithology Am Obstberg 178315 Radolfzell Germany; Department of Biology University of Konstanz 78457 Konstanz Germany
| | - Petra Quillfeldt
- Department of Migration and Immuno-Ecology Max Planck Institute for Ornithology Am Obstberg 178315 Radolfzell Germany; Department of Biology University of Konstanz 78457 Konstanz Germany; Department of Animal Ecology & Systematics Justus-Liebig University Gießen Heinrich-Buff-Ring 38D-35392 Gießen Germany
| | - Maud Poisbleau
- Department Biology - Behavioural Ecology & Ecophysiology Group University of Antwerp Campus Drie Eiken, Universiteitsplein 12610 Antwerp (Wilrijk) Belgium; Department of Migration and Immuno-Ecology Max Planck Institute for Ornithology Am Obstberg 178315 Radolfzell Germany; Department of Biology University of Konstanz 78457 Konstanz Germany
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19
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Warry FY, Reich P, Cook PLM, Mac Nally R, Thomson JR, Woodland RJ. Nitrogen loads influence trophic organization of estuarine fish assemblages. Funct Ecol 2016. [DOI: 10.1111/1365-2435.12647] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Fiona Y. Warry
- Water Studies Centre School of Chemistry Monash University Clayton VIC 3800 Australia
- Department of Environment, Land, Water and Planning Arthur Rylah Institute for Environmental Research Heidelberg VIC 3084 Australia
| | - Paul Reich
- Water Studies Centre School of Chemistry Monash University Clayton VIC 3800 Australia
- Department of Environment, Land, Water and Planning Arthur Rylah Institute for Environmental Research Heidelberg VIC 3084 Australia
| | - Perran L. M. Cook
- Water Studies Centre School of Chemistry Monash University Clayton VIC 3800 Australia
| | - Ralph Mac Nally
- Institute for Applied Ecology The University of Canberra Bruce ACT 2617 Australia
| | - James R. Thomson
- Department of Environment, Land, Water and Planning Arthur Rylah Institute for Environmental Research Heidelberg VIC 3084 Australia
| | - Ryan J. Woodland
- Water Studies Centre School of Chemistry Monash University Clayton VIC 3800 Australia
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20
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Chiaradia A, Ramírez F, Forero MG, Hobson KA. Stable Isotopes (δ13C, δ15N) Combined with Conventional Dietary Approaches Reveal Plasticity in Central-Place Foraging Behavior of Little Penguins Eudyptula minor. Front Ecol Evol 2016. [DOI: 10.3389/fevo.2015.00154] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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21
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Finger A, Lavers JL, Dann P, Nugegoda D, Orbell JD, Robertson B, Scarpaci C. The Little Penguin (Eudyptula minor) as an indicator of coastal trace metal pollution. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2015; 205:365-377. [PMID: 26160534 DOI: 10.1016/j.envpol.2015.06.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 06/02/2015] [Accepted: 06/11/2015] [Indexed: 06/04/2023]
Abstract
Monitoring trace metal and metalloid concentrations in marine animals is important for their conservation and could also reliably reflect pollution levels in their marine ecosystems. Concentrations vary across tissue types, with implications for reliable monitoring. We sampled blood and moulted feathers of the Little Penguin (Eudyptula minor) from three distinct colonies, which are subject to varying levels of anthropogenic impact. Non-essential trace metal and metalloid concentrations in Little Penguins were clearly linked to the level of industrialisation adjacent to the respective foraging zones. This trend was more distinct in blood than in moulted feathers, although we found a clear correlation between blood and feathers for mercury, lead and iron. This study represents the first reported examination of trace metals and metalloids in the blood of any penguin species and demonstrates that this high trophic feeder is an effective bioindicator of coastal pollution.
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Affiliation(s)
- Annett Finger
- Victoria University, Institute for Sustainability & Innovation, Hoppers Crossing, Werribee, Victoria 3030, Australia.
| | - Jennifer L Lavers
- Institute for Marine and Antarctic Studies, 20 Castray Esplanade, Battery Point, Tasmania 7004, Australia
| | - Peter Dann
- Phillip Island Nature Parks, Research Department, PO Box 97, Cowes, Victoria 3922, Australia
| | - Dayanthi Nugegoda
- RMIT University, School of Applied Science, GPO Box 2476, Melbourne, Victoria, Australia
| | - John D Orbell
- Victoria University, Institute for Sustainability & Innovation, Hoppers Crossing, Werribee, Victoria 3030, Australia
| | - Bruce Robertson
- Department of Environmental Management and Ecology, LaTrobe University, Wodonga, Victoria 3689, Australia
| | - Carol Scarpaci
- Victoria University, Institute for Sustainability & Innovation, Hoppers Crossing, Werribee, Victoria 3030, Australia
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22
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Brasso RL, Chiaradia A, Polito MJ, Raya Rey A, Emslie SD. A comprehensive assessment of mercury exposure in penguin populations throughout the Southern Hemisphere: Using trophic calculations to identify sources of population-level variation. MARINE POLLUTION BULLETIN 2015; 97:408-418. [PMID: 26072048 DOI: 10.1016/j.marpolbul.2015.05.059] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 05/19/2015] [Accepted: 05/21/2015] [Indexed: 06/04/2023]
Abstract
The wide geographic distribution of penguins (Order Sphenisciformes) throughout the Southern Hemisphere provided a unique opportunity to use a single taxonomic group as biomonitors of mercury among geographically distinct marine ecosystems. Mercury concentrations were compared among ten species of penguins representing 26 geographically distinct breeding populations. Mercury concentrations were relatively low (⩽2.00ppm) in feathers from 18/26 populations considered. Population-level differences in trophic level explained variation in mercury concentrations among Little, King, and Gentoo penguin populations. However, Southern Rockhopper and Magellanic penguins breeding on Staten Island, Tierra del Fuego, had the highest mercury concentrations relative to their conspecifics despite foraging at a lower trophic level. The concurrent use of stable isotope and mercury data allowed us to document penguin populations at the greatest risk of exposure to harmful concentrations of mercury as a result of foraging at a high trophic level or in geographic 'hot spots' of mercury availability.
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Affiliation(s)
- Rebecka L Brasso
- University of North Carolina at Greensboro, Biology Department, 356 Sullivan Science Building, 321 McIver Street, Greensboro, NC 27402, USA.
| | - André Chiaradia
- Research Department, Phillip Island Nature Park, PO Box 97, Cowes, Victoria 3922, Australia
| | - Michael J Polito
- Department of Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Andrea Raya Rey
- Consejo Nacional de Investigaciones Científicas y Técnicas, Centro Austral de Investigaciones Científicas, Houssay 200, 9410 Ushuaia, Tierra del Fuego, Argentina
| | - Steven D Emslie
- University of North Carolina Wilmington, Department of Biology and Marine Biology, 601 South College Rd, Wilmington, NC 28403, USA
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23
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Environmental variability drives shifts in the foraging behaviour and reproductive success of an inshore seabird. Oecologia 2015; 178:967-79. [PMID: 25894092 DOI: 10.1007/s00442-015-3294-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 03/10/2015] [Indexed: 10/23/2022]
Abstract
Marine animals forage in areas that aggregate prey to maximize their energy intake. However, these foraging 'hot spots' experience environmental variability, which can substantially alter prey availability. To survive and reproduce animals need to modify their foraging in response to these prey shifts. By monitoring their inter-annual foraging behaviours, we can understand which environmental variables affect their foraging efficiency, and can assess how they respond to environmental variability. Here, we monitored the foraging behaviour and isotopic niche of little penguins (Eudyptula minor), over 3 years (2008, 2011, and 2012) of climatic and prey variability within Port Phillip Bay, Australia. During drought (2008), penguins foraged in close proximity to the Yarra River outlet on a predominantly anchovy-based diet. In periods of heavy rainfall, when water depth in the largest tributary into the bay (Yarra River) was high, the total distance travelled, maximum distance travelled, distance to core-range, and size of core- and home-ranges of penguins increased significantly. This larger foraging range was associated with broad dietary diversity and high reproductive success. These results suggest the increased foraging range and dietary diversity of penguins were a means to maximize resource acquisition rather than a strategy to overcome local depletions in prey. Our results demonstrate the significance of the Yarra River in structuring predator-prey interactions in this enclosed bay, as well as the flexible foraging strategies of penguins in response to environmental variability. This plasticity is central to the survival of this small-ranging, resident seabird species.
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24
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Kowalczyk ND, Chiaradia A, Preston TJ, Reina RD. Fine-scale dietary changes between the breeding and non-breeding diet of a resident seabird. ROYAL SOCIETY OPEN SCIENCE 2015; 2:140291. [PMID: 26064628 PMCID: PMC4448858 DOI: 10.1098/rsos.140291] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 03/10/2015] [Indexed: 06/04/2023]
Abstract
Unlike migratory seabirds with wide foraging ranges, resident seabirds forage in a relatively small range year-round and are thus particularly vulnerable to local shifts in prey availability. In order to manage their populations effectively, it is necessary to identify their key prey across and within years. Here, stomach content and stable isotope analyses were used to reconstruct the diet and isotopic niche of the little penguin (Eudyptula minor). Across years, the diet of penguins was dominated by anchovy (Engraulis australis). Within years, during winter, penguins were consistently enriched in δ (15)N and δ (13)C levels relative to pre-moult penguins. This was probably due to their increased reliance on juvenile anchovies, which dominate prey biomass in winter months. Following winter and during breeding, the δ (13)C values of penguins declined. We suggest this subtle shift was in response to the increased consumption of prey that enter the bay from offshore regions to spawn. Our findings highlight that penguins have access to both juvenile fish communities and spawning migrants across the year, enabling these seabirds to remain in close proximity to their colony. However, annual fluctuations in penguin isotopic niche suggest that the recruitment success and abundance of fish communities fluctuate dramatically between years. As such, the continued monitoring of penguin diet will be central to their ongoing management.
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Affiliation(s)
- Nicole D. Kowalczyk
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - André Chiaradia
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
- Research Department, Phillip Island Nature Parks, PO Box 97, Cowes, Victoria 3922, Australia
| | - Tiana J. Preston
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Richard D. Reina
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
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