Inter-annual variation in the trophic niche of Magellanic penguins Spheniscus magellanicus during the pre-molt period in the Beagle Channel

2020 ◽  
Vol 655 ◽  
pp. 215-225
Author(s):  
S Dodino ◽  
L Riccialdelli ◽  
MJ Polito ◽  
K Pütz ◽  
A Raya Rey
Keyword(s):  
Diet Composition ◽  
Annual Variation ◽  
Isotope Analysis ◽  
Trophic Niche ◽  
Carbon And Nitrogen ◽  
Spheniscus Magellanicus ◽  
Beagle Channel ◽  
Annual Variations ◽  
Magellanic Penguins ◽  
Key Species

Inter-annual variations in the diets of seabirds are often a reflection of resource availability, with population dynamics and community structure implications. We investigated the trophic niche of Magellanic penguins Spheniscus magellanicus during the pre-molt stage in 6 years (2009 and 2013-2017) at Martillo Island, Beagle Channel, Argentina, using carbon and nitrogen stable isotope analysis of feathers. We found higher values in 2009 compared to the other years for both isotopes and estimated different proportions of prey in the diet of Magellanic penguins throughout the years. In 2009, penguins consumed mainly a mixture of benthic and benthopelagic fish, whereas from 2013 to 2017, the proportion of the pelagic form of squat lobster Munida gregaria, considered a key species in the Beagle Channel, increased over time and nearly dominated diets in 2017. Our results confirm that Magellanic penguins act as sentinels, reflecting shifts in the marine community of the Beagle Channel via inter-annual variation in their trophic niche and diet composition.

scholarly journals Sex-specific spatial use of the winter foraging areas by Magellanic penguins and assessment of potential conflicts with fisheries during winter dispersal

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256339
Author(s):  
Samanta Dodino ◽  
Nicolás A. Lois ◽  
Luciana Riccialdelli ◽  
Michael J. Polito ◽  
Klemens Pütz ◽  
...  
Keyword(s):  
Trophic Position ◽  
Isotope Analysis ◽  
Trophic Niche ◽  
Bottom Trawl ◽  
Winter Period ◽  
Shrimp Fishery ◽  
Trawl Fishery ◽  
Magellanic Penguins ◽  
Winter Foraging ◽  
Spatial Use

Magellanic penguins (Spheniscus magellanicus) disperse widely during winter and are a major consumer of marine resources over the Patagonian Shelf. Magellanic penguins were equipped with geolocators at Martillo Island in late February- early March 2017 and recaptured at the beginning of the next breeding season to recover the devices and to collect blood samples for stable carbon (δ13C) and nitrogen (δ15N) isotope analysis. We evaluated their whole winter dispersal and their trophic niche by sex during the last month of the winter dispersal. Also, we evaluated their spatial overlap with bottom trawl and shrimp fisheries using data from satellite fisheries monitoring. Penguins dispersed northwards up to 42°S and showed latitudinal spatial segregation between sexes during May to August (females were located further north than males). In contrast, during the last month of the winter dispersal females were located more southerly and showed lower trophic position than males. Also, females did not dive as deep as males during winter. We found high overlap between both fisheries and penguin’s spatial use in regions with documented interaction. However, no sex-specific statistical differences with fisheries overlap were found. Our results highlight the importance of understanding the spatial domains of each sex and assessment of their potential conflicts with bottom trawl fishery and shrimp fishery during the winter period.

scholarly journals Trophic niche partitioning in marine wood-borers revealed by stable isotope analysis

2020 ◽  
Vol 29 ◽  
pp. 33-43
Author(s):  
F Charles ◽  
P Riera ◽  
PG Sauriau ◽  
F Lantoine ◽  
B Lebreton ◽  
...  
Keyword(s):  
Isotope Analysis ◽  
Niche Partitioning ◽  
Nitrogen Sources ◽  
Nitrogen Isotope ◽  
Trophic Niche ◽  
Carbon And Nitrogen ◽  
Decaying Wood ◽  
The Impact ◽  
Wood Boring ◽  
Trophic Niches

Marine wood-borers often live in sympatry, sharing deadwood scattered at sea, both as food and habitat. In this study, carbon and nitrogen isotope compositions were determined to test the hypothesis that the trophic niches of Chelura terebrans, Limnoria quadripunctata, and Nototeredo norvagica obtained from softwood boards maintained in running, unfiltered seawater are different. Comparison of isotope compositions supports niche partitioning, with N. norvagica foraging primarily on wood, and crustaceans foraging on decaying wood. Needs and acquisition routes for nitrogen determine the trophic behavior of the species. Results presented here are valuable for assessing the impact of wood-boring species on each other, but also for evaluating the effect of the separation of carbon and nitrogen sources on the diversity of the interactions between co-existing species belonging to the same trophic guild.

The sensitivity of Neotoma to climate change and biodiversity loss over the late Quaternary

2021 ◽  
pp. 1-15
Author(s):  
Catalina P. Tomé ◽  
S. Kathleen Lyons ◽  
Seth D. Newsome ◽  
Felisa A. Smith
Keyword(s):  
Body Size ◽  
Late Quaternary ◽  
Climatic Variability ◽  
Isotope Analysis ◽  
Biodiversity Loss ◽  
Bone Collagen ◽  
Cam Plants ◽  
The Holocene ◽  
Carbon And Nitrogen ◽  
Terminal Pleistocene

Abstract The late Quaternary in North America was marked by highly variable climate and considerable biodiversity loss including a megafaunal extinction event at the terminal Pleistocene. Here, we focus on changes in body size and diet in Neotoma (woodrats) in response to these ecological perturbations using the fossil record from the Edwards Plateau (Texas) across the past 20,000 years. Body mass was estimated using measurements of fossil teeth and diet was quantified using stable isotope analysis of carbon and nitrogen from fossil bone collagen. Prior to ca. 7000 cal yr BP, maximum mass was positively correlated to precipitation and negatively correlated to temperature. Independently, mass was negatively correlated to community composition, becoming more similar to modern over time. Neotoma diet in the Pleistocene was primarily sourced from C3 plants, but became progressively more reliant on C4 (and potentially CAM) plants through the Holocene. Decreasing population mass and higher C4/CAM consumption was associated with a transition from a mesic to xeric landscape. Our results suggest that Neotoma responded to climatic variability during the terminal Pleistocene through changes in body size, while changes in resource availability during the Holocene likely led to shifts in the relative abundance of different Neotoma species in the community.

scholarly journals Assessment of trophic relationships between symbiotic tropical ophiuroids using C and N stable isotope analysis

2006 ◽  
Vol 86 (6) ◽  
pp. 1443-1447 ◽  
Author(s):  
D. Fourgon ◽  
G. Lepoint ◽  
I. Eeckhaut
Keyword(s):  
Stable Isotopes ◽  
Potential Benefit ◽  
Feeding Habits ◽  
Isotope Analysis ◽  
Tracer Experiment ◽  
Trophic Relationships ◽  
Nitrogen Stable Isotopes ◽  
Carbon And Nitrogen ◽  
C And N ◽  
The One

Analyses of the natural abundance of carbon and nitrogen stable isotopes were performed to investigate the feeding habits of two ophiuroids, Ophiomastix venosa and Ophiocoma scolopendrina, and to assess the potential benefit obtained by the symbiotic Ophiomastix venosa juveniles. A tracer experiment was also carried out to clarify the contribution of algae to the nitrogen uptake amongst the tested ophiuroids. Our results suggest that Ophiocoma scolopendrina adults occupy a higher position in the food web than Ophiomastix venosa and mainly feed on neuston. In contrast, O. venosa adults feed on the alga Sargassum densifolium and on organic matter associated with sediment. Free juveniles and symbiotic juveniles of O. venosa have intermediate δ13C values between both adult species. The high proportion of 13C in the symbiotic juveniles compared to the one in their conspecific adults indicates that their diet slightly differs from the latter and is closer to that of Ophiocoma scolopendrina. This raises the hypothesis that symbiotic juveniles steal neuston from their associated host, O. scolopendrina.

Health state and reproductive output in Magellanic penguins (Spheniscus magellanicus)

2002 ◽  
Vol 14 (1) ◽  
pp. 19-28 ◽  
Author(s):  
J. Moreno ◽  
P. Yorio ◽  
P. Garcia-Borboroglu ◽  
J. Potti ◽  
S. Villar
Keyword(s):  
Reproductive Output ◽  
Health State ◽  
Spheniscus Magellanicus ◽  
Magellanic Penguins

scholarly journals Occurrence of gastrointestinal parasites in Spheniscus magellanicus (Foster, 1781) located in Pontal do Sul, PR, Brazil

2018 ◽  
Vol 70 (2) ◽  
pp. 491-496
Author(s):  
M.S. Vanhoni ◽  
G.M. Arná ◽  
L.K. Sprenger ◽  
D.L. Vieira ◽  
L.W. Luis ◽  
...  
Keyword(s):  
Gastrointestinal Parasites ◽  
High Rate ◽  
Infected Bird ◽  
Brazilian Coast ◽  
Marine Animals ◽  
Spheniscus Magellanicus ◽  
Control Programs ◽  
Magellanic Penguins ◽  
Rehabilitation Centers ◽  
South Of Brazil

ABSTRACT Gastrointestinal parasitism is the main health problem faced by Spheniscus magellanicus, known as Magellanic penguins, in route on the Brazilian coast. The aim of this research was to report the occurrence and intensity of gastrointestinal parasites in S. magellanicus that reached Pontal do Sul, Paraná, South of Brazil. The study was performed at the Marine Study Center of the Federal University of Parana (CEM-UFPR) with 38 specimens, 31 were necropsied and seven were examined alive with coproparasitological exams. From the necropsied animals, 93.5% (29/31) were parasitized with at least one parasite species. Contracaecum pelagicum was the most prevalent 93,5% (29/31) parasite, followed by Cardiocephaloides physalis (64.5%) and Tetrabothrius lutzi (51.6%). Only one animal was free of parasites and the most infected bird had 1.076 parasites with an average of 194 worms. Willis-Mollay method revealed that 57.1% (4/7) had C. pelagicum eggs. In conclusion, the high rate of gastrointestinal parasites in S. magellanicus confirms the clinical exams, when animals had poor health conditions when they were found in the cost of Paraná. This study provides data to enrich the literature regarding the helminth fauna of the Magellanic penguins, assisting sanitary control programs in Rehabilitation Centers for Marine Animals.

scholarly journals Subcolony Variation in Breeding Success in the Tufted Puffin (Fratercula Cirrhata): Association With Foraging Ecology and Implications

The Auk ◽  
2007 ◽  
Vol 124 (4) ◽  
pp. 1149-1157
Author(s):  
J. Mark Hipfner ◽  
Mathieu R. Charette ◽  
Gwylim S. Blackburn
Keyword(s):  
Stable Isotope ◽  
Breeding Success ◽  
Large Scale ◽  
Foraging Ecology ◽  
Isotope Analysis ◽  
Egg Yolk ◽  
Foraging Strategies ◽  
Small Scale ◽  
Carbon And Nitrogen ◽  
Tufted Puffin

Abstract Large-scale oceanographic processes are the main drivers of seabird breeding success, but small-scale processes, though not as well understood, can also be important. We compared the success of Tufted Puffins (Fratercula cirrhata) breeding at two subcolonies only 1.5 km apart on Triangle Island, British Columbia, Canada, 2002–2005. In addition, we used stable-isotope analysis to test the hypothesis that parental foraging strategies differed between the two subcolonies, potentially underlying the variation in breeding success. Success was concordant across years at the two sites but, overall, Tufted Puffins bred more successfully at Strata Rock than at Puffin Rock. They raised chicks in all four years at Strata Rock, but in only three years at Puffin Rock; in two of those three years, Strata Rock chicks were, on average, 60 g and 100 g heavier than Puffin Rock chicks just before fledging. Discriminant analysis of carbon and nitrogen stable-isotope ratios in egg yolk and chick blood in 2004 and 2005 indicated that parental foraging differed between the two subcolonies, with both spatial (δ13C) and trophic-level (δ15N) differences involved. Thus, our study demonstrates the existence of foraging asymmetries in a pelagic seabird at a small spatial scale (between subcolonies), complementing patterns found at larger scales (between colonies). Moreover, the foraging asymmetries were associated with inequalities in fitness measures. We conclude that small-scale processes—in this case, systematic differences in the foraging ecology of local groups—can interact with large-scale oceanographic processes to determine seabird breeding success. Variation sous-coloniale du succès de reproduction de Fratercula cirrhata: Association avec l'écologie de la quête alimentaire et implications

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