scholarly journals Fine-scale spatial segregation in a pelagic seabird driven by differential use of tidewater glacier fronts

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Philip Bertrand ◽  
Joël Bêty ◽  
Nigel G. Yoccoz ◽  
Marie-Josée Fortin ◽  
Hallvard Strøm ◽  
...  
Keyword(s):  
Central Place ◽  
Spatial Segregation ◽  
The Arctic ◽  
Fine Scale ◽  
Foraging Patterns ◽  
Marine Bird ◽  
Rissa Tridactyla ◽  
Marine Predators ◽  
Tidewater Glacier ◽  
Pelagic Seabird

AbstractIn colonially breeding marine predators, individual movements and colonial segregation are influenced by seascape characteristics. Tidewater glacier fronts are important features of the Arctic seascape and are often described as foraging hotspots. Albeit their documented importance for wildlife, little is known about their structuring effect on Arctic predator movements and space use. In this study, we tested the hypothesis that tidewater glacier fronts can influence marine bird foraging patterns and drive spatial segregation among adjacent colonies. We analysed movements of black-legged kittiwakes (Rissa tridactyla) in a glacial fjord by tracking breeding individuals from five colonies. Although breeding kittiwakes were observed to travel up to ca. 280 km from the colony, individuals were more likely to use glacier fronts located closer to their colony and rarely used glacier fronts located farther away than 18 km. Such variation in the use of glacier fronts created fine-scale spatial segregation among the four closest (ca. 7 km distance on average) kittiwake colonies. Overall, our results support the hypothesis that spatially predictable foraging patches like glacier fronts can have strong structuring effects on predator movements and can modulate the magnitude of intercolonial spatial segregation in central-place foragers.

scholarly journals Individual-level memory is sufficient to create spatial segregation among neighboring colonies of central-place foragers

2021 ◽  
Author(s):  
Geert Aarts ◽  
Evert Mul ◽  
John Fieberg ◽  
Sophie Brasseur ◽  
Jan A. van Gils ◽  
...  
Keyword(s):  
Central Place ◽  
Spatial Segregation ◽  
Individual Level

scholarly journals Foraging movements are density-independent among straw-coloured fruit bats

2020 ◽  
Vol 7 (5) ◽  
pp. 200274
Author(s):  
María C. Calderón-Capote ◽  
Dina K. N. Dechmann ◽  
Jakob Fahr ◽  
Martin Wikelski ◽  
Roland Kays ◽  
...  
Keyword(s):  
Intraspecific Competition ◽  
Colony Size ◽  
Resource Depletion ◽  
Central Place ◽  
Long Distance ◽  
Foraging Patterns ◽  
Fruit Bat ◽  
Foraging Movements ◽  
Productive Landscapes ◽  
Eidolon Helvum

Intraspecific competition in large aggregations of animals should generate density-dependent effects on foraging patterns. To test how large differences in colony size affect foraging movements, we tracked seasonal movements of the African straw-coloured fruit bat ( Eidolon helvum ) from four colonies that range from 4000 up to 10 million animals. Contrary to initial predictions, we found that mean distance flown per night (9–99 km), number of nightly foraging sites (2–3) and foraging and commuting times were largely independent of colony size. Bats showed classic central-place foraging and typically returned to the same day roost each night. However, roost switching was evident among individuals in three of the four colonies especially towards the onset of migration. The relatively consistent foraging patterns across seasons and colonies indicate that these bats seek out roosts close to highly productive landscapes. Once foraging effort starts to increase due to local resource depletion they migrate to landscapes with seasonally increasing resources. This minimizes high intraspecific competition and may help to explain why long-distance migration, otherwise rare in bats, evolved in this highly gregarious species.

Deep-sea foraging pathways: an analysis of randomness and resource exploitation

Paleobiology ◽  
1979 ◽  
Vol 5 (2) ◽  
pp. 107-125 ◽  
Author(s):  
Jennifer A. Kitchell
Keyword(s):  
Deep Sea ◽  
Trace Fossil ◽  
Empirical Modeling ◽  
The Arctic ◽  
Foraging Strategies ◽  
Foraging Efficiency ◽  
Resource Exploitation ◽  
Foraging Patterns ◽  
Risk Of Predation ◽  
Random Behavior

The foraging paradigm of trace fossil theory has historically accorded random behavior to non-food-limited deposit-feeders and non-random behavior to food-limited feeders. A series of randomness measures derived from empirical modeling, simulation modeling, stochastic modeling and probability theory applied to foraging patterns observed in deep-sea bottom photographs from the Arctic and Antarctic yielded a behavioral continuum of increasing non-randomness. A linear regression of trace positions along the continuum to bathymetric data did not substantiate the optimal foraging efficiency-depth dependence model of trace fossil theory, except that all traces exhibited a greater optimization than that of simulated random foraging. It is hypothesized that optimization as evidenced by non-random foraging strategies represents maximization of the cost/benefit ratio of resource exploitation to risk of predation and that individual foraging patterns reflect an exploration response to the morphometry of a patchily distributed food resource. Differential predation and competition may account for the co-occurrence of random and non-random strategies within the same bathymetric zone.

Spatial segregation between immatures and adults in a pelagic seabird suggests age‐related competition

2019 ◽  
Vol 50 (5) ◽  
Author(s):  
Emeline Pettex ◽  
Charlotte Lambert ◽  
Jérôme Fort ◽  
Ghislain Dorémus ◽  
Vincent Ridoux
Keyword(s):  
Spatial Segregation ◽  
Age Related ◽  
Pelagic Seabird

scholarly journals Fine-scale zooplankton vertical distribution in relation to hydrographic and optical characteristics of the surface waters on the Arctic shelf

2014 ◽  
Vol 37 (1) ◽  
pp. 120-133 ◽  
Author(s):  
Emilia Trudnowska ◽  
Slawomir Sagan ◽  
Slawomir Kwasniewski ◽  
Miroslaw Darecki ◽  
Katarzyna Blachowiak-Samolyk
Keyword(s):  
Vertical Distribution ◽  
Surface Waters ◽  
Optical Characteristics ◽  
Arctic Shelf ◽  
The Arctic ◽  
Fine Scale

scholarly journals Fine-scale whisker growth measurements can reveal temporal foraging patterns from stable isotope signatures

2015 ◽  
Vol 523 ◽  
pp. 243-253 ◽  
Author(s):  
RS Beltran ◽  
M Connolly Sadou ◽  
R Condit ◽  
S Peterson ◽  
C Reichmuth ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Whisker Growth ◽  
Fine Scale ◽  
Foraging Patterns ◽  
Stable Isotope Signatures

scholarly journals Resting costs too: the relative importance of active and resting energy expenditure in a sub-arctic seabird

2022 ◽  
Author(s):  
Fred Tremblay ◽  
Shannon Whelan ◽  
Emily S. Choy ◽  
Scott A. Hatch ◽  
Kyle H. Elliott
Keyword(s):  
Energy Expenditure ◽  
Resting Energy Expenditure ◽  
Central Place ◽  
Average Concentration ◽  
Conservation Strategies ◽  
Energy Costs ◽  
Rissa Tridactyla ◽  
Long Time ◽  
Novel Method ◽  
Resting Energy

Breeding is costly for many animals, including birds that must deliver food to a central place (i.e. nest). Measuring energy expenditure throughout the breeding season can provide valuable insights on physiological limitations by highlighting periods of high demands, and ultimately allows to improve conservation strategies. However, quantifying energy expenditure in wildlife can be challenging, as existing methods do not measure both active (e.g. foraging) and resting energy costs across short and long time scales. Here, we develop a novel method for comparing active and resting costs in 66 pre-breeding and breeding seabirds (black-legged kittiwakes; Rissa tridactyla) by combining accelerometry and triiodothyronine (T3), as proxies for active and resting costs, respectively. Activity energy costs were higher during incubation (p=0.0004) and chick-rearing (p<0.0001) compared to pre-laying, due to an increase in time spent in flight of 11% (p=0.0005) and 15% (p<0.0001), respectively. Levels of T3, reflecting resting costs, peaked marginally during incubation with an average concentration of 4.71±1.97 pg mL−1 in comparison to 2.66±1.30 pg mL−1 in pre-laying (p=0.05), and 3.16±2.85 pg mL−1 in chick-rearing (p=11). Thus, although chick-rearing is often assumed to be the costliest breeding stage by multiple studies, our results suggest that incubation could be more costly due to high resting costs. We highlight the importance of accounting for both active and resting costs when assessing energy expenditure.

scholarly journals Arctic Ocean outflow and glacier–ocean interactions modify water over the Wandel Sea shelf (northeastern Greenland)

Ocean Science ◽  
2017 ◽  
Vol 13 (6) ◽  
pp. 1045-1060 ◽  
Author(s):  
Igor A. Dmitrenko ◽  
Sergey A. Kirillov ◽  
Bert Rudels ◽  
David G. Babb ◽  
Leif Toudal Pedersen ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Continental Slope ◽  
The Arctic ◽  
Ambient Water ◽  
Pacific Water ◽  
The Pacific ◽  
Tidewater Glacier ◽  
The Arctic Ocean ◽  
Water Outflow ◽  
Polar Water

Abstract. The first-ever conductivity–temperature–depth (CTD) observations on the Wandel Sea shelf in northeastern Greenland were collected in April–May 2015. They were complemented by CTDs taken along the continental slope during the Norwegian FRAM 2014–2015 drift. The CTD profiles are used to reveal the origin of water masses and interactions with ambient water from the continental slope and the tidewater glacier outlet. The subsurface water is associated with the Pacific water outflow from the Arctic Ocean. The underlying halocline separates the Pacific water from a deeper layer of polar water that has interacted with the warm Atlantic water outflow through the Fram Strait, recorded below 140 m. Over the outer shelf, the halocline shows numerous cold density-compensated intrusions indicating lateral interaction with an ambient polar water mass across the continental slope. At the front of the tidewater glacier outlet, colder and turbid water intrusions were observed at the base of the halocline. On the temperature–salinity plots these stations indicate a mixing line that is different from the ambient water and seems to be conditioned by the ocean–glacier interaction. Our observations of Pacific water are set within the context of upstream observations in the Beaufort Sea and downstream observations from the Northeast Water Polynya, and clearly show the modification of Pacific water during its advection across the Arctic Ocean. Moreover, ambient water over the Wandel Sea slope shows different thermohaline structures indicating the different origin and pathways of the on-shore and off-shore branches of the Arctic Ocean outflow through the western Fram Strait.

scholarly journals Fine-scale gas distribution in marine sediments assessed from deep-towed seismic data

2014 ◽  
Vol 196 (3) ◽  
pp. 1466-1470 ◽  
Author(s):  
S. Ker ◽  
Y. Le Gonidec ◽  
B. Marsset ◽  
G. K. Westbrook ◽  
D. Gibert ◽  
...  
Keyword(s):  
High Resolution ◽  
Seismic Data ◽  
The Arctic ◽  
Bright Spot ◽  
Fine Scale ◽  
Wavelet Domain ◽  
Gas Distribution ◽  
Reverse Polarity ◽  
Western Margin ◽  
Normal Polarity

Abstract In the context of seismic imaging of gas/gas-hydrate systems, the fine-scale structure of subseabed gas-related reflections is assessed by taking advantage of the source signature of the deep-towed high-resolution SYSIF seismic device. We demonstrate the value of an original wavelet-based method and associated multiscale seismic attributes, applied to seismic data recently acquired on the western margin of the Arctic archipelago of Svalbard. From analysis in the wavelet domain, we recognize two types of gas-related reflections associated with submetre-scale distribution of gas. We identify a thin gas-charged layer associated with an apparent normal polarity reflection, and we detect gas patches associated with a reverse-polarity bright spot with frequency-dependent elastic properties at small seismic wavelengths. The results provide valuable information on the scale of features through which gas migrates and resolve ambiguities in the interpretation of the seismic data.

scholarly journals To breed or not to breed: endocrine response to mercury contamination by an Arctic seabird

2013 ◽  
Vol 9 (4) ◽  
pp. 20130317 ◽  
Author(s):  
Sabrina Tartu ◽  
Aurélie Goutte ◽  
Paco Bustamante ◽  
Frédéric Angelier ◽  
Børge Moe ◽  
...  
Keyword(s):  
Mercury Concentration ◽  
Sex Steroids ◽  
Reproductive Effort ◽  
Environmental Changes ◽  
Endocrine System ◽  
Mercury Contamination ◽  
The Arctic ◽  
Endocrine Response ◽  
Rissa Tridactyla ◽  
High Mercury

Mercury, a ubiquitous toxic element, is known to alter expression of sex steroids and to impair reproduction across vertebrates but the mechanisms underlying these effects are not clearly identified. We examined whether contamination by mercury predicts the probability to skip reproduction in black-legged kittiwakes ( Rissa tridactyla ) from Svalbard. We also manipulated the endocrine system to investigate the mechanism underlying this relationship. During the pre-laying period, we injected exogenous GnRH (gonadotropin-releasing hormone) to test the ability of the pituitary to release luteinizing hormone (LH, a key hormone for the release of sex steroids and hence breeding) in relation to mercury burden. Birds that skipped reproduction had significantly higher mercury concentration in blood than breeders. Endocrine profiles of these birds also varied based on breeding status (breeders versus non-breeders), mercury contamination and sex. Specifically, in skippers (birds that did not breed), baseline LH decreased with increasing mercury concentration in males, whereas it increased in females. GnRH-induced LH levels increased with increasing mercury concentration in both sexes. These results suggest that mercury contamination may disrupt GnRH input to the pituitary. Thus, high mercury concentration could affect the ability of long-lived birds to modulate their reproductive effort (skipping or breeding) according to ongoing environmental changes in the Arctic, thereby impacting population dynamics.

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