Can variations in the spatial distribution at sea and isotopic niche width be associated with consistency in the isotopic niche of a pelagic seabird species?

2014 ◽  
Vol 161 (8) ◽  
pp. 1861-1872 ◽  
Author(s):  
Filipe R. Ceia ◽  
Vitor H. Paiva ◽  
Stefan Garthe ◽  
João C. Marques ◽  
Jaime A. Ramos
Keyword(s):  
Spatial Distribution ◽  
Niche Width ◽  
Isotopic Niche ◽  
Seabird Species ◽  
Pelagic Seabird ◽  
Isotopic Niche Width

Size‐based differences in isotopic niche width (δ 13 C and δ 15 N) of green turtles ( Chelonia mydas ) nesting on Príncipe Island, Gulf of Guinea

2021 ◽  
Vol 42 (1) ◽  
Author(s):  
Rogério L. Ferreira ◽  
Filipe R. Ceia ◽  
Teresa C. Borges ◽  
Jaime A. Ramos ◽  
Alan B. Bolten
Keyword(s):  
Chelonia Mydas ◽  
Niche Width ◽  
Isotopic Niche ◽  
Gulf Of Guinea ◽  
Green Turtles ◽  
Isotopic Niche Width

The effects of spatial scale and isoscape on consumer isotopic niche width

2018 ◽  
Vol 32 (4) ◽  
pp. 904-915 ◽  
Author(s):  
Carl J. Reddin ◽  
John H. Bothwell ◽  
Nessa E. O'Connor ◽  
Chris Harrod
Keyword(s):  
Spatial Scale ◽  
Niche Width ◽  
Isotopic Niche ◽  
Isotopic Niche Width

scholarly journals Resource use and the impacts of fisheries on two sympatric sea snake species on the West Coast of India.

2021 ◽  
Author(s):  
Shawn Dsouza ◽  
Chetan Rao ◽  
Muralidharan Manoharakrishnan ◽  
Kartik Shanker
Keyword(s):  
Food Webs ◽  
Resource Use ◽  
West Coast ◽  
Niche Width ◽  
Isotopic Niche ◽  
The West ◽  
Sea Snake ◽  
Snake Species ◽  
West Coast Of India ◽  
Isotopic Niche Width

Abstract Species interactions are central to community assembly and ecosystem functioning. Sea snakes play an important role as mesopredators and as intermediate links in coastal marine food webs. However, they are impacted by anthropogenic pressures such as fisheries throughout their range. We investigated differences in resource use between two sympatric sea snake species from the west coast of India, Hydrophis curtus and H. schistosus, and described the impacts of fishing on the interactions of these species. We compared habitat use, diet, and isotopic niche width between species to determine resource overlap. We then compared trophic overlap of each species with the fisheries in the region and tested the effect of fishing intensity on their isotopic niche width. We found that H. curtus used deeper habitats than H. schistosus, resulting in increased spatial overlap with fisheries. The two species also had distinct trophic niches and H. curtus prey formed a larger proportion of fishery catch on average than H. schistosus. This greater overlap could make H. curtus more vulnerable to the effects of fisheries. Both species exhibited expansion in short-term and long-term isotopic niche width along a gradient of fishing intensity which may indicate behavioural changes associated with the presence of fisheries. Hydrophis curtus is a trophic generalist, competes with syntopic species and is dominant in most assemblages. However, H. schistosus exhibits higher plasticity in resource use and may have an advantage over H. curtus. Thus, fishing could alter the relative abundance of these mesopredators with cascading effects through coastal food webs.

scholarly journals Inter-Specific and Intra-Specific Competition of Two Sympatrically Breeding Seabirds, Chinstrap and Gentoo Penguins, at Two Neighboring Colonies

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 482
Author(s):  
Won Young Lee ◽  
Seongseop Park ◽  
Kil Won Kim ◽  
Jeong-Hoon Kim ◽  
Jong-Ku Gal ◽  
...  
Keyword(s):  
Isotope Analysis ◽  
Niche Partitioning ◽  
Limited Resources ◽  
Isotopic Niche ◽  
Seabird Species ◽  
Δ13c And Δ15n ◽  
Foraging Area ◽  
Colonial Seabird ◽  
Gps Tracks ◽  
Colony Level

Theory predicts that sympatric predators compete for food under conditions of limited resources. Competition would occur even within the same species, between neighboring populations, because of overlapping foraging habits. Thus, neighboring populations of the same species are hypothesized to face strong competition. To test the hypothesis that intra-specific competition is more intense than inter-specific competition owing to a lack of niche partitioning, we estimated the foraging area and diving depths of two colonial seabird species at two neighboring colonies. Using GPS and time-depth recorders, we tracked foraging space use of sympatric breeding Chinstrap and Gentoo penguins at Ardley Island (AI) and Narębski Point (NP) at King George Island, Antarctica. GPS tracks showed that there was a larger overlap in the foraging areas between the two species than within each species. In dive parameters, Gentoo penguins performed deeper and longer dives than Chinstrap penguins at the same colonies. At the colony level, Gentoo penguins from NP undertook deeper and longer dives than those at AI, whereas Chinstrap penguins did not show such intra-specific differences in dives. Stable isotope analysis of δ13C and δ15N isotopes in blood demonstrated both inter- and intra-specific differences. Both species of penguin at AI exhibited higher δ13C and δ15N values than those at NP, and in both locations, Gentoo penguins had higher δ13C and lower δ15N values than Chinstrap penguins. Isotopic niches showed that there were lower inter-specific overlaps than intra-specific overlaps. This suggests that, despite the low intra-specific spatial overlap, diets of conspecifics from different colonies remained more similar, resulting in the higher isotopic niche overlaps. Collectively, our results support the hypothesis that intra-specific competition is higher than inter-specific competition, leading to spatial segregation of the neighboring populations of the same species.

scholarly journals Widespread gene flow between oceans in a pelagic seabird species complex

2017 ◽  
Vol 26 (20) ◽  
pp. 5716-5728 ◽  
Author(s):  
Katherine A. Booth Jones ◽  
Malcolm A. C. Nicoll ◽  
Claire Raisin ◽  
Deborah A. Dawson ◽  
Helen Hipperson ◽  
...  
Keyword(s):  
Gene Flow ◽  
Species Complex ◽  
Seabird Species ◽  
Pelagic Seabird

Sympatric population divergence within a highly pelagic seabird species complex (Hydrobatesspp.)

2018 ◽  
Vol 49 (1) ◽  
Author(s):  
Rebecca S. Taylor ◽  
Anna Bailie ◽  
Previn Gulavita ◽  
Tim Birt ◽  
Tomas Aarvak ◽  
...  
Keyword(s):  
Species Complex ◽  
Population Divergence ◽  
Sympatric Population ◽  
Seabird Species ◽  
Pelagic Seabird

scholarly journals Foraging plasticity in a pelagic seabird species along a marine productivity gradient

2010 ◽  
Vol 398 ◽  
pp. 259-274 ◽  
Author(s):  
VH Paiva ◽  
P Geraldes ◽  
I Ramírez ◽  
A Meirinho ◽  
S Garthe ◽  
...  
Keyword(s):  
Seabird Species ◽  
Productivity Gradient ◽  
Marine Productivity ◽  
Pelagic Seabird

scholarly journals Isotopic Niche Partitioning and Individual Specialization in an Arctic Raptor Guild

2021 ◽  
Author(s):  
Devin L. Johnson ◽  
Michael T. Henderson ◽  
David L. Anderson ◽  
Travis L. Booms ◽  
Cory T. Williams
Keyword(s):  
Resource Availability ◽  
Niche Overlap ◽  
Niche Width ◽  
Foraging Strategies ◽  
Foraging Efficiency ◽  
Isotopic Niche ◽  
Individual Specialization ◽  
Niche Specialization ◽  
Niche Variation ◽  
Golden Eagles

Abstract Intra- and inter-specific resource partitioning within predator communities is a fundamental component of trophic ecology, and one proposed mechanism for how populations partition resources is through individual niche variation. The Niche Variation Hypothesis (NVH) predicts that interindividual trait variation leads to functional trade-offs in foraging efficiency, resulting in populations comprised of individual dietary specialists. A modified version of the NVH [mNVH] predicts niche specialization is plastic and responsive to fluctuating resource availability. We quantified niche overlap and tested the mNVH within an Arctic raptor guild, focusing on three species that employ different foraging strategies: Golden Eagles (generalists); Gyrfalcons (facultative specialists); and Rough-legged Hawks (specialists). Tundra ecosystems exhibit cyclic populations of arvicoline rodents (lemmings and voles), providing a unique system under which to examine interannual fluctuations in predator resource availability. Using blood δ13C & δ15N values from 189 raptor nestlings on Alaska’s Seward Peninsula (2014–2019), we calculated isotopic niche width and used Bayesian stable isotope mixing models (BSIMMs) to characterize individual specialization and test the mNVH. We observed a high degree of isotopic niche overlap between the three species and variable trophic responses to different stages of the arvicoline rodent cycle. Elevated arvicoline rodent abundance corresponded to reduced niche overlap among species and increased individual specialization in Golden Eagles and Gyrfalcons. Further, Gyrfalcons displayed a positive relationship between individual specialization and population niche width on an interannual basis consistent with the mNVH. Our findings suggest plasticity in niche specialization may reduce intra- and inter-specific resource competition under dynamic ecological conditions.

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