Social, spatial and isotopic niche partitioning identify an estuarine community of bottlenose dolphins as a discrete management unit

2021 ◽  
Author(s):  
Krista Nicholson ◽  
Neil Loneragan ◽  
Hugh Finn ◽  
Lars Bejder
Keyword(s):  
Bottlenose Dolphins ◽  
Niche Partitioning ◽  
Management Unit ◽  
Isotopic Niche

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 Temporal Variation in the Niche Partitioning of Lake Michigan Salmonines as it Relates to Alewife Abundance and Size Structure.

2021 ◽  
Author(s):  
Benjamin A. Turschak ◽  
Charles R. Bronte ◽  
Sergiusz J. Czesny ◽  
Brandon S. Gerig ◽  
Austin Happel ◽  
...  
Keyword(s):  
Ecological Niche ◽  
Lake Michigan ◽  
Nitrogen Isotopes ◽  
Size Structure ◽  
Prey Availability ◽  
Habitat Preferences ◽  
Niche Partitioning ◽  
Niche Overlap ◽  
Isotopic Niche ◽  
Resource Gradient

Stable isotope analyses offer a useful means for quantifying ecological niche dimensions, though few studies have examined isotopic response of an ecological community with respect to resource gradients such as fluctuations in prey availability. Stable carbon and nitrogen isotopes were measured for Lake Michigan salmonines and their prey collected from 2014 to 2016. Bayesian ellipse and mixing model analyses were used to quantify isotopic niche characteristics and diets, respectively, among species and years. During the three-year study period, abundance and size structure of preferred alewife prey changed substantially and offered an opportunity to explore predator isotopic niche response and diet shifts along a prey resource gradient. Results suggested increased reliance on alewives, especially small alewives, over the study period and were consistent with greater availability of this prey. However, differential use of alewife size classes and alternative prey sources by salmonine predators was apparent, which suggested possible resource partitioning. Characterization of ecological niche overlap using stable isotopes likely requires consideration of shared resource availability as well as specific prey and habitat preferences.

scholarly journals Isotopic niche partitioning between two apex predators over time

2017 ◽  
Vol 86 (4) ◽  
pp. 766-780 ◽  
Author(s):  
Massimiliano Drago ◽  
Luis Cardona ◽  
Valentina Franco-Trecu ◽  
Enrique A. Crespo ◽  
Damián G. Vales ◽  
...  
Keyword(s):  
Niche Partitioning ◽  
Isotopic Niche ◽  
Apex Predators ◽  
Over Time

Consistent differential resource use by sympatric lake (Coregonus clupeaformis) and round (Prosopium cylindraceum) whitefish in Lake Huron: a multi-time scale isotopic niche analysis

2016 ◽  
Vol 73 (7) ◽  
pp. 1072-1080 ◽  
Author(s):  
Rebecca L. Eberts ◽  
Björn Wissel ◽  
Richard G. Manzon ◽  
Joanna Y. Wilson ◽  
Douglas R. Boreham ◽  
...  
Keyword(s):  
Resource Use ◽  
Niche Partitioning ◽  
Niche Overlap ◽  
Lake Huron ◽  
Feeding Strategies ◽  
Isotopic Niche ◽  
Coregonus Clupeaformis ◽  
Spawning Period ◽  
Spawning Aggregations

Lake (Coregonus clupeaformis) and round (Prosopium cylindraceum) whitefish are sympatric benthivores in Lake Huron that are thought to coexist via niche partitioning. However, little is known about long-term resource use and niche overlap across different temporal scales. We used a multiyear (2010–2012) and multi-tissue (liver, muscle, and bone layers) isotopic niche analysis to characterize and compare resource use by lake and round whitefish across several time scales. Lake whitefish consistently used more diverse, 13C-depleted (mean δ13C = −21.9‰) and 15N-enriched (mean δ15N = +9.3‰) resources than round whitefish (mean δ13C = −18.2‰; mean δ15N = +8.3‰). Niche overlap occurred only in liver, representing the spawning period, while niche segregation was highest in juvenile life stages. Individuals of both species made variable resource shifts among time periods, suggesting that spawning aggregations are composed of individuals representing a variety of feeding strategies and locations. Our study confirms that differential resource use is an important strategy for these fish as adults and demonstrates life-long niche partitioning beginning before age-2.

New insight into trophic niche partitioning and diet of mackerel (Scomber scombrus) and herring (Clupea harengus) in Icelandic waters

2021 ◽  
Author(s):  
Cecilia Kvaavik ◽  
Gudmundur J Óskarsson ◽  
Hildur Pétursdóttir ◽  
Gudrun Marteinsdóttir ◽  
Anna Kristín Daníelsdóttir
Keyword(s):  
Trophic Position ◽  
Niche Partitioning ◽  
Clupea Harengus ◽  
Isotopic Niche ◽  
Similar Species ◽  
Calanoid Copepods ◽  
Fish Prey ◽  
Scomber Scombrus ◽  
Prey Preferences ◽  
Icelandic Waters

Abstract Understanding the competitive interactions of ecological similar species is essential to determine their role and niche in the ecosystem. Using both conventional dietary methods and stable isotope analysis, we examined the feeding ecology, trophic position and possible niche partitioning of Northeast Atlantic mackerel (Scomber scombrus), Icelandic summer spawning (ISS) herring (Clupea harengus), and Norwegian spring spawning (NSS) herring from Icelandic waters during the spring and summer 2012 and 2014. The stomach analysis showed differences in prey preferences among the species during summer, where mackerel diets were almost exclusively calanoid copepods, while herring ate larger zooplankton, i.e. euphausiids and amphipods. Analysis of isotopic diet contribution of mackerel and herring using Bayesian mixing models, representing mainly the spring consumption, revealed that euphausiids were the main dietary contributor of both mackerel and herring. Fish prey were also an important dietary source for ISS herring, and amphipods were important to the diet of NSS herring. In addition, mackerel encompassed a broad isotopic niche, whereas the two herring stocks had narrower and separated niches from each other. The results from this analysis reveal new and holistic information into the diet of these species, which have various ecological implications.

scholarly journals Isotopic niche partitioning in two sympatric howler monkey species

2020 ◽  
Vol 172 (3) ◽  
pp. 438-446
Author(s):  
Elizabeth Flores‐Escobar ◽  
Carolina Sanpera ◽  
Lluís Jover ◽  
Liliana Cortés‐Ortiz ◽  
Ariadna Rangel‐Negrín ◽  
...  
Keyword(s):  
Niche Partitioning ◽  
Howler Monkey ◽  
Isotopic Niche ◽  
Monkey Species
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