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 The isotopic niche of Atlantic, biting marine mammals and its relationship to skull morphology and body size

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Massimiliano Drago ◽  
Marco Signaroli ◽  
Meica Valdivia ◽  
Enrique M. González ◽  
Asunción Borrell ◽  
...  
Keyword(s):  
Body Size ◽  
Atlantic Ocean ◽  
Fisheries Management ◽  
Marine Mammals ◽  
Trophic Position ◽  
Sympatric Species ◽  
Isotopic Niche ◽  
Apex Predators ◽  
Skull Morphology ◽  
Ecosystem Based Fisheries Management

AbstractUnderstanding the trophic niches of marine apex predators is necessary to understand interactions between species and to achieve sustainable, ecosystem-based fisheries management. Here, we review the stable carbon and nitrogen isotope ratios for biting marine mammals inhabiting the Atlantic Ocean to test the hypothesis that the relative position of each species within the isospace is rather invariant and that common and predictable patterns of resource partitioning exists because of constrains imposed by body size and skull morphology. Furthermore, we analyze in detail two species-rich communities to test the hypotheses that marine mammals are gape limited and that trophic position increases with gape size. The isotopic niches of species were highly consistent across regions and the topology of the community within the isospace was well conserved across the Atlantic Ocean. Furthermore, pinnipeds exhibited a much lower diversity of isotopic niches than odontocetes. Results also revealed body size as a poor predictor of the isotopic niche, a modest role of skull morphology in determining it, no evidence of gape limitation and little overlap in the isotopic niche of sympatric species. The overall evidence suggests limited trophic flexibility for most species and low ecological redundancy, which should be considered for ecosystem-based fisheries management.

scholarly journals Three-dimensional niche partitioning between two colonially nesting ardeid species in central China

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yuanxing Ye ◽  
Canshi Hu ◽  
Yiting Jiang ◽  
Geoffrey W. H. Davison ◽  
Changqing Ding
Keyword(s):  
Niche Partitioning ◽  
Trophic Niche ◽  
Egg Laying ◽  
Central China ◽  
Paddy Fields ◽  
Shaanxi Province ◽  
Similar Species ◽  
Wetland Birds ◽  
Cattle Egret ◽  
River Banks

Abstract Background Interspecific competition is known to be strongest between those species that are both closely related and sympatric. Egrets are colonially nesting wetland birds that often overlap and can therefore be expected to compete in roosting and nesting habitat as well as in diet. According to the niche partitioning hypothesis, it is to be expected that these similar species would show differentiation in at least one of the main niche dimensions to reduce competition. We tested niche partitioning between the colonially nesting Little Egret (Egretta garzetta) and Cattle Egret (Bubulcus ibis) in temporal, spatial and trophic dimensions. Methods Field study was conducted in three mixed egret colonies in Yangxian County, southwest Shaanxi Province, central China. For each nest colony we recorded its spatial location, the height of nesting trees and of nests, the height of roosting trees and of roosting individuals within the trees. We determined the first egg-laying and first hatching dates of the two species. Craw dissection of storm-killed egret nestlings was used to measure the diet. Six transects were surveyed to study foraging habitat selection. Results We found that hatching time of Little Egrets peaked earlier (by about 1 month) than that of Cattle Egrets. Cattle Egrets nested and roosted higher than Little Egrets. The foraging habitats used by Little Egrets were dominated by river banks (73.49%), followed by paddy fields (13.25%) and reservoirs (10.84%), whereas Cattle Egret foraging sites were characterized by grasslands (44.44%), paddy fields (33.33%) and river banks (22.22%). Little Egrets consumed more fishes (65.66%) and Odonata larvae (13.69%) than Cattle Egrets, while Cattle Egrets were found feeding mainly on Coleoptera (29.69%) and Orthoptera (23.29%). Little Egrets preyed on larger mean biomasses of food items than Cattle Egrets. Conclusions Our results confirm the niche partitioning hypothesis as a mechanism for coexistence among ecologically similar species. In two coexisting egret species, niche partitioning is multidimensional, such that the two coexistent species occupy differing ecological space based on all three temporal, spatial and trophic niche dimensions.

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 Perch Selection by Three Cooccurring Species ofCelithemis(Odonata: Libellulidae): Testing for a Competitive Hierarchy among Similar Species

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Wade B. Worthen ◽  
Parker H. Morrow
Keyword(s):  
Body Size ◽  
Niche Partitioning ◽  
Open Water ◽  
The Other ◽  
Similar Species ◽  
Male Body ◽  
Size Dependent ◽  
Anatomical Characters ◽  
Relative Abundances ◽  
Imagej Software

In many communities of perching dragonflies (Odonata: Libellulidae), a size-dependent competitive hierarchy creates a positive relationship between male body size and perch height. We tested for this pattern among three similar-sized species:Celithemis elisa,C. fasciata, andC. ornata.Males were caught and photographed from May to July 2015 at Ashmore Heritage Preserve, Greenville County, SC, USA, and perch heights and perch distance to open water were measured. Five indices of body size were measured with ImageJ software: abdomen length, forewing length, hindwing length, area of forewing, and area of hindwing.Celithemis fasciatawas significantly larger than the other two species for all five anatomical characters and used perches that were significantly taller and closer to open water than the other species, though these differences changed over the summer. Aggressive interactions between and within species were tallied and compared to expected distributions based on mean relative abundances derived from hourly abundance counts. Patterns of interspecific aggression were also consistent with a size-dependent hierarchy: the largeC. fasciatawas attacked less frequently, and the smallC. ornatamore frequently, than predicted by their relative abundances. We conclude that even small differences in body size may contribute to niche partitioning in perch selection.

Identification of trophic niches of subterranean diving beetles in a calcrete aquifer by DNA and stable isotope analyses

2014 ◽  
Vol 65 (2) ◽  
pp. 95 ◽  
Author(s):  
Tessa M. Bradford ◽  
William F. Humphreys ◽  
Andrew D. Austin ◽  
Steven J. B. Cooper
Keyword(s):  
Stable Isotope ◽  
Trophic Ecology ◽  
Niche Partitioning ◽  
Niche Differentiation ◽  
Trophic Niche ◽  
Coi Gene ◽  
Stable Isotope Analyses ◽  
Prey Preferences ◽  
Diving Beetles ◽  
Isotope Analyses

The Yilgarn calcrete aquifers in Western Australia are an interesting system for investigating the process of speciation within subterranean habitats, because of the limited opportunities for dispersal between isolated calcretes. The presence of different-sized diving beetles (Dytiscidae) in separate calcretes, including sympatric sister-species pairs, suggests that species may have evolved within calcretes by an adaptive shift as a result of ecological-niche differentiation. We have studied the potential for trophic niche partitioning in a sister triplet of diving beetles, of distinctly different sizes, from a single aquifer. Fragments of the mitochondrial COI gene, specific to known species of amphipods and copepods, were polymerase chain reaction-amplified from each of the three beetle species, indicating that there is an overlap in their prey items. Significant differences were found in the detected diets of the three species, and results showed a propensity for prey preferences of amphipods by the large beetles and one species of copepod for the small beetles. A terrestrial source of carbon to the calcrete was suggested by stable isotope analyses. The combined approach of molecular, stable isotope and behavioural studies have provided insight into the trophic ecology of this difficult-to-access environment, providing a framework for more fine-scale analyses of the diet of different-sized species to examine speciation underground.

scholarly journals Size-Dependent Trophic Patterns of Pallid Sturgeon and Shovelnose Sturgeon in a Large River System

2013 ◽  
Vol 4 (1) ◽  
pp. 41-52 ◽  
Author(s):  
William E. French ◽  
Brian D. S. Graeb ◽  
Katie N. Bertrand ◽  
Steven R. Chipps ◽  
Robert A. Klumb
Keyword(s):  
South Dakota ◽  
Trophic Position ◽  
Fork Length ◽  
Missouri River ◽  
River System ◽  
Large River ◽  
Diet Shift ◽  
Fish Prey ◽  
Shovelnose Sturgeon ◽  
Pallid Sturgeon

Abstract This study compared patterns of δ15N and δ13C enrichment of pallid sturgeon Scaphirhynchus albus and shovelnose sturgeon S. platorynchus in the Missouri River, United States, to infer their trophic position in a large river system. We examined enrichment and energy flow for pallid sturgeon in three segments of the Missouri River (Montana/North Dakota, Nebraska/South Dakota, and Nebraska/Iowa) and made comparisons between species in the two downstream segments (Nebraska/South Dakota and Nebraska/Iowa). Patterns in isotopic composition for pallid sturgeon were consistent with gut content analyses indicating an ontogenetic diet shift from invertebrates to fish prey at sizes of >500-mm fork length (FL) in all three segments of the Missouri River. Isotopic patterns revealed shovelnose sturgeon did not experience an ontogenetic shift in diet and used similar prey resources as small (<500-mm FL) pallid sturgeon in the two downstream segments. We found stable isotope analysis to be an effective tool for evaluating the trophic position of sturgeons within a large river food web.

scholarly journals High-throughput sequencing reveals dietary segregation in Malaysian babblers

2021 ◽  
Author(s):  
Mohammad Saiful Mansor ◽  
Fasihah Zarifah Rozali ◽  
Sian Davies ◽  
Shukor Md Nor ◽  
Rosli Ramli
Keyword(s):  
High Throughput ◽  
High Throughput Sequencing ◽  
Prey Selection ◽  
Niche Partitioning ◽  
Peninsular Malaysia ◽  
Similar Species ◽  
Insectivorous Birds ◽  
Dietary Overlap ◽  
Dietary Flexibility ◽  
Wide Range

Abstract The coexistence of numerous species within a community results from how those species use available resources. Babblers are one of the major groups of Malaysian insectivorous birds, which frequently forage in dense vegetation cover and have a high level of sympatry. Therefore, examining the diet, prey selection and niche segregation of babblers can be challenging. In this study, we used high-throughput sequencing to investigate potential dietary overlap or segregation among 10 babbler species of the four genera of the family Pellorneidae and Timaliidae: Pellorneum, Malacopteron, Stachyris and Cyanoderma in central peninsular Malaysia. We tested the hypothesis that trophically similar species may differ in resource use to avoid competitive exclusion. We identified 81 distinct arthropod taxa from fecal samples, belonging to 71 families representing 13 orders, which were predominantly from 16 dipteran, 13 lepidopteran and 10 coleopteran families. Of all the prey taxa consumed, 45% were found to be distinct across the 10 babbler species, and less than 35% were shared simultaneously by three or more babbler species, indicating minimal dietary overlap. The black-throated babbler Stachyris nigricollis and moustached babbler Malacopteron magnirostre had the most generalist tendencies because they consumed a greater variety of prey taxa. Small dietary overlap values (Ojk) and a relatively wide range of food resources suggest that dietary segregation occurred among the studied babblers. The great diversity of prey consumed revealed the presence of dietary flexibility among the sympatric insectivorous birds, thus reducing any active dietary competition and facilitating the coexistence through niche partitioning.

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