scholarly journals Trophic ecology of sea urchins in coral-rocky reef systems, Ecuador

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1578 ◽  
Author(s):  
Nancy Cabanillas-Terán ◽  
Peggy Loor-Andrade ◽  
Ruber Rodríguez-Barreras ◽  
Jorge Cortés
Keyword(s):  
Stable Isotope ◽  
Trophic Ecology ◽  
Habitat Degradation ◽  
Sea Urchins ◽  
Relative Proportion ◽  
Isotope Analysis ◽  
Niche Overlap ◽  
Trophic Niche ◽  
Rocky Reef ◽  
Trophic Overlap

Sea urchins are important grazers and influence reef development in the Eastern Tropical Pacific (ETP).Diadema mexicanumandEucidaris thouarsiiare the most important sea urchins on the Ecuadorian coastal reefs. This study provided a trophic scenario for these two species of echinoids in the coral-rocky reef bottoms of the Ecuadorian coast, using stable isotopes. We evaluated the relative proportion of algal resources assimilated, and trophic niche of the two sea urchins in the most southern coral-rocky reefs of the ETP in two sites with different disturbance level. Bayesian models were used to estimate the contribution of algal sources, niche breadth, and trophic overlap between the two species. The sea urchins behaved as opportunistic feeders, although they showed differential resource assimilation.Eucidaris thouarsiiis the dominant species in disturbed environments; likewise, their niche amplitude was broader than that ofD. mexicanumwhen conditions were not optimal. However, there was no niche overlap between the species. The Stable Isotope Analysis in R (SIAR) indicated that both sea urchins shared limiting resources in the disturbed area, mainlyDictyotaspp. (contributions of up to 85% forD. mexicanumand up to 75% forE. thouarsii). The Stable Isotope Bayesian Ellipses in R (SIBER) analysis results indicated less interspecific competition in the undisturbed site. Our results suggested a trophic niche partitioning between sympatric sea urchin species in coastal areas of the ETP, but the limitation of resources could lead to trophic overlap and stronger habitat degradation.

scholarly journals Trophic ecology of the seagrass-inhabiting footballer demoiselle Chrysiptera annulata (Peters, 1855); comparison with three other reef-associated damselfishes

2020 ◽  
Vol 146 (1) ◽  
Author(s):  
Gilles Lepoint ◽  
Loïc N. Michel ◽  
Eric Parmentier ◽  
Bruno Frédérich
Keyword(s):  
Stable Isotope ◽  
Trophic Ecology ◽  
Close Association ◽  
Isotope Analysis ◽  
Niche Overlap ◽  
Trophic Niche ◽  
Isotopic Niche ◽  
Seagrass Meadows ◽  
Turf Algae ◽  
Herbivorous Species

Many damselfishes (Pomacentridae) are herbivorous or omnivorous with an important contribution from different kinds of algae in their diet. They display different levels of territoriality and farming behavior, from almost non territorial to monoculture farmers. In addition, a few species inhabit seagrass meadows but, presently, none can be considered as seagrass-eating specialists. The footballer demoiselle, Chrysiptera annulata, is found in the seagrass meadows on the reef flat of the Great Reef of Toliara (Madagascar, Mozambique Channel). In the light of this unusual habitat for a pomacentrid, this study aimed to answer three questions: 1) What is the diet of C. annulata? 2) Do the resources supporting this diet include seagrass? 3) Does its trophic niche overlap those of other sympatric damselfishes (Pomacentrus trilineatus, Chrysiptera unimaculata and Plectroglyphidodon lacrymatus) living in close association with macrophytes or eating algae? Stomach content examination and stable isotope analysis showed that the footballer demoiselle is not a seagrass consumer but is an omnivorous/herbivorous species heavily relying on algal resources and small invertebrates. SIAR, a stable isotope mixing model, indicated it assimilated large amounts of turf algae, and various benthic or planktonic invertebrates in lower proportions. SIBER metrics revealed that the isotopic niche of the footballer demoiselle partly overlaps that of its congener, C. unimaculata, but not those of P. trilineatus and P. lacrymatus. Trophic strategies of C. annulata differed both from farming species such as P. lacrymatus and from less territorial herbivores such as P. trilineatus. Its seagrass meadow habitat on the Great Reef of Toliara allows the conquest of an unusual habitat for damselfishes and could limit competition with C. unimaculata, a species displaying the same territorial behavior and the same isotopic niche but living on the reef itself.

Evidence for inter- and intraspecific trophic niche separation among deepwater elasmobranchs on the southern Great Barrier Reef, Australia

2020 ◽  
Vol 636 ◽  
pp. 107-121
Author(s):  
SEM Munroe ◽  
CL Rigby ◽  
NE Hussey
Keyword(s):  
Great Barrier Reef ◽  
Trophic Ecology ◽  
Isotope Analysis ◽  
Niche Overlap ◽  
Trophic Niche ◽  
Feeding Strategies ◽  
Niche Separation ◽  
Isotopic Niche ◽  
Barrier Reef ◽  
Trawl Fishery

Quantifying the trophic structure and interactions of deepwater (>200 m depth) elasmobranch assemblages is required to improve our understanding of deepwater ecosystems and the impacts of increased deepwater exploitation. To this end, we investigated the trophic ecology of deepwater elasmobranchs on the Great Barrier Reef (GBR) using a stable isotope (δ13C and δ15N) approach. Our study included 4 species captured in the southern GBR deepwater eastern king prawn trawl fishery: the eastern spotted gummy shark Mustelus walkeri, the piked spurdog Squalus megalops, the pale spotted catshark Asymbolus pallidus, and the Argus skate Dentiraja polyommata. The δ13C and δ15N values of all 4 species ranged from -18.6 to -16.2‰ and 8.3 to 13.8‰, respectively. The small δ13C range was likely due to the limited number of unique carbon baseline sources typically found in deepwater environments. Despite this, 3 of the 4 species exhibited relatively low core (40% SEAb) isotopic niche overlap (<1 to 44%). Isotopic niche separation may be driven by multiple interacting factors including morphology, feeding strategies, or resource partitioning to reduce competition. Isotope analysis also provided evidence for intraspecific variation; S. megalops, D. polyommata and M. walkeri exhibited significant increases in δ15N (~3‰) and δ13C (~2‰) with size. Latitude, longitude, and depth had statistically significant but comparatively minor effects on isotope values (≤1‰) of the 4 species. Cumulatively, our results indicate that isotopic variation among deepwater elasmobranchs on the GBR is principally driven by size and species-level differences in resource use.

Diet and isotopic niche of eastern sand darter (Ammocrypta pellucida) near the northern edge of its range: a test of niche specificity

2019 ◽  
Vol 97 (9) ◽  
pp. 763-772 ◽  
Author(s):  
Jacob Burbank ◽  
Mary Finch ◽  
D. Andrew R. Drake ◽  
Michael Power
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Stomach Content ◽  
Isotope Analysis ◽  
Resource Limitation ◽  
Niche Overlap ◽  
Stomach Content Analysis ◽  
Trophic Niche ◽  
Isotopic Niche ◽  
Population Declines

Niche specificity can predispose species to population declines during periods of resource limitation, yet trophic niche specificity is poorly known for many small-bodied freshwater fishes. Applying a two-tiered approach involving stomach content and stable isotope analyses, we examined the diet and trophic niche of the threatened eastern sand darter (Ammocrypta pellucida (Putnam, 1863)) and co-occurring fishes in the Thames River, Ontario, Canada. As with previous studies, stomach content analysis revealed that eastern sand darter consumed a variety of benthic organisms including Chironomidae, Cladocera, Ostracoda, Oligochaeta, and Ephemeroptera; however, proportional contributions of prey groups differed based on stable isotope analysis, highlighting the potential for seasonal variation in prey consumption. Despite evidence of a generalist strategy, stable isotope analysis indicated eastern sand darter exhibited a relatively narrow trophic niche relative to co-occurring fishes. Trophic niche overlap was relatively minor between eastern sand darter and drift-feeding fishes (spotfin shiner (Cyprinella spiloptera (Cope, 1867)), emerald shiner (Notropis atherinoides Rafinesque, 1818), and buffalo sp. (genus Ictiobus Rafinesque, 1820)), but was more evident between eastern sand darter and benthic and benthopelagic fishes (johnny darter (Etheostoma nigrum Rafinesque, 1820) and blackside darter (Percina maculata (Girard, 1859))), indicating that competition with these species may be more likely during periods of prey scarcity.

Trophic ecology of syntopic anurans of tropical stream communities

2021 ◽  
pp. 1-9
Author(s):  
Jeszianlenn L. Plaza ◽  
Ephrime B. Metillo ◽  
Marites B. Sanguila
Keyword(s):  
Resource Partitioning ◽  
Trophic Ecology ◽  
Isotope Analysis ◽  
Niche Overlap ◽  
Trophic Niche ◽  
Generalist Predators ◽  
Stream Communities ◽  
Island Endemic ◽  
Trophic Resource ◽  
Prey Items

Abstract We investigated trophic resource partitioning in seven syntopic anurans from low- and mid-elevation stream habitats of a tropical riparian ecosystem by utilising stomach content analysis (SCA) and stable isotope analysis (SIA). Our SCA data revealed dietary similarities, narrow trophic niche breadth, and low dietary niche overlap in Ansonia muelleri, Limnonectes magnus, Occidozyga laevis, Megophrys stejnegeri, Pulchrana grandocula, Sanguirana mearnsi, and Staurois natator which could be attributed to these anurans’ selection of available local prey items. We confirmed ant-specialisation (myrmecophagy) of the Mindanao island endemic bufonid A. muelleri based on our temporal SCA dietary data. Our SIA estimates of assimilation of potential prey sources confirmed that L. magnus, P. grandocula, and O. laevis are generalist predators, opportunistically feeding on locally abundant insect prey items. This study on trophic resource partitioning in syntopic anurans provides the first picture of trophic interactions, i.e., predation and competition in stream communities in tropical riparian zones of a watershed ecosystem in northeast Mindanao of the southern Philippines.

Trophic ecology of a large-bodied marine predator, bluntnose sixgill shark Hexanchus griseus, inferred using stable isotope analysis

2020 ◽  
Vol 103 (2) ◽  
pp. 147-162
Author(s):  
Jonathan C. P. Reum ◽  
Gregory D. Williams ◽  
Chris J. Harvey ◽  
Kelly S. Andrews ◽  
Phillip S. Levin
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Trophic Ecology ◽  
Isotope Analysis ◽  
Marine Predator ◽  
Hexanchus Griseus

Stable isotope analysis reveals partitioning in prey use by Kajikia audax (Istiophoridae), Thunnus albacares, Katsuwonus pelamis, and Auxis spp. (Scombridae) in the Eastern Tropical Pacific of Ecuador

2021 ◽  
Vol 19 (4) ◽  
Author(s):  
Rigoberto Rosas-Luis ◽  
Nancy Cabanillas-Terán ◽  
Carmen A. Villegas-Sánchez
Keyword(s):  
Stable Isotope ◽  
Food Web ◽  
Stable Isotope Analysis ◽  
Trophic Ecology ◽  
Isotope Analysis ◽  
Middle Level ◽  
Food Sources ◽  
Thunnus Albacares ◽  
Katsuwonus Pelamis ◽  
Δ13c And Δ15n

Abstract Kajikia audax, Thunnus albacares, Katsuwonus pelamis, and Auxis spp. occupy high and middle-level trophic positions in the food web. They represent important sources for fisheries in Ecuador. Despite their ecological and economic importance, studies on pelagic species in Ecuador are scarce. This study uses stable isotope analysis to assess the trophic ecology of these species, and to determine the contribution of prey to the predator tissue. Isotope data was used to test the hypothesis that medium-sized pelagic fish species have higher δ15N values than those of the prey they consumed, and that there is no overlap between their δ13C and δ15N values. Results showed higher δ15N values for K. audax, followed by T. albacares, Auxis spp. and K. pelamis, which indicates that the highest position in this food web is occupied by K. audax. The stable isotope Bayesian ellipses demonstrated that on a long time-scale, these species do not compete for food sources. Moreover, δ15N values were different between species and they decreased with a decrease in predator size.

scholarly journals Stable isotopes of fatty acids: current and future perspectives for advancing trophic ecology

2020 ◽  
Vol 375 (1804) ◽  
pp. 20190641 ◽  
Author(s):  
Cornelia W. Twining ◽  
Sami J. Taipale ◽  
Liliane Ruess ◽  
Alexandre Bec ◽  
Dominik Martin-Creuzburg ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Stable Isotope ◽  
Best Practices ◽  
Resource Use ◽  
Trophic Ecology ◽  
Isotope Analysis ◽  
Dietary Fatty Acids ◽  
Food Web Ecology ◽  
Dietary Requirements

To understand consumer dietary requirements and resource use across ecosystems, researchers have employed a variety of methods, including bulk stable isotope and fatty acid composition analyses. Compound-specific stable isotope analysis (CSIA) of fatty acids combines both of these tools into an even more powerful method with the capacity to broaden our understanding of food web ecology and nutritional dynamics. Here, we provide an overview of the potential that CSIA studies hold and their constraints. We first review the use of fatty acid CSIA in ecology at the natural abundance level as well as enriched physiological tracers, and highlight the unique insights that CSIA of fatty acids can provide. Next, we evaluate methodological best practices when generating and interpreting CSIA data. We then introduce three cutting-edge methods: hydrogen CSIA of fatty acids, and fatty acid isotopomer and isotopologue analyses, which are not yet widely used in ecological studies, but hold the potential to address some of the limitations of current techniques. Finally, we address future priorities in the field of CSIA including: generating more data across a wider range of taxa; lowering costs and increasing laboratory availability; working across disciplinary and methodological boundaries; and combining approaches to answer macroevolutionary questions. This article is part of the theme issue ‘The next horizons for lipids as ‘trophic biomarkers’: evidence and significance of consumer modification of dietary fatty acids’.

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