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

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.

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

PeerJ ◽

10.7717/peerj.1578 ◽

2016 ◽

Vol 4 ◽

pp. e1578 ◽

Cited By ~ 8

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.

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

Marine Ecology Progress Series ◽

10.3354/meps13221 ◽

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.

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Comparison of isotopic niches of four sea cucumbers species (Holothuroidea: Echinodermata) inhabiting two seagrass meadows in the southwestern Mediterranean Sea (Mostaganem, Algeria)

Belgian Journal of Zoology ◽

10.26496/bjz.2019.32 ◽

2019 ◽

Vol 149 (1) ◽

Cited By ~ 1

Author(s):

Nor Eddine Belbachir ◽

Gilles Lepoint ◽

Karim Mezali

Keyword(s):

Stable Isotope ◽

Human Activities ◽

Seagrass Meadow ◽

Niche Overlap ◽

Posidonia Oceanica ◽

Trophic Niche ◽

Food Sources ◽

Isotopic Niche ◽

North West ◽

Seagrass Meadows

Among the fauna inhabiting the Posidonia oceanica seagrass meadow, holothurians are particularly abundant and provide essential ecological roles, including organic matter recycling within seagrass sediments. This study aimed to investigate the trophic niche of four holothurians of the order Holothuriida [Holothuria poli (Delle Chiaje, 1824), Holothuria tubulosa (Gmelin, 1791), Holothuria sanctori (Delle Chiaje, 1823) and Holothuria forskali (Delle Chiaje, 1823)] inhabiting P. oceanica meadows, through the measurement of nitrogen and carbon stable isotope ratios. Two shallow and contrasting sites of the littoral region of Mostaganem (North West Algeria) were chosen. The first site, located in Stidia, is weakly impacted by human activities. The second site, located in Salamandre, is highly impacted by human activities (industries, harbor facilities). High values of δ15N in holothurians and their food sources were observed at both sites. The δ13C values showed a lower contribution from detritic Posidonia than in other areas. This could be a consequence of P. oceanica bed degradation in the studied area. The stable isotope approach did not reveal dietary differences between species, and the four holothurians species exhibited significant isotopic niche overlap. However, niche sizes differed between species showing more variable individual trophic diversity in some species (H. tubulosa and H. sanctori in Salamandre; H. forskali in Stidia). If niche segregation does occur, it is not in terms of general resource use. More likely, it would be the abundance of food sources, the different life habits and their micro-habitats that may explain their co-existence in the P. oceanica seagrass meadow.

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

Canadian Journal of Zoology ◽

10.1139/cjz-2018-0291 ◽

2019 ◽

Vol 97 (9) ◽

pp. 763-772 ◽

Cited By ~ 2

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.

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How fishing intensity affects the spatial and trophic ecology of two gull species breeding in sympatry

ICES Journal of Marine Science ◽

10.1093/icesjms/fsy096 ◽

2018 ◽

Vol 75 (6) ◽

pp. 1949-1964 ◽

Cited By ~ 11

Author(s):

Diana M Matos ◽

Jaime A Ramos ◽

Joana G Calado ◽

Filipe R Ceia ◽

Jessica Hey ◽

...

Keyword(s):

Trophic Ecology ◽

Habitat Preferences ◽

Isotope Analysis ◽

Demersal Fish ◽

Trophic Niche ◽

Isotopic Niche ◽

Temporal Segregation ◽

Fishery Discards ◽

Individual Tracking ◽

South Portugal

Abstract Fisheries produce large quantities of discards, an important resource for scavenging seabirds. However, a policy reform banning discards, which is soon to be implemented within the EU, will impose a food shortage upon scavengers, and it is still largely unknown how scavengers will behave. We studied the diet (hard remains), trophic (stable isotope analysis), and foraging (individual tracking) ecology of two gull species breeding in sympatry: Audouin’s gull Larus audouinii (AG) and yellow-legged gull Larus michahellis (YLG), in South Portugal, under normal fishery activity (NFA; work days) and low fishery activity (LFA; weekends), over two consecutive years. We established a pattern of dietary, spatial, and temporal segregation between the two gull species. Under LFA, yellow-legged gulls reduced their time spent at-sea, thus foraging more in alternative habitats (e.g. refuse dumps) and widening their isotopic niche (i.e. generalist behaviour). Contrastingly, Audouin’s gull had a narrower trophic niche (i.e. specialist behaviour), foraging exclusively at-sea, reducing the amount of demersal fish and increasing the amount of pelagic fish in their diet. Under NFA, both species foraged mostly at-sea, feeding almost exclusively on fish, with increased consumption of demersal species (i.e. fishery discards). In general, yellow-legged gull had a broader trophic niche (i.e. generalist behaviour) when compared with the narrower isotopic niche of Audouin’s gull (i.e. specialist behaviour). Overall, both gull species relied heavily on fishery discards. However, there was visible dietary, spatial, and temporal segregation between the two species, associated with their dietary and habitat preferences that could be attributed to the availability of anthropogenic resources, such as fishery discards.

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Individual niche trajectories in nesting green turtles on Rocas Atoll, Brazil: an isotopic tool to assess diet shifts over time

Biota Neotropica ◽

10.1590/1676-0611-bn-2020-1099 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Karoline Fernanda Ferreira Agostinho ◽

Leandro Rabello Monteiro ◽

Ana Paula Madeira Di Beneditto

Keyword(s):

Trophic Ecology ◽

Isotope Analysis ◽

Trophic Niche ◽

Northeastern Brazil ◽

Diet Shift ◽

Isotopic Niche ◽

Temporal Window ◽

Temporal Dimension ◽

Green Turtles ◽

Diet Shifts

Abstract In this study, multi-tissue (yolk and carapace) stable isotope analysis was used to assess individual isotopic niche trajectories of nesting green turtles on Rocas Atoll, off northeastern Brazil, and to reveal a diet shift in the temporal dimension. The diet trajectories of individual green turtles were highly directional, with a stronger component towards decreasing values of δ15N from carapace to yolk. When the green turtles are in their foraging sites (temporal window measured by the yolk samples), they are more herbivores. Conversely, in a broader temporal window, the green turtles demonstrate a carnivore-omnivore strategy, such as represented by heavier δ15N values in the carapace. This finding confirms a temporal diet shift. This is the first study that applies trophic niche trajectories for sea turtles, adding a new isotopic tool to understand the trophic ecology of these migrant animals.

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Stable isotope analysis indicates resource partitioning and trophic niche overlap in larvae of four tuna species in the Gulf of Mexico

Marine Ecology Progress Series ◽

10.3354/meps12958 ◽

2019 ◽

Vol 619 ◽

pp. 53-68 ◽

Cited By ~ 3

Author(s):

R Laiz-Carrión ◽

T Gerard ◽

JJ Suca ◽

E Malca ◽

A Uriarte ◽

...

Keyword(s):

Stable Isotope ◽

Gulf Of Mexico ◽

Stable Isotope Analysis ◽

Resource Partitioning ◽

Isotope Analysis ◽

Niche Overlap ◽

Trophic Niche

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Trophic ecology of syntopic anurans of tropical stream communities

Journal of Tropical Ecology ◽

10.1017/s0266467421000158 ◽

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.

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