Isotopic niche of two coastal dolphins in a tropical marine area: specific and age class comparisons

2015 ◽  
Vol 96 (4) ◽  
pp. 853-858 ◽  
Author(s):  
Ana Paula Madeira Di Beneditto ◽  
Leandro Rabello Monteiro
Keyword(s):  
Stomach Contents ◽  
Niche Overlap ◽  
Niche Differentiation ◽  
Trophic Levels ◽  
Food Sources ◽  
Isotopic Niche ◽  
Marine Area ◽  
Age Class ◽  
Niche Metrics ◽  
Pontoporia Blainvillei

Niche differentiation is the process by which species evolve different forms of resource use, and is used to explain the co-occurrence in a variety of habitats. The Bayesian framework of isotopic niche through quantitative niche metrics was applied to estimate and compare the niche breadth of two sympatric coastal dolphinsPontoporia blainvilleiandSotalia guianensisin a tropical marine area. The standard ellipse areas (SEAs) based on species were quite similar, but the SEAs based on age class showed that the matures’ niche space is larger than the immatures’ for both dolphins. A probabilistic comparison of SEAs indicated that specific differences are negligible compared with age class differences. Trophic level measures (δ15N range) indicated that the dolphins are comparable as top predators, and that immature specimens have a lower range of trophic levels than mature ones. In terms of variability of food sources (δ13C range),S. guianensisshowed a larger value thanP. blainvilleiand mature specimens had larger δ13C range than immatures for both species. In general,P. blainvilleiandS. guianensiswere similar in the niche metrics, with SEAs overlap of 52.1 and 39.7%. The immature specimens showed reduced isotopic niche overlap between species (<3%). In conclusion,Pontoporia blainvilleiandS. guianensisspecimens have similar isotopic niches, but pronounced differences between immature and mature specimens, both intraspecific and interspecific. Isotopic niche and quantitative metrics along with previous data on stomach contents provide a strong representation of species niche and their relationships.

scholarly journals Competition and feeding ecology in two sympatric Xenopus species (Anura: Pipidae)

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3130 ◽  
Author(s):  
Solveig Vogt ◽  
F. André de Villiers ◽  
Flora Ihlow ◽  
Dennis Rödder ◽  
John Measey
Keyword(s):  
Food Preferences ◽  
Stomach Contents ◽  
Niche Overlap ◽  
Niche Differentiation ◽  
Shannon Index ◽  
Trophic Niche ◽  
Western Cape ◽  
The South ◽  
Amphibian Species ◽  
Study Sites

The widespread African clawed frog (Xenopus laevis) occurs in sympatry with the IUCN Endangered Cape platanna (Xenopus gilli) throughout its entire range in the south-western Cape, South Africa. In order to investigate aspects of the interspecific competition between populations of X. laevis and X. gilli, an assessment of their niche differentiation was conducted through a comprehensive study on food composition and trophic niche structure at two study sites: the Cape of Good Hope (CoGH) and Kleinmond. A total of 399 stomach contents of X. laevis (n = 183) and X. gilli (n = 216) were obtained together with samples of available prey to determine food preferences using the Electivity index (E*), the Simpson’s index of diversity (1 − D), the Shannon index (H′), and the Pianka index (Ojk). Xenopus gilli diet was more diverse than X. laevis, particularly in Kleimond where the Shannon index was nearly double. Both species were found to consume large amounts of tadpoles belonging to different amphibian species, including congeners, with an overall higher incidence of anurophagy than previously recorded. However, X. laevis also feeds on adult X. gilli, thus representing a direct threat for the latter. While trophic niche overlap was 0.5 for the CoGH, it was almost 1 in Kleinmond, suggesting both species utilise highly congruent trophic niches. Further, subdividing the dataset into three size classes revealed overlap to be higher in small frogs in both study sites. Our study underlines the importance of actively controlling X. laevis at sites with X. gilli in order to limit competition and predation, which is vital for conservation of the south-western Cape endemic.

Trophic niches and diet shifts of juvenile mullet species coexisting in marine and estuarine habitats

2021 ◽  
pp. 1-11
Author(s):  
Sabrina Radunz Vollrath ◽  
Bianca Possamai ◽  
Fabiana Schneck ◽  
David Joseph Hoeinghaus ◽  
Edélti Faria Albertoni ◽  
...  
Keyword(s):  
Surf Zone ◽  
Isotope Analysis ◽  
Stomach Contents ◽  
Niche Overlap ◽  
Marine Area ◽  
Coexisting Species ◽  
Food Partitioning ◽  
Trophic Shifts ◽  
Diet Shifts ◽  
Trophic Niches

Abstract Food partitioning among coexisting species is often considered advantageous to minimize niche overlap and avoid inter-specific competition. Congeneric fish species such as the mullets Mugil curema and Mugil liza, which co-occur across marine and estuarine habitats, are good models to evaluate resource use and niche overlap or partitioning. We used stomach contents (SCA) and stable isotope analysis (SIA) to assess potential trophic shifts and changes in niche overlap associated with the mullets transitioning from marine to estuarine habitats. SIA included different fractions of organic matter in suspension and in the sediment to estimate the contribution of micro, nano and pico-organisms to the mullets’ diets. We hypothesized higher resource partitioning in the less resource-diverse system (marine surf-zone) than in the more diverse one (estuary). SCA showed diet differences between M. curema and M. liza according to the habitat. They showed distinct diets in the marine area (P < 0.001), but similar diets in the estuary (P = 0.226). A lower niche breadth was observed for both species in the marine area (M. curema = 0.03, M. liza = 0.06) compared with the estuary (M. curema = 0.14, M. liza = 0.16). Isotopic niches of both species were higher in the estuary (64.7%) compared with the marine area (0.7%). These findings corroborated our hypothesis of higher food partitioning in the marine surf-zone. We also demonstrated using SIA the shift from planktonic to benthic feeding following the recruitment of the mullets from the surf-zone into the estuary.

A historical perspective of niche differentiation between two top predators in the Uruguayan coastal area

2019 ◽  
Vol 46 (2) ◽  
pp. 136 ◽  
Author(s):  
Florencia Artecona ◽  
Maite De María ◽  
Leandro Bergamino ◽  
Diana Szteren
Keyword(s):  
Marine Mammals ◽  
Species Abundance ◽  
Niche Differentiation ◽  
Trophic Niche ◽  
Trophic Levels ◽  
Isotopic Niche ◽  
Recent Period ◽  
The South ◽  
Coastal Habitat ◽  
Top Predators

Context As top predators, marine mammals play a key role consuming in different trophic levels and the trophic niche characterization may help to understand how species utilize and share resources . On the coast of the Río de la Plata and the South-west Atlantic, the South American sea lion (Otaria flavescens) and the franciscana dolphin (Pontoporia blainvillei) are two important predators. Aims The present study investigated potential trophic overlap of both species by measuring stable carbon (δ13C) and nitrogen (δ15N) isotopes over two periods: historical (1959–79) and recent (2002–15) on the Uruguayan coast. Methods Bone samples of P. blainvillei and O. flavescens were used to determine the isotopic niche using the Stable Isotope Bayesian Ellipses in R (SIBER) analysis. Key results The isotopic niche did not overlap between species in any period. δ15N was higher in O. flavescens in both periods (20.29‰±0.73 in the historical and 19.95‰±1.0 in the recent period), indicating that it feeds at a higher trophic level than P. blainvillei. The δ13C was also significantly higher in O. flavescens than in P. blainvillei during the two periods (O. flavescens: –11.43±0.6‰ historic, –12.72±0.4‰ recent, and P. blainvillei: –12.69±1.1‰ historic, –13.84±1.3‰ recent). The isotopic niche areas of P. blainvillei in recent and historic periods confirmed they forage in 2 distinct environments, marine and estuarine, with low isotopic overlap. This overlap was higher in the recent period. Conclusions and Implications O. flavescens and both P. blainvillei groups were segregated in both periods, with a higher overlap in the recent. These species appear to reduce competition by using different resources in the same coastal habitat. O. flavescens preferentially feeds on benthic fish and showed wider trophic amplitude in both periods, whereas P. blainvillei has a more coastal–pelagic diet and included a greater variability of resources in its diet. The differences between species trophic niches can still be detected after both marine mammals species abundance has declined and after the development of fisheries.

High Dietary Niche Overlap Between Non-native and Native Ant Species in Natural Ecosystems

2020 ◽  
Author(s):  
Anna F Probert ◽  
Darren F Ward ◽  
Jacqueline R Beggs ◽  
Sarah J Bury ◽  
Syrie M Hermans ◽  
...  
Keyword(s):  
Native Species ◽  
Sequence Data ◽  
Niche Overlap ◽  
Trophic Levels ◽  
Gut Contents ◽  
Isotopic Niche ◽  
Dietary Overlap ◽  
Natural Ecosystems ◽  
Pattern Sequence ◽  
Dietary Niche

Abstract Ants represent a highly diverse and ecologically important group of insects found in almost all terrestrial ecosystems. A subset of ant species have been widely transported around the globe and invade many natural ecosystems, often out-competing native counterparts and causing varying impacts on recipient ecosystems. Decisions to control non-native ant populations require an understanding of their interactions and related impacts on native communities. We employed stable isotope analysis and metabarcoding techniques to identify potential dietary niche overlap and identify gut contents of 10 ant species found in natural ecosystems in Aotearoa New Zealand. Additionally, we looked at co-occurrence to identify potential competitive interactions among native and non-native ant species. Ants fed mainly across two trophic levels, with high dietary overlap. Relative to other ant species sampled, two non-native ant species, Linepithema humile and Technomyrmex jocosus, were found to feed at the lowest trophic level. The largest isotopic niche overlap was observed between the native Monomorium antarcticum and the invasive Ochetellus glaber, with analyses revealing a negative co-occurrence pattern. Sequence data of ant gut content identified 51 molecular operational taxonomic units, representing 22 orders and 34 families, and primarily consisting of arthropod DNA. Although we generally found high dietary overlap among species, negative occurrence between a dominant, non-native species and a ubiquitous native species indicates that species-specific interactions could be negatively impacting native ecosystems. Our research progresses and informs the currently limited knowledge around establishing protocols for metabarcoding to investigate ant diet and interactions between native and non-native ant species.

scholarly journals Implications of low food availability on resource partitioning among three species of Cichlidae (Pisces: Perciformes) in a Brazilian semi-arid reservoir

2015 ◽  
Vol 27 (1) ◽  
pp. 93-104 ◽  
Author(s):  
Bruno Renaly Souza Figueiredo ◽  
Gabrielle Joanne Medeiros Araujo ◽  
Márcio Joaquim da Silva ◽  
Elvio Sergio Figueredo Medeiros
Keyword(s):  
Food Availability ◽  
Fish Species ◽  
Resource Partitioning ◽  
Food Resource ◽  
Stomach Contents ◽  
Niche Overlap ◽  
Trophic Levels ◽  
Feeding Mode ◽  
Food Items ◽  
Semi Arid

AimResource partitioning has been recognized as a major driver affecting fish communities, with the potential to reduce interespecific competition. This is the result of differences in feeding apparatuses and feeding mode, location of the fish species in the water column and swimming ability, as well as type and size of prey and its availability. The present study surveys a highly limited aquatic system in semi-arid Brazil with regard to habitat and food availability, with very low diversity of fish, and poor in underwater habitat structures and prey, with the objective of understanding resource partitioning among fish species under such conditions.MethodsThree species of Cichlidae (Pisces: Perciformes) were sampled during the dry and wet seasons and had their stomach contents analyzed to evaluate food consumption. The resource partition among fish species was evaluated based on Pianka’s niche overlap index and tested for significance against null models.ResultsIt was observed a low overlap among the study species in food resource use, with individuals tending to specialize to select some food items. This is likely the result of low natural variation in abundance of specific food items associated with fish preferences (both morphological and behavioral).ConclusionsThese results support evidence that, in Brazilian semi-arid aquatic systems, coexistence of fish species seems to be enhanced by the partition of food items at specific trophic levels. Within this context, flow variability would have a key hole in fish coexistence by promoting a high diversity of aquatic habitat elements available for colonization of fish and their prey. Furthermore, food resources available to fish play an important role in this dynamics since prey foods are expected to vary in abundance as the habitat changes.

Use of stable isotopes in the evaluation of fish trophic guilds from a tropical hypersaline lagoon

2020 ◽  
Vol 100 (6) ◽  
pp. 979-988
Author(s):  
Marcos A. L. Franco ◽  
Alejandra F. G. N. Santos ◽  
Abílio S. Gomes ◽  
Marcelo G. de Almeida ◽  
Carlos E. de Rezende
Keyword(s):  
Stable Isotopes ◽  
Fish Species ◽  
Prey Availability ◽  
Niche Overlap ◽  
Abundant Species ◽  
Mean Value ◽  
Trophic Levels ◽  
Isotopic Niche ◽  
Trophic Guilds ◽  
Piscivorous Fish

AbstractEnvironmental factors, size-related isotopic changes of the most abundant species and isotopic niche overlap were investigated using stable isotopes in order to evaluate spatial changes of fish trophic guilds in the Araruama Lagoon. Based on 440 muscle samples, 17 fish species were grouped into five trophic guilds. Mean salinity was above 40 at both sites sampled and a significant spatial difference was observed. The highest δ13C mean value was observed for an omnivorous species, whereas the lowest carbon signatures were found for the three fish species belonging to the planktivorous guild. Analysis of the carbon signature of fish species in lower trophic levels showed influence of salinity variation, whilst size appeared to play a role for others. A narrow δ15N difference was observed, but the piscivorous fish species showed the highest δ15N values. The Standard Ellipses Analysis (SEA) detected spatial differences and varying degrees of isotopic niche overlap among trophic guilds, but the percentages of most overlaps (<60%) suggest that, to some extent, the guilds had a unique isotopic niche space. These results are in agreement with data previously reported for the Araruama Lagoon, that found the same prey items with varying relative importance among the most abundant species. Further studies are necessary to understand how the interaction between salinity and other factors, such as migration patterns, changes in prey availability, changes in contribution of primary sources and changes in baseline isotopic signatures could affect the stable isotope signatures shown here.

scholarly journals Changes in prey importance and prey niche overlap of sexes during the alpine newt breeding season

2020 ◽  
Vol 146 (2) ◽  
Author(s):  
Oldřich Kopecký
Keyword(s):  
Breeding Season ◽  
Stomach Contents ◽  
Niche Overlap ◽  
Trophic Niche ◽  
Sexual Differences ◽  
Food Sources ◽  
Quantitative Composition ◽  
Important Prey ◽  
Alpine Newt ◽  
Prey Items

Urodeles, including European newts, are usually sexually dimorphic predators. Among newts, the alpine newt has the most pronounced sexual size dimorphism (in favour of females). Gender is a factor that is often associated with intra-specific diet differences. Despite the significant number of dietary studies on the alpine newt, some topics such as the breadth of the trophic niche and its overlap between sexes, or inter-sexual differences in qualitative and quantitative composition of prey remain unresolved. The present study dealing with these questions was conducted at two localities (ponds at an elevation of about 450 m) in the Czech Republic. Newts were captured from the banks during the entire breeding season using a dip net, and the stomach contents were extracted using a stomach flushing technique. Altogether 190 individuals were sampled, and a total of 1,417 prey items were obtained. The available food sources differed over the course of the breeding season, as newts changed the taxa they preyed on. This reflects the ability of newts to switch between several hunting strategies. The overall food niche overlap between the sexes was relatively large (C = 0.761, resp. C = 0.797). Inter-sexual differences were detected at both localities, mainly in the number of prey items consumed from the most important prey categories such as Rana eggs or Isopoda, which were consumed in higher numbers by females. The findings of this study suggest that females are more sensitive to the trade-off between energy intake and expenditure during the breeding season.

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

2019 ◽  
Vol 149 (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.

Trophic structure of the bathyal benthos at an area with evidence of methane seep activity off southern Chile (~45°S)

2014 ◽  
Vol 94 (4) ◽  
pp. 659-669 ◽  
Author(s):  
Germán Zapata-Hernández ◽  
Javier Sellanes ◽  
Andrew R. Thurber ◽  
Lisa A. Levin
Keyword(s):  
Trophic Structure ◽  
Trophic Position ◽  
Demersal Fish ◽  
Trophic Levels ◽  
Food Sources ◽  
Isotopic Niche ◽  
Methane Seep ◽  
Southern Chile ◽  
Close Proximity ◽  
Third Trophic Level

Through application of carbon (C) and nitrogen (N) stable isotope analyses, we investigated the benthic trophic structure of the upper-slope off southern Chile (~45°S) including a recent methane seep area discovered as part of this study. The observed fauna comprised 53 invertebrates and seven fish taxa, including remains of chemosymbiotic fauna (e.g. chemosymbiotic bivalves and siboglinid polychaetes), which are typical of methane seep environments. While in close-proximity to a seep, the heterotrophic fauna had a nutrition derived predominantly from photosynthetic sources (δ13C > –21‰). The absence of chemosynthesis-based nutrition in the consumers was likely a result of using an Agassiz trawl to sample the benthos, a method that is likely to collect a mix of fauna including individuals from adjacent non-seep bathyal environments. While four trophic levels were estimated for invertebrates, the fish assemblage was positioned within the third trophic level of the food web. Differences in corrected standard ellipse area (SEAC), which is a proxy of the isotopic niche width, yielded differences for the demersal fish Notophycis marginata (SEAC = 5.1‰) and Coelorinchus fasciatus (SEAC = 1.1‰), suggesting distinct trophic behaviours. No ontogenic changes were detected in C. fasciatus regarding food sources and trophic position. The present study contributes the first basic trophic data for the bathyal area off southern Chile, including the identification of a new methane seep area, among the furthest south ever discovered. Such information provides the basis for the proper sustainable management of the benthic environments present along the vast Chilean continental margin.

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