scholarly journals Temporally varying isotopic niche overlap of the invasive ctenophore Mnemiopsis leidyi with other zooplanktivores in the western Dutch Wadden Sea

2018 ◽  
Author(s):  
Lodewijk van Walraven ◽  
Wouter van Looijengoed ◽  
A. Sarina Jung ◽  
Victor T. Langenberg ◽  
Henk W. van der Veer
Keyword(s):  
Fish Species ◽  
Wadden Sea ◽  
Niche Overlap ◽  
Nitrogen Isotope ◽  
Gelatinous Zooplankton ◽  
Early Summer ◽  
Mnemiopsis Leidyi ◽  
Isotopic Niche ◽  
Tissue Samples ◽  
Carbon And Nitrogen

AbstractThe invasive ctenophore Mnemiopsis leidyi can be a major predator of zooplankton in areas where it has been introduced. In this study, the possible competition of M. leidyi with native macroplankton and nekton in the western Dutch Wadden Sea was investigated in March–August, 2011 by determining and comparing isotopic niches of zooplanktivores. Stable carbon and nitrogen isotope signatures were determined from tissue samples of fish, scyphozoa, hydromedusa, ctenophores, crustaceans and cephalopods. δ15N of M. leidyi was positively related to ctenophore size, suggesting that small ctenophores occupied a lower trophic level than large ones. A cluster analysis showed that in the spring and early summer period, when M. leidyi densities are low, average δ13C and δ15N ratios of the invasive M. leidyi were similar to those of most other gelatinous zooplankton and pelagic fish species sampled. At the beginning of the bloom period in August there was no overlap in isotopic niche of M. leidyi with that of any other pelagic zooplanktivore. During this month the population consisted mainly of larvae and juveniles with lower δ15N ratios. At present, M. leidyi appears not to be a significant competitor for other gelatinous zooplankton and fish species because the period of high diet overlap with other consumers was also the period in which M. leidyi was least abundant.

scholarly journals Feeding ecology and niche overlap of Lake Ontario offshore forage fish assessed with stable isotopes

2018 ◽  
Vol 75 (5) ◽  
pp. 759-771 ◽  
Author(s):  
James A. Mumby ◽  
Timothy B. Johnson ◽  
Thomas J. Stewart ◽  
Edmund A. Halfyard ◽  
Brian C. Weidel ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Fish Species ◽  
Round Goby ◽  
Lake Ontario ◽  
Niche Overlap ◽  
Neogobius Melanostomus ◽  
Forage Fish ◽  
Isotopic Niche ◽  
Ecosystem Structure ◽  
Rainbow Smelt

The forage fish communities of the Laurentian Great Lakes continue to experience changes that have altered ecosystem structure, yet little is known about how they partition resources. Seasonal, spatial, and body size variation in δ13C and δ15N was used to assess isotopic niche overlap and resource and habitat partitioning among the five common offshore Lake Ontario forage fish species (n = 2037; alewife (Alosa pseudoharengus), rainbow smelt (Osmerus mordax), round goby (Neogobius melanostomus), and deepwater (Myoxocephalus thompsonii) and slimy (Cottus cognatus) sculpins). Round goby had the largest isotopic niche (6.1‰2, standard ellipse area), followed by alewife (3.4‰2), while rainbow smelt, slimy sculpin, and deepwater sculpin had the smallest and similar niche size (1.7‰2–1.8‰2), with only the sculpin species showing significant isotopic niche overlap (>63%). Stable isotopes in alewife, round goby, and rainbow smelt varied with location, season, and size, but did not vary in the sculpin species. Lake Ontario forage fish species have partitioned food and habitat resources, and non-native alewife and round goby have the largest isotopic niche, suggestive of a boarder ecological niche, and may contribute to their current high abundance.

scholarly journals Isotopic niches of sympatric native and exotic fish species in a Neotropical floodplain

2015 ◽  
Vol 87 (2) ◽  
pp. 825-833 ◽  
Author(s):  
Juliana S. Philippsen ◽  
Marília Hauser ◽  
Evanilde Benedito
Keyword(s):  
Exotic Species ◽  
Fish Species ◽  
Intraspecific Competition ◽  
Native Species ◽  
Niche Overlap ◽  
Food Resources ◽  
Foraging Strategies ◽  
Isotopic Niche ◽  
Exotic Fish ◽  
Niche Concept

This study investigated the isotopic niches of two fish species, one exotic and one native. It was hypothesized that these species would show little or no isotopic niche overlap. This hypothesis was tested with the isotopic niche concept and the trophic Layman's metrics. A considerable isotopic niche overlap was observed between the species, mainly for the exotic that showed the greater percentage of overlapping, indicating an interspecific competition for food resources. Layman's metrics also showed this species probably exploits a more specific array of food resources when compared with the native species. The native species probably has the ability to exploit a wider array of resources, highlighted by the higher values given for the Layman's metrics. The juveniles and adults of native species showed minor overlapping between the isotopic niches. This indicates that they have probably adopted different foraging strategies, minimizing intraspecific competition. Evidences that the exotic species explores a narrower range of resources and that the native species has a greater isotopic niche and possibly suffer less intraspecific competition, indicates that the native species can tolerate the presence of the exotic species and promote survival and maintenance of its population even under possible competition effects imposed by the exotic species.

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 C3 plant isotopic variability in a boreal mixed woodland: implications for bison and other herbivores

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12167
Author(s):  
Jessica Z. Metcalfe
Keyword(s):  
Niche Partitioning ◽  
Nitrogen Isotope ◽  
Isotopic Niche ◽  
C3 Plant ◽  
Carbon And Nitrogen ◽  
Plant Parts ◽  
Research Questions ◽  
Animal Diet ◽  
Dietary Plants ◽  
Reporting Data

Plant isotopic baselines are critical for accurately reconstructing ancient diets and environments and for using stable isotopes to monitor ecosystem conservation. This study examines the stable carbon and nitrogen isotope compositions (δ13C, δ15N) of terrestrial C3 plants in Elk Island National Park (EINP), Alberta, Canada, with a focus on plants consumed by grazers. EINP is located in a boreal mixed woodland ecozone close to the transition area between historic wood and plains bison habitats, and is currently home to separate herds of wood and plains bison. For this study, 165 C3 plant samples (grasses, sedges, forbs, shrubs, and horsetail) were collected from three habitat types (open, closed, and wet) during two seasons (summer and fall). There were no statistically significant differences in the δ13C or δ15N values of grasses, sedges, shrubs and forbs. On the other hand, plant δ13C and δ15N values varied among habitats and plant parts, and the values increased from summer to fall. These results have several implications for interpreting herbivore tissue isotopic compositions: (1) consuming different proportions of grasses, sedges, shrubs, and forbs might not result in isotopic niche partitioning, (2) feeding in different microhabitats or selecting different parts of the same types of plants could result in isotopic niche partitioning, and (3) seasonal isotopic changes in herbivore tissues could reflect seasonal isotopic changes in dietary plants rather than (or in addition to) changes in animal diet or physiology. In addition, the positively skewed plant δ15N distributions highlight the need for researchers to carefully evaluate the characteristics of their distributions prior to reporting data (e.g., means, standard deviations) or applying statistical models (e.g., parametric tests that assume normality). Overall, this study reiterates the importance of accessing ecosystem-specific isotopic baselines for addressing research questions in archaeology, paleontology, and ecology.

Impacts of zebra mussels (Dreissena polymorpha) on isotopic niche size and niche overlap among fish species in a mesotrophic lake

2021 ◽  
Author(s):  
Alexandra L. Morrison ◽  
Mary A. Thelen ◽  
Sarah E. Howe ◽  
Kyle D. Zimmer ◽  
Brian R. Herwig ◽  
...  
Keyword(s):  
Fish Species ◽  
Dreissena Polymorpha ◽  
Niche Overlap ◽  
Zebra Mussels ◽  
Isotopic Niche ◽  
Mesotrophic Lake

Carbon and Nitrogen Isotope Composition of the Wood of Pinus sylvestris, Betula pendula and Populus tremula

2020 ◽  
Vol 54 (8) ◽  
pp. 819-824
Author(s):  
P. Yu. Voronin ◽  
V. A. Mukhin ◽  
T. A. Velivetskaya ◽  
A. V. Ignatiev ◽  
Vl. V. Kuznetsov
Keyword(s):  
Pinus Sylvestris ◽  
Betula Pendula ◽  
Isotope Composition ◽  
Nitrogen Isotope ◽  
Populus Tremula ◽  
Carbon And Nitrogen ◽  
Nitrogen Isotope Composition

scholarly journals Seasonal feeding plasticity can facilitate coexistence of dominant omnivores in Neotropical streams

2021 ◽  
Author(s):  
Mayara P. Neves ◽  
Pavel Kratina ◽  
Rosilene L. Delariva ◽  
J. Iwan Jones ◽  
Clarice B. Fialho
Keyword(s):  
Seasonal Variation ◽  
Fish Species ◽  
Resource Availability ◽  
Seasonal Changes ◽  
Dry Season ◽  
Diet Overlap ◽  
Isotopic Niche ◽  
Neotropical Streams ◽  
Feeding Plasticity ◽  
The Impact

AbstractCoexistence of ecomorphologically similar species in diverse Neotropical ecosystems has been a focus of long-term debate among ecologists and evolutionary biologists. Such coexistence can be promoted by trophic plasticity and seasonal changes in omnivorous feeding. We combined stomach content and stable isotope analyses to determine how seasonal variation in resource availability influences the consumption and assimilation of resources by two syntopic fish species, Psalidodon aff. gymnodontus and P. bifasciatus, in the Lower Iguaçu basin. We also tested the impact of seasonality on trophic niche breadth and diet overlap of these two dominant omnivores. Seasonal changes in resource availability strongly influenced the consumption and assimilation of resources by the two fish species. Both species exhibited high levels of omnivory, characterized by high diversity of allochthonous resources in the wet season. Terrestrial invertebrates were the main component of diet during this season. However, in the dry season, both species reduced their isotopic niches, indicating diet specialization. High diet overlap was observed in both seasons, but the isotopic niche overlap was smaller in the dry season. Substantial reduction in the isotopic niche of P. bifascistus and a shift toward aquatic invertebrates can facilitate coexistence during this season of resource shortage. Feeding plasticity allows omnivorous fish to adjust their trophic niches according to seasonality, promoting the exploitation of different resources during periods of greater resource diversity. This seasonal variation could be an important mechanism that contributes to the resource partitioning and coexistence of dominant omnivores in Neotropical streams.

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