scholarly journals On the Use of Stable Hydrogen Isotope Measurements (δ2H) to Discern Trophic Level in Avian Terrestrial Food Webs

Diversity ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 202
Author(s):  
Rien E. van Wijk ◽  
Yahkat Barshep ◽  
Keith A. Hobson
Keyword(s):  
Food Webs ◽  
Hydrogen Isotope ◽  
Trophic Position ◽  
Terrestrial Ecosystems ◽  
Forest Site ◽  
Trophic Enrichment ◽  
Terrestrial Environments ◽  
Closed Canopy ◽  
Stable Hydrogen Isotope ◽  
Δ15n And Δ13c

The measurement of stable hydrogen isotope ratios (δ2H) in animal tissues is a popular means of inferring spatial origins and migratory connections. However, the use of this isotope to infer diet and potentially trophic position remains poorly understood, especially in non-aquatic terrestrial ecosystems. In many animal communities, tissue δ15N values are strongly associated with trophic position. Correlations between tissue δ2H and δ15N are expected, then, if δ2H is affected by trophic enrichment of 2H. In addition, within sites, we would expect higher tissue δ2H values in insectivorous species compared to granivores or nectarivores. We tested these hypotheses for two resident avian communities in Nigeria consisting of 30 species representing a range of dietary guilds (granivores, frugivores, nectarivores, omnivores, insectivores) by comparing feather δ2H, δ15N and δ13C values. We found considerable isotopic overlap among all guilds except granivores, with no clear pattern of enrichment in 2H with trophic position. However, at one of our sites (open scrubland), feather δ2H was positively correlated with feather δ15N (R2 = 0.30) compared to a closed canopy forest site (R2 = 0.09). Our results indicate weak evidence for predictable trophic enrichment in 2H in terrestrial environments and indicate that controlled studies are now required to definitively elucidate the behavior of H isotopes in terrestrial food webs.

Trophic Position of Consumers and Size Structure of Food Webs across Aquatic and Terrestrial Ecosystems

2019 ◽  
Vol 194 (6) ◽  
pp. 823-839 ◽  
Author(s):  
Anton M. Potapov ◽  
Ulrich Brose ◽  
Stefan Scheu ◽  
Alexei V. Tiunov
Keyword(s):  
Food Webs ◽  
Size Structure ◽  
Trophic Position ◽  
Terrestrial Ecosystems

Ecosystem differences in the trophic enrichment of 13C in aquatic food webs

1997 ◽  
Vol 54 (6) ◽  
pp. 1255-1258 ◽  
Author(s):  
R L France ◽  
R H Peters
Keyword(s):  
Food Webs ◽  
Trophic Position ◽  
Open Ocean ◽  
Food Sources ◽  
Regression Equations ◽  
Combining Data ◽  
Trophic Enrichment ◽  
Aquatic Food ◽  
Alternative Food Sources ◽  
Estuarine Coastal

Data from 35 published studies were collated to examine patterns in the trophic enrichment of 13C of consumers. Because both delta 13C and delta 14N vary systematically across ecosystems, it was necessary to standardize for such differences before combining data from numerous sources. Relationships of these measures of ecosystem-standardized delta 13C to ecosystem-standardized trophic position ( DELTA delta 15N) for freshwater, estuarine, coastal, and open-ocean and for all aquatic ecosystems yielded regression equations of low predictive capability (average of 20% explained variance in delta 13C). However, differences were observed in the slopes between delta 13C and standardized trophic position when data were examined study-specifically: the average trophic fractionation of 13C was found to increase from + 0.2omicron for freshwater to + 0.5omicron for estuarine to + 0.8omicron for coastal, and to + 1.1omicron for open-ocean food webs. This ecosystem-specific gradient in 13C enrichment for consumers supports previous findings of a similar continuum existing for zooplankton - particulate organic matter differences in delta 13C. Possible mechanisms to explain these ecosystem-specific patterns in 13C enrichment may be related to the relative importance of detritus, heterotrophic respiration, partial reliance on alternative food sources, and lipid influences in the different ecosystems.

scholarly journals First study of food webs in a large glacial river: the trophic role of invasive trout

2020 ◽  
Vol 18 (3) ◽  
Author(s):  
Marina Tagliaferro ◽  
Sean P. Kelly ◽  
Miguel Pascual
Keyword(s):  
Rainbow Trout ◽  
Food Webs ◽  
Fish Species ◽  
Lake Trout ◽  
Trophic Position ◽  
Life Stage ◽  
Trophic Levels ◽  
Basal Resources ◽  
Ecological Importance ◽  
Δ15n And Δ13c

Abstract The aim of this study was to determine the food webs structure of a large Patagonian river in two river sections (Upstream and Midstream) and to evaluate isotopic overlap between native and introduced species. We used stable isotope analyses of δ15N and δ13C and stomach content. The Upstream section had a more complex food webs structure with a greater richness of macroinvertebrates and fish species than Midstream. Upstream basal resources were dominated by filamentous algae. Lake Trout were found to have a higher trophic position than all other fish species in that area although, the most abundant fish species, were Rainbow Trout. Depending on the life stage, Rainbow Trout shifted from prey to competitor/predator. In the Midstream section, the base of the food webs was dominated by coarse particulate organic matter, and adult Rainbow Trout had the highest trophic level. Isotopic values changed among macroinvertebrates and fish for both areas. The two most abundant native and invasive species — Puyen and Rainbow Trout — showed an isotopic separation in Midstream but did not in Upstream areas. The presence of invasive fish that occupy top trophic levels can have a significant impact on native fish populations that have great ecological importance in the region.

Effects of size and diet on stable hydrogen isotope values (δD) in fish: implications for tracing origins of individuals and their food sources

2011 ◽  
Vol 68 (11) ◽  
pp. 2011-2019 ◽  
Author(s):  
David X. Soto ◽  
Leonard I. Wassenaar ◽  
Keith A. Hobson ◽  
Jordi Catalan
Keyword(s):  
Fish Species ◽  
Hydrogen Isotope ◽  
Trophic Position ◽  
Feeding Habits ◽  
Food Sources ◽  
Nutrient Inputs ◽  
Roach Rutilus Rutilus ◽  
Trophic Effect ◽  
Silurus Glanis ◽  
Stable Hydrogen Isotope

Recent studies suggest that stable hydrogen isotope ratios (δD) of fish can be used to track their watershed origin and the relative contributions of source material. Both applications assume that there is no metabolic or trophic effect on tissue δD. We studied the local variation of δD values in four fish species of contrasting size and feeding habits in an isotopically homogenous reservoir (Flix, Spain). Other isotopic values (δ15N, δ13C) and trace metal content were measured as indicators of trophic and bioaccumulation patterns. In addition, isotopic values (δD, δ15N, δ13C) of other food web components were measured for comparison. Muscle δD values differed greatly among fish species: European catfish, Silurus glanis (–131‰); common carp, Cyprinus carpio (–141‰); rudd, Scardinius erythrophthalmus (–158‰); and roach, Rutilus rutilus (–163‰). The influence of fish size and trophic position affected the fish δD values. Possible mechanisms that drive δD variation among fish might be a metabolic effect and (or) the compounding effect of ambient water δD on exchangeable H at each trophic stage. Our findings showed that size and feeding habits are factors that should be controlled when tracing origins of fish or their dependence on nutrient inputs using δD measurements.

scholarly journals Eutrophication induces shifts in the trophic position of invertebrates in aquatic food webs

Ecology ◽  
2020 ◽  
Author(s):  
Gea H. Lee ◽  
J. Arie Vonk ◽  
Ralf C.M. Verdonschot ◽  
Michiel H.S. Kraak ◽  
Piet F.M. Verdonschot ◽  
...  
Keyword(s):  
Food Webs ◽  
Trophic Position ◽  
Aquatic Food Webs ◽  
Aquatic Food

scholarly journals Mass spectrometric measurement of hydrogen isotope fractionation for the reactions of chloromethane with OH and Cl

2018 ◽  
Author(s):  
Frank Keppler ◽  
Enno Bahlmann ◽  
Markus Greule ◽  
Heinz Friedrich Schöler ◽  
Julian Wittmer ◽  
...  
Keyword(s):  
Hydrogen Isotope ◽  
Isotope Fractionation ◽  
Isotope Effects ◽  
Isotope Analysis ◽  
Isotope Ratio Mass Spectrometry ◽  
Detailed Knowledge ◽  
Mass Spectrometric Measurement ◽  
Isotopic Analyses ◽  
Chlorine Radicals ◽  
Stable Hydrogen Isotope

Abstract. Chloromethane (CH3Cl) is an important provider of chlorine to the stratosphere but yet lacks detailed knowledge of its budget. Stable isotope analysis is potentially a powerful tool to constrain CH3Cl flux estimates. The largest degree of isotope fractionation is expected to occur for deuterium in CH3Cl in the hydrogen abstraction reactions with its main sink reactant tropospheric OH and its minor sink reactant Cl atoms. We determined the isotope fractionation by stable hydrogen isotope analysis of the fraction of CH3Cl remaining after reaction with hydroxyl and chlorine radicals in a 3.5 m3 Teflon smog-chamber at 293 ± 1 K. We measured the increasing stable hydrogen isotope values of the unreacted CH3Cl using compound specific thermal conversion isotope ratio mass spectrometry. The isotope fractionations of CH3Cl for the reactions with hydroxyl and chlorine radicals were found to be −242 ± 7 mUr (or ‰) and −280 ± 11 mUr, respectively. For comparison, we performed similar experiments using methane (CH4) as the target compound with OH and obtained a fractionation constant of −205 ± 6 mUr which is in good agreement with values previously reported. The observed large kinetic isotope effects are helpful when employing isotopic analyses of CH3Cl in the atmosphere to improve our knowledge of its atmospheric budget.

scholarly journals On the biogeography of salt limitation: A study of ant communities

2008 ◽  
Vol 105 (46) ◽  
pp. 17848-17851 ◽  
Author(s):  
Michael Kaspari ◽  
Stephen P. Yanoviak ◽  
Robert Dudley
Keyword(s):  
Global Change ◽  
Food Webs ◽  
New World ◽  
Terrestrial Ecosystems ◽  
Forest Litter ◽  
Sodium Concentration ◽  
Ant Communities ◽  
Sodium Toxicity ◽  
Changing Patterns ◽  
Essential Nutrient

Sodium is an essential nutrient whose deposition in rainfall decreases with distance inland. The herbivores and microbial decomposers that feed on sodium-poor vegetation should be particularly constrained along gradients of decreasing sodium. We studied the use of sucrose and NaCl baits in 17 New World ant communities located 4–2757 km inland. Sodium use was higher in genera and subfamilies characterized as omnivores/herbivores compared with those classified as carnivores and was lower in communities embedded in forest litter than in those embedded in abundant vegetation. Sodium use was increased in ant communities further inland, as was preference for the baits with the highest sodium concentration. Sucrose use, a measure of ant activity, peaked in communities 10–100 km inland. We suggest that the geography of ant activity is shaped by sodium toxicity near the shore and by sodium deficit farther inland. Given the importance of ants in terrestrial ecosystems, changing patterns of rainfall with global change may ramify through inland food webs.

scholarly journals Round-trip across the Sahara: Afrotropical Painted Lady butterflies recolonize the Mediterranean in early spring

2018 ◽  
Vol 14 (6) ◽  
pp. 20180274 ◽  
Author(s):  
Gerard Talavera ◽  
Clément Bataille ◽  
Dubi Benyamini ◽  
Martin Gascoigne-Pees ◽  
Roger Vila
Keyword(s):  
Hydrogen Isotope ◽  
Migratory Birds ◽  
Early Spring ◽  
Round Trip ◽  
Reverse Migration ◽  
Vanessa Cardui ◽  
Tangible Evidence ◽  
Stable Hydrogen Isotope ◽  
Sub Saharan ◽  
Work Supports

The Palearctic–African migratory circuit has been typically associated with birds. Very few insects are known to endure annual trans-Saharan circuits, but the Painted Lady butterfly ( Vanessa cardui ) is an exception. While it was demonstrated that this species massively migrates from Europe to the Afrotropics during the autumn, the existence of a reverse migration from the Afrotropics to Europe in the early spring remains hypothetical. Here, we analysed wing stable hydrogen isotope values (δ 2 H) of V. cardui migrants collected from February to April across the circum-Mediterranean region. We assessed their region of natal origin by comparing their wing isotope signature predicted δ 2 H values (isoscape). The results unambiguously demonstrate a sub-Saharan origin for many individuals, especially those collected in February, representing the first tangible evidence for a reverse northwards trans-Saharan migration in spring. This work supports the view that the Afrotropics (mostly exploited from September to February) is key in the V. cardui Palearctic–African population dynamics. This species relies on both temperate and tropical habitats to complete their multigenerational cycle, an unprecedented adaptation for butterflies and for most migratory insects. Such a migratory circuit has strong parallelisms with those of migratory birds.

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