Using stable isotopes to track frugivory in migratory passerines

2009 ◽  
Vol 87 (11) ◽  
pp. 981-992 ◽  
Author(s):  
Chantal Gagnon ◽  
Keith A. Hobson
Keyword(s):  
Stable Isotopes ◽  
A Priori ◽  
Late Summer ◽  
Constrained Systems ◽  
American Robin ◽  
Migratory Songbirds ◽  
Isotope Technique ◽  
Dumetella Carolinensis ◽  
Empidonax Minimus ◽  
Diet Shifts

Several species of North American migratory songbirds undergo seasonal diet shifts from insects to fruits, but this phenomenon is poorly quantified. Measurement of naturally occurring stable isotopes of carbon (δ13C) and nitrogen (δ15N) are linked to sources of diets and trophic level, respectively. We used stable carbon (δ13C) and nitrogen (δ15N) isotope analyses of blood and claw tissues of 16 species of migratory songbirds to evaluate the timing and extent of frugivory over different periods. Species differed considerably in their tissue δ15N values, but we found poor isotopic segregation of species according to our a priori classifications as insectivores or omnivores. Season accounted for considerable variance in tissue δ15N values. However, only American Robin ( Turdus migratorius L., 1766), Northern Oriole ( Icterus galbula (L., 1758)), Gray Catbird ( Dumetella carolinensis (L., 1766)), Least Flycatcher ( Empidonax minimus (W.M. Baird and S.F. Baird, 1843)), and Warbling Vireo ( Vireo gilvus (Vieillot, 1808)) showed expected decrease in winter-grown tissue δ15N values compared with those grown in late summer. This indicates either that our a priori guild associations were incorrect and (or) that using stable isotopes to track frugivory at continental scales is problematic. We recommend that the isotope technique be used to track frugivory only in well-constrained systems where food-web δ15N follows reliable and understood trophic enrichment patterns.

Stable isotopes reveal habitat-related diet shifts in facultative deposit-feeders

2015 ◽  
Vol 95 ◽  
pp. 172-179 ◽  
Author(s):  
Francesca Rossi ◽  
Alexandra Baeta ◽  
João C. Marques
Keyword(s):  
Stable Isotopes ◽  
Deposit Feeders ◽  
Diet Shifts

Estimating the timing of diet shifts using stable isotopes

Oecologia ◽  
2005 ◽  
Vol 147 (2) ◽  
pp. 195-203 ◽  
Author(s):  
Donald L. Phillips ◽  
Peter M. Eldridge
Keyword(s):  
Stable Isotopes ◽  
Diet Shifts

scholarly journals Isotope Evidence of Rainfall and Groundwater for Tracing Recharge Areas in Kaeng Khoi District, Saraburi Province, Thailand

2016 ◽  
pp. 49-58 ◽  
Author(s):  
Wanlapa Wisittammasri ◽  
Srilert Chotpantarat
Keyword(s):  
Stable Isotopes ◽  
Surface Water ◽  
Stable Isotope ◽  
Meteoric Water ◽  
Water Line ◽  
Meteoric Water Line ◽  
Isotope Technique ◽  
Isotope Evidence ◽  
Stable Isotope Technique ◽  
Central Thailand

This study was conducted in the districts of Kaeng Khoi and Muang, located in the center of Saraburiprovince, Central Thailand. The purpose was to use a stable isotope technique to iden-tify recharge areas where rainfall infiltrates. Analysis of stable isotopes in groundwater, surface water and rainwater were conducted in September 2014. Isotope compositions of groundwater were found to have δD values that ranged from -37.55‰ to -48.04‰ while δ18O values ranged from -5.30‰ to -7.34‰. The Local Meteoric Water Line (LMWL) in the study area was indis-tinguishablefrom the Bangkok Local Meteoric Water Line (BKK LMWL), and the stable iso-tope values of rainwater in area were more depleted than BKK LMWL. The isotope compo-sitions of surface water revealed that the effect of evaporation could divide the groundwater into two groups, with the first group locally receiving rainfall and the second group interacting directly with surface water. Therefore, care must be taken to prevent groundwater contamination in the latter group due to polluted surface water caused by human activities.

Tolerance Optimization: A Decomposition Scheme, Variance Reduction and Fractional Approximation

2001 ◽  
Author(s):  
Mohamed H. Gadallah
Keyword(s):  
Variance Reduction ◽  
A Priori ◽  
Statistical Design ◽  
Global Optimum ◽  
Constrained Systems ◽  
Statistical Design Of Experiments ◽  
System Decomposition ◽  
Decomposition Scheme ◽  
Statistical Measures ◽  
Original Objective

Abstract Development of involved optimization algorithms is not an easy task for several reasons: First, every analyst is interested in a specific problem; Second, the capabilities of these methods may not be fully understood a priori; Third, coding of multi-purpose and more involved algorithms is not an easy job. In this paper, the optimization problem employing the near to global optimum algorithm is studied (Gadallah, M.H., 2000). The focus is to exploit 2 ideas: First, the algorithm can be modified to act as a variance reduction technique; Second, the algorithm can be modified to tackle the problem of system decomposition. Both ideas are novel within the context of statistical design of experiments. The first, if fully proved experimentally could yield the simultaneous integration of nominal and variance optimization possible. The second, can be extended to deal with multi-dimensional highly constrained systems with ease. These two ideas are explained wife the use of a simple example to illustrate the idea. An algorithm is developed that deal with the problem in several stages according to a predetermined decomposition scheme. The original objective and constraint functions are dealt with to suit each stage. Accordingly, all NP hard problems can ideally be transformed into NP complete ones with a consequence on the number of stages resulting from decomposition. Several decomposition scenarios are used and their results are compared numerically. Two orthogonal arrays and four composite arrays are used to plan experimentation; these are L27OA and L54OA and their subfamilies. These arrays are compared with respect to their statistical measures. The algorithm as such, is very promising optimization tool, especially for coupling system decomposition and variance reduction. Past work focused on either decomposition or statistical optimization. This work offers both capabilities. Several studies are reviewed and conclusions are drawn.

scholarly journals Reconstruction of Thermal Conditions in the Subboreal Inferred from Isotopic Studies of Groundwater and Calcareous Tufa from the Spring Mire Cupola in Wardzyń (Central Poland)

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1945 ◽  
Author(s):  
Tomasz Gruszczyński ◽  
Jerzy Małecki ◽  
Anastasiia Romanova ◽  
Maciej Ziułkiewicz
Keyword(s):  
Stable Isotopes ◽  
Environmental Changes ◽  
Dissolved Inorganic Carbon ◽  
A Priori ◽  
Thermal Conditions ◽  
Climate Conditions ◽  
Calcareous Tufa ◽  
Isotopic Studies ◽  
Living Organisms ◽  
Cool Climate

Studies with application of stable isotopes of oxygen and carbon have been performed on calcareous tufa, groundwater and dissolved inorganic carbon (DIC) from the spring mire cupola in Wardzyń. This study was focused on the verification of the a priori hypothesis that the analysed calcareous tufa is a chemical deposit and on the attempt to supplement an earlier scenario of environmental changes in the Subboreal with oscillations of water temperature. The constructed model of chemical and isotope balance, and δ13C determinations in DIC, allowed for calculating ratios of stable isotopes of carbon in particular speciations and in gaseous CO2. The obtained results coupled with δ13C values in calcite indicate that this mineral precipitated from the solution chemically (without the contribution of living organisms). Additionally, it was possible to reconstruct the temperature range at which the calcareous tufa was formed. The reconstructed scenario of changes in the thermal conditions was refined based on δ18O determinations in groundwater and calcite. Accordingly, the oldest calcareous tufa, with an age of about 5500 cal years BP, was formed in cool climate conditions (with average annual temperatures by about 3 °C lower than presently). The formation of younger series of the calcareous tufa took place between 4400–2900 cal years BP and represents a much warmer period with two distinct cooler episodes at 3900 and 3000 cal years BP, respectively. The course of the obtained temperature curves correlates well with the GISP2 curve and curves obtained for other sites in Northern, and Central Europe.

Spatial and Temporal Changes in Habitat Conditions in the Na'aman Stream Ecosystem, Israel

1993 ◽  
Vol 27 (7-8) ◽  
pp. 387-395
Author(s):  
Jean-Jacques Jennings ◽  
Avital Gasith
Keyword(s):  
Water Quality ◽  
Species Diversity ◽  
A Priori ◽  
Hydrological Regime ◽  
Late Summer ◽  
Polluted Water ◽  
Habitat Conditions ◽  
Stream Ecosystem ◽  
Lowland Streams ◽  
Coastal Streams

Nahal Na'aman is a small, shallow coastal stream in northern Israel. A three year study was conducted to examine the effect of habitat conditions on the biological structure and function of the stream ecosystem. Here we describe temporal and spatial changes in the water regime and water quality as measures of the stream's habitat conditions. Habitat condition is strongly influenced by the hydrological regime and the water quality. In dry years the water level drops and the upper section of the stream may dry up completely. Inflow of polluted water from various sources increasingly reduces water quality downstream. In general, the Na'aman may be categorized as oligo- to mesohaline stream, highly enriched with organic matter and nutrients. Sporadic pollution events markedly affect the water quality resulting in hypertrophic conditions, particularly at times of low stream levels. Low water quality was detected also in association with the drying and refilling of the stream's sections in late summer and in fall, respectively, and following runoff in winter. The oligohaine nature of the stream a priori reduces species diversity relative to other freshwater, lowland streams/Based on water quality conditions, highest species diversity may be expected in the spring area and the upper section of the stream. However, habitat conditions in this section are most unstable due to changes of the hydrological regime. This, in turn, is expected to further reduce species richness and diversity. The extreme conditions are expected to determine the limit for the development of plant and animal life in the stream. This study illustrates the inherent problems of the coastal streams of Israel, namely, diminishing natural flow which is often replaced by discharge of effluent or sewage. Rehabilitation of the Na'aman and other coastal streams demands a radical solution for these problems.

scholarly journals A four-compartment compartmental model to assess net whole body protein breakdown using a pulse of phenylalanine and tyrosine stable isotopes in humans

2017 ◽  
Vol 313 (1) ◽  
pp. E63-E74 ◽  
Author(s):  
Alvise Mason ◽  
Mariëlle P. K. J. Engelen ◽  
Ivan Ivanov ◽  
Gianna M. Toffolo ◽  
Nicolaas E. P. Deutz
Keyword(s):  
Stable Isotopes ◽  
A Priori ◽  
Flux Ratio ◽  
Fat Free Mass ◽  
Whole Body ◽  
Protein Breakdown ◽  
Detailed Model ◽  
Body Protein ◽  
Health And Disease ◽  
Net Protein

The stable isotopes of phenylalanine (Phe) and tyrosine (Tyr) are often used to study whole body protein metabolism in humans. Noncompartmental approaches give limited physiological insight in the compartmental characteristics. We therefore developed a compartmental mathematical model of Phe/Tyr metabolism to describe protein fluxes by using stable tracer dynamic data in plasma following intravenous bolus of l-[ring-13C6]Phe and l-[ ring-2H4]Tyr in healthy subjects. The model consists of four compartments describing Phe/Tyr kinetics. Because the model is a priori nonidentifiable, it is quantified in terms of two uniquely identifiable submodels representing two limit case scenarios, based on known physiology. The two submodels, identified by using the software SAAM II, fit well the experimental data of all individuals and provide an unbiased overview of the metabolic pathway in terms of intervals of validity of the non-uniquely identifiable variables. The model provides estimates of the flux from Phe to Tyr [4.1 ± 1.0 µmol·kg fat-free mass (FFM)−1·h−1 (mean ± SE)] and intervals of validity of the flux and pool estimates. Our preferred submodel yielded protein breakdown flux (50.5 ± 5.2 µmol·kg FFM−1·h−1), net protein breakdown (4.1 ± 1.0 µmol·kg FFM−1·h−1), Tyr from Phe hydroxylation (~12%), hydroxylated Phe (~8%), and flux ratio of Tyr to Phe arising from protein catabolism (0.68), consistent with available literature. The other submodel suggest that the assumptions made by noncompartmental analysis are consistently underestimated. Our accurate and detailed model for estimating Phe/Tyr metabolic pathways in humans might be essential to applications in a variety of scenarios describing whole body protein synthesis and breakdown in health and disease.

scholarly journals Stomach contents and stable isotopes confirm ontogenetic diet shifts of Nile perch, Lates niloticus, in southern Lake Victoria

2018 ◽  
Vol 44 (6) ◽  
pp. 1264-1272 ◽  
Author(s):  
I.J.M. Cornelissen ◽  
J. Vijverberg ◽  
A.M. van den Beld ◽  
N.R. Helmsing ◽  
J.A.J. Verreth ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Lake Victoria ◽  
Stomach Contents ◽  
Nile Perch ◽  
Ontogenetic Diet Shifts ◽  
Lates Niloticus ◽  
Diet Shifts

Energetic consequences of diet shifts in Lake Erie rainbow smelt (Osmerus mordax)

2005 ◽  
Vol 62 (1) ◽  
pp. 145-152 ◽  
Author(s):  
SL Parker Stetter ◽  
L D Witzel ◽  
L G Rudstam ◽  
D W Einhouse ◽  
E L Mills
Keyword(s):  
Lake Erie ◽  
Food Resource ◽  
Fork Length ◽  
Late Summer ◽  
Osmerus Mordax ◽  
Bythotrephes Longimanus ◽  
Rainbow Smelt ◽  
The 1960S ◽  
Diet Shifts ◽  
Bioenergetics Models

The diet of eastern Lake Erie rainbow smelt (Osmerus mordax) has changed since the 1960s, reflecting food resource shifts due to phosphorus reductions and the invasion of exotic species (dreissenid mussels and Bythotrephes longimanus). Since rainbow smelt growth was lower in the 1990s than in the 1960s, we considered diet changes as an explanation. A decrease in the proportion of zooplankton occurred in the summer (May–August) diet of two size classes (63–88 and 89–114 mm fork length) between 1961 and 1999. Within the zooplankton, the proportion of Bythotrephes increased. In spite of these changes, energy density (joules per gram) of the summer (June–August) diet has not changed since 1961. However, during the late-summer and fall, predation on Bythotrephes, and therefore the proportion of indigestible spines in the stomach, increases. Using bioenergetics models, we show that Lake Erie rainbow smelt could achieve 66%–155% greater growth between June and October if Bythotrephes spines were replaced with digestible prey items, resulting in end-of-season weights and lengths similar to the 1985–1990 period. Our results indicate that indigestible Bythotrephes spines may reduce growth by occupying space in the stomach but providing no nutritional value to the fish, thereby reducing the realized daily ration for rainbow smelt.

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