scholarly journals The value of coastal saltpans for migratory shorebirds: conservation insights from a stable isotope approach based on feeding guild and body size

2021 ◽  
Author(s):  
Weipan Lei ◽  
Jose A. Masero ◽  
Caroline Dingle ◽  
Yang Liu ◽  
Ziwen Chai ◽  
...  
Keyword(s):  
Body Size ◽  
Stable Isotope ◽  
Feeding Guild ◽  
Migratory Shorebirds

scholarly journals Body size and stable isotope composition of zooplankton in the western tropical Atlantic

2020 ◽  
Vol 212 ◽  
pp. 103449
Author(s):  
Gabriela Guerra Araújo Abrantes de Figueiredo ◽  
Ralf Schwamborn ◽  
Arnaud Bertrand ◽  
Jean-Marie Munaron ◽  
François Le Loc'h
Keyword(s):  
Body Size ◽  
Stable Isotope ◽  
Isotope Composition ◽  
Tropical Atlantic ◽  
Stable Isotope Composition

scholarly journals Sex, Age, and Body Size Distributions of Western Sandpipers During the Nonbreeding Season With Respect to Local Habitat

The Condor ◽  
2006 ◽  
Vol 108 (3) ◽  
pp. 547-557 ◽  
Author(s):  
Guillermo Fernández ◽  
David B. Lank
Keyword(s):  
Population Structure ◽  
Body Size ◽  
Local Density ◽  
Late Winter ◽  
Size Distributions ◽  
Nonbreeding Season ◽  
Age Class ◽  
Migratory Shorebirds ◽  
Western Sandpipers ◽  
Northwestern Mexico

AbstractWe documented the local density and sex, age-class, and body size distributions of Western Sandpipers (Calidris mauri) among habitats at Bahía Santa María, northwestern Mexico, during the nonbreeding season. Three habitats were recognized: brackish flats, mangroves, and cattail marshes, which we ranked as richest to poorest in food resources and safest to most dangerous in predation danger. Western Sandpiper population structure differed among habitats. Bird densities were highest in brackish flats, the richest and safest habitat, and males and adults of both sexes were overrepresented. In cattail marshes, which appeared to be the poorest and most dangerous habitat, bird densities were lower, and the sex ratio and age ratios within each sex were more even. In mangroves, bird densities were similar to those in cattail marshes, but sex and age ratios were similar to those in brackish flats. Exposed culmen, an index of structural size, was not related to habitat use in either sex. Body mass of immature males was more variable than that of adults among habitats and immature males gained mass throughout the winter. Birds in brackish flats and mangroves were initially heavier, but tended to lose mass, whereas birds in cattail marshes were initially lighter, but tended to gain mass. Mass distributions thus converged in late winter. While the social and ecological causes and significance of differential sex and age-class distributions among habitats remain largely unquantified, evidence from this and previous studies suggests that nonbreeding population structure is a common phenomenon with important implications for migratory shorebirds.

scholarly journals Increase in stable isotope ratios driven by metabolic alterations in amphipods exposed to the beta-blocker propranolol

2019 ◽  
Author(s):  
Caroline Ek ◽  
Zhenyang Yu ◽  
Andrius Garbaras ◽  
Hanna Oskarsson ◽  
Ann-Kristin Eriksson Wiklund ◽  
...  
Keyword(s):  
Body Size ◽  
Stable Isotope ◽  
Sublethal Effects ◽  
Isotope Ratios ◽  
Stable Isotope Ratios ◽  
Anthropogenic Pressures ◽  
Contaminant Exposure ◽  
Scope For Growth ◽  
Oxidative Balance ◽  
Stable Isotope Signatures

AbstractAnthropogenic pressures, such as contaminant exposure, may affect stable isotope ratios in biota. These changes are driven by alterations in the nutrient allocation and metabolic pathways induced by specific stressors. In a controlled microcosm study with the amphipod Gammarus spp., we studied effects of the β-blocker propranolol on stable isotope signatures (δ15N and δ13C), elemental composition (%C and %N), and growth (protein content and body size) as well as biomarkers of oxidative status (antioxidant capacity, ORAC; lipid peroxidation, TBARS) and neurological activity (acetylcholinesterase, AChE). Based on the known effects of propranolol exposure on cellular functions, i.e., its mode of action (MOA), we expected to observe a lower scope for growth, accompanied by a decrease in protein deposition, oxidative processes and AChE inhibition, with a resulting increase in the isotopic signatures. The observed responses supported most of these predictions. In particular, %N was positively affected by propranolol, whereas both protein allocation and body size declined. Moreover, both ORAC and TBARS levels decreased with increasing propranolol concentration, with the decrease being more pronounced for TBARS, which indicates the prevalence of the antioxidative processes. These changes resulted in a significant increase of the δ15N and δ13C values in the propranolol-exposed animals compared to the control. These findings suggest that MOA of β-blockers may be used to predict sublethal effects in nontarget species, including inhibited AChE activity, improved oxidative balance, and elevated stable isotope ratios. The latter also indicates that metabolism-driven responses to environmental contaminants can alter stable isotope signatures, which should be taken into account when interpreting trophic interactions in the food webs.

Liver breath tests non-invasively predict higher stages of non-alcoholic steatohepatitis

2006 ◽  
Vol 111 (2) ◽  
pp. 135-143 ◽  
Author(s):  
Piero Portincasa ◽  
Ignazio Grattagliano ◽  
Bernhard H. Lauterburg ◽  
Vincenzo O. Palmieri ◽  
Giuseppe Palasciano ◽  
...  
Keyword(s):  
Body Size ◽  
Stable Isotope ◽  
Predictive Value ◽  
Breath Tests ◽  
Alcoholic Fatty Liver ◽  
Simple Steatosis ◽  
Non Invasive ◽  
Alcoholic Steatohepatitis ◽  
Metabolic Functions ◽  
Mitochondrial Functions

Effectively assessing subtle hepatic metabolic functions by novel non-invasive tests might be of clinical utility in scoring NAFLD (non-alcoholic fatty liver disease) and in identifying altered metabolic pathways. The present study was conducted on 39 (20 lean and 19 obese) hypertransaminasemic patients with histologically proven NAFLD {ranging from simple steatosis to severe steatohepatitis [NASH (non-alcoholic steatohepatitis)] and fibrosis} and 28 (20 lean and eight overweight) healthy controls, who underwent stable isotope breath testing ([13C]methacetin and [13C]ketoisocaproate) for microsomal and mitochondrial liver function in relation to histology, serum hyaluronate, as a marker of liver fibrosis, and body size. Compared with healthy subjects and patients with simple steatosis, NASH patients had enhanced methacetin demethylation (P=0.001), but decreased (P=0.001) and delayed (P=0.006) ketoisocaproate decarboxylation, which was inversely related (P=0.001) to the degree of histological fibrosis (r=−0.701), serum hyaluronate (r=−0.644) and body size (r=−0.485). Ketoisocaproate decarboxylation was impaired further in obese patients with NASH, but not in patients with simple steatosis and in overweight controls. NASH and insulin resistance were independently associated with an abnormal ketoisocaproate breath test (P=0.001). The cut-off value of 9.6% cumulative expired 13CO2 for ketoisocaproate at 60 min was associated with the highest prediction (positive predictive value, 0.90; negative predictive value, 0.73) for NASH, yielding an overall sensitivity of 68% and specificity of 94%. In conclusion, both microsomal and mitochondrial functions are disturbed in NASH. Therefore stable isotope breath tests may usefully contribute to a better and non-invasive characterization of patients with NAFLD.

scholarly journals Zooplankton predators and prey: body size and stable isotope to investigate the pelagic food web in a deep lake (Lake Iseo, Northern Italy)

2016 ◽  
Author(s):  
Barbara Leoni
Keyword(s):  
Body Size ◽  
Stable Isotope ◽  
Body Length ◽  
Trophic Position ◽  
Isotope Analysis ◽  
Large Body ◽  
Zooplankton Community ◽  
Open Water ◽  
Northern Italy ◽  
Food Sources

<p>Seasonal changes in trophic position and food sources of deep subalpine lake (Lake Iseo, Northern Italy) zooplankton taxa were investigated during the year 2011. Furthermore, it's combined carbon and nitrogen Stable Isotope Analysis (SIA) with size-specific analyses of both, the major predatory cladoceran (<em>Leptodora kindtii</em><em>,</em> Focke) and two potential preys (<em>Daphnia</em> <em>longispina</em> complex and <em>Eubosmina longicornis</em>). SIA studies have been extremely useful to track the energy flow through complex trophic network, however, if it is applied to analyze relation between two/few species may lead to misleading interpretations. In fact, integrating size-specificity allowed for understanding why <em>L. kindtii</em> nitrogen isotopic fingerprint fully overlapped with <em>Daphnia</em>, in spring. By investigating changes in <em>L. kindtii</em>'s feeding basket, we found that in spring, <em>L. kindtii </em>mainly relied upon <em>E. longicornis </em>as prey, <em>Daphnia</em> being of too large body size for being captured by <em>L. kindtii.</em> Among preys encountered directly in front by a free-swimming <em>Leptodora</em>, only those able to fit into basket opening can be captured. As basket diameter increases with animal body length, size selection of prey depends on <em>L. kindtii</em> body length. As in other deep, subalpine lakes, <em>E. longicornis </em>was less <sup>15</sup>N-enriched than <em>Daphnia</em>, most likely because of exploiting nitrogen fixing, cyanobacteria colonies, commonly detected in Lake Iseo with the onset of thermal stratification. Cyclopoid adults were at the top of zooplankton food chain and they could potentially be feeding on <em>Daphnia</em>. They, however, likely fed in a different habitat (&gt;20 m deep water), as suggested by a rather than negligible carbon fractionation. The results overall suggest that size-specificity is crucial for addressing space and time changes in trophic links between organisms composing the two hierarchical levels within open water zooplankton community.</p><p> </p>

scholarly journals Isotopic niche reflects stress-induced variability in physiological status

2018 ◽  
Vol 5 (2) ◽  
pp. 171398 ◽  
Author(s):  
Agnes M. L. Karlson ◽  
Martin Reutgard ◽  
Andrius Garbaras ◽  
Elena Gorokhova
Keyword(s):  
Body Size ◽  
Stable Isotope ◽  
Trophic Ecology ◽  
Physiological Stress ◽  
Isotope Composition ◽  
Stress Factors ◽  
Physiological Status ◽  
Isotopic Niche ◽  
Control Groups ◽  
Oxygen Conditions

The isotopic niche has become an established concept in trophic ecology. However, the assumptions behind this approach have rarely been evaluated. Evidence is accumulating that physiological stress can affect both magnitude and inter-individual variability of the isotopic signature in consumers via alterations in metabolic pathways. We hypothesized that stress factors (inadequate nutrition, parasite infestations, and exposure to toxic substances or varying oxygen conditions) might lead to suboptimal physiological performance and altered stable isotope signatures. The latter can be misinterpreted as alterations in isotopic niche. This hypothesis was tested by inducing physiological stress in the deposit-feeding amphipod Monoporeia affinis exposed to either different feeding regimes or contaminated sediments. In the amphipods, we measured body condition indices or reproductive output to assess growth status and δ 13 C and δ 15 N values to derive isotope niche metrics. As hypothesized, greater isotopic niche estimates were derived for the stressed animals compared to the control groups. Moreover, the δ 15 N values were influenced by body size, reproductive status and parasite infestations, while δ 13 C values were influenced by body size, oxygen conditions and survival. Using regression analysis with isotope composition and growth variables as predictors, we were able to discriminate between the amphipods exposed to nutritionally or chemically stressful conditions and those in the control groups. Thus, interpretation of isotopic niche can be confounded by natural or anthropogenic stressors that may induce an apparent change in isotopic niche. These findings stress the importance of including measures of growth and health status when evaluating stable isotope data in food web studies.

scholarly journals Body size is more important than diet in determining stable-isotope estimates of trophic position in crocodilians

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Francisco Villamarín ◽  
Timothy D. Jardine ◽  
Stuart E. Bunn ◽  
Boris Marioni ◽  
William E. Magnusson
Keyword(s):  
Body Size ◽  
Stable Isotope ◽  
Trophic Position

scholarly journals Responses of invertebrate trophic level, feeding guild and body size to the management of improved grassland field margins

2009 ◽  
Vol 46 (4) ◽  
pp. 920-929 ◽  
Author(s):  
Ben A. Woodcock ◽  
Simon G. Potts ◽  
Thomas Tscheulin ◽  
Emma Pilgrim ◽  
Alex J. Ramsey ◽  
...  
Keyword(s):  
Body Size ◽  
Trophic Level ◽  
Field Margins ◽  
Feeding Guild
Sign in / Sign up

Export Citation Format

Share Document