scholarly journals Foraging behaviour and habitat-use drives niche segregation in sibling seabird species

2020 ◽  
Vol 7 (9) ◽  
pp. 200649
Author(s):  
Ryan R. Reisinger ◽  
Tegan Carpenter-Kling ◽  
Maëlle Connan ◽  
Yves Cherel ◽  
Pierre A. Pistorius
Keyword(s):  
Stable Isotope ◽  
Habitat Use ◽  
Foraging Behaviour ◽  
Trophic Ecology ◽  
Sympatric Species ◽  
Environmental Data ◽  
Niche Segregation ◽  
Seabird Species ◽  
Carbon And Nitrogen ◽  
Gps Tracks

To mediate competition, similar sympatric species are assumed to use different resources, or the same but geographically separated resources. The two giant petrels ( Macronectes spp.) are intriguing in that they are morphologically similar seabirds with overlapping diets and distributions. To better understand the mechanisms allowing their coexistence, we investigated intra- and interspecific niche segregation at Marion Island (Southern Indian Ocean), one of the few localities where they breed in sympatry. We used GPS tracks from 94 individuals and remote-sensed environmental data to quantify habitat use, combined with blood carbon and nitrogen stable isotope ratios from 90 individuals to characterize their foraging habitat and trophic ecology. Females of both species made distant at-sea foraging trips and fed at a similar trophic level. However, they used distinct pelagic habitats. By contrast, males of both species mainly foraged on or near land, resulting in significant sexual segregation, but high interspecific habitat and diet overlap. However, some males showed flexible behavioural strategies, also making distant, pelagic foraging trips. Using contemporaneous tracking, environmental and stable isotope data we provide a clear example of how sympatric sibling species can be segregated along different foraging behaviour dimensions.

Stable isotopes of carbon and nitrogen in the study of avian and mammalian trophic ecology

2000 ◽  
Vol 78 (1) ◽  
pp. 1-27 ◽  
Author(s):  
Jeffrey F Kelly
Keyword(s):  
Stable Isotopes ◽  
Stable Isotope ◽  
Carbon Isotope ◽  
Isotope Ratio ◽  
Trophic Ecology ◽  
Nitrogen Isotope ◽  
Isotope Ratios ◽  
Food Chains ◽  
Stable Isotope Ratios ◽  
Carbon And Nitrogen

Differential fractionation of stable isotopes of carbon during photosynthesis causes C4 plants and C3 plants to have distinct carbon-isotope signatures. In addition, marine C3 plants have stable-isotope ratios of carbon that are intermediate between C4 and terrestrial C3 plants. The direct incorporation of the carbon-isotope ratio (13C/12C) of plants into consumers' tissues makes this ratio useful in studies of animal ecology. The heavy isotope of nitrogen (15N) is preferentially incorporated into the tissues of the consumer from the diet, which results in a systematic enrichment in nitrogen-isotope ratio (15N/14N) with each trophic level. Consequently, stable isotopes of nitrogen have been used primarily to assess position in food chains. The literature pertaining to the use of stable isotopes of carbon and nitrogen in animal trophic ecology was reviewed. Data from 102 studies that reported stable-isotope ratios of carbon and (or) nitrogen of wild birds and (or) mammals were compiled and analyzed relative to diet, latitude, body size, and habitat moisture. These analyses supported the predicted relationships among trophic groups. Carbon-isotope ratios differed among species that relied on C3, C4, and marine food chains. Likewise, nitrogen-isotope ratios were enriched in terrestrial carnivorous mammals relative to terrestrial herbivorous mammals. Also, marine carnivores that ate vertebrates had nitrogen-isotope ratios that were enriched over the ratios of those that ate invertebrates. Data from the literature also indicated that (i) the carbon-isotope ratio of carnivore bone collagen was inversely related to latitude, which was likely the result of an inverse relationship between the proportion of carbon in the food chain that was fixed by C4 plants and latitude; (ii) seabirds and marine mammals from northern oceans had higher nitrogen-isotope ratios than those from southern oceans; (iii) the nitrogen-isotope ratios of terrestrial mammals that used xeric habitats were higher than the ratios of those that used mesic habitats, indicating that water stress can have important effects on the nitrogen-isotope ratio; (iv) there was no relationship between body mass and nitrogen-isotope ratio for either bone collagen or muscle of carnivores; and (v) there was linear covariation between stable-isotope ratios of carbon and nitrogen in marine food chains (but not in terrestrial C3 or C4 food chains), which is likely a product of increases in carbon-isotope ratio with trophic level in marine food chains. Differences in stable-isotope composition among trophic groups were detected despite variation attributable to geographic location, climate, and analytical techniques, indicating that these effects are large and pervasive. Consequently, as knowledge of the distribution of stable isotopes of carbon and nitrogen increases, they will probably become an increasingly important tool in the study of avian and mammalian trophic ecology.

scholarly journals Trophic levels of marine consumers from nitrogen stable isotope analysis: estimation and uncertainty

2015 ◽  
Vol 72 (8) ◽  
pp. 2289-2300 ◽  
Author(s):  
Simon Jennings ◽  
Johan van der Molen
Keyword(s):  
Stable Isotope ◽  
Body Mass ◽  
North Sea ◽  
Trophic Ecology ◽  
Human Impacts ◽  
Spatial Scales ◽  
Trophic Levels ◽  
Environmental Data ◽  
Irish Sea ◽  
Nitrogen Stable Isotope

Abstract Estimates of trophic levels (TLs) are used to calibrate, parameterize, and validate foodweb models and to calculate metrics and indicators of foodweb structure and human impacts. We develop a method to estimate TL from nitrogen stable isotope data (δ15N) and apply it to 5535 individuals from 62 species of marine fish and squids sampled from the Celtic Sea, English Channel, Irish Sea, and North Sea. With this method, uncertainties in δ15N at the base of the foodweb (from a marine isoscape generated with environmental data) and in trophic fractionation (from existing fixed and scaled fractionation models) are propagated through the analysis to quantify uncertainty in TL. Higher values of base and consumer δ15N lead to greater uncertainty in TL estimates for individual consumers. Base and consumer δ15N are higher in coastal regions with lower salinity, such as the Irish Sea and Channel coasts, so uncertainty in individual TL estimates is relatively high in these regions. Conversely, when base and consumer δ15N are low, as in the high salinity waters of the northern North Sea, uncertainty is relatively low. Uncertainty intervals for species' predicted TL at a reference mass (based on ≥10 individuals spanning a range of body sizes) are small compared with estimates for individual consumers, as are estimates of slope of the TL body mass relationship. For ∼50% of region and species combinations showing trends in TL with body mass, there are eight times more positive relationships than negative ones. Our approach can be applied at large spatial scales. It generates estimates of uncertainty that support more rigorous and informed comparisons of the trophic ecology of size classes, species, and species-groups. A data file that includes estimates of TL and associated uncertainty for all sampled individuals accompanies this study.

Habitat exploitation by a gleaning bat, Plecotus auritus

1996 ◽  
Vol 351 (1342) ◽  
pp. 921-931 ◽  
Keyword(s):  
Habitat Use ◽  
Activity Pattern ◽  
Foraging Behaviour ◽  
Activity Patterns ◽  
Interspecific Variation ◽  
Sympatric Species ◽  
Palaearctic Species ◽  
Feeding Sites ◽  
Deciduous Woodland ◽  
Individual Trees

The brown long-eared bat, Plecotus auritus , differs from most other Palaearctic bats in having broad wings and long ears, which are linked to its slow flight, and its ability to hover and thus glean insects from surfaces. Previous studies have suggested a relation between interspecific variation in morphology of bats, particularly the shape of the wing, and differences in foraging behaviour. It might be predicted therefore that the foraging behaviour of P. auritus would differ from other Palaearctic species that have been studied. To examine activity patterns and habitat use, 16 P. auritus were radio-tracked from six roost sites in northeast Scotland. Differences in behaviour compared to other Palaearctic species were found in the nocturnal activity pattern, habitat use and distance travelled to foraging areas. Plecotus auritus emerged later than other sympatric species, at around 55 min after sunset, and remained active throughout the night, with a generally unimodal activity pattern. Individual bats used a series of feeding sites, to which they returned regularly, and sometimes shared with others from the same roost. Plecotus auritus foraged exclusively in woodland and around individual trees. The bats displayed a preference for deciduous over coniferous woodland, probably reflecting higher insect availability in the former. Hedgerows, tree lines and fence lines were used as commuting routes between roosts and feeding sites. Bats travelled up to 2.8 km from the roost site, but spent most time foraging within 0.5 km of the roost, although males foraged further from the roost than females. The foraging behaviour of P. auritus reflected the morphological specializations of this species, but displayed a degree of intraspecific flexibility. Deciduous woodland in the vicinity of roost sites appeared to be key foraging habitat for P. auritus .

scholarly journals Compound-Specific Stable Isotope Analysis of Amino Acids in Pelagic Shark Vertebrae Reveals Baseline, Trophic, and Physiological Effects on Bulk Protein Isotope Records

2021 ◽  
Vol 8 ◽  
Author(s):  
Sarah Magozzi ◽  
Simon R. Thorrold ◽  
Leah Houghton ◽  
Victoria A. Bendall ◽  
Stuart Hetherington ◽  
...  
Keyword(s):  
Amino Acids ◽  
Stable Isotope ◽  
Carbon Isotope ◽  
Trophic Ecology ◽  
Carbon Isotopic Composition ◽  
Nitrogen Isotope ◽  
Essential Amino Acids ◽  
Carbon And Nitrogen ◽  
Isotope Data ◽  
Bulk Tissue

Variations in stable carbon and nitrogen isotope compositions in incremental tissues of pelagic sharks can be used to infer aspects of their spatial and trophic ecology across life-histories. Interpretations from bulk tissue isotopic compositions are complicated, however, because multiple processes influence these values, including variations in primary producer isotope ratios and consumer diets and physiological processing of metabolites. Here we challenge inferences about shark tropho-spatial ecology drawn from bulk tissue isotope data using data for amino acids. Stable isotope compositions of individual amino acids can partition the isotopic variance in bulk tissue into components associated with primary production on the one hand, and diet and physiology on the other. The carbon framework of essential amino acids (EAAs) can be synthesised de novo only by plants, fungi and bacteria and must be acquired by consumers through the diet. Consequently, the carbon isotopic composition of EAAs in consumers reflects that of primary producers in the location of feeding, whereas that of non-essential amino acids (non-EAAs) is additionally influenced by trophic fractionation and isotope dynamics of metabolic processing. We determined isotope chronologies from vertebrae of individual blue sharks and porbeagles from the North Atlantic. We measured carbon and nitrogen isotope compositions in bulk collagen and carbon isotope compositions of amino acids. Despite variability among individuals, common ontogenetic patterns in bulk isotope compositions were seen in both species. However, while life-history movement inferences from bulk analyses for blue sharks were supported by carbon isotope data from essential amino acids, inferences for porbeagles were not, implying that the observed trends in bulk protein isotope compositions in porbeagles have a trophic or physiological explanation, or are suprious effects. We explored variations in carbon isotope compositions of non-essential amino acids, searching for systematic variations that might imply ontogenetic changes in physiological processing, but patterns were highly variable and did not explain variance in bulk protein δ13C values. Isotopic effects associated with metabolite processing may overwhelm spatial influences that are weak or inconsistently developed in bulk tissue isotope values, but interpreting mechanisms underpinning isotopic variation in patterns in non-essential amino acids remains challenging.

scholarly journals Bulk tissue and amino acid stable isotope analyses reveal global ontogenetic patterns in ocean sunfish trophic ecology and habitat use

2020 ◽  
Vol 633 ◽  
pp. 127-140 ◽  
Author(s):  
ND Phillips ◽  
EA Elliott Smith ◽  
SD Newsome ◽  
JDR Houghton ◽  
CD Carson ◽  
...  
Keyword(s):  
Amino Acid ◽  
Stable Isotope ◽  
Habitat Use ◽  
Trophic Ecology ◽  
Stable Isotope Analyses ◽  
Ocean Sunfish ◽  
Acid Stable ◽  
Bulk Tissue ◽  
Isotope Analyses

Isotopic variation in delphinids from the subtropical western South Atlantic

2011 ◽  
Vol 92 (8) ◽  
pp. 1689-1698 ◽  
Author(s):  
Silvina Botta ◽  
Aleta A. Hohn ◽  
Stephen A. Macko ◽  
Eduardo R. Secchi
Keyword(s):  
Stable Isotope ◽  
Habitat Use ◽  
Continental Shelf ◽  
Trophic Ecology ◽  
Nitrogen Isotope ◽  
Southern Brazil ◽  
Stenella Frontalis ◽  
Delphinus Delphis ◽  
Coastal Species ◽  
Lagenodelphis Hosei

A dual stable isotope approach (δ13C and δ15N) was used to investigate inter- and intra-specific variations in feeding ecology and habitat use of 7 delphinids from coastal/estuarine, continental shelf and offshore marine environments from southern Brazil: Tursiops sp., Orcinus orca, Stenella frontalis, Steno bredanensis, Delphinus delphis, Pseudorca crassidens and Lagenodelphis hosei. Teeth from 50 specimens acquired from stranded animals were analysed in this study. Tursiops sp. and O. orca are the most coastal species, and had the highest δ13C values followed by the continental shelf species S. frontalis, S. bredanensis and D. delphis. Lagenodelphis hosei showed the lowest δ13C value, demonstrating its typical offshore habitat. One group of P. crassidens had the lowest δ15N values, indicating their low trophic level feeding habit while two specimens of the same species showed the highest mean nitrogen isotope value. This first study on stable isotope values of delphinids from southern Brazil provides substantial new information about the trophic ecology, habitat use and feeding environments of these animals.

TRANSFER EFFICIENCY FROM PRIMARY PRODUCERS TO RUDITAPES PHILIPPINARUM ON AN INTERTIDAL FLAT IN HIROSHIMA BAY, JAPAN

2017 ◽  
Author(s):  
Sosuke Otani ◽  
Sosuke Otani ◽  
Akira Umehara ◽  
Akira Umehara ◽  
Haruka Miyagawa ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Secondary Production ◽  
Isotope Ratios ◽  
Ruditapes Philippinarum ◽  
Transfer Efficiency ◽  
Food Sources ◽  
Stable Isotope Ratios ◽  
Primary Producers ◽  
Nitrogen Stable Isotope ◽  
Carbon And Nitrogen

Fish yields of Ruditapes philippinarum have been decreased and the resources have not yet recovered. It needs to clarify food sources of R. philippinarum, and relationship between primary and secondary production of it. The purpose on this study is to reveal transfer efficiency from primary producers to R. philippinarum and food sources of R. philippinarum. The field investigation was carried out to quantify biomass of R. philippinarum and primary producers on intertidal sand flat at Zigozen beach in Hiroshima Bay, Japan. In particular, photosynthetic rates of primary producers such as Zostera marina, Ulva sp. and microphytobenthos were determined in laboratory experiments. The carbon and nitrogen stable isotope ratios for R. philippinarum and 8 potential food sources (microphytobenthos, MPOM etc) growing in the tidal flat were also measured. In summer 2015, the primary productions of Z. marina, Ulva sp. and microphytobenthos were estimated to be 70.4 kgC/day, 43.4 kgC/day and 2.2 kgC/day, respectively. Secondary production of R. philippinarum was 0.4 kgC/day. Contribution of microphytobenthos to R. philippinarum as food source was 56-76% on the basis of those carbon and nitrogen stable isotope ratios. Transfer efficiency from microphytobenthos to R. philippinarum was estimated to be 10-14%. It was suggested that microphytobenthos might sustain the high secondary production of R. philippinarum, though the primary production of microphytobenthos was about 1/10 compared to other algae.

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