Trophic ecology of a tropical aquatic and terrestrial food web: insights from stable isotopes (15N)

We used stable isotope analysis (15N/14N) to characterize the trophic relationships of consumer communities of an aquatic food web (a permanent pond) and the adjacent terrestrial food web (secondary dry dipterocarp forest) from a seasonal tropical field site in north-eastern Thailand. In general, isotopic signatures of aquatic vertebrates were higher (δ15N range = 4.51–9.90‰) than those of invertebrates (δ15N range = 1.10–6.00‰). High 15N signatures identified water snakes and swamp eels as top predators in the pond food web. In the terrestrial food web 15N signatures of saprophagous litter invertebrates (diplopods, earthworms), termites, ants and beetle larvae were lower than in those of predatory invertebrates (scolopendrids, scorpions, whip spiders). Predatory terrestrial frogs and caecilians had lower 15N signatures than snakes, indicating that snakes are among the top predators in the terrestrial web. Based on the distribution of isotopic signatures, we estimated five trophic levels for both the aquatic and terrestrial food web. The food chains of a seasonal tropical site studied were rather short, which implies similarities to the structure of temperate food webs.

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A stable isotope study of a neotropical stream food web prior to the extirpation of its large amphibian community

Journal of Tropical Ecology ◽

10.1017/s0266467407004518 ◽

2007 ◽

Vol 23 (6) ◽

pp. 643-651 ◽

Cited By ~ 36

Author(s):

Piet Verburg ◽

Susan S. Kilham ◽

Catherine M. Pringle ◽

Karen R. Lips ◽

Dana L. Drake

Keyword(s):

Stable Isotope ◽

Food Web ◽

Isotope Analysis ◽

Trophic Relationships ◽

Population Declines ◽

Isotopic Signatures ◽

Top Predators ◽

Forest Stream ◽

Nitrogen Concentrations ◽

Stable Isotope Study

Rapid and massive amphibian population declines have been reported throughout upland areas of the Neotropics. The abundance and species richness of Neotropical amphibian communities suggest that losses of this magnitude are likely to have strong effects at the ecosystem level. To improve understanding of the implications of their loss we used stable isotope analysis to examine trophic relationships in an ecosystem in which amphibians are dominant in a second-order forest stream at 750 m asl in Parque Nacional Omar Torrijos Herrera, Panama. We analysed δ13C, δ15N and C:N ratios of major biotic components (basal resources, invertebrates, amphibians, fish and reptiles) in the stream and of the adjacent riparian food web. Tadpoles (mean δ15N = 4.49‰) and adult amphibians (mean δ15N = 5.45‰) were intermediate links in the aquatic and terrestrial food web respectively. High δ15N signatures identified fish as top predators in the aquatic food web and snakes and the toad Bufo as top predators in the terrestrial food web. Isotopic signatures clearly distinguished between trophic groups of tadpoles: microbial feeders (Centrolenidae, δ15N range = 0.91–3.05‰), herbivores (Rana and Hyla, δ15N range = 4.74–5.15‰) and neuston feeders (Colostethus, δ15N range = 5.31–6.40‰). Dependence on autotrophic production was indicated by enriched signatures of carbon isotopes in pool dwellers versus those that reside in faster-flowing sections of the stream. High nitrogen concentrations in detrital matter (average 0.8%, C:N = 10.3) suggested that grazing tadpoles enhanced nitrogen fluxes and improved the quality of organic matter available to detritivores.

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The Use of Carbon and Nitrogen Stable Isotope Analysis to Characterize Food Web Changes in Aquatic Systems for Reclamation of Oil Sands Process-Affected Materials

Water Quality Research Journal ◽

10.2166/wqrj.2009.032 ◽

2009 ◽

Vol 44 (4) ◽

pp. 313-322 ◽

Cited By ~ 4

Author(s):

Monalisa Elshayeb ◽

Michael D. MacKinnon ◽

D. George Dixon ◽

Michael Power

Keyword(s):

Food Web ◽

Oil Sands ◽

Isotope Analysis ◽

Naphthenic Acid ◽

Carbon Sources ◽

Nitrogen Isotope ◽

Isotopic Signatures ◽

Carbon And Nitrogen ◽

Aquatic Food ◽

Northern Alberta

Abstract One strategy for reclamation of oil sands leases in northern Alberta is the construction of lakes and wetlands by capping oil sands process-affected material (OSPM) with water. To assess this approach, experimental sites containing a range of OSPM have been constructed to monitor the evolution of the resulting aquatic habitats. Stable isotopes of carbon and nitrogen were used to assess the effects of OSPM on aquatic food webs. Carbon and nitrogen isotopic signatures of sediment, dissolved inorganic and organic carbon, particulate organic matter, periphyton, plants, plankton, aquatic invertebrates, and fish were used to assess differences related to the naphthenic acid (NA) concentration in OSPM and reference sites. NAs are a principal contaminant of concern in OSPM. Sites were grouped into low (0 to 4 mg/L), medium (4 to 15 mg/L), and high (>15 mg/L) NA concentrations. There were no significant differences in food web area or length among the three NA groupings. In most cases, carbon isotope analyses of samples from low, medium, and high NA concentration sites were not significantly different, suggesting that OSPM is not a significant contributor to food web carbon sources. Significant differences were found in nitrogen isotope signatures between low, medium, and high NA sites. Ammonia from OSPM is suggested as the main contributor to δ15N enrichment.

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Trophic relationships of breeding Red-necked Grebes (Podiceps grisegena) on wetlands with and without fish in the Aspen Parkland

Canadian Journal of Zoology ◽

10.1139/z09-132 ◽

2010 ◽

Vol 88 (2) ◽

pp. 186-194 ◽

Cited By ~ 7

Author(s):

C. E. McParland ◽

C. A. Paszkowski ◽

J. L. Newbrey

Keyword(s):

Egg Production ◽

Trophic Position ◽

Isotope Analysis ◽

Trophic Levels ◽

Trophic Relationships ◽

Breeding Sites ◽

Top Predators ◽

Aspen Parkland ◽

Wintering Areas ◽

Podiceps Grisegena

Dietary overlap between waterbirds and fish in many freshwater systems can lead to competition for food resources and changes in the trophic position of top predators. We used stable isotope analysis of carbon and nitrogen from egg tissues to document differences in the trophic position of breeding Red-necked Grebes ( Podiceps grisegena (Boddaert, 1783)) on wetlands with and without fish in the Aspen Parkland of Alberta, Canada. Grebes occupied higher trophic levels in the presence of fish than in their absence, suggesting that small-bodied fish in Aspen Parkland food webs may lengthen food chains in which grebes are top predators. A mixed diet of invertebrates and fishes may be adaptive for grebes in this highly variable ecosystem where fish colonize wetlands in wet years and are extirpated in dry years. Carbon analyses indicated that female grebes likely obtained resources for egg production from breeding sites and not from wintering areas, as eggs had similar δ13C values to wetland primary producers, invertebrates, and fishes.

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Food-web modification in the eastern Gulf of Finland after invasion of Marenzelleria arctia (Spionidae, Polychaeta)

NeoBiota ◽

10.3897/neobiota.66.63847 ◽

2021 ◽

Vol 66 ◽

pp. 75-94

Author(s):

Sergey Golubkov ◽

Alexei Tiunov ◽

Mikhail Golubkov

Keyword(s):

Food Web ◽

Food Webs ◽

Food Chain ◽

Native Species ◽

Isotope Analysis ◽

Marine Species ◽

Trophic Levels ◽

Benthivorous Fish ◽

Neva Estuary ◽

The Baltic

The paucity of data on non-indigenous marine species is a particular challenge for understanding the ecology of invasions and prioritising conservation and research efforts in marine ecosystems. Marenzelleria spp. are amongst the most successful non-native benthic species in the Baltic Sea during recent decades. We used stable isotope analysis (SIA) to test the hypothesis that the dominance of polychaete worm Marenzelleria arctia in the zoobenthos of the Neva Estuary after its invasion in the late 2000s is related to the position of this species in the benthic food webs. The trend towards a gradual decrease in the biomass of Marenzelleria worms was observed during 2014–2020, probably due to significant negative relationships between the biomass of oligochaetes and polychaetes, both of which, according to SIA, primarily use allochthonous organic carbon for their production. The biomass of benthic crustaceans practically did not change and remained very low. The SIA showed that, in contrast to the native crustacean Monoporeia affinis, polychates are practically not consumed either by the main invertebrate predator Saduria entomon, which preys on M. affinis, oligochaetes and larvae of chironomids or by benthivorous fish that prefer native benthic crustaceans. A hypothetical model for the position and functional role of M. arctia in the bottom food web is presented and discussed. According the model, the invasion of M. arctia has created an offshoot food chain in the Estuary food webs. The former dominant food webs, associated with native crustaceans, are now poorly developed. The lack of top-down control obviously contributes to the significant development of the Marenzelleria food chain, which, unlike native food chains, does not provide energy transfer from autochthonous and allochthonous organic matter to the upper trophic levels. The study showed that an alien species, without displacing native species, can significantly change the structure of food webs, creating blind offshoots of the food chain.

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Stable isotope analysis reveals partitioning in prey use by Kajikia audax (Istiophoridae), Thunnus albacares, Katsuwonus pelamis, and Auxis spp. (Scombridae) in the Eastern Tropical Pacific of Ecuador

Neotropical Ichthyology ◽

10.1590/1982-0224-2020-0015 ◽

2021 ◽

Vol 19 (4) ◽

Author(s):

Rigoberto Rosas-Luis ◽

Nancy Cabanillas-Terán ◽

Carmen A. Villegas-Sánchez

Keyword(s):

Stable Isotope ◽

Food Web ◽

Stable Isotope Analysis ◽

Trophic Ecology ◽

Isotope Analysis ◽

Middle Level ◽

Food Sources ◽

Thunnus Albacares ◽

Katsuwonus Pelamis ◽

Δ13c And Δ15n

Abstract Kajikia audax, Thunnus albacares, Katsuwonus pelamis, and Auxis spp. occupy high and middle-level trophic positions in the food web. They represent important sources for fisheries in Ecuador. Despite their ecological and economic importance, studies on pelagic species in Ecuador are scarce. This study uses stable isotope analysis to assess the trophic ecology of these species, and to determine the contribution of prey to the predator tissue. Isotope data was used to test the hypothesis that medium-sized pelagic fish species have higher δ15N values than those of the prey they consumed, and that there is no overlap between their δ13C and δ15N values. Results showed higher δ15N values for K. audax, followed by T. albacares, Auxis spp. and K. pelamis, which indicates that the highest position in this food web is occupied by K. audax. The stable isotope Bayesian ellipses demonstrated that on a long time-scale, these species do not compete for food sources. Moreover, δ15N values were different between species and they decreased with a decrease in predator size.

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Aquatic food web research in mesocosms: a literature survey

Journal of Limnology ◽

10.4081/jlimnol.2020.1949 ◽

2020 ◽

Author(s):

Csenge Póda ◽

Ferenc Jordán

Keyword(s):

Food Web ◽

Multiple Stressors ◽

Experimental Testing ◽

Literature Survey ◽

Trophic Levels ◽

Combined Effects ◽

Theoretical Concepts ◽

Aquatic Food ◽

Emerging Topics ◽

Web Research

Food web research feeds ecology with elementary theoretical concepts that need controlled experimental testing. Mesocosm facilities offer multiple ways to execute experimental food web research in a rigorous way. We performed a literature survey to overview food web research implementing the mesocosm approach. Our goal was to summarise quantitatively how the mesocosm approach has formerly been used and question how to best utilise mesocosms for the emerging topics in food web research in the future. We suggest increasing the number of replicates, extending the duration of the experiments, involving higher trophic levels and addressing the combined effects of multiple stressors.

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Invaders induce coordinated isotopic niche shifts in native fish species

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2019-0346 ◽

2020 ◽

Vol 77 (8) ◽

pp. 1348-1358 ◽

Cited By ~ 1

Author(s):

Jane S. Rogosch ◽

Julian D. Olden

Keyword(s):

Food Web ◽

Native Species ◽

Fish Assemblages ◽

Isotope Analysis ◽

Carbon Sources ◽

Unintended Consequences ◽

Trophic Levels ◽

Isotopic Niche ◽

Mesopredator Release ◽

Native Fishes

Food-web investigations inform management strategies by exposing potential interactions between native and nonnative species and anticipating likely outcomes associated with species removal efforts. We leveraged a natural gradient of compositional turnover from native-only to nonnative-only fish assemblages, combined with an intensive removal effort, to investigate underlying food-web changes in response to invasive species expansion in a Lower Colorado River tributary. Nonnative fishes caused coordinated isotopic niche displacement in native fishes by inducing resource shifts toward lower trophic positions and enriched carbon sources. By contrast, nonnative fishes did not experience reciprocal shifts when native fishes were present. Asymmetrical outcomes between native and nonnative fishes indicated species displacement may result from competitive or consumptive interactions. Native species’ isotopic niches returned to higher trophic levels after nonnative green sunfish (Lepomis cyanellus) removal, indicating removal efforts can support trophic recovery of native fishes like desert suckers (Catostomus clarkii) and roundtail chub (Gila robusta). Using stable isotope analysis in preremoval assessments provides opportunities to identify asymmetric interactions, whereas postremoval assessments could identify unintended consequences, like mesopredator release, as part of adaptive decision making to recover native fishes.

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Trophic ecology of the chihuil sea catfish (Bagre panamensis) in the south-east Gulf of California, México

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315417000170 ◽

2017 ◽

Vol 98 (4) ◽

pp. 885-893 ◽

Cited By ~ 1

Author(s):

Víctor M. Muro-Torres ◽

Felipe Amezcua ◽

Raul E. Lara-Mendoza ◽

John T. Buszkiewicz ◽

Felipe Amezcua-Linares

Keyword(s):

Gulf Of California ◽

Trophic Ecology ◽

Trophic Position ◽

Feeding Habits ◽

Isotope Analysis ◽

Demersal Fish ◽

Trophic Levels ◽

High Plasticity ◽

Combined Use ◽

Ecosystem Based Fisheries Management

The trophic ecology of the chihuil sea catfish Bagre panamensis was studied through high-resolution variations in its feeding habits and trophic position (TP) in the SE Gulf of California, relevant to sex, size and season. The combined use of stomach content (SCA) and stable isotope analysis (SIA) allowed us to perform these analyses and also estimate the TP of its preys. Results of this study show that the chihuil sea catfish is a generalist and opportunistic omnivore predator that consumes primarily demersal fish and peneid shrimps. Its diet did not vary with climatic season (rainy or dry), size or sex. Results from the SIA indicated high plasticity in habitat use and prey species. The estimated TP value was 4.19, which indicates a tertiary consumer from the soft bottom demersal community in the SE Gulf of California, preying on lower trophic levels, which aids in understanding the species' trophic role in the food web. Because this species and its prey are important to artisanal and industrial fisheries in the Gulf of California, diet assimilation information is useful for the potential establishment of an ecosystem-based fisheries management in the area.

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South American sea lions Otaria byronia as biological samplers of local cephalopod fauna in the Patagonian shelf marine ecosystem

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315419000432 ◽

2019 ◽

Vol 99 (06) ◽

pp. 1459-1463

Author(s):

R. L. Bustos ◽

G. A. Daneri ◽

E. A. Varela ◽

A. Harrington ◽

A. V. Volpedo ◽

...

Keyword(s):

Marine Mammals ◽

Marine Ecosystem ◽

Isotopic Signature ◽

Trophic Levels ◽

Trophic Relationships ◽

South American ◽

Sea Lions ◽

Patagonian Shelf ◽

Important Prey ◽

Top Predators

AbstractCephalopods are important prey in the diet of top predators, such as marine mammals and seabirds. However, detailed information on their trophic relationships in the Patagonian marine ecosystem is scarce, including those cephalopod species with commercial interest. The aims of this study were to evaluate the composition of the cephalopod component in the diet of Otaria byronia and determine the habitat use and trophic levels of their main cephalopod prey by measuring the stable isotopic signature of cephalopod beaks. Between May 2005 and February 2009, fresh faecal samples were collected from two sea lions rookeries in San Matias Gulf. Cephalopods occurred in 39.4% of the 1112 samples collected during the whole period of study. The dominant prey species was Octopus tehuelchus, which occurred in 45.8% of scats containing cephalopod remains, and represented 58.7% in terms of numerical abundance and 52.0% in mass of cephalopods consumed. The second species most consumed was the myopsid Doryteuthis gahi. The significant higher δ15N values of O. tehuelchus beaks in comparison with those of D. gahi showed that these two species have different trophic levels while occupying similar habitat (δ13C values) in neritic waters of the Patagonian shelf.

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