scholarly journals Mouth gape determines the response of marine top predators to long-term fishery-induced changes in food web structure

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Massimiliano Drago ◽  
Valentina Franco-Trecu ◽  
Angel M. Segura ◽  
Meica Valdivia ◽  
Enrique M. González ◽  
...  
Keyword(s):  
Food Web ◽  
Food Web Structure ◽  
Web Structure ◽  
Top Predators ◽  
Induced Changes

Spatio-temporal reproducibility of the microbial food web structure associated with the change in temperature: Long-term observations in the Adriatic Sea

2018 ◽  
Vol 161 ◽  
pp. 87-101 ◽  
Author(s):  
Mladen Šolić ◽  
Branka Grbec ◽  
Frano Matić ◽  
Danijela Šantić ◽  
Stefanija Šestanović ◽  
...  
Keyword(s):  
Food Web ◽  
Adriatic Sea ◽  
Microbial Food Web ◽  
Food Web Structure ◽  
Web Structure ◽  
Spatio Temporal

Food web structure within an estuary of the southern Gulf of St. Lawrence undergoing eutrophication

2013 ◽  
Vol 70 (12) ◽  
pp. 1805-1812 ◽  
Author(s):  
Allison Schein ◽  
Simon C. Courtenay ◽  
Karen A. Kidd ◽  
K. Alexander Campbell ◽  
Michael R. van den Heuvel
Keyword(s):  
Food Web ◽  
Fundulus Heteroclitus ◽  
Structural Changes ◽  
Stomach Contents ◽  
Individual Species ◽  
Food Web Structure ◽  
Web Structure ◽  
Top Predators ◽  
Apeltes Quadracus ◽  
Anoxic Events

This study compared food web structure in eutrophied Ulva lactuca-dominated areas within an estuary in the Southern Gulf of St. Lawrence, with Zostera marina beds within the same estuary. The estuarine food web consisted only of primary producers, mesograzers, and secondary grazers, with the absence of piscivorous top predators. It was hypothesized that the altered plant habitat would lead to structural changes in the food web and the dominance of benthic carbon. Stomach contents from mummichog (Fundulus heteroclitus), fourspine stickleback (Apeltes quadracus), and American eel (Anguilla rostrata) showed that only mummichog had significant differences in prey items between the different habitats. Stable isotopes showed that there were no significant differences in the food web structure and individual species’ 13C values. A 13C spike in particulate organic matter during the onset of anoxia in July, presumably due to bacterial blooms, indicated the complete dominance of benthic carbon the pelagic food web during this month. Thus, blooms of heterotrophs during anoxic events may have the greatest influence on nutrient cycling in estuaries undergoing eutrophication.

scholarly journals Effects of ontogeny and invasive crayfish on feeding ecology and mercury concentrations of predatory fishes

2019 ◽  
Vol 76 (11) ◽  
pp. 1929-1939 ◽  
Author(s):  
Kate Prestie ◽  
Iain D. Phillips ◽  
Douglas P. Chivers ◽  
Timothy D. Jardine
Keyword(s):  
Invasive Species ◽  
Food Web ◽  
Littoral Zone ◽  
Trophic Position ◽  
Trophic Levels ◽  
Food Web Structure ◽  
Web Structure ◽  
Top Predators ◽  
Invasive Crayfish ◽  
Predatory Fishes

Lake food web structure dictates the flow of energy and contaminants to top predators, and addition of invasive species can shift these flows. We examined trophic position (TP), proportional reliance on the littoral zone (Proplittoral), and mercury (Hg) concentrations across the life-span of two predatory fishes, walleye (Sander vitreus) and northern pike (Esox lucius), in lakes with and without invasive virile crayfish (Faxonius virilis). The littoral zone was the dominant foraging zone for both species regardless of size, accounting for 59% and 80% of the diet of walleye and pike, respectively. Both species increased in TP and Hg with body size, as did crayfish. Walleye in crayfish-present lakes had lower Proplittoral, TP, and Hg concentrations compared with non-present lakes, but trophic magnification of Hg through the food web was consistent across all six lakes. These findings underscore a strong role for the littoral zone in channeling energy and contaminants to higher trophic levels and how invasive species can occupy new habitats at low abundance while altering food web structure and contaminant bioaccumulation.

Food Web Structure and Long-Term Phosphorus Recycling: A Simulation Model Evaluation

1993 ◽  
Vol 122 (5) ◽  
pp. 773-783 ◽  
Author(s):  
Xi He ◽  
James F. Kitchell ◽  
Stephen R. Carpenter ◽  
James R. Hodgson ◽  
Daniel E. Schindler ◽  
...  
Keyword(s):  
Simulation Model ◽  
Food Web ◽  
Model Evaluation ◽  
Food Web Structure ◽  
Web Structure ◽  
Phosphorus Recycling

scholarly journals Cladocera paleocommunity to disentangle the impact of anthropogenic and climatic stressors on a deep subalpine lake ecosystem (Lake Iseo, Italy)

2021 ◽  
Author(s):  
Barbara Leoni ◽  
Martina Patelli ◽  
Veronica Nava ◽  
Monica Tolotti
Keyword(s):  
Species Composition ◽  
Food Web ◽  
Anthropogenic Pressure ◽  
Food Web Structure ◽  
Subfossil Cladocera ◽  
Web Structure ◽  
Pelagic Food Web ◽  
The Impact ◽  
Plankton Communities

AbstractIn big lakes with strong anthropogenic pressure, it is usually difficult to disentangle the impacts of climate variability from those driven by eutrophication. The present work aimed at the reconstruction of change in the species distribution and density of subfossil Cladocera in Lake Iseo (Italy) in relation to climate and anthropogenic pressure. We related subfossil Cladocera species composition and density in an 80-cm sediment core collected in the pelagic zone of Lake Iseo to long-term temperature trends and phosphorus concentration inferred by diatoms frustules. The Cladocera remains detected in Lake Iseo sediment reflected the species composition and density of modern pelagic Cladocera assemblages. Cladocera rapidly respond to environmental change, and that climate change combined with eutrophication can induce changes in community composition and species density. At the beginning of twentieth century, when global warming was not yet so accentuated, the nutrient increase in water resulted as the principal driver in determining the long-term development of plankton communities and pelagic food web structure. Moreover, catchment-related processes may decisively affect both species composition and density of the lake planktonic communities due to the decrease of lake water transparency induced by input of inorganic material from the catchment area to the lake. The paleolimnological investigation, through the combined study of biotic and abiotic factor, allowed clarifying the synergic effects of the most important drivers of change in lake ecosystems, suggesting that climatic factors should be considered with nutrient availability as determinant element in controlling the temporal development of plankton communities and pelagic food web structure.

scholarly journals Thermal preference influences depth use but not biomass of predatory fishes in response to lake morphometry

2019 ◽  
Author(s):  
Timothy J. Bartley ◽  
Matthew M. Guzzo ◽  
Kevin Cazelles ◽  
Alex Verville ◽  
Bailey C. McMeans ◽  
...  
Keyword(s):  
Food Web ◽  
Abiotic Factors ◽  
Thermal Preference ◽  
Lake Morphometry ◽  
Top Predator ◽  
Food Web Structure ◽  
Web Structure ◽  
Top Predators ◽  
Thermal Preferences ◽  
Depth Use

ABSTRACTTop predators’ responses to environmental conditions shape food web architecture and influence ecosystem structure and stability. Yet the impacts of fundamental properties like ecosystem size and morphometry on top predators’ behaviour are poorly understood. We examined how lake morphometry impacts the behaviour (inferred by depth use) of three key fish top predators—the cold-adapted lake trout, the cool-adapted walleye, and the warm-adapted smallmouth bass— which can each strongly impact local food web structure. We used catch-per-unit-effort data from nearly 500 boreal lakes of Ontario, Canada to evaluate the role of thermal preference in dictating mean depth of capture and biomass index in response to lake morphometry. We found evidence that thermal preferences influence how species’ depth use and biomass changed with lake size, proportion of littoral area, and maximum lake depth, although we found no relationship with lake shape. However, found no strong evidence that lake morphology influences these species’ biomasses, despite theory that predicts such a relationship. Our results suggest that some aspects of lake morphometry can alter habitat accessibility and productivity in ways that influence the behaviour and biomass of these top predator species depending on their thermal preferences. Our results have implications for how lake food webs expand and contract with lake morphometry and other key abiotic factors. We argue that several key abiotic factors likely drive top predator depth use in ways that may shape local food web structure and play an important role in determining the ultimate fate of ecosystems with environmental change.

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