scholarly journals Seaside Sparrows reveal contrasting food web responses to large-scale stressors in coastal Louisiana saltmarshes

Ecosphere ◽  
2017 ◽  
Vol 8 (7) ◽  
pp. e01878 ◽  
Author(s):  
Jill A. Olin ◽  
Christine M. Bergeon Burns ◽  
Stefan Woltmann ◽  
Sabrina S. Taylor ◽  
Philip C. Stouffer ◽  
...  
Keyword(s):  
Food Web ◽  
Large Scale ◽  
Coastal Louisiana

scholarly journals River Food Web Response to Large-Scale Riparian Zone Manipulations

PLoS ONE ◽  
2012 ◽  
Vol 7 (12) ◽  
pp. e51839 ◽  
Author(s):  
J. Timothy Wootton
Keyword(s):  
Food Web ◽  
Large Scale ◽  
Riparian Zone

scholarly journals Molecular diet analysis in zebra and quagga mussels (Dreissena spp.) and an assessment of the utility of aquatic filter feeders as biological eDNA filters

2021 ◽  
Author(s):  
Sven Weber ◽  
Lukas Brink ◽  
Manuel Wörner ◽  
Sven Künzel ◽  
Michael Veith ◽  
...  
Keyword(s):  
Food Web ◽  
Water Samples ◽  
Large Scale ◽  
Ecological Impact ◽  
Diet Analysis ◽  
Alternative Source ◽  
Dietary Analysis ◽  
Alpha And Beta Diversity ◽  
Invasive Bivalves ◽  
Primer Sets

AbstractMolecular gut content analysis is a popular tool to study food web interactions and was recently also suggested as an alternative source for DNA based biomonitoring. However, the overabundant consumer’s DNA often outcompetes that of its diet during PCR. Blocking approaches are an efficient means to reduce consumer amplification while retaining broad specificity for dietary taxa. We here designed an assay to monitor the eukaryotic diet of mussels and test their utility as biological eDNA filters to monitor planktonic communities. We designed several rDNA primer sets with a broad taxonomic suitability for eukaryotes, which suppress the amplification of mussels. The primers were tested using mussel DNA extracts and the results were compared to eDNA water samples collected next to the mussel colonies. Taxonomic recovery, as well as patterns of alpha and beta diversity, were compared between mussels and water samples. In addition, we analyzed time series samples of mussel samples from different German rivers. Our primer sets efficiently block the amplification of various mussel genera. The recovered DNA reflects a broad dietary preference across the eukaryotic tree of life and considerable taxonomic overlap with filtered water samples. We also recover various taxa of possible commensals and parasites, associated with the mussels. Our protocol will enable large scale dietary analysis in mussels, facilitate aquatic food web analysis, elucidate the ecological impact of invasive bivalves and the rapid survey of mussel aquacultures for pathogens. Moreover, we show that mussels could serve as an interesting complementary DNA source for biomonitoring.

scholarly journals Food web on ice: a pragmatic approach to investigate the trophic magnification of chemicals of concern

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Verena Kosfeld ◽  
Heinz Rüdel ◽  
Christian Schlechtriem ◽  
Caren Rauert ◽  
Jan Koschorreck
Keyword(s):  
Food Web ◽  
Large Scale ◽  
Freshwater Ecosystems ◽  
Freshwater Ecosystem ◽  
Pragmatic Approach ◽  
Magnification Factor ◽  
Environmental Specimen Bank ◽  
Environmental Specimen ◽  
Specimen Bank ◽  
Biota Samples

Abstract Background The trophic magnification factor (TMF) is a metric that describes the average trophic magnification of a chemical through a food web. TMFs may be used for the risk assessment of chemicals, although TMFs for single compounds can vary considerably between studies despite thorough guidance available in the literature to eliminate potential sources of error. The practical realization of a TMF investigation is quite complex and often only a few chemicals can be investigated due to low sample masses. This study evaluated whether a pragmatic approach involving the large-scale cryogenic sample preparation practices of the German Environmental Specimen Bank (ESB) is feasible. This approach could provide sufficient sample masses for a reduced set of samples allowing screenings for a broad spectrum of substances and by that enabling a systematic comparison of derived TMFs. Furthermore, it was assessed whether plausible TMFs can be derived with the ‘Food web on ice’ approach via a comparison with literature TMF values. Results This investigation at Lake Templin near Potsdam is the first TMF study for a German freshwater ecosystem and aimed to derive TMFs that are appropriate for regulatory purposes. A set of 15 composite biota samples was obtained and analyzed for an extended set of benchmark chemicals such as persistent organic pollutants, mercury and perfluoroalkyl substances. TMFs were calculated for all substances that were present in > 80% of the biota samples. For example, in the case of polychlorinated biphenyls, TMFs from 1.7 to 2.5 were determined and comparisons to literature TMFs determined in other freshwater ecosystems showed similarities. We showed that 32 out of 35 compounds analyzed had TMFs significantly above 1. In the remaining three cases, the correlations were not statistically significant. Conclusions The derived food web samples allow for an on-demand analysis and are ready-to-use for additional investigations. Since substances with non-lipophilic accumulation properties were also included in the list of analyzed substances, we conclude that the ‘Food web on ice’ provides samples which could be used to characterize the trophic magnification potential of substances with unknown bioaccumulation properties in the future which in return could be compared directly to the benchmarking patterns provided here.

scholarly journals First attempt to apply whole-lake food-web manipulation on a large scale in The Netherlands

1990 ◽  
pp. 291-301
Author(s):  
E. Van Donk ◽  
M. P. Grimm ◽  
R. D. Gulati ◽  
P. G. M. Heuts ◽  
W. A. de Kloet ◽  
...  
Keyword(s):  
The Netherlands ◽  
Food Web ◽  
Large Scale

scholarly journals Contribution of hardwood trees to budworm – parasitoid food web dynamics

2021 ◽  
Author(s):  
Christopher J. Greyson-Gaito ◽  
Sarah J. Dolson ◽  
Glen Forbes ◽  
Rosanna Lamb ◽  
Wayne E. MacKinnon ◽  
...  
Keyword(s):  
Food Web ◽  
Natural Enemies ◽  
Large Scale ◽  
Tree Mortality ◽  
Isotope Analysis ◽  
Balsam Fir ◽  
Mixed Stands ◽  
Enemies Hypothesis ◽  
Hardwood Trees ◽  
Natural Enemies Hypothesis

A major pest of Atlantic forests is the spruce budworm caterpillar which outbreaks every 35 years and causes large scale tree mortality. Historically, budworm management has largely ignored other species in the food web. Broadening the focus could reduce budworm outbreaks while balancing the multiple demands on our forests. However, the food web surrounding budworm including other caterpillar species that are attacked by budworm parasitoids has been relatively undersampled and under-researched. Therefore, we tested two hypotheses: the alternating hardwood-softwood parasitoids hypothesis where parasitoids attack other caterpillars on hardwoods when budworm are rare and attack budworm on balsam fir or other softwoods when budworm are plentiful, and the mixed stands natural enemies hypothesis where stands with a mixture of softwood and hardwood trees harbour greater abundances and diversity of budworm parasitoids. We tested these hypotheses using stable isotope analysis of budworm parasitoids and through community analyses of parasitoids sampled along a hardwood gradient. We found indications that parasitoids do attack caterpillars on hardwoods and budworm on balsam fir, but found mixed results for the natural enemies hypothesis. Our study highlights the importance for budworm management of understanding the dynamics of the food web surrounding budworm.

Large-scale responses of nematode communities to chronic otter-trawl disturbance

2008 ◽  
Vol 65 (4) ◽  
pp. 723-732 ◽  
Author(s):  
Hilmar Hinz ◽  
Jan G Hiddink ◽  
James Forde ◽  
Michel J Kaiser
Keyword(s):  
Food Web ◽  
North Sea ◽  
Large Scale ◽  
Life Cycles ◽  
Irish Sea ◽  
Otter Trawl ◽  
Food Web Structure ◽  
Nematode Communities ◽  
The North ◽  
The North Sea

Nematodes, because of their small size and short life cycles, are thought to be less affected by direct trawling mortality compared with the larger macrofauna. However, nematodes may still be indirectly affected by the physical disturbance of trawling through changing sediment characteristics and food web structure. We determined whether nematode communities on two muddy fishing grounds located in the North Sea and Irish Sea were affected by chronic otter-trawl disturbance and quantified these effects. Nematode abundance, production, and genus richness declined in response to trawling within both areas. Nematode biomass did not respond to trawling intensity. Genus composition was affected by trawling only in the North Sea. The responses in abundance of individual nematode genera to increasing trawling intensity were negative as well as positive. These results indicate that despite their size and fast life cycle, nematodes are affected by intensive trawling on muddy fishing grounds. The loss in secondary production from nematodes can have far-reaching consequences for the integrity of the benthic food web. As bottom trawl fisheries are expanding into ever deeper muddy habitats, the results presented here are an important step towards understanding the global ecosystem effects of bottom trawling.

Coupling Modules in Space: A Landscape Theory

2011 ◽  
Author(s):  
Kevin S. McCann
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Large Scale ◽  
Landscape Scale ◽  
Food Web Structure ◽  
Web Structure ◽  
Web Architecture ◽  
Individual Traits ◽  
Bird Feeder

This chapter examines food webs at the landscape scale by focusing on the large-scale food web architecture that is deeply constrained by space. It begins with a discussion of how variability in space, time, and food web structure, coupled with the ability of organisms to rapidly respond to variation, affect the maintenance of the food web and its functions. It then explains how individual traits such as body size and foraging behavior relate to food web structure in space and time. It also considers the role of spatial constraints on food webs and how the existence of fast–slow pathways coupled by mobile adaptive predators gives rise to spatial asynchrony in the resources. The chapter concludes with a review of some empirical examples to show that some food webs display the bird feeder effect and that resource coupling of distinct habitats appears to stabilize food webs.

scholarly journals Advection, krill, and Antarctic marine ecosystems

2004 ◽  
Vol 16 (4) ◽  
pp. 487-499 ◽  
Author(s):  
EILEEN E. HOFMANN ◽  
EUGENE J. MURPHY
Keyword(s):  
Southern Ocean ◽  
Food Web ◽  
Large Scale ◽  
Antarctic Krill ◽  
Euphausia Superba ◽  
Marine Ecosystems ◽  
Research Programmes ◽  
Dominant Process ◽  
Ocean Ecosystem ◽  
Circumpolar Current

Advective processes are recognized as being important in structuring and maintaining marine ecosystems. In the Southern Ocean advective effects are perhaps most clearly observed because the Antarctic Circumpolar Current (ACC) provides a connection between most parts of the system, including open ocean and continental shelf regions. The ACC also provides a mechanism for large-scale transport of plankton, such as Antarctic krill (Euphausia superba Dana), which is an important component of the Southern Ocean food web. This overview provides a summary of recent observational and modelling results that consider the importance of advection to the Southern Ocean ecosystem and, in particular, the role of advection in structuring the large-scale distribution of Antarctic krill. The results of these studies show that advection is a dominant process controlling Antarctic krill distribution and by inference an important process affecting overall structure and production of the Southern Ocean food web. The overview shows that quantifying the roles of advective and retentive physical processes, and population dynamic and behavioural biological processes in determining the regional and local distribution of krill and abundance will be an important research focus. Strategies for future Antarctic multidisciplinary research programmes that are focused on understanding advective processes at a circumpolar scale are suggested.

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