Longer food chains and crowded niche space: effects of multiple invaders on desert stream food web structure

2013 ◽  
Vol 22 (3) ◽  
pp. 439-452 ◽  
Author(s):  
Timothy E. Walsworth ◽  
Phaedra Budy ◽  
Gary P. Thiede
Keyword(s):  
Food Web ◽  
Food Chains ◽  
Niche Space ◽  
Food Web Structure ◽  
Web Structure ◽  
Space Effects ◽  
Desert Stream

Food Chains and Omnivory

2011 ◽  
Author(s):  
Kevin S. McCann
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Empirical Evidence ◽  
Food Chain ◽  
Stage Structure ◽  
Food Chains ◽  
Dependent Manner ◽  
Food Web Structure ◽  
Web Structure ◽  
Consumer Resource

This chapter extends the consumer–resource theory to include simple but common three-species modules behind the construction of whole food webs, with particular emphasis on food chains and omnivory. It first considers some common simple modular food web structures and whether the dynamics of subsystems can be seen using the framework laid out in previous chapters. Specifically, it asks when common food web structure increases or weakens the relative interaction strengths and/or when a food web structure modifies flux between consumers and resources in a density-dependent manner such that the food web tends to increase flux rates in some situations and decrease the coupling in other situations. The chapter also explores how stage structure can influence food chain stability before concluding with a review of empirical evidence on the dynamical implications of omnivory for food webs.

scholarly journals Food-web structure in low- and high-dimensional trophic niche spaces

2010 ◽  
Vol 7 (53) ◽  
pp. 1735-1743 ◽  
Author(s):  
Axel G. Rossberg ◽  
Åke Brännström ◽  
Ulf Dieckmann
Keyword(s):  
Food Web ◽  
Trophic Niche ◽  
High Dimensional ◽  
Niche Space ◽  
Food Web Structure ◽  
One Dimensional ◽  
Evolutionary Diversification ◽  
Web Structure ◽  
Higher Dimensional ◽  
Consumer Resource

A question central to modelling and, ultimately, managing food webs concerns the dimensionality of trophic niche space, that is, the number of independent traits relevant for determining consumer–resource links. Food-web topologies can often be interpreted by assuming resource traits to be specified by points along a line and each consumer's diet to be given by resources contained in an interval on this line. This phenomenon, called intervality, has been known for 30 years and is widely acknowledged to indicate that trophic niche space is close to one-dimensional. We show that the degrees of intervality observed in nature can be reproduced in arbitrary-dimensional trophic niche spaces, provided that the processes of evolutionary diversification and adaptation are taken into account. Contrary to expectations, intervality is least pronounced at intermediate dimensions and steadily improves towards lower- and higher-dimensional trophic niche spaces.

scholarly journals Flooding affects food web structure and basal sources supporting fish guilds in a subtropical wetland and shallow lake

2021 ◽  
Author(s):  
Rodrigo Ferreira Bastos ◽  
Alexandre Miranda Garcia ◽  
Kirk O. Winemiller ◽  
Nelson Ferreira Fontoura
Keyword(s):  
Organic Matter ◽  
Food Web ◽  
Shallow Lake ◽  
Trophic Structure ◽  
Terrestrial Ecosystems ◽  
Spatial And Temporal Variation ◽  
Food Chains ◽  
Food Web Structure ◽  
Aquatic Animals ◽  
Web Structure

Abstract Aquatic ecosystems exchange nutrients and organic matter with surrounding terrestrial ecosystems, and floods import allochthonous material from riparian areas into fluvial systems. We surveyed food web components of a wetland and shallow lake in a subtropical coastal region of Brazil to examine how community trophic structure and the entrance of allochthonous material into the food web were affected by floods. Stable isotope analysis was performed for samples of terrestrial and aquatic basal production sources and aquatic animals to trace the origin of organic matter assimilated by aquatic animals and estimate vertical trophic positions and food chain length. Lake and wetland trophic structures were compared for cool/wet and warm/dry seasons. Food web structure was hypothesized to differ based on hydrology, with the more stable lake having greater food web complexity, and seasonal flooding resulting in greater allochthonous inputs to the aquatic food web. We compared spatial and temporal variation in assemblage trophic structure using an adapted isotopic ellipse approach that plots assemblage elements according to δ13C on the x-axis and estimated TP on the y-axis. Lake trophic structure was more complex with longer food chains compared to that of the wetland. A greater contribution from terrestrial resources to animal biomass was observed in the wetland during the cool/wet period, and food chains in both habitats tended to be longer during the cool/wet period. Findings supported the hypothesis of greater assimilation of allochthonous sources during floods and greater trophic complexity in the more hydrologically stable system.

Invasive rodents have multiple indirect effects on seabird island invertebrate food web structure

2017 ◽  
Vol 27 (4) ◽  
pp. 1190-1198 ◽  
Author(s):  
Joshua J. Thoresen ◽  
David Towns ◽  
Sebastian Leuzinger ◽  
Mel Durrett ◽  
Christa P. H. Mulder ◽  
...  
Keyword(s):  
Food Web ◽  
Indirect Effects ◽  
Food Web Structure ◽  
Web Structure ◽  
Invasive Rodents

scholarly journals Hydrodynamics drive pelagic communities and food web structure in a tidal environment

2020 ◽  
Vol 106 (2) ◽  
pp. 69-85
Author(s):  
Matthew J. Young ◽  
Frederick Feyrer ◽  
Paul R. Stumpner ◽  
Veronica Larwood ◽  
Oliver Patton ◽  
...  
Keyword(s):  
Food Web ◽  
Food Web Structure ◽  
Web Structure ◽  
Pelagic Communities

scholarly journals The more food webs change, the more they stay the same

2009 ◽  
Vol 364 (1524) ◽  
pp. 1789-1801 ◽  
Author(s):  
Kevin Shear McCann ◽  
Neil Rooney
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Temporal Variability ◽  
Spatial And Temporal Variability ◽  
Scale Invariant ◽  
Food Web Structure ◽  
Behavioural Responses ◽  
Web Structure ◽  
Food Web Ecology ◽  
Food Web Theory

Here, we synthesize a number of recent empirical and theoretical papers to argue that food-web dynamics are characterized by high amounts of spatial and temporal variability and that organisms respond predictably, via behaviour, to these changing conditions. Such behavioural responses on the landscape drive a highly adaptive food-web structure in space and time. Empirical evidence suggests that underlying attributes of food webs are potentially scale-invariant such that food webs are characterized by hump-shaped trophic structures with fast and slow pathways that repeat at different resolutions within the food web. We place these empirical patterns within the context of recent food-web theory to show that adaptable food-web structure confers stability to an assemblage of interacting organisms in a variable world. Finally, we show that recent food-web analyses agree with two of the major predictions of this theory. We argue that the next major frontier in food-web theory and applied food-web ecology must consider the influence of variability on food-web structure.

Environmental warming alters food-web structure and ecosystem function

Nature ◽  
10.1038/47023 ◽  
1999 ◽  
Vol 402 (6757) ◽  
pp. 69-72 ◽  
Author(s):  
Owen L. Petchey ◽  
P. Timon McPhearson ◽  
Timothy M. Casey ◽  
Peter J. Morin
Keyword(s):  
Food Web ◽  
Ecosystem Function ◽  
Food Web Structure ◽  
Web Structure ◽  
Environmental Warming
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