Trophic interactions affect the population dynamics and risk of extinction of basal species in food webs

Trophic levels can be applied to describe the ecological role of organisms in food webs and assess changes in ecosystems. Stable isotopes analysis can assist in the understanding of trophic interactions and use of food resources by aquatic organisms. The local ecological knowledge (LEK) of fishers can be an alternative to advance understanding about fish trophic interactions and to construct aquatic food webs, especially in regions lacking research capacity. The objectives of this study are: to calculate the trophic levels of six fish species important to fishing by combining data from stable isotopes analysis and fishers’ LEK in two clear water rivers (Tapajós and Tocantins) in the Brazilian Amazon; to compare the trophic levels of these fish between the two methods (stable isotopes analysis and LEK) and the two rivers; and to develop diagrams representing the trophic webs of the main fish prey and predators based on fisher’s LEK. The fish species studied were Pescada (Plagioscion squamosissimus), Tucunaré (Cichla pinima), Piranha (Serrasalmus rhombeus), Aracu (Leporinus fasciatus), Charuto (Hemiodus unimaculatus), and Jaraqui (Semaprochilodus spp.). A total of 98 interviews and 63 samples for stable isotopes analysis were carried out in both rivers. The average fish trophic levels did not differ between the stable isotopes analysis and the LEK in the Tapajós, nor in the Tocantins Rivers. The overall trophic level of the studied fish species obtained through the LEK did not differ from data obtained through the stable isotopes analysis in both rivers, except for the Aracu in the Tapajós River. The main food items consumed by the fish according to fishers’ LEK did agree with fish diets as described in the biological literature. Fishers provided useful information on fish predators and feeding habits of endangered species, such as river dolphin and river otter. Collaboration with fishers through LEK studies can be a viable approach to produce reliable data on fish trophic ecology to improve fisheries management and species conservation in tropical freshwater environments and other regions with data limitations.

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More Modules

Food Webs (MPB-50) ◽

10.23943/princeton/9780691134178.003.0008 ◽

2011 ◽

Cited By ~ 1

Author(s):

Kevin S. McCann

Keyword(s):

Population Dynamics ◽

Food Webs ◽

Empirical Evidence ◽

Intraguild Predation ◽

Weak Interactions ◽

Apparent Competition ◽

Trade Offs ◽

Variable Population ◽

The Stability

This chapter considers four-species modules and the role of generalism (effectively a three-species module with a consumer feeding on two resources). It first examines how generalists affect the dynamics of food webs by focusing on a set of modules that contrast generalist consumer dynamics relative to the specialist case. It then discusses organismal trade-offs that play a role in governing the diamond food web module and the intraguild predation module, arguing that such tradeoffs influence the flux of matter, the organization of interaction strengths, and ultimately the stability of communities. The chapter also reviews empirical evidence showing that apparent competition and the diamond module with and without intraguild predation are ubiquitous, and that weak interactions in simple modules seem to promote less variable population dynamics.

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Resolving Food-Web Structure

Annual Review of Ecology Evolution and Systematics ◽

10.1146/annurev-ecolsys-110218-024908 ◽

2020 ◽

Vol 51 (1) ◽

pp. 55-80

Author(s):

Robert M. Pringle ◽

Matthew C. Hutchinson

Keyword(s):

Food Web ◽

Food Webs ◽

Trophic Interactions ◽

Sampling Methods ◽

Taxonomic Resolution ◽

Major Focus ◽

Web Data ◽

Food Web Structure ◽

Web Structure ◽

Abundant Evidence

Food webs are a major focus and organizing theme of ecology, but the data used to assemble them are deficient. Early debates over food-web data focused on taxonomic resolution and completeness, lack of which had produced spurious inferences. Recent data are widely believed to be much better and are used extensively in theoretical and meta-analytic research on network ecology. Confidence in these data rests on the assumptions ( a) that empiricists correctly identified consumers and their foods and ( b) that sampling methods were adequate to detect a near-comprehensive fraction of the trophic interactions between species. Abundant evidence indicates that these assumptions are often invalid, suggesting that most topological food-web data may remain unreliable for inferences about network structure and underlying ecological and evolutionary processes. Morphologically cryptic species are ubiquitous across taxa and regions, and many trophic interactions routinely evade detection by conventional methods. Molecular methods have diagnosed the severity of these problems and are a necessary part of the cure.

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Reconstructing hyperdiverse food webs: Gut content metabarcoding as a tool to disentangle trophic interactions on coral reefs

Methods in Ecology and Evolution ◽

10.1111/2041-210x.13206 ◽

2019 ◽

Vol 10 (8) ◽

pp. 1157-1170 ◽

Cited By ~ 16

Author(s):

Jordan M. Casey ◽

Christopher P. Meyer ◽

Fabien Morat ◽

Simon J. Brandl ◽

Serge Planes ◽

...

Keyword(s):

Coral Reefs ◽

Food Webs ◽

Trophic Interactions ◽

Gut Content

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POPULATION DYNAMICS ON COMPLEX FOOD WEBS

Advances in Complex Systems ◽

10.1142/s0219525911003116 ◽

2011 ◽

Vol 14 (04) ◽

pp. 635-647 ◽

Cited By ~ 2

Author(s):

GIAN MARCO PALAMARA ◽

VINKO ZLATIĆ ◽

ANTONIO SCALA ◽

GUIDO CALDARELLI

Keyword(s):

Population Dynamics ◽

Simple Model ◽

Food Web ◽

Food Webs ◽

Real Data ◽

Niche Model ◽

Ecological Complexity ◽

Overlap Graphs ◽

Dynamical Properties ◽

The Stability

In this work we analyze the topological and dynamical properties of a simple model of complex food webs, namely the niche model. In order to underline competition among species, we introduce "prey" and "predators" weighted overlap graphs derived from the niche model and compare synthetic food webs with real data. Doing so, we find new tests for the goodness of synthetic food web models and indicate a possible direction of improvement for existing ones. We then exploit the weighted overlap graphs to define a competition kernel for Lotka–Volterra population dynamics and find that for such a model the stability of food webs decreases with its ecological complexity.

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