A trophic characterization of intertidal consumers on Chilean rocky shores

Camus, Patricio A.; Arancibia, Paulina A.; Ávila‐Thieme, M. Isidora

doi:10.4067/s0718-19572013000300003

Cited by 21 publications

(34 citation statements)

References 41 publications

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“…However, at PSA, these species seem to prefer other food sources, which indicate a certain alimentary flexibility. Our findings, however, contradict earlier studies from northern Chile that found species of the genus Fissurella to be omnivorous (Camus et al 2009(Camus et al , 2013.…”

Section: Insights From Isotopic Composition To Consumers Feeding Ecologycontrasting

confidence: 99%

Trophic structure of shallow-water benthic communities in the sub-Antarctic Strait of Magellan

et al. 2016

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Trophic structure is among the most fundamental characteristics of an ecosystem since it is a useful way to determine the main energy flow at the ecosystem level. In the Magellan Strait, the local spatial heterogeneity at the shallow-waters ecosystems may have a great variety of potential food sources; however, knowledge about their biological communities and their structure is still unclear. We examined the trophic structure of shallow-water-mixed bottom communities at two sites in the sub-Antarctic Magellan Strait based on carbon (d 13 C) and nitrogen (d 15 N) stable isotope ratios. The benthic communities were composed of 46 species from 20 major taxa at Bahía Laredo (BL) and 55 species from 18 major taxa at Punta Santa Ana (PSA). Benthic macroalgae and organic matter associated with sediment are the major primary food sources at both sites. Although both sites are quite similar in their food sources and in their vertical trophic structure (Cthree trophic levels), the food web structure varied distinctly. Functionally, predators and grazers dominated both communities, but top predators were shorebirds, carnivore anemones and predatory nemerteans at BL, and sea stars, shorebirds, crabs and fishes at PSA. The distinct differences in the trophic structure at BL and PSA highlight the important variability of d 15 N at the base of the benthic food web, the role of local environmental conditions and community dynamics in structuring shallow-water communities.

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Section: Insights From Isotopic Composition To Consumers Feeding Ecologycontrasting

confidence: 99%

Trophic structure of shallow-water benthic communities in the sub-Antarctic Strait of Magellan

et al. 2016

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“…The observed high prevalence large trophic networks. However, we did not found a relationship between density and the number of dietary items per species using the data published by Camus et al (2013), thus, generalist predators were not necessarily the most abundant.…”

Section: Persistence In the Occurrence Of C-r Interactionscontrasting

confidence: 72%

“…Therefore, the dominance of generalist predators, coupled with a significant spatiotemporal variation in prey abundances, could be part of a mechanism determining the transient nature of large trophic networks. However, we did not found a relationship between density and the number of dietary items per species using the data published by Camus et al (), thus, generalist predators were not necessarily the most abundant.…”

Section: Discussioncontrasting

confidence: 55%

“…In the laboratory, the prey items of each consumer individual were identified to the lowest possible taxonomic level by means of gut content examination (Camus and Daroch , Camus et al ). Across the four sites we recorded more than 1000 interactions, and nearly 80% of the samples were identified to the species level (Camus and Daroch , Camus et al ). For each site, we constructed a C‐R matrix with the number of times that each C‐R interaction was observed in the 10 sample events (the ‘persistence matrix’).…”

Section: Methodsmentioning

confidence: 99%

“…This expected high variability has been observed in several networks, which differ in the number of species involved (nodes), interactions (links), the number of species at each trophic level, and changes in the complexity (i.e. connectance) of the network (Winemiller , Martinez , Moore and de Ruiter , Martinez et al , Akin and Winemiller , Camus et al ). However, continuous tracking of all network interactions over time and at different environmental conditions is still lacking, and therefore the quantification of the persistence of trophic interactions in the long‐term has been difficult.…”

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confidence: 95%

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High temporal variability in the occurrence of consumer–resource interactions in ecological networks

López

Camus

Valdivia

et al. 2017

Oikos

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Ecological networks are theoretical abstractions that represent ecological communities. These networks are usually defined as static entities, in which the occurrence of a particular interaction between species is considered fixed despite the intrinsic dynamics of ecological systems. Trophic interactions, in particular, are often temporally dynamic in nature, ranging from so-called first-order dynamics to cyclical. However, empirical analysis of the temporal variation of trophic interactions is constrained by the lack of data with high spatial, temporal, and taxonomic resolution. Here, we evaluate the spatiotemporal variability of multiple consumer-resource interactions of large marine intertidal rockyshore networks. In order to generate the networks, more than 1,000 km of the coast of northern Chile was monitored seasonally over 3 years. The trophic interactions of all of the analyzed networks had low temporal persistence, which was well described by a common exponential decay in the rankfrequency relationship of consumer-resource interactions. This common pattern of low temporal persistence was evident despite the dissimilarities of environmental conditions among sites. Betweensite rank correlations of frequency of occurrence of interactions ranged from 0.59 to 0.73. After removing the interactions with <50% frequency, the between-site correlations decreased to values between 0.60 and 0.28, indicating that low-frequency interactions accounted for the apparent similarities between sites. Our results demonstrate, therefore, that the communities studied were characterized by few persistent interactions and a large number of transient trophic interactions. We suggest that consumer-resource temporal asynchrony in addition to varying local environmental conditions and opportunistic foraging could be among the mechanisms generating the observed rankfrequency relationship of trophic interactions. Therefore, our results question the analysis of ecological communities as static and persistent natural entities and stress the need for strengthening the analysis of temporal variability in ecological networks and long-term studies.

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Species co‐occurrence networks: Can they reveal trophic and non‐trophic interactions in ecological communities?

Freilich

Wieters

Broitman

et al. 2018

Ecology

294

218

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Co-occurrence methods are increasingly utilized in ecology to infer networks of species interactions where detailed knowledge based on empirical studies is difficult to obtain. Their use is particularly common, but not restricted to, microbial networks constructed from metagenomic analyses. In this study, we test the efficacy of this procedure by comparing an inferred network constructed using spatially intensive co-occurrence data from the rocky intertidal zone in central Chile to a well-resolved, empirically based, species interaction network from the same region. We evaluated the overlap in the information provided by each network and the extent to which there is a bias for co-occurrence data to better detect known trophic or non-trophic, positive or negative interactions. We found a poor correspondence between the co-occurrence network and the known species interactions with overall sensitivity (probability of true link detection) equal to 0.469, and specificity (true non-interaction) equal to 0.527. The ability to detect interactions varied with interaction type. Positive non-trophic interactions such as commensalism and facilitation were detected at the highest rates. These results demonstrate that co-occurrence networks do not represent classical ecological networks in which interactions are defined by direct observations or experimental manipulations. Co-occurrence networks provide information about the joint spatial effects of environmental conditions, recruitment, and, to some extent, biotic interactions, and among the latter, they tend to better detect niche-expanding positive non-trophic interactions. Detection of links (sensitivity or specificity) was not higher for well-known intertidal keystone species than for the rest of consumers in the community. Thus, as observed in previous empirical and theoretical studies, patterns of interactions in co-occurrence networks must be interpreted with caution, especially when extending interaction-based ecological theory to interpret network variability and stability. Co-occurrence networks may be particularly valuable for analysis of community dynamics that blends interactions and environment, rather than pairwise interactions alone.

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A trophic characterization of intertidal consumers on Chilean rocky shores

Cited by 21 publications

References 41 publications

Trophic structure of shallow-water benthic communities in the sub-Antarctic Strait of Magellan

Trophic structure of shallow-water benthic communities in the sub-Antarctic Strait of Magellan

High temporal variability in the occurrence of consumer–resource interactions in ecological networks

Species co‐occurrence networks: Can they reveal trophic and non‐trophic interactions in ecological communities?

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