Structure and Stability in Natural and Randomly Constructed Competitive Communities

Lawlor, Lawrence R.

doi:10.1086/283634

Cited by 187 publications

(134 citation statements)

References 27 publications

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“…The method employs a bootstrap randomization of the raw data (predator × prey matrix) to generate a distribution of overlap indices reflecting the null hypothesis of no consistent diet composition within predators. We employed a randomization scheme whereby zeros in the predator-prey matrix were retained in their origi- (Lawlor 1980, Winemiller & Pianka 1990). The algorithm randomly rearranges the proportions (e.g., p ik in Eq.…”

Section: Methodsmentioning

confidence: 99%

Dietary guild structure of the fish community in the Northeast United States continental shelf ecosystem

Garrison

Link²

2000

Mar. Ecol. Prog. Ser.

206

180

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Trophic guild analysis identifies groups of species that use similar resources within a community. We evaluated the trophic guild structure in an assemblage of 40 fish species in the Northeast United States shelf ecosystem using a 25 yr database of food habits. We explicitly accounted for ontogenetic diet shifts by separating predator species into size classes. There were 14 significant trophic guilds. These distinguished predators based upon prey size and location in the water column (i.e., benthic to pelagic feeding). Ontogenetic diet shifts were important in guild structure, particularly within dominant piscivores. The mean dietary overlap both between and within guilds was notably lower than in other fish communities due to the broad spatial and temporal scale of the study, the diversity of prey types consumed, and the generalist nature of predators in this system. The guild concept is a useful framework to simplify highly connected, complex ecosystems like the Northeast US continental shelf and identify ecologically similar functional units.

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Section: Methodsmentioning

confidence: 99%

Dietary guild structure of the fish community in the Northeast United States continental shelf ecosystem

Garrison

Link²

2000

Mar. Ecol. Prog. Ser.

206

180

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“…In addition, diet data from stations where two or more fish species were caught together was treated separately in order to investigate whether cooccurrence influenced prey selection and diet overlap on fine scale and obtain information about the station-to-station variability in diet and diet overlap. In order to test for significance, the proportion of a given prey group in a given diet was randomized according to the Randomization Algorithm (RA2) of Lawlor (1980) and iterated 1000 times for each comparison of diet overlap using EcoSim v.7.72 (Gotelli & Entsminger 2004). Lawlor (1980) described four randomization algorithms (RA1ÁRA4) for niche overlap in which the zero states, i.e.…”

Section: Diet Analysesmentioning

confidence: 99%

“…In order to test for significance, the proportion of a given prey group in a given diet was randomized according to the Randomization Algorithm (RA2) of Lawlor (1980) and iterated 1000 times for each comparison of diet overlap using EcoSim v.7.72 (Gotelli & Entsminger 2004). Lawlor (1980) described four randomization algorithms (RA1ÁRA4) for niche overlap in which the zero states, i.e. the empty prey groups, and the niche breadth, i.e.…”

Section: Diet Analysesmentioning

confidence: 99%

Overlap in distribution and diets of Atlantic mackerel (Scomber scombrus), Norwegian spring-spawning herring (Clupea harengus) and blue whiting (Micromesistius poutassou) in the Norwegian Sea during late summer

Langøy

Nøttestad

Skaret

et al. 2012

Marine Biology Research

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Based on two large-scale surveys in the Norwegian Sea in July 2004 and 2006 we investigated the potential overlap in distribution and diets and association with environmental variables for mackerel, herring and blue whiting. Mackerel and blue whiting had low overlap in both distribution and diets, and were associated with warm Atlantic and cold prey-rich Arctic waters, respectively. Also, herring and mackerel were negatively correlated, associated with different environmental variables and even had low diet overlap in Atlantic water where the highest overlap in distribution was observed, but these trends were much clearer in 2006 than in 2004. Prey was patchily distributed and data from single stations indicated that feeding was opportunistic, in particular for mackerel. However, mackerel diet width and feeding incidence were similar between the years, whereas herring was more selective in 2004, probably reaching the end of the feeding season. A delayed peak in Calanus availability was indicated in 2006 and may have prolonged the feeding season, partly explain the difference between the years. Our data did not indicate a prey shift due to encounters between mackerel and herring. Concentrated efforts in limited areas are needed to further elucidate this aspect of interaction.

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“…The availability of resources can be influenced by spatial and temporal physical variables (Lawlor, 1980) and the presence or absence of vegetation cover which can affect the density of resources (Pinto and Uieda, 2007). Some studies have demonstrated that fish select food resources based on their availability in the environment (e.g.…”

Section: Introductionmentioning

confidence: 99%

Plasticity in the diet of Astyanax taeniatus in a coastal stream from south-east Brazil

Rezende

Mazzoni

2012

Braz. J. Biol.

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In this work we aimed to characterise the diet of Astyanax taeniatus (Jenyns 1842) (Characiformes, Characidae) along the Mato Grosso stream and we hypothesised that the diet of this species would vary according to spatial, seasonal and ontogenetic differences. Specimens were collected every second month at three sites with different physical attributes. The feeding habits of 651 specimens were analysed using the Alimentary Index (IA i ). Analysis of the diet showed an effect of spatial, temporal and ontogenetic factors. Vegetal allochthonous items were more important in the diet of Astyanax taeniatus in upstream sites while animal autochthonous items were more important downstream. Ontogenetic differences in the diet were significant only in upstream sites, where adults consumed a greater amount of vegetal matter than juveniles. These results reinforce the idea that Astyanax species are opportunistic and show trophic plasticity.Keywords: feeding, opportunism, stream fish. Plasticidade trófica em Astyanax taeniatus de um riacho costeiro do Sudeste do Brasil ResumoNeste trabalho, objetivou-se caracterizar a dieta de Astyanax taeniatus (Jenyns 1842) (Characiformes, Characidae) ao longo do Rio Mato Grosso, com a hipótese de que a espécie apresente variações espaciais, sazonais e ontogenéticas. Os exemplares foram coletados bimestralmente em três localidades, que diferiram pelas variáveis físicas. As preferências alimentares foram analisadas a partir de 651 exemplares, utilizando-se o Índice Alimentar (IA i ). Foram avaliadas diferenças espaciais, sazonais e ontogenéticas a partir dos dados de dieta. Os itens de origem vegetal e alóctone foram mais importantes na dieta da espécie para as localidades com maior altitude, enquanto os itens animais e autóctones, na localidade baixa. Na dieta de jovens e adultos, houve diferença significativa na contribuição de itens de origem vegetal e animal somente na localidade mais alta, onde os adultos consumiram maior quantidade de matéria vegetal. Os resultados reforçam a ideia de que as espécies de Astyanax possuem hábito alimentar onívoro e oportunista, evidenciando sua alta plasticidade alimentar ao longo do riacho.Palavras-chave: alimentação, oportunismo, peixe de riacho.

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Structure and Stability in Natural and Randomly Constructed Competitive Communities

Cited by 187 publications

References 27 publications

Dietary guild structure of the fish community in the Northeast United States continental shelf ecosystem

Dietary guild structure of the fish community in the Northeast United States continental shelf ecosystem

Overlap in distribution and diets of Atlantic mackerel (Scomber scombrus), Norwegian spring-spawning herring (Clupea harengus) and blue whiting (Micromesistius poutassou) in the Norwegian Sea during late summer

Plasticity in the diet of Astyanax taeniatus in a coastal stream from south-east Brazil

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