Food Web Structure in a Subtropical Lake Ecosystem

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Food webs, Freshwater fish, Zooplanton, Ominvores, macrointerebrates

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This study considered trophic interactions in the pelagic and littoral regions of Lake Okeechobee, a large subtropical lake ecosystem in Florida, USA. Food web models were developed from species lists and diet information, and web attributes were utilized to compare and contrast the structurally-simple pelagic and structurally-complex littoral habitats, in terms of taxonomic structure and consumer-resource relationships. Consumers in four major trophic guilds (wading birds, fish, benthic macroinvertebrates, and Zooplankton) were identified, in most cases to their biological species level, and their trophic interactions were determined based on a combination of direct measurements (for 37% of the consumers) and published diet information. Complex food webs were documented in both the pelagic and littoral habitats. The littoral web contained more species (324), links, and trophic guilds, than the pelagic web (218 species). In both webs, macroinvertebrates were the most speciose group, and periphyton/ detritus was the most frequently utilized food resource. Most consumers were omnivores that exploited periphyton/detritus and some other living component of the community. A high degree of omnivory and detritus-feeding appear to be general features of aquatic food webs.

Citation / Publisher Attribution

Oikos, v. 75, issue 1, p. 20-32