Pelagic ecosystems are dynamic ocean regions whose immense natural capital is affected by climate change, pollution, and commercial fisheries. Trophic level-based indicators derived from fishery catch data may reveal the food web status of these systems, but the utility of these metrics has been debated because of targeting bias in fisheries catch. We analyze a unique, fishery-independent data ...

Persistent organic pollutants (POPs) and stable isotopes of nitrogen (delta 15N) were measured in zooplankton (6 species), a benthic invertebrate (Anonyx nugax), Arctic cod (Boreogadus saida), seabirds (6 species), and ringed seals (Phoca hispida) collected in 1998 in the Northwater Polynya to examine effects of biological and chemical factors on trophic transfer of POPs in an Arctic marine foo...

Trophic levels are critical for synthesizing species' diets, depicting energy pathways, understanding food web dynamics and ecosystem functioning, and monitoring ecosystem health. Specifically, trophic levels describe the position of species in a food web, from primary producers to apex predators (range, 1-5). Small differences in trophic level can reflect large differences in diet. Although tr...

Investigating the relations and mechanisms of coexistence among sympatric species is essential to comprehend their ecological roles in the food webs. In the present study, the diet and trophic interactions of 5 abundant teleost species coexisting in the northern Oman Sea were examined using stomach contents analyses. The cumulative prey curves showed that the sample size of each studied species...

Reservoirs are artificial environments built by humans, and the impacts of these environments are not completely known. Retention time and high nutrient availability in the water increases the eutrophic level. Eutrophication is directly correlated to primary productivity by phytoplankton. These organisms have an important role in the environment. However, high concentrations of determined speci...

It is widely recognized that trophic interactions structure ecological communities, but their effects are usually only demonstrated on a small scale. As a result, landscape-level documentations of trophic cascades that alter entire communities are scarce. Islands invaded by animals provide natural experiment opportunities both to measure general trophic effects across large spatial scales and t...

Inducible defenses are dynamic traits that modulate the strength of both plant-herbivore and herbivore-carnivore interactions. Surprisingly few studies have considered the relative contributions of induced plant and herbivore defenses to the overall balance of bottom-up and top-down control. Here we compare trophic cascade strengths using replicated two-level and three-level plankton communitie...

We summarize research on diversity and trophic interactions under a trophic cascades model that is reframed and expanded from the traditional biomassor abundancebased indirect effects and discuss the response of such ―diversity cascades‖ to climate change and other global change parameters. The studies we summarize encompass dynamic processes in which species richness or evenness in one trophic...

abstract studies have shown that birds due to being in the high trophic levels on the ecosystems, and also high sensitivity to toxic substances are a useful indicator for the evaluation of mercury pollution. the objective of the present study was to evaluate mercury level in the feathers of turdus philomelos and turdus merula in khanikan forests as an indicator of mercury contamination. to atta...

Using donor-controlled, bottom-up equations to describe network collapse we systematically investigate the impact each species has on the survival or extinction of other species. Short of extinction, one can determine the integrated losses experienced by the ecosystem. These losses are aggregated into system level indicators, such as entropy, average gain/loss, average time to extinction, etc. ...