Food web ecologists have long sought to characterize the trophic niches of animals using stable isotopic analysis. However, distilling trophic position from isotopic composition has been difficult, largely because of the variability associated with trophic discrimination factors (inter-trophic isotopic fractionation and routing). We circumvented much of this variability using compound-specific ...

The telotrophic ovary of Notonecta glauca glauca consists of 7 ovarioles. Each ovanole comprises, from front to rear, a terminal filament, a trophic region, a prefolhcular region, and a series of 10-15 follicles of progressively increasing size The trophic region is largely syncytial and is made up of polyploid trophic nuclei packed around a central trophic core The cytoplasm of the trophic cor...

Based on the law of mass action (and its microscopic foundation) and mass conservation, we present here a method to derive consistent dynamic models for the time evolution of systems with an arbitrary number of species. Equations are derived through a mechanistic description, ensuring that all parameters have ecological meaning. After discussing the biological mechanisms associated to the logis...

Hydraulic fracturing has become the method of choice for extracting natural gas from shale deposits in the United States. As time has passed, environmental concerns have been raised as a result of research from the EPA and independent organizations, though most of it has focused strictly on the consequences this has for human health and land use, and little has focused on its effects on trophic...

A principal aim of ecologists is to identify critical levels of environmental change beyond which ecosystems undergo radical shifts in their functioning. Both food-web theory and alternative stable states theory provide fundamental clues to mechanisms conferring stability to natural systems. Yet, it is unclear how the concept of food-web stability is associated with the resilience of ecosystems...

The ecological impacts of anthropogenic activities on aquatic environments have led to the development of new methods of environmental monitoring (Cohen et al 1993, Kelly and Whitton 1995). Benthic algae represent a ubiquitous group of photosynthetic organisms that play a pivotal role in stream food webs but may also be used for observing long-term trends in community changes that can occur bec...

eutrophication is known as the most common problem in water bodies, caused by high concentrations of different nutrients leading to unbalanced growth of aquatic plants, among other symptoms. hence, the possibility of eutrophication prediction can be beneficial to the sustainable management of these natural resources and create an opportunity to control their trophic conditions over time. a soft...

Models of biomass size spectra assume that organisms with higher body mass feed at higher trophic levels, but explicit empirical tests of this pattern are rare. We used nitrogen stable isotopes (δ15N) as an index of the trophic level in a benthic fish and invertebrate size-spectrum, and demonstrated that body mass was positively and significantly related to trophic level. This pattern was consi...

Food webs are known to have myriad trophic links between resource and consumer species. While herbivores have well-understood trophic tendencies, the difficulties associated with characterizing the trophic positions of higher-order consumers have remained a major problem in food web ecology. To better understand trophic linkages in food webs, analysis of the stable nitrogen isotopic composition...