Ecosystem structure—that is the species present, functions they represent, and how those interact—is an important determinant of community stability. This in turn affects ecosystems respond to natural anthropogenic crises, whether or ecological that represent are able persist. Here we use fossil data from museum collections, literature, Paleobiology Database reconstruct trophic networks Tethyan...

The aim of this study was to assess the eutrophication and trophic status of the Caspian Sea based on different indices and also compare its status with the reference threshold values in the Iranian coastal waters of Caspian Sea (hereafter ICWCS). The water samples (three replicates) were collected along four transects (off the coast from Anzali, Tonekabon, Nowshahr and Amirabad) between spring...

the parameters used to determine the trophic state of a water body are: total phosphorus (tp),transparency (secchi disk depth) and chlorophyll a. however, these parameters show strong seasonalfluctuations which may hinder the estimation of trophic state. some authors have proposed that sediments be used as an additional tool to evaluate the trophic state of a water body. the aim of this study w...

The bioaccumulations of metals Cu, Cd, Ni, Cr, Co, Mn, Zn and Fe were measured in bivalves, Cerastoderma glucaum, and four species of fishes including Alburnus chalcoides, Liza aurata, Rutilus frisii and Sander lucioperca from various trophic levels of the Caspian food web. The concentrations of Cd, Cr, Co and Ni in most samples of fish were below the detection limits; while the concentrations ...

Analyses of trophic structure and feeding habits the fish community can provide information on complex biotic abiotic interactions in lake ecosystems. Based stomach content δ13C δ15N stable isotope analyses, we conducted a comprehensive study diet its subtropical Lake Zacapu central Mexico. Overall, there was good agreement between results based analysis. Fish diets consisted mainly aquatic mac...

Competition and predation alter individual traits of organisms, and these effects can scale-up to have consequences on community structure and dynamics. The relative importance of competition and predation will depend largely on the local assemblage of species, the type of predators, or the degree of niche segregation. We experimentally investigated the interplay of competition and predation on...

iv FOREWORD Chapters 2, 3, 4, and 5 are either in review, in revision or will be submitted, and thus are formatted according to specific journal formats: Ecology (Chapter 1), Hydrobiologia Food webs and aquatic ecology of subtropical South American streams are poorly understood. I investigated the trophic structure of the upper Rio Cuareim (Uruguay, South America). I analyzed the stable isotope...

Macroscopic ecosystem properties, such as major material pathways and community biomass structure, underlie the ecosystem services on which humans rely. While ecologists have long sought to identify the determinants of the trophic height of food webs (food chain length), it is somewhat surprising how little research effort is invested in understanding changes among other food web properties acr...