Stable isotope ratios (typically of carbon and nitrogen) provide one representation an organism's trophic niche are widely used to examine aspects food web structure. Yet stable isotopes have not been applied quantitatively characterize community-wide structure (i.e., at the level entire web). We propose quantitative metrics that can be this end, drawing on similar approaches from ecomorphology research. For example, convex hull area occupied by species in δ13C–δ15N space is a total extent...

Genera within the South American cichlid tribe Geophagini display specialized feeding and reproductive strategies, with some taxa for both substrate-sifting mouth brooding. Several lineages clade also possess an epibranchial lobe (EBL), a unique pharyngeal structure that has been proposed to have function in and/or A recently published genus-level phylogeny of Neotropical cichlids was used as evolutionary framework investigating evolution morphological features presumably correlated diet...

Abstract Predators typically are larger than their prey, and consequently, trophic level should increase with body size. Whereas this relationship has helped in developing predictions about food web structure dynamics mesocosms simple communities, a trophic‐level–body‐size may not exist for all kinds of communities or taxa, especially those many non‐carnivorous species. Moreover, functional traits associated generally have been considered. Herein, we examine the correlation between size...

Despite divergent evolutionary histories, Neotropical cichlids (Cichlidae) and Nearctic sunfishes (Centrarchidae) appear to have similar functional morphotypes occupy ecological niches. We applied an integrative approach analyzing morphological traits, stomach contents, stable isotope ratios (δ13C, δ15N) investigate whether local assemblages of (Venezuela, Peru) centrarchids (Texas) reveal one-to-one patterns convergence. Multivariate ordinations performed on diet morphology datasets...

Variable hydrology of rivers strongly affects biophysical factors that influence primary production and population densities, thereby affecting the relative bottom‐up top‐down processes in trophic networks. Many tropical floodplain have sustained seasonal flood pulses driven by precipitation patterns Intertropical Convergence Zone. These changes flow alter concentrations dissolved nutrients, aquatic productivity, per‐unit‐area densities organisms. Therefore, one would predict strength...

Abstract The Casiquiare River is a unique biogeographic corridor between the Orinoco and Amazonas basins. We investigated importance of this connection for Neotropical fishes using peacock cichlids ( Cichla spp.) as model system. tested whether provides conduit gene flow contemporary populations, origin distributions that span Casiquiare. Using sequences from mitochondrial control region three focal species C. temensis , monoculus orinocensis ) whose include Amazonas, Orinoco, Casiquiare, we...

Community assembly is affected by environmental filtering that restricts viable phenotypes and species interactions impose limits on interspecific trait similarity. Relative influences of these processes should vary according to habitat features dispersal. Species dispersion within assemblage space also in relation richness, strength competition, the spatiotemporal scale analysis. We examined ecomorphological diversity two freshwater fish families (Neotropical Cichlidae, Nearctic...

Summary Freshwater pond communities exhibit strong patterns in species composition response to environmental gradients such as ecosystem size, disturbance and productivity, serving excellent systems for studies of food‐web structure. We surveyed 13 ponds that varied along canopy cover, size hydroperiod at the beginning end rainy season semi‐arid thorn forests Gran Chaco ecoregion Bolivia. collected basal resources consumers (tadpoles, macroinvertebrates fishes) from these used stable isotope...

Montaña CG, Winemiller KO. Local‐scale habitat influences morphological diversity of species assemblages cichlid fishes in a tropical floodplain river. Ecology Freshwater Fish 2010: 19: 216–227. © 2010 John Wiley & Sons A/S Abstract – We examined the taxonomic and fish river Venezuela during dry season at two spatial scales: macrohabitats (lagoons, main channels creeks) mesohabitats (leaf litter, sand banks, rocky shoals woody debris). Nonmetric multidimensional scaling did not reveal...

Body size is frequently claimed to be a major determinant of animal trophic interactions, yet few studies have explored relationships between body and interactions in rivers, especially within the tropics. We examined position (TP) fish assemblages four lowland rivers Lower Mekong Basin Cambodia. Stable isotope analysis (based on δ15N) was used estimate TP common species each river, were classified according occupation benthic versus pelagic habitats feeding guilds. Regression yielded strong...

Feeding behavior and habitat use of two species pike cichlids, or mataguaros, (Crenicichla lugubris C. aff. wallacii) were studied in the río Cinaruco, a floodplain river Venezuelan llanos. We examined 309 individuals 270 wallacii from both main channel lagoons throughout falling-water phase annual hydrological cycle. Crenicichla was common within habitats that contained rocks woody debris, whereas more abundant than channel, especially shallow areas containing leaf litter. Although we did...

We examined diets of four piscivores, two in the order Perciformes (Cichla temensis and C. orinocensis) Characiformes (Boulengerella cuvieri B. lucius), from Cinaruco, La Guardia, Ventuari rivers Venezuela throughout wet-dry seasonal cycle. The piscivores consumed a phylogenetically morphologically diverse group fishes, reflecting overall diversity fish species these rivers. At start falling-water period, Cichla large prey, especially abundant, migratory, genus Semaprochilodus. As relatively...

Abstract During adaptive radiation, diversification within clades is limited by adaptation to the available ecological niches, and this may drive patterns of both trait species diversity. However, disparate niches result in varied impacts on timing, pattern rate morphological evolution. In study, we examined relationship between feeding ecology functional across a diverse clade freshwater fishes, Neotropical cichlids. Species dietary were ordinated via multivariate analysis stomach content...

Abstract The alligator snapping turtle ( Macrochelys temminckii ) is a long‐lived species that widely distributed across the southeastern United States. Both these characteristics make monitoring its occupancy and abundance particularly challenging. In 2020 2021, we conducted hoop trap surveys at 51 permanent water bodies Texas, USA, range of to estimate average with site models multinomial N ‐mixture models, respectively. We confirmed be present 61% surveyed locations. Mean detection...

Abstract Monthly surveys of local fisheries from five principal landing sites on the River Ganges at Bhagalpur, India, were conducted 2001 to 2007. Fishes a range sizes with mostly periodic‐type life‐history strategies, including many catfishes and carps, dominated catch. Average annual yield (total mean monthly catch in units biomass) was highly variable but trended downward during study. Statistical ordination revealed associations between assemblage composition hydrological seasons....

Abstract The loss of riparian forests can disrupt the structure and function lotic ecosystems through increased habitat homogenization decreased resource diversity. We conducted a field experiment manipulated structural complexity basal diversity to determine their effect on multiple aspects community food‐web degraded tropical streams. In‐stream manipulations included addition woody debris ( WD ) wood leaf packs WLP ). streams promoted detritus retention had positive stream taxonomic...

The dry Chaco, a semiarid thorn forest, is experiencing some of the highest deforestation rates globally, coupled with fact that small-bodied fish are at risk extinction, killifish inhabiting this region may be most threatened taxa. Yet, aspects ecology and life history for Neotropical killifishes in Bolivian Gran Chaco completely lacking, basic life-history data critical importance design implementation conservation measures. Collections were conducted during early (January 2011) late...

Abstract In South America, mercury contamination due to gold mining operations is a threat both biodiversity and human health. We examined (Hg) concentrations in fishes that constitute important subsistence fisheries from mined non-mined tributaries the middle Mazaruni River, Guyana. Mercury trophic food web structure (based on carbon nitrogen stable isotopes) were characterized for primary basal sources 39 fish species representing seven guilds. Fishes collected at sites had higher...