Integrating ontogenetic shift, growth and mortality to determine a species' ecological role from isotopic signatures

• Autor(a) principal: Fontoura, Nelson Ferreira
• Data de Publicação: 2015
• Outros Autores: Rodrigues, Lúcia Helena Ribeiro, Rosemberg, Cibele Boeira Batista, Persch, Tanilene Sotero Pinto, Janowicz, Mariola E.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRGS
• Texto Completo: http://hdl.handle.net/10183/180388
• topic: Ontogenética; Cadeias alimentares; Mortalidade animal; Isótopos estáveis; Dinâmica populacional; Peixes; Modelagem ecológica; Ecossistemas aquáticos; Lagoas; Níveis tróficos; Desenvolvimento animal

Understanding species linkages and energy transfer is a basic goal underlying any attempt at ecosystem analysis. Although the first food-web studies were based on gut contents of captured specimens, the assessment of stable isotopes, mainly δ13C and δ15N, has become a standard methodology for wide-range analyses in the last 30 years. Stable isotopes provide information on the trophic level of species, food-web length, and origin of organic matter ingested by consumers. In this study, we analyzed the ontogenetic variability of δ13C and δ15N obtained from samples of three Neotropical fish species: silver sardine (Lycengraulis grossidens, n=46), white lambari (Cyanocharax alburnus, n= 26), and the red-tail lambari (Astyanax fasciatus, n=23) in Pinguela Lagoon, southern Brazil. We developed a new metric, called the Weighted Isotopic Signature (φ 15N or φ 13C,‰), that incorporates ontogenetic variability, body growth, and natural mortality into a single number.