Dieta de Lontra longicaudis (Olfers) (Carnivora, Mustelidae) em um arroio costeiro da região sul do Estado do Rio Grande do Sul, Brasil

Abstract

Resumo Este estudo apresenta dados referentes à composição da dieta de Lontra longicaudis em um arroio costeiro com vegetação ripária, localizado na região sul da Planície Costeira do Rio Grande do Sul, Brasil. Entre fevereiro de 2007 e maio de 2008, 242 amostras de fezes e seis restos alimentares foram coletados em um trecho de aproximadamente 1.100 m do arroio Bolaxa, na Área de Proteção Ambiental da Lagoa Verde. Os itens identificados como os mais consumidos foram peixes (82,6%), seguidos por crustáceos decápodes (20,6%). Outros itens, encontrados em menor freqüência, foram: aves, mamíferos, répteis, anfíbios, insetos e moluscos. Na análise dos restos alimentares, foi possível a identificação de Conepatus chinga (Carnivora: Mephitidae) e Rhamdia quelem (Siluriformes: Heptapteridae). Dentre os peixes, a família mais freqüente nas amostras fecais foi Cichlidae (59,5%), seguida por Curimatidae (32,6%). Outras famílias, encontradas em menor freqüência, foram Erythrinidae, Heptapteridae, Characidae, Mugilidae, Callichthyidae e Synbranchidae. Foi verificada uma dieta variada, reflexo, em parte, da influência dos ecossistemas adjacentes sobre a área de estudo.

Diet of Lontra longicaudis (Olfers, 1818) (Carnivora: Mustelidae) in three limnic systems in Southern Rio Grande do Sul State, Brazil

“…Other identified invertebrates (gastropod mollusks, insects) occurred in relative low frequencies, which is in agreement with most of the previous studies (e.g. Helder-José and De Andrade, 1997;Quadros and Monteiro-Filho, 2001;Alarcon and Simões-Lopes, 2004;Kasper et al, 2004;Quintela et al 2008).…”

“…A noteworthy higher frequency of birds in the anthropogenic shallow lake samples is observed when compared to other studies (see Helder-José and De Andrade 1997;Pardini 1998;Colares and Waldemarin 2000;Quadros and Monteiro-Filho 2001;Kasper et al 2008, Quintela et al 2008 and with the other two systems sampled in the present study. In Lake A, two small islands are used as a dormitory mainly by egrets (Ardea alba, Egretta thula, E. caerulea, Bubulcus ibis), herons (Nycticorax nicticorax, Butorides striatus) and cormorants (Phalacrocorax brasilianus).…”

“…Cyphocharax voga is active in midwater (Tagliani 1994) and feeds on bottom organic matter when adult (Bemvenuti and Moresco 2005). Callichthyds and heptapterids have benthic habits (Tagliani 1994;Koch et al, 2000;Rosso 2006) while S. marmoratus was classified as necktobenthic (Ferreira 2007 Quintela et al 2008;Carvalho-Junior et al 2010), whose authors attribute the high frequencies to the species low motility and availability in the environment. In random sampling performed in both pluvial channel and coastal stream, decapods (mainly Callinectes sapidus) were commonly trapped and may represent a highly available food resource in these systems.…”

“…Its highest frequency in samples from "Navio Altair" coastal stream and the pluvial channel highlights the coastal-estuarine influence over these lymnic systems. It is also noteworthy the high frequency of the swamp eel Synbranchus marmoratus (Synbranchidae) in the pluvial channel and shallow lakes, a fish species usually not determined or found in low frequencies in the otter diet (see Quintela et al 2008). Identification on predated species/groups provides relevant information on predatory behavior and use of microhabitats.…”

“…South America host four species and the Neotropical river otter Lontra longicaudis (Olfers 1818) is the widest distributed, ranging from Mexico to northern Argentina (Mason, 1990;Eisenberg and Redford 1999). Studies on the feeding habits of the neotropical river otter have been conducted in several environments in Costa Rica (Spinola and Vaughan 1995;1998), Ecuador (Uteras et al 1998), northern Argentina (Parera 1993;Gori et al 2003), southern and southeastern Brazil (Passamani and Camargo 1995;Helder-José and De Andrade 1997;Pardini 1998;Colares and Waldemarin 2000;Quadros and Monteiro-Filho 2001;Alarcon and Simões-Lopes 2004;Kasper et al 2004;Quintela et al 2008). These studies revealed fishes as a major prey item, while other items such as crustaceans, insects, mollusks, mammals, birds, amphibians and vegetables were also recorded in varied frequencies.…”