Trophic ecology and the use of shelters and latrines by the Neotropical otter (Lontra longicaudis) in the Taquari Valley, Southern Brazil

Abstract

ABSTRACT. This manuscript presents information about the ecology of Lontra longicaudis (Olfers, 1818) in the Taquari Valley, State of Rio Grande do Sul, southern Brazil. The study was carried out in two areas located in the Forquetinha Creek and in the Forqueta River from January to December 2003. The otters are specialist feeders (B sta = 0.24), with a diet based mostly on fish, especially those of the families Loricariidae and Cichlidae. Most shelters used by the species were excavated burrows underneath tree roots, while shelters within rocks were used less frequently. The burrows showed great variation in size, being found on average 3.5 m (sd = 3.6 m) away from the margin and 2.5 m (sd = 1.2 m) above the water level. Scent marks were made preferentially on rocks and fallen tree trunks at the edge of the water. There was a tendency to increase the reutilization of latrines in detriment of using new sites throughout the sample period. KEYWORDS.Neotropical otter, feeding habit, scent marking, resting sites, Brazil. RESUMO. Ecologia trófica e o uso de abrigos e latrinas pela lontra Neotropical (Lontra longicaudis) no Vale do Taquari, RioGrande do Sul, Brasil. O presente estudo apresenta dados sobre a ecologia de Lontra longicaudis (Olfers, 1818) no Vale do Taquari, sul do Brasil. O trabalho foi realizado em duas áreas localizadas no arroio Forquetinha e rio Forqueta, entre janeiro e dezembro de 2003. A população apresentou hábito alimentar especialista (B sta = 0,24), baseado em peixes das famílias Loricariidae e Cichlidae. Os abrigos utilizados pela espécie foram formados em sua maioria, por escavações sob raízes de árvores e, com menor freqüência, entre rochas. Os abrigos escavados apresentaram dimensões bastante variáveis, sendo que estiveram em média a 3,5 m (s = 3,6 m) de distância da margem e 2,5 m (s = 1,2 m) de altura em relação ao nível da água. A utilização de marcas odoríferas se deu preferencialmente sobre rochas e troncos caídos na margem, sendo que houve uma tendência de aumento na reutilização de latrinas, em detrimento de novos pontos de deposição de fezes, no decorrer do período amostrado. PALAVRAS CHAVE. Lontra Neotropical, hábito alimentar, marcação odorífera, locais de descanso, Brasil.

Defining Neotropical Otter Lontra Longicaudis Distribution, Conservation Priorities and Ecological Frontiers

“…This difference between previous studies and our work is probably due to scaling, as we used a larger, less accurate scale (0.2 decimal degree cell size) to identify the fine scale of microhabitat selection. In microhabitat scale, there are evidences of Neotropical otter using more forested areas to select their holts [55,56]. Another environmental variable previously suggested as important, but not supported by our model, is altitude.…”

Mammalian Diversity and Matses Ethnomammalogy in Amazonian Peru Part 2: Xenarthra, Carnivora, Perissodactyla, Artiodactyla, and Sirenia

“…The Neotropical otter eats all kinds of fish, including armored catfish, large pimelodid catfishes, tëpuşh (Erythrinus erythrinus [Erythrinidae] Remarks: Matses interviews about Neotropical otters are consistent with the results of most published studies of this widespread taxon (e.g., Kasper et al, 2008;Silva, 2010), notably with respect to its fondness for slowmoving benthic prey (such as armored catfish and erythrinids), but Amazonian field studies are almost nonexistent, so these observations also provide novel details of habitat use and behavior that may be peculiar to the local subspecies (Lontra longicaudis enudris; see above). Matses accounts that Neotropical otters make transient and opportunistic use of makeshift shelters (including burrows made by other species) is interesting by comparison with the fixed den sites of sympatric giant otters (see below).…”

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

“…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).…”

“…Considering records of daily movements of up to 1km (NakanoOliveira et al, 2004) should also be considered the utilization of distinct limnic systems located adjacent to or near the studied areas so that remains found in latrines in a given area may not necessarily indicate the presence of the corresponding taxa in this same area. Kasper et al (2008) (2001) found a negative selection of the cichlid Geophagus brasiliensis, with a lower consumption when compared to its environmental availability. The highest frequency of cichlids in the scat samples from the anthropogenic shallow lakes and the coastal stream investigated in the present study could be a reflex of the high abundance of these fishes in these environments.…”