Habitat Use and Food Niche Overlap by Neotropical Otter, Lontra longicaudis, and Giant Otter, Pteronura brasiliensis, in the Pantanal Wetland, Brazil

Environmental variables that can influence the presence of giant otter (Pteronura brasiliensis) and Neotropical otter (Lontra longicaudis) otters were studied in Correntoso River, Pantanal, Brazil. In this study site both species are diurnal and primarily piscivorous. Descriptive variables of habitats were selected based on literature related to other otter species around the world, and based on the judgment of the authors, using the concept of niche gestalt and the field experience with the species. Statistical analyses included Non-metric multidimensional scaling (NMS) using the Euclidean Distances matrix and the Principal Component Analysis (PCA). NMS was used to graphically summarize and analyse the multidimensional space components of the niche of both species. The results showed that giant otter has a smaller ecological space, enclosed by the Neotropical otter space. The ecological interpretation is that the Neotropical otter tends to be more generalist regarding the structure of habitat used. PCA was used to analyse differences between the species in subsets of variables. The variables were grouped in two subsets: one with variables about the structure of banks and the other about characteristics of water bodies. The main differences between the two species of otters are expressed through the axes related to water body’s features; the condition of banks appears to have less relevance.