Trophic ecology and sympatry of otters (Lontra felina and Lontra provocax) at Añihué Reserve, Patagonia, Chile

Abstract

An overlap in distribution has been described for Lontra felina and Lontra provocax
from Aisén southward; with a differential habitat use as a probable strategy to reduce competitive
interactions in Austral channels and fjords. Here, we describe the presence of both species in southern
Añihué Reserve and present the preliminary results of a 2014-2016 trophic ecology study through
feces and feeding remains analysis, and graphic records both direct and autonomous in a seasonal and
habitat exposition comparative approach. Respectively, Chordata, Crustacea, Equinodermata, Mollusca
and unknown prey groups, contributed 36.90 % (n= 69), 99.47 % (n= 186), 0.53 % (n= 1), 0.53 % (n=
1) y 10.70 % (n= 20) of the identified preys frequency on the recollected feces (n= 187). No significant
differences were found between the exposed (ZE, 393.2 g) and protected (ZP, 667.83 g) dry weight
values (W= 1097.5, p= 0.8728), neither on the occurrence, frequency of occurrence and the group
preys feces dry weight in both environments. A diet composition pattern, mainly of crustaceans (≈90
%) and fish (≈8 %), is repeated. Qualitatively, no relevant seasonal variations were found. Graphic
material indicates fine scale sympatry between the two species that were sharing the area spatially but
not necessarily temporally. The sympatry could be explained by local food abundance and little local
disturbance. We propose to include the degree of sympatry of these species among their management
and conservation criteria.