Do alien North American mink compete for resources with native South American otter in Argentinean Patagonia?

FASOLA, L., CHEHÉBAR, C., MACDONALD, D., PORRO, G., CASSINI, M.

JOURNAL OF ZOOLOGY (1987)

Año: 2009 vol. 277 p. 187 - 195

0952-8369

American mink Mustela vison, originally bred in fur farms, have becomeestablished in areas occupied by native endangered Southern river otter Lontraprovocax, in Patagonia. In accordance with European experience, this biologicalinvasion in South America raises questions about the interaction between invasivemink and native otter, from the viewpoints of both community assembly andconservation.We set out (1) to find which aspects of habitat structure were relatedto the distribution of signs of both this invasive species and Southern river otterLontra provocax, in Argentinean Patagonia and their most common prey and (2)to test general predictions of niche partitioning between these two species. Basedon surveys of 447 of 600m transects for otter and mink scats/footprints along thewaterside of lakes and rivers in the Andean Patagonian region, we compared dietcomposition (from scat analysis) and micro-habitat preferences (from field signs)of the two species. Otters were more specialist than mink in habitat use and diet.Mink used different habitats in other river basins where otters were absent.Wherethey occurred together in the basin of the Limay River, the distributions of theirsigns were similar, and mink diet was more similar to that of otters. There was nodetectable difference in otter diet before and after mink arrival in the Limay basin.Contrary to the prediction of niche partitioning, and to the findings of Europeanstudies, resource use by mink was more similar to that of otters where the speciesoccurred sympatrically than where they were allopatric.