Diet of the American mink Mustela vison and its potential impact on the native fauna of Navarino Island, Cape Horn Biosphere Reserve, Chile

Abstract

Invasive exotic species of mammalian predators represent a major cause of vertebrate animal extinctions on islands, particularly those that lack native mammalian carnivores. In 2001, the American mink (Mustela vison) was recorded for the first time on Navarino Island, in the Cape Horn Biosphere Reserve (55° S) in Chile, representing the southernmost population of mink worldwide. In order to assess its potential impact on native fauna, we studied its diet on Navarino Island, as part of an integrative management program on invasive species. Over a three-year period (2005-2007) we collected 512 scats in semi-aquatic habitats: marine coasts, riparian and lake shores. Overall, the main prey was mammals (37 % biomass), and birds (36 %), followed by fish (24 %). Over the spring and summer, mink consumed significantly more birds, whereas mammals constituted the main prey over the autumn and winter when migratory birds had left the area. Among birds, the mink preyed mainly on adult Passeriformes, followed by Anseriformes and Pelecaniformes, caught as chicks. Among mammals, the exotic muskrat (Ondatra zibethicus) was the most important prey, and together with the native rodent Abrothrix xanthorhinus it accounted for 78 % of the biomass intake. For an integrated management of invasive exotic mammal species on Navarino Island and in the Cape Horn Biosphere Reserve it is important to further research interactions established here among the various introduced mammals, and to initiate immediate control of the mink population in its initial stage of invasion.

Range expansion and prey use of American mink in Argentinean Patagonia: dilemmas for conservation

“…We found that coastal mink on Tierra del Fuego ate mammals and fish at similar frequencies, whereas Schüttler et al (2008) reported that mink on the north coast of Navarino Island (south of the Beagle Channel), consumed prey in descending order from mammals, birds, fish and crustaceans (Table 3). These differences could fruitfully be explored by systematic study of larger samples, in relation to prey availability, on both sides of the Beagle Channel.…”

“…The same anxiety concerns the likelihood of their colonisation of other islands of the Fuegian Archipelago currently free of terrestrial carnivores. Mink have already crossed the Beagle Channel from Tierra del Fuego to parts of the Cape Horn Biosphere Reserve, specifically Hoste Island (Anderson et al 2006) and Navarino Island (Rozzi and Sherrifs 2003), where their summer diet is heavily dependent on native birds (Schüttler et al 2008;Ibarra et al 2009). …”

“…We used scat results grouped by watersheds to compute three different indices: the relative frequency of occurrence of prey items (RFO; Bonesi et al 2004), the percentage of occurrence of the dominant item (PDO; Schüttler et al 2008) and mean percentage of scat volume (PV). RFO was calculated as the number of occurrences of a prey class divided by the total number of occurrences of all prey classes multiplied by 100.…”

“…Once this range expansion became evident in Patagonia by the 1980s and 1990s, interest began to mount in the invasive status of American mink in Chile and Argentina (Jaksik et al 2002;Anderson et al 2006;Novillo and Ojeda 2008). Ecological studies also emerged, focused on (a) mink diet and habitat associations (Previtali et al 1998), (b) mink ecology in the context of intra-guild interactions (Chehébar et al 1986;Medina 1997;Aued et al 2003;Delibes et al 2003;Fasola et al 2009) and (c) more recently studies on mink diet in relation to native and exotic prey (Ibarra et al 2009;Schüttler et al 2008), waterfowl vulnerability to mink predation (Schüttler et al 2009) and waterfowl abundance fluctuations in relation to mink invading process (Peris et al 2009). However, these studies were focused on restricted areas or areas of special interest (e.g.…”

Primera década de investigación y educación en la Reserva de la Biosfera Cabo de Hornos: El enfoque biocultural del Parque Etnobotánico Omora

“…Fuentes: (1) Arróniz-Crespo et al 2014;Jofre et al 2010, Lewis et al 2014aMéndez, 2013;Méndez et al 2013;Rozzi et al 2008b; (2) Mansilla et al 2012Mansilla et al , 2013aMansilla et al , 2014aOjeda et al 2014Ojeda et al , 2015; (3) Contador et al 2012Contador et al , 2014; (4) Merino et al 2008;Reyes et al 2015;(5) Crego et al 2014(5) Crego et al , 2015Ibarra et al 2009Ibarra et al , 2010Schüttler et al 2008Schüttler et al , 2009Schüttler et al , 2010Schüttler et al , 2011Jiménez et al 2014;(6) Berghöfer et al 2008(6) Berghöfer et al , 2010Jax & Rozzi, 2004;Rozzi & Schüttler, 2013;Rozzi, 2004, Rozzi et al 2006a,b, 2007, 2012a; (7) Aguirre, 2015; Ibarra et al 2012;Massardo et al 2012;Poole et al 2013;Rozzi 2012aRozzi ,b, 2013Rozzi et al 2010bRozzi et al ,c, 2014Rozzi et al , 2015(8) Medina, 2013;Pizarro & Caballero, 2011;Sherriffs et al 2005;Zárraga et a...…”