Exotic Vertebrate Fauna in the Remote and Pristine Sub-Antarctic Cape Horn Archipelago, Chile

Abstract

Pristine wilderness is a scarce global resource, but exotic species are so common that they constitute a principal component of worldwide ecological change. The relationship between these two topics, invasion and remoteness, was the impetus behind five years of fieldwork aimed at identifying the assemblage and range of exotic vertebrates in Cape Horn, Chile, identified as one of the world's most pristine wilderness areas. While the archipelago has extremely low human population density and vast tracts of undisturbed land, we discovered that several terrestrial vertebrate groups were dominated by exotic species. Native birds were diverse (approx. 154 spp), and only 1.3% (or two spp.) were introduced. In contrast, exotic terrestrial mammals (12 spp.) and freshwater fish (three spp.) outnumbered their native counterparts, constituting 55% and 75% of the assemblages. Using GIS, we found that not all areas were impacted equally, largely due to intensity of human occupation. Human settled islands (Navarino and Tierra del Fuego) hosted the greatest number of exotics, but humans alone did not explain observed patterns. Remote islands also had introduced species. North American beavers (Castor canadensis), American minks (Mustela vison) and feral domestic dogs and cats were particularly widespread, and their range in isolated parts of the study area raised important ecological and management questions. In conclusion, the Cape Horn Archipelago retained areas free of exotic vertebrates, particularly parts of the Cape Horn and Alberto D'Agostini National Parks, but at many sites introduced species were overwhelming native biota and altering these previously remote natural ecosystems.Abbreviations: TDF -Tierra del Fuego Biodiversity and Conservation (2006) 15:3295-3313 Ó Springer 2006

Domestic dogs in Atlantic forest preserves of south-eastern Brazil: a camera-trapping study on patterns of entrance and site occupancy rates

“…Domestic animals can impact native fauna in several ways, including increased predation (Lepczyk et al, 2004;Kays and DeWan, 2004), especially on islands (Burbidge, 1999;Anderson et al, 2006), and genetic introgression (Vilà and Wayne, 1999;Adams et al, 2003), which sometimes might disturb the genetic integrity of native species (Pierpaoli et al, 2003). Disease transmission seems, however, to be the most important disturbance effect in many continental countries (Cleaveland et al, 2000;Frolich et al, 2000;Anderson et al, 2003;Hammer et al, 2004).…”

“…Disease transmission seems, however, to be the most important disturbance effect in many continental countries (Cleaveland et al, 2000;Frolich et al, 2000;Anderson et al, 2003;Hammer et al, 2004). Past studies have explored the presence of domestic dogs in wild areas or their impact on wild species (Herranz et al, 2002;Butler et al, 2004;Manor and Saltz, 2004;Anderson et al, 2006), however few studies have been conducted in Neotropical forests. These include predation on native species (Kruuk and Snell, 1981;Barnett and Rudd, 1983), potential disease transmission (Ryan et al, 2003;Fiorello et al, 2004;Deem and Emmons, 2005;McFadden et al, 2005;Fiorello et al, 2006), and social biology of free-roaming dogs (Daniels and Bekoff, 1989;Fielding and Mather, 2001).…”

Comparison of two mammalian surveys made with camera traps in southeastern Brazil, focusing the abundance of wild mammals and domestic dogs

“…Dogs can prey upon other mammals, mainly C. paca, M. gouazoubira, and D. azarae. Several authors showed that the presence of dogs in forests can lead to the decline of native species, causing a negative environmental impact (Horowitz, 1992;Lacerda et al, 2009;Oliveira and Cavalcanti, 2002;Butler et al, 2004;Anderson et al, 2006;Galetti and Sazima, 2006;Srbek-Araújo and Chiarello, 2008). Torres and Prado (2010) concluded that by increasing the awareness of residents in the surroundings of a forest is crucial to reduce the impacts of domestic dogs.…”

“…Pets can also affect the native fauna in several ways, including increase in predation (Kruuk and Snell, 1981;Barnett and Rudd, 1983;Lepczyk et al, 2004;Kays and Dewan, 2004) and disease transmission (Anderson et al, 2006;Hammer et al, 2004). Galetti and Sazima (2006) stated that the high impact of feral dogs on some mammals is probably the major cause of extinction in their study area (Santa Genebra Forest, southeastern Brazil).…”

Potencial presencia del castor norteamericano en el Parque Nacional Cabo de Hornos

“…Hasta la fecha, no se han confirmado registros en algunos lugares remotos del archipiélago, como la Isla de los Estados (Argentina) y el Archipiélago Wollaston que constituye el Parque Nacional Cabo de Hornos (Anderson et al 2006;Valenzuela et al 2014 En este contexto, las imágenes satelitales resultan útiles para el estudio de distribución del castor en lugares remotos o difícil acceso. A partir de un reconocimiento visual de castoreras en imágenes de alta resolución espacial disponibles en Google Earth® (http://earth.google.com), se realizaron recorridos (transectas) en sentido Este-Oeste en toda la Reserva de Biosfera Cabo de Hornos (RBCH), a 1 km de "altura visual o de Ojo".…”