Resumo

MARTIN-ALBARRACIN, Valeria L; AMICO, Guillermo C  e  NUNEZ, Martín A. The introduced Silver Pheasant (Lophura nycthemera) in Patagonia: abundance, group structure, activity patterns and association to human disturbance. Hornero [online]. 2017, vol.32, n.2, pp.227-236. ISSN 0073-3407.

Phasianids are one of the groups of introduced birds with highest impact on native ecosystems. In Patagonia several phasianids are established or in process of establishment, thus it is relevant to know their impacts on ecosystems. The Silver Pheasant (Lophura nycthemera) was introduced to Isla Victoria in the 1950's and successfully established all over the island. The aim of this work is to study the population of this species on Isla Victoria in terms of abundance and association to human disturbance as a first step to know its potential impact in the ecosystem. We conducted camera-trapping and direct observations in linear transects located in highly disturbed and in lowly disturbed areas. Using camera-trapping data we estimated an index of relative abundance to compare habitat use between areas. We used the distance-sampling approach to estimate population density with the data from direct observations. The Silver Pheasant used much more frequently areas with a high level of disturbance, suggesting that the presence of disturbed habitats could facilitate establishment and spread of this species in Patagonia. Population densities in areas with high and with low levels of disturbance were higher than those reported from the native distribution area, showing that the Silver Pheasant had a great success on Isla Victoria. The high abundance, together with distinctive characteristics such as a large body size, foraging habits and social behaviour can shape the interactions with native species and influence its impact on native communities.

Palavras-chave : Habitat use; Isla Victoria; Lophura nycthemera; Phasianids; Silver Pheasant.

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