The introduced silver pheasant Lophura nycthemera (Phasianidae) in Patagonia: abundance, group structure, activity patterns and association to anthropic disturbance

MARTÍN, V; AMICO, GC; NUÑEZ, MA

El Hornero

Asociación Ornitológica del Plata

Año: 2017 p. 227 - 236

0073-3407

Phasianids are one of the groups of introduced birds with greatest impact on native ecosystems. In Patagonia there are several introduced phasianid species established or in process of establishment, thus it is relevant to know their impacts on ecosystems. Silver pheasant was introduced to Isla Victoria in the 1950s and successfully established all over the island. The aim of this work is to study the population of silver pheasant on Isla Victoria in terms of abundance and association to anthropic disturbance as a first step to know the potential impact of the species in the ecosystem. We conducted cameratrapping (1253 camera-days) and direct counts in linear transects 500 m long (n = 10) in two areas with different level of anthropic disturbance: high (n = 4) and low (n = 6). 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 the population density of pheasants with the data from direct counts. Silver pheasant used much more frequently areas with a high degree of disturbance, suggesting that the presence of environments with these traits could facilitate their establishment and spread in Patagonia. Population densities of silver pheasant (in areas with high and with low degree of disturbance) were greatest than those reported from their native distribution area, showing that pheasants had a great success on Isla Victoria. This abundance, together with distinctive traits such as body size, foraging habits and social behaviour can shape their interactions with native species and determine their effect on native communities