Frugivory of silver pheasant in the patagonian forests

MARTÍN, V; AMICO, GC; NUÑEZ, MA

Mar del Plata

Congreso; 2nd World Conference on Biological Invasions and Ecosystem Functioning; 2011

Grupo de Investigación y Educación en Temas Ambientales (GrIETA)

Although avian invasions are common around the world, and despite abundant information available on the introduction and spread of birds in non-native environments, the impact of exotic birds on native communities has been relatively understudied. The silver pheasant (Lophura nycthemera) is a gamebird species originary from southeastern Asia that was introduced in the middle of the 20th century to Isla Victoria, Nahuel Huapi National Park, Argentina, and spread to the whole island. In its native habitat, silver pheasant has a wide diet including fleshy fruits, seeds, plant shoots and invertebrates, so it is possible that on Isla Victoria it is consuming fleshy fruits of native and exotic plants, and dispersing and/or eating seeds. We studied the spring and autumn diet of the species through analyses of droppings. The silver pheasant diet was broad and diverse, including more fleshy fruits of various species during the autumn, when they are more available (an average of 15.35 seeds/dropping), and fewer in spring (an average of 0.60 seeds/dropping). Many other plant and insect remains were also present. We found seeds of both native and exotic species -most abundant were those of a native plant, Raphithamnus spinosus (48.40%) and of two invasive exotics, Rubus ulmifolius (31.16%) and Rosa rubiginosa (14.43%)-. The majority of seeds did not appear to be mechanically damaged, so it is likely that the silver pheasant is dispersing seeds in the Patagonian forests.