ECOLOGICAL CHARACTERIZATION OF THE TETRAPOD ASSEMBLAGE OF NAHUEL-HUAPI-NATIONAL-PARK-AND-RESERVE, ARGENTINA

One hundred and sixty nine autochthonous tetrapod species were studied in the Nahuel Huapi National Park and Reserve, to obtain a general description of the ecological-structural pattern of the assemblage, with emphasis on trophic aspects. Residence status, body mass, abundance, diet, site of food resources, and feeding time were considered for each species, in relation to its presence within each of the environments in the area: High Andean, Humid Forest, Transition Forest and Steppe. The results indicate that these species respond in distinct fashions to the three bioclimatic environments, considering that the fauna belonging to the two types of forest behave similarly. The species as a whole generally exhibit small body size and diurnal feeding habits, diet is usually quite narrow, and insects are the main food resource. Fauna composition shows seasonal variations in the High Andean area, but in the forest is more stable throughout the year. Fluctuations in availability of food, particularly insects, seem to be the main cause of winter migrations.