CONICET | Buscador de Institutos y Recursos Humanos

AREAS OF ENDEMISM OF SOUTHERN SOUTH AMERICA: An example using a large data base of insect distributions. The studied area is located in Southern South America and correspond to the Patagonian and Subantartic subregions (Morrone, 2001). The definition of this region has been based mainly on its floristic composition and only a few studies were based on mammal or insect distributions. The present study is to our knowledge, the largest of this kind for the area. Distributional data for 999 species of insects were gathered and a matrix based on more than 12000 georeferenced data entries of insects of orders Coleoptera and Hymenoptera was constructed. This information was gathered from systematic revisions and from the collections of the main museums and institutions of Argentina, Chile and Brazil. The program NDM version 2.2 was used to analyze the matrix by using different grid sizes and fill scores. Five analyses were made: 1) 1º X 1º grid without fill, 2) 1º X 1º grid with fill of 30, 3) 0.5º X 0.5º grid, 4) 1º X 0.5º (West East oriented grid) and 5) 0.5º X 1º (North south oriented grid). Nested areas, conflictive areas and disjunctive areas were identified. Results of the search 1º X 1º grid with fill of 30 with posterior strict consensus of 40% was selected for a more detailed analyses This search was selected because it recognizes the mayor number of not superimposed areas, 17 in total. The same search but without fill recognize six more areas not found in the first analysis. The others searches did not recognize new areas. Finally, four of the seven areas recognized by Dominguez et al.,(2006) for the Patagonian steppe were recovered here. Furthermore, were recovered six areas matching with only one ecoregion (Valdivian forest, Chilean matorral, Magallanic sub-antartic forest, Patagonian steppe), several areas with associations of two or more ecoregions that were also proposed in previous studies (eg: Patagonian steppe - Low Monte), and two major areas that cover most of Chile and part of western Argentina.