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STUDY AREA
 
  A distinct and widely recognized biogeographical region is targeted as the focal region for analysis. Southern South America is distinct for its biota (see Darlington 1965, Crisci et al. 1991, Linder and Crisp 1995, Morrone et al. 1996, Humphries and Parenti 1999, Katinas et al. 1999, Posadas et al. 1999). Many papers have been published recognizing high levels of endemicity insouthern South America. The study area includes Chile south of Coquimbo and adjacent areas of Argentina roughly southwest of a diagonal line between Mendoza and the Península Valdés (including the provinces of Neuquen, Río Negro, Chubut, Santa Cruz, and Tierra del Fuego). The study area is comprised of many different types of habitats, including Valdivian temperate rain forests, high elevation grasslands in the Andes, Patagonian steppe and grasslands, Mediterranean climate rain forests in Central Chile, and subantarctic Nothofagus forests. From west to east there is a rapid change in elevation and habitat from
coastal forests and a coastal mountain range to a forested central valley, then the high Andes and drier steppe and grasslands beyond in Argentina.
 
 
 

Crisci et al. (1991) examined the historical biogeography of southern South
America and concluded that the area is more biologically similar to other southern hemispheric landmasses (Australia, New Zealand, New Guinea, etc.) than to northern South America. The relationships of numerous groups of organisms support this southern hemispheric biogeographical pattern including scarab beetles (Howden 1981, Smith 2002), staphylinid beetles (Newton 1985, Thayer 1985), silphid beetles (Peck and Anderson 1985), carabid beetles (Darlington 1979, Erwin 1979), chironomid flies (Brundin 1981), spiders (Goloboff and Platnick 1987, Platnick 1991), waratahs plants (Weston and Crisp 1987), and Nothofagus trees (Linder and Crisp 1995). My preliminary estimates for scarabs support these findings because about 60% of scarab species from southern South America have their closest relatives outside the region occurring in Australia and New Zealand. Crisci et al. (1991) also suggested that southern South America could be further subdivided into subregions. Morrone (1999b) did this when he recently summarized the biogeographical regions of South America. He defined southern South America as consisting of three biologically related subregions: the Central Chilean, Subantarctic, and Patagonian biogeographic subregions.

 

See highlights from an expedition to Argentina.

 

This website is based upon work supported by the National Science Foundation under Grant No. 0342189.
Generated on: 15/MAR/2007

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