Areas of endemism of the Patagonian steppe: An approach based on insect distributional patterns using endemicity analysis.

DOMÍNGUEZ, M.C., S. ROIG-JUÑENT, J.J. TASSIN, F.C. OCAMPO & G.E. FLORES

JOURNAL OF BIOGEOGRAPHY

Blackwell publishing

Lugar: Londres; Año: 2006 vol. 33 p. 1527 - 1537

0305-0270

Aims To delimit areas of endemism in the Patagonian steppe using endemicityanalysis (EA), which evaluates areas of endemism by means of an endemicityindex, and to compare the resulting endemic areas with those proposed for thePatagonian steppe by previous authors.Location The Patagonian steppe, a region of South America foundapproximately below parallel 36º S to the east of the Andes Mountains.Methods Distributional data for 159 species of insects collected in the Patagoniansteppe, and consisting of 1317 georeferenced samples were used to identify areas ofendemism. A data grid of presence and absence (with cells of 1 · 1) wasconstructed. Initially, two different types of EA were performed, seeking areasdefined by ?four or more? species. A first analysis was performed without takinginto consideration those quadrats where no species had been recorded (emptyquadrats), which in many cases meant a discontinuous distribution. The secondanalysis was performed assuming a continuous distribution for each species.A third analysis, assuming continuous distributions, was performed using ?three ormore? as the number of species necessary for an area to be identified as an endemicarea.Results In the first two analyses, EA recognized the same five areas of endemism:western Patagonia, south-western Payunia, northern Suabandean, southernSubandean and Austral Patagonia. The results of the third analysis allowed theidentification of three more areas of endemism: northern Payunia, Chubutianand Santacrucian.Main conclusions We identified five areas of endemism for the Patagoniansteppe, some of which have been defined in previous contributions. These areasare: Western Patagonia, Payunia and Subandean Patagonia (which can be dividedinto septentrional and meridional), Central Patagonia (Chubutence andSantacrucense) and Austral Patagonia.