The Patagonian Steppe Biogeographic province: Andean Region or South American transition zone?

ROIG-JUÑENT, S.A., M. GRIOTTI, M.C. DOMÍNGUEZ, F.A. AGRAIN, P. CAMPOS-SOLDINI, R. CARRARA, G. CHELI, F. FERNÁNDEZ CAMPÓN, G.E. FLORES, L. KATINAS, J.R. MUZÓN, J.C. NEITA MORENO, P. PESSACQ, G. SAN BLAS, E.E. SCHEIBLER & J.V. CRISCI

ZOOLOGICA SCRIPTA

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2018 vol. 47 p. 623 - 629

0300-3256

America comprises three biogeographic regions: Nearctic, Neotropical and Andean.In between them, two transition zones (TZ) have been proposed: Mexican and SouthAmerican. The biogeographic provinces belonging to a TZ have no predominance ofbiotic elements pertaining to each of its bordering regions. Regarding the Andeanregion, one of its provinces, the Patagonian Steppe, presents a mixture of differentbiogeographic elements, which are typical of transition zones. Because of this, weassessed whether the Patagonian Steppe belongs to the Andean region or whether itforms the southernmost part of the South American TZ. We gathered phylogeneticinformation from 177 taxa that inhabit the Patagonian Steppe and established towhich biogeographic element they belong. We followed the criterion that an area canbe considered as part of a region when at least 70% of its biota has the same origin,that is belongs to the same biogeographic element. In contrast, when the biota of anarea presents a similar percentage of its different biogeographic elements, it could beconsidered as belonging to a transition zone. We found that the Patagonian Steppepresents a similar proportion of genera of Andean as well as neotropical origin.Therefore, we propose that this province should be included in the South Americantransition zone. Moreover, inclusion of the Patagonian Steppe as part of this TZ willmake it the largest TZ of America, encompassing most of the arid lands of SouthAmerica.