Resumen

DELGADO, Bárbara R.; MOGNI, Virginia Y.; ARIAS, Natalia Trujillo  y  CABANNE, Gustavo S.. BIOGEOGRAPHY OF THE GRAN CHACO: NICHE MODELING AND PHYLOGEOGRAPHY OF MICROSPINGUS MELANOLEUCUS (AVES: THRAUPIDAE). Hornero [online]. 2021, vol.36, n.2, pp.107-119. ISSN 0073-3407.

The Gran Chaco, which is part of the diagonal of Neotropical open formations, is a fundamental region to test hypotheses of past connections among the Atlantic Forest, the Amazon and the Yungas. The aim of this study was to evaluate whether the Gran Chaco was fragmented by ex-pansions of wet forests during Pleistocene climatic oscillations, which could have connected the Atlantic Forest and the Yungas’s southern sector (Tucuman-Bolivian Forest). To test the hypothesis, we studied an endemic bird of the region, the Black-capped Warbling Finch (Microspingus melanoleucus). We conducted phylogeographic analyses employing DNA sequences of nuclear and mitochondrial markers, as well as ecological niche mode-ling (ENM) for the present and past periods (Last Interglacial, Last Glacial Maximum and Middle Holocene). The results indicated high gene flow among the studied populations, with no geographically restricted lineages. The niche models showed a relatively conserved distribution range across historic periods, although they suggested for the present, and particularly for the Mid Holocene, a lack of habitat suitability along a geographic diagonal from northeast to the southwest of the study region. These results supported temporal habitat stability in the Gran Chaco ecoregion, and did not support the hypothesis of expansions of wet-forests that could have fragmented the region and linked neighboring domains such as Andean and Atlantic forests.

Palabras clave : Ecological Niche Modeling; Gran Chaco; Microspingus; Phylogeography; Pleistocene.

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