Pan-biogeografia dos ungulados viventes (Mammalia: Cetartiodactyla e Perissodactyla) da região Neotropical, da Zona de Transição Sul-americana e região Andina: aspectos históricos e conservacionistas

Abstract

The living ungulates (Cetartiodactyla and Perissodactyla) are represented in the studied regions by 11 genera and 24 species. This study proposes to recognize the distribution patterns of these species, using the panbiogeographical method of track analysis. This method is a useful tool in a priori understanding of the congruent distribution patterns and in the knowledge of patterns and processes of geographical differentiation in time and space, reconstructing the biogeography of taxa. Regarding conservationist approaches, it was applied in order to identify priority conservation areas. The panbiogeographical method consists basically of plotting locality records of different taxa on maps and connecting them using lines following a criterion of minimum distance, resulting in the so-called individual tracks, which were plotted on maps of biomes of Central America and South America from the ArcView GIS 3.2. The individual tracks are superimposed and the coincidence of them corresponds to generalized tracks, indicating a common history, that is, the existence of an ancestral biota widespread in the past and later fragmented by vicariant events. The intersection of two or more generalized tracks corresponds to a biogeographic node, which represents composite and complex areas, implying that different ancestral biotas interrelated, possibly in different geologic times. The analysis was carried out with the aid of the software ArcView v3.2 and the Trazos2004 extension. From the overlapping of the 24 individual tracks, five generalized tracks (GTs) were recognized: GT1, Mesoamerican/Chocó, composed by Mazama pandora, M. temama and Tapirus bairdii; GT2, Northern Andes (Mazama rufina, Pudu mephistophiles and Tapirus pinchaque); GT 3, Central Andes (Hippocamelus antisensis, Lama guanicoe, Mazama chunyi and Vicugna vicugna); GT4, Chilean Patagonia (Hippocamelus bisulcus and Pudu puda); GT5, Chaco/Center-West Brazil (Blastocerus dichotomus, Catagonus wagneri and Ozotocerus bezoarticus); and a biogeographic node in Antioquia, northwestern Colombia. The species Mazama americana, M. bricenii, M. goazoubira, M. nana, Tapirus terrestris, Tayassu pecari and T. tajacu did not participate in the composition of any generalized track. The distribution patterns formed from the generalized tracks indicate that living ungulates were fragmented and differentiated in the Pleistocene, related to historical events in Neotropical region, South American Transition Zone and Andean region, explained by movements in Tectonic Fault Zones of Central America and South America, by volcanism and climate change. The formation of the Altiplano-Puna plateau seemed to be a geographic barrier in past and present times for most of the South American biota, except for camelids, which inhabit these areas in Argentina, western Bolivia and southeastern Peru. The biogeographic node confirmed the presence of biotic components of different origins, being an area with great biological diversity and endemicity, therefore suggesting a conservation unit in northwestern South America.