Interactions between late Pleistocene/Holocene floristic and megafaunal migration corridors of the Caatinga in the State of Pernambuco, Brazil

Abstract

Classical botanical studies of the Brazilian flora suggest the occurrence of former migration corridors between various ecosystems which were possibly established during climatic phases of the Pleistocene/Holocene, as well they reveal that various arboreal and herbal taxa migrated from Andes and southern Brazil to the Atlantic coast and to the presently semi-arid interior of northeastern region. Likewise, paleontological studies in deposits of this region, presently covered by Caatinga vegetation, reveal the presence of megafaunal taxa, extinct at the end of the Pleistocene around 10,000 years ago, of North American and Andean origins as well as some of rainforest habitats. Recent multi and interdisciplinary studies, based on palynological, paleobotanical, geochemical analyses, propose new climatic scenarios for various Brazilian ecosystems during the chronological period synchronous to the last glacial phase of the northern hemisphere. Among them, a considerable increase in humidity and expansion of Amazonian/Atlantic rainforests into regions presently covered by semi-arid vegetation as well as the migration of southern botanical taxa to latitudes near the equator. Therefore, there is considerable evidence for the existence of various generations of migration corridors that were established and dismantled in synchrony with climatic alterations, which up to the present, is one of the most widely accepted hypotheses for the Pleistocene megafaunal extinction. Based on these considerations, this project has as its major objective the palynological analysis of the deposits with megafaunal remains in the State of Pernambuco in order to correlate Late Pleistocene/Holocene vegetational and climatic changes with distribution patterns of that extinct fauna by testing various vegetational/climatic and paleontological hypotheses. (AU)