Endemism centres, refugia and botanical collection density in Brazilian Amazonia

Abstract

HERBARIUM specimen collecting in the Brazilian Amazon has been concentrated in widely scattered collecting centres associated with some proposed centres of substrate-independent endemism1-3, suggesting that these may be sampling artefacts. Furthermore, many Amazonian plant species are uncommon, so the more intensely a local flora is studied, the more it will seem to be unique. This weakens the botanical argument for a dry Pleistocene Amazon4 and the associated forest refuge theory for the origin of Amazonian plant diversity1-3, because modern endemism centres are used as evidence to define past isolated forest patches-sites of allopatric speciation in a supposedly dry climate (Fig. 1). With a detailed map of botanical collection density, it is possible to recognize the true concentrations of plant endemism, which is important for selecting priority conservation areas to guarantee preservation of unique species. © 1990 Nature Publishing Group.