Prioritization of areas for conservation in Amazonia is based on estim
ates of modern biodiversity and the distribution of endemic species. T
he refugial hypothesis provided an important conceptual basis for unde
rstanding the effects of climatic change on these reserve areas. The h
ypothesis predicted that ice-age aridity in Amazonia would have been t
he dominant force that resulted in modern patterns of endemism. Howeve
r, recent paleoecological data indicate that cooling, rather than dryi
ng, was the predominant climatic influence on the ice-age Amazon fores
ts, and this leads to a re-evaluation of forces structuring Amazonian
diversity patterns. Modern forest clearance may result in a warmer and
drier Amazon basin; conditions now seen to be without past analog. In
the light of these data, assumptions regarding the survival of forest
isolates in a drying landscape must be revised. Habitat functions in
the sense of hydrogeomorphic processes and climate are recommended as
conservation goals rather than explicitly attempting to save biodivers
ity. Reserve areas should be established in the expectation of future
climatic change and be large enough to allow the ensuing migration of
species. Copyright (C) 1996 Elsevier Science Limited.