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Though usually under-represented in palaeobiogeographical models, northeastern Spain is one of the regions of southern Europe with the greatest biodiversity. Strong climatic and geographic gradients and topographic contrasts have contributed to the marked physiographic heterogeneity of the region. Pollen sites from the Ebro River Basin (northeastern Spain) have been insufficiently studied, perhaps because of the scarcity of suitable sites for conventional pollen analyses (i.e. lakes, peatbogs) and the characteristic mosaic vegetation patterns. Glacial and Lateglacial pollen records from a variety of archives located along a N-S transect: Glacial lakes, periglacial screes, peatbogs, hyena coprolites and archaeological sites were analyzed.

The reconstruction of full and Lateglacial landscapes in the Ebro River valley provides new insights into the vegetational history of the region: (i) the abundance of steppe formations with Artemisia, Poaceae, Chenopodiaceae, Ephedra, Asteraceae during the most intensive cold-arid episodes in both the non-glaciated mountains and the lowlands, (ii) the continuous occurrence of woody taxa, even at high areas, (iii) the expansion of these woody taxa during Lateglacial climatic ameliorations, (iv) the survival of mesothermophytes in small refuge areas during full-glacial stages. There was great vegetation diversity in the northeastern Iberian landscapes during the Last Glacial and Lateglacial stages, suggesting patches of vegetation with steppic areas, Mediterranean shrubs, coniferous forest and refuges of mesothermophilous taxa. (c) 2005 Elsevier Ltd and INQUA. All rights reserved.