Summary• Here, palaeobotanical and genetic data for common beech ( Fagus sylvatica ) in Europe are used to evaluate the genetic consequences of long-term survival in refuge areas and postglacial spread.• Four large datasets are presented, including over 400 fossil-pollen sites, 80 plant-macrofossil sites, and 450 and 600 modern beech populations for chloroplast and nuclear markers, respectively.• The largely complementary palaeobotanical and genetic data indicate that: (i) beech survived the last glacial period in multiple refuge areas; (ii) the central European refugia were separated from the Mediterranean refugia; (iii) the Mediterranean refuges did not contribute to the colonization of central and northern Europe; (iv) some populations expanded considerably during the postglacial period, while others experienced only a limited expansion; (v) the mountain chains were not geographical barriers for beech but rather facilitated its diffusion; and (vi) the modern genetic diversity was shaped over multiple glacialinterglacial cycles.• This scenario differs from many recent treatments of tree phylogeography in Europe that largely focus on the last ice age and the postglacial period to interpret genetic structure and argue that the southern peninsulas (Iberian, Italian and Balkan) were the main source areas for trees in central and northern Europe.

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Three sedimentary sequences from the southeastern littoral of the Iberian Peninsula have been palynologically studied. The results obtained show that during the Holocene no significant forest cover existed in the studied area, so that the different phases identified mainly show an alternation of shrub formations and steppe communities probably determined by limitations that are fundamentally bioclimatic. Highest values of arboreal pollen at the bottom of the San Rafael sequence would correspond to an older period, when the area appears to be dominated by shrub communities with a high proportion of wild olive, whereas at the beginnings of the Holocene it is dominated by steppe formations. Between 7000 and 4500 yr BP the Holocene optimum is recorded, with a significant degree of vegetational cover. This period ends abruptly with a radical transform ation of the landscape that reflects the establishment of the steppe conditions that persist today, which lead to the marginalization of the maquis and the impact of intense erosion processes on a gradually deforested countryside.

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Abstract:This study presents an objective mapping of monthly mean air temperature over the Iberian Peninsula using the spatial interpolation of climatological data. The research focuses on an interpolation method (multiple regression with residual correction) that combines statistical global analysis with a local interpolation (splines and inverse distance weighting). Geographical information (the independent variables) is used to predict air temperature (the dependent variable) through the regression relationship and to test several approaches. A comprehensive GIS implementation makes it possible to address many cartographic issues and to produce mean minimum, mean and mean maximum air temperature surfaces for the entire Iberian Peninsula. The spatial resolution of the maps is 200 m and their temporal resolution is monthly and annual. An associated error level obtained through validation tests with independent data is computed for each map. These validation tests show that the best results have an average R 2 (mean of all months) of 0.91 (mean temperature), 0.87 (mean maximum temperature) and 0.83 (mean minimum temperature). When the objective is to map a large area, best results are obtained when the model uses all stations of the Iberian Peninsula together (general peninsular model) and not when using different local subsets (hydrographical basins regional models). However, when the objective is mapping a regional area, basin models produce better outcomes than the general model being applied to these regional areas.

Four pollen diagrams from Minorca (Balearic Islands) have been correlated with other previously studied sequences from Majorca and Minorca to define a Holocene landscape sequence for the region from 8000 yr B.P. to the present. The lower part of the pollen diagrams reflects a climatic phase with more rain and less-marked seasonality than today. Significant quantities of Corylus, Buxus, and mesophilous taxa are found. In the middle part, between 5000 and 4000 yr B.P., a strong change is recorded in composition and structure of the vegetational landscape, with vegetation appearing that was adapted to Mediterranean conditions. This episode coincided with the first human colonization of the island and also with a widespread climatic change in the western Mediterranean region. The change in taxa was complex and some sclerophyllous taxa such Olea played an important role in the transformation of the landscape physiognomy from the mid-Holocene until the present. Although human activities have removed much of the Mediterranean vegetation on the Balearic Islands, it seems clear that the changes have been brought about, in part, by increasing dryness.

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In thc Iberian Pcninsula and Balearic Islands thcrc arc several bioclimatic regions which result in many differcnt and fragmentary landscapes. Results obtained from monitoring 18 localities in Spain allow an outline of thc aeropollen dynamics of some of these cnvironrnents. Thc major pollen types arc: 1. trees: Pinits, Qiwcics, Olea, Cupressaceae. 2. shrubs: Corjlrrs. I'istacia and 3. herbs: Poaccac. Urticaccae, Chcnopodiaceae-Amaranthaccac. Plarrrngo and Asteraceae. In some locations Alirrrs, Artciiiisia, Bicxrrs. Betitla, Casiaiica, Eitcaljptics, I'opithrs, Ulitiirs, and Epliedra also have to be considcred. Quantitatively, pollcn from trees predominates over that from herbs and shrubs, although at some localitics this trend varics. The first pollcn grains found in the ivcckly atrnosphcric analyscs arc from trccs (winter). In spring tree pollen grains share the atmosphcrc with herb pollen. For this reason it is usual to find peak values of pollcn content in the atmosphere during this part of the year, while winter and autumn are characterized by low pollen counts.