A detailed pollen analysis has been carried out on two sediment cores taken from a marsh area located in the Doñana National Park, southwestern Spain. The studied sedimentary sequences contain a similar late Holocene record of vegetation and climate and show a progressive aridification trend since at least 5000 cal. yr BP, through a decrease in forest cover in this area. Long-term vegetation changes shown here (semi-desert expansion and Mediterranean forest decline) paralleled declining summer insolation. Decreasing summer insolation most likely impacted negatively on tree growing season as well as on winter precipitation in the area. Superimposed on the long-term aridification trend were multi-centennial scale periods characterized by forest reductions or increases in arid and halophytic plants that can be interpreted as produced by enhanced droughts and/or by local geodynamic processes. These are centered at ca. 4000, 3000–2500, and 1000 cal. yr BP, coinciding in timing and duration with well-known dry events in the western Mediterranean and other areas but could have also been generated by local sedimentary or geodynamic processes such as a marine transgression in a subsidence context and extreme wave events (EWEs). The alternation of persistent North Atlantic Oscillation modes probably played an important role in controlling these relatively humid–arid cycles.

A multidisciplinary study from a number of drilled cores in the Guadalquivir estuary has made possible to identify as many as three extreme wave events and their facies in the 4th millennium BP (A: ~ 4000 cal yr BP, B: ~ 3550 cal yr BP, and C: ~ 3150 cal yr BP). These events, which caused strong erosion in the Guadalquivir sandy barrier and in the neighboring aeolian systems of El Abalario, brought about significant paleogeographical changes that may have affected human settlements established in the area during the Neolithic and Copper Age periods and during the Middle Bronze Age. The three events can be spatially correlated and their facies differentiated from more proximal to more distal from the coastline. The most proximal facies is characterized by a massive accumulation of shells, a sandy or sandy–muddy matrix, an erosive base, a highly diverse mixture of species (marine and estuarine), and lithoclasts. The most distal facies presents a muddy–sandy matrix, dominance of estuarine fauna, shell accumulation, presence of terrestrial species, mudpebbles, pebbles in a clayey matrix, and bioturbation. The evidence presented will further advance scientific knowledge about the impact of extreme wave events on coastal areas in SW Iberia and NW Africa.

The megalithic sites from southwest Iberia represent one of the largest clusters of prehistoric monuments in Europe from the Neolithic and Copper Age (fifth and third millennia cal bc). Unlike other regions from western Europe, there has not been a recent effort to map the distribution of these kinds of burials across this vast territory. Therefore, this article aims to collect geographic information from three regions of southwest Iberia (Alentejo and Beira Baixa from Portugal and Extremadura from Spain) and to compare the archaeological evidence between different landscape units. We have mapped already known megaliths (ca 2000) and settlements (ca 1500) in this area. Moreover, through the interpretation of light detection and ranging (LiDAR) datasets, we have identified new walled enclosures and megaliths in the Extremadura region (Spain), the only one of the three where LiDAR data are available. The new data reveals new connections between settlements, burials and other archaeological evidence. Finally, we discuss the impact that these new data have on a new overall interpretation of megalithic landscapes from the Iberian Peninsula, stressing also the potential risks that the massive application of remote sensing can have in the production of archaeological knowledge.