A Holocene palaeoecological sequence from Villaverde, south-central Spain, is presented. The pollen stratigraphy is used to infer past vegetation changes within a catchment area that represents the boundary between semi-arid, plateau and mountain vegetation. From c. 9700-7530 cal. yr BP, Pinus is dominant, probably as a result of a combination of a relatively dry climate and natural fire disturbance. From c. 7530-5900 cal. yr BP, moderate invasion by Quercus appears to be a migrational response following increased moisture and temperature, but in part shaped by competitive adjustments. From c. 5900-5000 cal. yr BP, the pine forests are replaced by deciduous-Quercus forests with an important contribution from Corylus, Betula, Fraxinus and Alnus. Mediterranean-type forests spread from c. 5000 to 1920 cal. yr BP coincident with expansions of Artemisia, Juniperus and other xerophytes. From c. 1920-1160 cal. yr BP, Pinus becomes dominant after a disturbance- mediated invasion of the oak forests. Human impact upon the regional landscape was negligible during the Neolithic, and limited in the Bronze and Iron Ages. Local deforestation and the expansion of agro-pastoral activities occur after c. 1600 cal. yr BP.

Summary 1The fossil pollen record of Cañada de la Cruz in the Segura mountains of southern Spain yields insights into high-elevation vegetational dynamics over the last c . 8320 years. Phases of xerophytic grassland alternate with high-mountain open pine forests and expansion of deciduous forests and Mediterranean scrub at lower altitudes. 2 Longer-term stable vegetation patterns are interrupted by multidecadal to centuryscale shifts at about 7770, 3370, 2630, 1525 and 790 years BP. 3 Some of the vegetation types have no modern analogues and represent high-altitude remnants of widespread last-glacial xerophytic communities. Other species patterns, characteristic of current scrub associations, appeared only within the last 800 years. 4 The sequence fits within the regional context of a generally wet mid-Holocene ( c . 7700 -3300 years BP) characterized by spread of mesophilous vegetation, between drier conditions characterized by greater abundance of xerophytes. 5 The pollen record and current ecological studies on high-elevation vegetation of Mediterranean Spain suggest that control of vegetation is primarily climatic although grazing pressure, which would have pushed vegetation over a threshold for change, cannot be discounted.

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New pollen-analytical data from the Navarrés peatbog (Valencia, eastern Spain) show a synchronous Late-Quaternary fluctuation of P. pinaster- (cluster pine) and Quercus- (oak) dominated assemblages. During glacial times, P. pinaster survived in refugia together with other trees such as Corylus, Fraxinuv Quercus, and a number of Mediterranean shrubs such as Arbutus, Erica arboreal Olea, Phyllirea, Pistacia terebinthus, Myrtus communis and Viburnum finus. These nuclei of vegetation expanded around c. 30 000-27 000 BP invading areas formerly occupied by pine forests. P. pinaster retreated considerably during the last glacial maximum and the Younger Dryas event, but not as much as Quercus. During c. 10 00-6000 BP, a local pine forest resisted possible oak and P. pinaster invasion. Around 6000 BP, P. pinaster was involved in a post-fire change towards oak-dominated vegetation. This work supports the contention that P. pinaster is native to the Iberian Peninsula and that well-developed P. pinaster forests, particularly if mixed with oaks, are a natural feature of the landscape. The data presented here disagree with the floristic-phytosociological assumption that considers that the forest patches of P. pinaster and other Mediterranean species of pines are incidental and mainly derived from afforestation.