Abrupt vegetation changes in the Segura Mountains of southern Spain throughout the Holocene

1 The fossil pollen record of Canada 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 century-scale shifts at about 7770, 3370, 2630, 1525 and 790 years BR 3 Some of the vegetation types have no modem 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.