Pollen stratigraphy of sediment sequences from crater lakes (Lago Albano and Lago di Nemi) and the Central Adriatic spanning the interval from Oxygen isotope Stage 2 to the present day.

Pollen-stratigraphic data are presented for sediment cores obtained from the floor of twocrater lakes situated close to Rome (Lake Albano and Lake Nemi) and from 4 sediment coresrecovered from the floor of the Central Adriatic Sea. Lake Albano sequence spans theinterval from OIS 2 to the present time, while that from the Lake Nemi provides a detailedrecord of the Holocene. The longest of the Central Adriatic cores probably extends back tobefore the last glacial maximum, though the precise age of the base of the sequence isunknown. Two other core sequences span the Lateglacial and Holocene, while the fourthprovides a high-resolution record of the mid- to late-Holocene. The results are comparedwith the recently-published pollen-stratigraphic data from Lago Grande di Monticchio(Watts et al. 1996) and also with a number of other published pollen records obtained fromsites in Italy and adjacent marine basins. It is shown that the new pollen data are not onlyinternally consistent, but also show strong resemblances to previously-published pollenrecords from both terrestrial and marine sites. Pollen stratigraphy thus provides a basis forthe correlation and relative dating of lake and marine sequences. For these purposes, anumber of very clear pollen-stratigraphic ‘marker’ horizons can be recognised. Theseinclude (i) a series of very abrupt fluctuations in pollen concentrations during the last(Würm) glacial maximum, (ii) the expansion of deciduous trees at the onset of the Lateglacialperiod, (iii) the revertance to steppic plant associations during the Younger Dryas coldoscillation, (iv) the marked expansion of a number of tree types at the start of the Holocene,(v) progressive deforestation, accompanied by the increasing importance of so-called‘anthropogenic indicator plants’ (e.g., cereal grasses, weeds of cultivated land), during themid-Holocene, (vi) the rising percentages of olive, chestnut and the vine from the Romanperiod onwards, and (vii) the appearance of Zea mays during the historical period.