干旱区生态环境知识资源中心

The pollen record of a marine core in the south Adriatic basin that is radiometrically dated and correlated to the global climate variation by the oxygen isotope curve, documents the vegetation changes which occurred around that basin since 17 ka (thousands year BP). During the end of the last glacial maximum, at 16.7-15 ka, the altitudinal range is occupied at low and high elevations by a desert and a semi-desert dominated by the shrubby sage-brush, Artemisia, and at middle elevation, by a grass steppe, with stands of Pine trees where soil conditions are favourable. During the deglaciation between 15 and 10 ka, a steppe-forest with a succession of deciduous trees appears at middle elevation within the grass steppe, but its development is interrupted by a set-back, a re-expansion of the semi-desert, which is coeval with the Younger Dryas of higher European latitude. The Holocene is identified by the spread of the mixed deciduous and Mediterranean forests, which culminates between 8.6 and 6 ka, during the end of the Boreal and the Atlantic chronozones, while the most recent sapropel is formed in the deep marine basins of the eastern Mediterranean, including the south Adriatic one. Between the cold and arid glacial maximum, and the warmest and wettest climate optimum during the Atlantic chronozone, this vegetation dynamics is constrained by the availability of moisture at low elevation, by temperature at high elevation, and by a combination of both at middle elevation.