A METHOD TO DETERMINE WARM AND COOL STEPPE BIOMES FROM POLLEN DATA - APPLICATION TO THE MEDITERRANEAN AND KAZAKSTAN REGIONS

An objective method for the assignment of pollen spectra to appropriat e biomes has been published recently. The aim of this paper is to impr ove the distinction between warm and cool steppes, thus refining veget ation and climate reconstruction, particularly during the Last Glacial Maximum. A set of modern pollen spectra from the Mediterranean and Ka zakhstan regions, dominated today by open vegetation types, has been a nalysed statistically in order to relate pollen taxa abundances to war m acid cool grass/shrub plant functional types (PFTs). A statistical t est using modern pollen data shows that the method is able to distingu ish between cool and warm steppe biomes with a high degree of confiden ce. The method has been applied to two fossil pollen records. The resu lts of this exercise showed that cool steppe dominated in central Gree ce between 18 000 and 13 000 yr BP, while in western Iran the vegetati on was at the boundary between cool and warm steppes. These vegetation types were replaced by warm mixed forest in Greece and warm steppe in Iran after that time span. (C) 1998 John Wiley & Sons, Ltd.