The first palaeoecological record from a wetland site located on the English chalk has provided data indicating that the early postglacial flora of the Yorkshire Wolds contained a strong species-rich grassland element. It is suggested that before postglacial forests had become fully established, mesolithic peoples had occupied the area and were causing forest disturbance as early as c. 8900 BP. Consequently, the species-rich grasslands, which had never been completely ousted by the initial forest expansion, were able to survive the Boreal and Atlantic periods and were a consistent component of the postglacial chalkland landscape. -- AATA