Biological Conservation 57 (1991) 89-109 A Palaeoecological Evaluation of Environmental Degradation in Lake Mikri Prespa, NW Greece A. C. Stevenson Department of Geography, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, UK & R. J. Flower Palaeoecology Research Unit, Department of Geography, University College London, 26 Bedford Way, London WC1H 0AP, UK (Received 25 May 1990; revised version received 20 September 1990; accepted 23 October 1990) ABSTRACT Sediment cores from Lake Mikri Prespa, NW Greece were examined to determine the extent and possible causes of environmental degradation in the wetland. While diatom analyses of a z 10pb_dated sediment core demonstrate that the lake does not appear to have undergone any significant changes in water quality within the last seventy years, significant variations in the sediment accumulation rate were discovered. These changes appear to be linked to changing anthropogenic pressures on the landscape involving river diversion, rural depopulation and abandonment of terracing cultivation and development of an extensive irrigation network in the catchment. It is concluded that the application of palaeoecological methods has an important role to play in the management of wetland ecosystems by providing a temporal context in which the timing, trends and nature of environmental degradation can be established and evaluated. INTRODUCTION Lake Mikri Prespa (Fig. 1) is an internationally important site for breeding waterfowl including Dalmatian pelican Pelicanus crispus, white pelican 89 Biol. Conserv. 0006-3207/91/$03" 50 © 1991 ElsevierScience Publishers Ltd, England. Printed in Great Britain