LA NDSC A PE AND URBA N PLANNING zyxwvutsrq ELSEVIER Landscape and Urban Planning 35 ( 1996) 53-70 Ecoseries for potential site mapping, an example from the Netherlands Frans Klijn a’ * , Cornelis LG. Groen a, J. Philip M. Witte b a Centre of Environmental Science, Leiden University, Pd. Box 9518, NL-2300 RA, Leiden, Netherlands b Department of Water Resources, Wageningen Agricultural Universiry, Nieuwe Kamal I I, NL-6709 PA, Wageningen, Netherlands Accepted 12 October 1995 Abstract Ecoseries are ecological land units which are classified by means of characteristics of soil and groundwater that can be regarded as conditioning site factors. These conditioning site factors control so-called operative site factors, such as moisture availability, nutrient availability, or acidity, which determine the species composition of the vegetation. Under undisturbed circumstances, each ecoseries type is characterized by a specific frequency distribution of operative abiotic site types. The latter may each carry vegetations in different stages of succession. Thanks to the relations between vegetation, operative site factors and conditioning site factors, an adequate ecoseries classification is a valuable tool for environmental policy analyses, for example in the context of predictive modelling or for assessing nature’s recovery potential for physical planning, environmental management and nature conservation policy. In this paper, we explain how we achieved an ecoseries classification and nationwide 1 km* database for the Netherlands, primarily intended for national water management questions. The database is derived from existing maps of soil and groundwater which were re-interpreted from an ecological point of view. We especially treat the use of the ecoseries classification for ‘potential site mapping’, where ‘site’ is used in the sense of abiotic conditions determining natural vegetation development. The occurrence probability of potential sites is calculated by applying site-diagrams which introduce a probabilistic element. The resulting maps are intended as an aid to focussing the national policy’s financial means aimed at ‘nature development’ and restoration projects. The maps inspire confidence in the approach as they show a considerable overlap with actual sites’ Occurrence as established from separately gathered floristic and vegetation data. Keywords: Ecological land classification; Potential vegetation; Nature conservation; Site 1. Introduction Nature conservation often demands some kind of management. In semi-cultural ecosystems this may * Corresponding author. CML P.O. Box 9518 NL-2300 RA Leiden, The Netherlands. Tel.: (31) 71 277481; Fax: (31) 71 275611. be confined to managing the vegetation cover by mowing, grazing, fencing or cutting, but generally some management of the abiotic environment is also required. Restoring nature values may even require radical and costly interventions, for example by changing the groundwater regime back from well drained to the previous waterlogged conditions. In the Netherlands, where nature suffers severe drought 0169-2046/%/$15.00 Published by Elsevier Science B.V. SSDI 0169-2046(95)0021 I-1