Practical aspects of biotope mapping in cities: methods, problems and solutions. An example of Mainz

‘Biotope mapping of Mainz’ - this is the name of a research project commissioned by the City of Mainz and carried out by an interdisciplinary group of geographers, biologists and environmental planners at Mainz University between 1993 and 1997. The project’s goal was not only to gather, analyse and evaluate data relating to urban biotopes, but also to apply and - if necessary - modify the ‘Basic program for biotope mapping in urban areas’, which was set up by a working group at the German Federal Nature Conservancy in 1993. In conformity with the legal mandate, the work followed the strategy of integrated nature conservation, i.e. simultaneous protection of biotic, abiotic and aesthetic resources, which is considered as an inevitable component of sustainable development in urban areas. Some of the methodological aspects recommended in the ‘Basic program’ and completed in the ‘Biotope mapping of Mainz’ are: the application of a well-structured biotope type reference key, the elaboration of a microsite key with relevance to flora, fauna and aesthetics, very detailed mapping and description of biotope types, subtypes and variations, as well as mappings and descriptions of the phenomena of nature, recreational activities and environmental impacts related to biotope types. Further, the ‘Biotope mapping of Mainz’ supplemented some new spatial aspects and assessment procedures that might eventually get planning authorities more adopted to the idea of sustainable land use in populated areas, such as the environmental zoning of the landscape within the city limits, the delimitation and description of ‘urban landscape units’ in detail (including climate, soil and water conditions, flora and fauna as well as historical and cultural features), the development of environmental quality targets and standards specified for each ‘urban landscape unit’, the assessment of the unit’s biotope types with reference to the established environmental quality standards, and last, suggestions and recommendations for urban planning and environmental management. With the items mentioned, the research project ‘Biotope mapping of Mainz’ made its scientific outcome more accessible and understandable. As a consequence, it is reported that local planning authorities are applying the project’s findings and giving a positive feedback of the results.