Die Karte „Ökologische Standorttypen“ 1:750 000 im „Atlas DDR“

Summary

This article explains the conceptual foundations, data sources, methodology, classification system, and practical significance of the 1:750,000 map “Ecological Site Types,” prepared for the second installment of the Atlas of the German Democratic Republic. Conceived as a model-oriented thematic map, it moves beyond the depiction of isolated natural phenomena toward a geographical and cartographic typification of complex environmental relationships. The natural environment is treated, in systems-theoretical terms, as the surroundings of biological systems. Its ecological qualities are therefore defined only by properties that are ecophysiologically relevant to organisms, especially plants. Plant growth, development, productivity, product quality, and resistance to diseases and pests depend primarily on the potential supply of water, energy, and nutrients or structural substances. For regional mapping, the study focuses on water, heat, and mineral nutrients, while light, atmospheric carbon dioxide, and root-zone oxygen are either unsuitable for representation at the selected scale or indirectly incorporated into other factors. Climate and soil are regarded as determining environmental components rather than directly acting growth factors; their interaction controls the natural productivity of a site. Particular importance is assigned to limiting factors that fall below, or exceed, the relative optimum. The map was compiled using nationally consistent information from climate atlases, climatological normals, meteorological records, the 1:500,000 soil map, and maps of potential natural vegetation. Soil mapping units were interpreted separately according to their capacity to provide water and mineral nutrients, allowing pedologically different soil associations with similar ecological behavior to be grouped together. Climatic conditions were evaluated through a modified Walter–Gaussen climate-diagram method, which integrates the seasonal relationship between temperature and precipitation and thus better reflects ecological conditions during the growing period than separate climatic-element maps. These evaluations were synthesized into ecological site types represented by numerical codes expressing different levels and combinations of water, heat, and nutrient supply. Types near the center of the classification indicate comparatively balanced conditions and high natural productivity. Inner groups show a moderate limitation of one or two factors—for example, water deficits in dry regions, heat deficits in northeastern or submontane areas, and nutrient limitations on sandy, stony, or base-poor soils. Outer groups are characterized by severe minima, sharply restricted crop choice, lower and less reliable yields, greater management costs, and, in extreme cases, the impossibility of agricultural or forestry use. Irrigation and other ameliorative measures, fertilization, suitable crop and cultivar selection, and ecologically informed cultivation can partly compensate for such limitations. The map thus provides a scientific basis for regional agricultural planning, efficient use of natural resources, and further research on crop suitability and the spatial occurrence of diseases and pests, although detailed recommendations for individual crops and pathogens remain beyond the article’s scope.