Supplementary material 1 from: Hristova D, Stoycheva V (2021) Mapping of ecosystems in Bulgaria for the needs of natural heritage assessment. Journal of the Bulgarian Geographical Society 45: 89-98. https://doi.org/10.3897/jbgs.e76457

Abstract

The main purpose of the paper is to explore the relationship between the CORINE Land Cover (CLC) classification and the MAES typology in order to develop a basis for mapping of ecosystems at national level in Bulgaria, which could ensure a spatial framework for mapping and assessment of the ecosystem services provided by the natural heritage. Identifying the necessary data for our purposes, we found that, in spatial terms, CLC data is the only appropriate data source. The subtypes of ecosystems at Level 3 of the classification of ecosystems in Bulgaria (based on the European MAES classification) are identified as mapping units. Firstly, we decided to analyze the links between the CLC and the MAES BG classes through five categories of correspondence: 1) full correspondence – one CLC class corresponds to one MAES BG subtype; 2) multi-directional links – one or more CLC classes correspond to one MAES BG subtype; 3) discrepancies that necessitate further analyses; 4) CLC classes that are not found in Bulgaria; 5) MAES BG subtypes that have no correspondence to a CLC class. Secondly, we prepared a comparison table to determine the correspondence between the CLC classes and ecosystem subtypes, which we integrated into the GIS environment. Thirdly, we developed an algorithm for modifications of the spatial distribution of ecosystem subtypes. The algorithm was applied particularly to grasslands, where at Level 3 of CLC there are two classes of "grassland”, whereas at Level 3 of the classification of ecosystems in Bulgaria, the subtypes are five. This algorithm was applied to the 2018 CLC spatial data so as to develop a GIS database providing the basis for subsequent analyzes related to ecosystems. The database was used to delineate and map the ecosystems at national level in Bulgaria. Furthermore, a map of the potential of the natural heritage to provide ecosystem services was produced.