Abstract:
Karst geosystems are characterized by high vulnerability and increased risk of impacts, especially against the background of growing global change. Bilateral direct and indirect connections are established between human activities and karst processes and the ongoing intensive changes in land use in karst territories are an active factor in modern karstogenesis. On the other hand, the changed and disturbed karst environment leads to serious environmental damage, which, due to the specifics of karst geosystems, may remain poorly visible, but with lasting and increasing effects over time, especially on soil and vegetation cover and the quantity and quality of underground karst water. Therefore, studies based on land cover and land use play an important role in optimizing land management in karst areas and in developing policies for strategic development of karst areas. This article examines the impact of land cover and land use change on different types of karst in Bulgaria. For this purpose, five karst regions were selected, based on representative model karst geosystems: Model area1 (MA1) “Brestnitsa”, MA2 “Devetashko plateau”, MA3 “Shumensko plateau”, MA4 “Dabrash” and MA5 “Buynovsko-Mursalishki”. A GIS database (KARST.gdb) with a set of vector and raster layers has been created for each region. The change of the land cover was traced on the basis of the data from CORINE land cover for the period 1990-2018. Each region is presented with brief descriptions of the karst, the administrative-territorial location and the nature protection status under the Protected Areas Act (PAA) and NATURA 2000. The changes of the land cover at level 1 of CORINE are analyzed, represented mainly by two classes – agricultural lands and forests and semi-natural areas. The use of level 3 gives more details in order to take into account potential negative impacts on the karst territories in the different model areas. The changes for four periods are analyzed: 1990-2000, 2000- 2006, 2006-2012, 2012-2018. The large data set makes it possible to trace how the land cover has changed over the last 30 years in the selected model karst areas. Emphasis is placed on changes in CORINE land cover in the class of agricultural lands and the class of forests and semi-natural areas. Each model area, according to its specifics, has predominance of one or another class of land cover, which has a changing in time effect on the karst. Due to the overlap in the regions with developed karst of the karst and socio-economic systems and the interconnections and relationships created between them, a number of negative effects and transformations are manifested. This requires good knowledge and monitoring of karst geosystems, including changes in land cover and land use. Information about these changes is an important additional data source for the current state of specific and highly vulnerable karst areas. Therefore, the CORINE information can also be considered as part of integrated monitoring of the karst and karst areas.