Human Activities, Soil Properties and Landscape Relations in Two Mountain Regions in Bulgaria.
Emiliya Velizarova1, Jaume Bech2, Maria Sokolovska1, and Alejandro Lansac2. (1) Forest Pedology Dept, Forest Research Inst, Bulgarian Academy of Sciences, 132 St. Kliment Ohridski Blvd 1756, Sofia, Bulgaria, (2) Univ de Barcelona, Avda. Diagonal 645, Barcelona, 08028, Spain
The status of forest soils is of great importance for productivity and sustainable management of forest ecosystems. The soil physical properties and chemical composition, water movement, climate and micro-relief all influence the processes occurring in soil. Human activity, including atmospheric pollution by heavy metals, significantly alters the natural processes in forest soils. This impact first becomes visible in coniferous and later on deciduous trees. The present investigation was aimed at emphasizing the role of landscape in characterizing the behavior of Cu, Zn and Pb in natural and human-influenced forest ecosystems. The sampling plots were established on the south slopes of the Rila mountain and on the south and east slopes of the Stara Planina mountain in the surroundings of the industrial region of Elisejna. The regions selected for the field survey are similar in altitude (between 850 and 1250 m above sea level), parent material (granites, gneisses, shiest), tree species (Scots pine, Pinus sylvestris Arn.) and soil types (Dystric, Eutric Cambisols). The landscapes of studied regions differ in exposure and human impact. The soil taken from the Rila mountain region is unpolluted, whereas the soil samples from the Stara Planina mountain are located at three heavy metal pollution distances (750, 1500 and 9000 meters) from a copper smelter. Soil acidity variation and heavy metal accumulation were measured in the soil samples along the whole profile and in the sub layers of forest litter. The results indicate no substantial differences in the distribution of heavy metals throughout the depth of the unpolluted soils and sub layers of forest litter in the region of the Rila mountain. In the soil samples from the Stara planina region, which is influenced by a human activity, the highest accumulation of heavy metals was registered in the top 10 cm of soil and in the H sub-horizon of the forest litter. The composition of litter sub-layers, soil properties and exposure were found to contribute significantly to the distribution of heavy metal pollutants Cu, Zn, and Pb in forest soils. The results obtained may be used for managing activities in the regions studied as well for the comparison and evaluation of the status of other forest ecosystems with similar characteristics. KEYWORDS: landscape, natural forest ecosystem, forest soil, forest-litter, heavy-metals, scots pine