Abstract:The aim of this research was to analyse the changes in the soil erosion intensity caused by erosion control works (ECW) in Grdelica Gorge (The South Morava River) in the period between 1953 and 2016. For the purpose of quantifying the erosion intensity changes, the erosion potential model (EPM) was used to calculate the annual gross erosion (W), sediment transport (G), and erosion coefficient (Z) in the study area. As a result of the performed technical and biotechnical erosion control works, there was a general decreasing trend in the intensity of soil erosion processes in the last 63 years. The specific annual gross erosion in Grdelica Gorge was 1920.34 m 3 /km −2 /year −1 in 1953, while in 2016 it was 492.42 m 3 /km −2 /year −1 . The specific sediment transport was 1421.05 m 3 /km −2 /year −1 in 1953 and 364.39 m 3 /km −2 /year −1 in 2016. Due to the changes in the intensity of erosion processes, the specific annual gross erosion in the study area decreased by 1427.92 m 3 /km −2 /year −1 and the specific sediment transport by 1056.66 m 3 /km −2 /year −1 . The value of the erosion coefficient was reduced from Z = 0.84 in 1953 to Z = 0.32 in 2016. The results show that there is a significant correlation between the soil erosion intensity (erosion coefficient) and ECW (biotechnical works) performed in Grdelica Gorge. The permanent control of erosion processes in Grdelica Gorge is very important for torrential flood prevention and protection of two very important traffic routes (Belgrade-Skopje-Athens railway and motorway-Corridor X), as well as settlements, local roads, and other facilities in this area. Furthermore, these results are the basis for future water management projects, soil and environmental protection, spatial planning, agriculture, and other human activities.

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To address the issues of taxonomic delimitation and to select the material with desirable traits for horticultural use, a comprehensive study of the total variability of morphological characters of two naturally occurring snowdrop species (Galanthus nivalis L. and Galanthus elwesii Hook.) in the central part of the Balkan Peninsula was conducted. The analyses were performed for 16 quantitative characters of aboveground parts of 630 plants collected at 21 geographical points in the territory of the Republic of Serbia. To identify the trends in morphological differentiation, descriptive, univariate and multivariate statistical procedures were employed. Most of the examined characters exhibited moderate degrees of variability (cv from 10% to 20%) and the values of several characters exceeded the limits of variation stated in literature. Samples were mostly morphometrically homogeneous, with comparatively high similarity; only four populations of G. nivalis from the southern and southeastern part of the country were discrete. It is questionable whether these populations merit formal taxonomic recognition at any infraspecific level, but given their decorative qualities, the selected plants can be introduced into cultivation as horticultural plants.

The paper presents environmental conditions and morphological characteristics of pyramidal fir (Abies alba var. pyramidalis) in the locality of Ogorijevac in southwestern Serbia. Pyramidal fir trees grow in three localities in Europe, but only as individual trees. A site of pyramidal fir (Abies alba var. pyramidalis) in the locality of Ogorijevac near the town of Sjenica in Serbia was first studied by Tosic in 1963, who described some characteristics of the locality in which the pyramidal fir occurs and some morphological characteristics of the trees. This paper provides a detailed description of the parent rock, soil, climate characteristics of the locality and morphological characteristics of the trees.