DIGITALNA ARHIVA ŠUMARSKOG LISTA
prilagođeno pretraživanje po punom tekstu
|ŠUMARSKI LIST 7-8/2023 str. 86 <-- 86 --> PDF|
communities started to form on those surfaces (Leuschner and Ellenberg, 2017a). The vegetation of the entire Europe, and therefore of the continental sand dunes, has been under great anthropogenic influence since the Neolithic Era. Devastation in the sandy regions led to the gradual degradation of autochthonous vegetation and open sands appeared. This process intensified in the Middle Ages, and the damage was further exacerbated by widespread deforestation and livestock grazing (especially by sheep and goats). Through these practices, throughout history, humans have facilitated re-expansion of sandy material and movement of dunes (Ellenberg, 2009).
Sandy habitats are populated by sparse vegetation with relatively rapid successive changes in plant cover (Mucina et al., 2016). Thus, throughout the history of sandy vegetation, periods of progression and regression frequently alternated. As this type of habitat is often threatened by the development of agriculture and modern society in general, it has undergone significant changes in the last few centuries (Edwards et al., 2007; Butorac and Panjković, 2013; Leuschner and Ellenberg, 2017b).
Inland sand dunes in Serbia are distributed along the Danube River. According to the geographical location, they can be divided into three groups—the Subotica-Horgoš Sands with the Selevenj wastelands, the Deliblato Sands and a series of sandy habitats along the right bank of the Danube from Ram to Kladovo, and downstream to the mouth of Timok River (Butorac et al., 2002; Figure 1). Most authors concur that the inland sand dunes in Serbia were formed at the end of the Pleistocene, i.e., about 11,000 years ago. Regardless of whether the sand was brought by river flows, the water mass of the Pannonian Sea or the wind, the prevailing scientific stance is that the southeasterly wind Košava has played a key role in the geomorphology and relief of sands in Serbia and the Deliblato Sands in particular (Wesely, 1853; Cholnoky, 1910; Bulla, 1938; Milojević et al., 1949;Marković-Marjanović, 1950; Bukurov, 1953, 1955; Rakić et al., 1980/81; Menković, 2013).
Research area characteristics – Karakteristike područja istraživanja
The Deliblato Sands is located in the central part of southern Banat, extending in the southeast−northwest direction, whereby the broader area covered by sand almost 600 km2 (Menković, 2013). This is the largest sand-covered region in Serbia, as well as in Europe. It is of ellipsoidal shape and extends from the Tamiš valley to the Danube River. The main feature of the Deliblato Sands relief are the dunes, which extend in the southeast−northwest direction and are up to 1 km long, with their height above sea level ranging from 80 m on the Danube riverbanks, to 197 m in the extreme northwest. As the area is devoid of any springs and surface watercourses, water availability in the topsoil is low due to the high sand permeability, which allows precipitation to sink to the water-bearing layers. Groundwater is located at depth of 2−10 m in the southeastern and 100−150 m in the northwestern parts of Deliblato Sands, respectively.
A 30−50 m thick sand layer covers the previously blown loess plain (Menković, 2013). The soil of Deliblato Sands is aeolian alluvium, mostly comprising agenetic or young genetic soil (Bura, 1969). The primary substrate is sand, covered by shallower or deeper horizons with 0−7% humus content (Pavlović et al., 2017). Sand composition is dominated by calcium carbonate, as indicated by the presence of lime tiles and concretions. The soil has basic (pH = 7.30−8.50) character, and the humus and moisture content in the substrate determine the types of vegetation in different parts of the Deliblato Sands.
In the Deliblato Sands area, the influences of the moderate-continental climate of the Pannonian Plain, the climate of the Southern Carpathians, and the sub-Mediterranean climate via the South and Great Morava valleys are intertwined, leading to the average annual temperature of 12.5 °C (RHMZ, Meteorological Station Banatski Karlovac, 2018). The amplitude of annual temperature variations is higher than in the surrounding area, as the sandy substrate heats up and cools down quickly. Consequently, in summer, the temperature can reach 60 °C on the sunny dunes with southern aspect, whereas it does not exceed 45 °C on those north facing slopes (Butorac and Panjković, 2013). The air temperature is the lowest in January (-4.4 °C), while the average temperature in July and August is around 24 °C,