Impacts of Climate Change on Landscapes in Central Europe, Hungary (original) (raw)

The study area is located in Central Europe and focusing on Mecsek Hills, a low mountain range in the south western part of Hungary. The region of central Europe includes complex mis of elements from mediterranean and continental climate, since the area is located in transitional zone of sub-atlantic and sub-mediterranean climate types. Mecsek Hills is a unique region of the Hungarian environment. Its central European location specifies distribution of diverse landscape types, formed under conditions of transitional climatic settings, mixed from sub-atlantic to sub-mediterranean. The distribution of ecosystems in the region illustrate adaptation of soil properties to actual climate conditions. As determined by the present-day climatic and geomorphological settings, soils in the Mecsek region are rich in nutrients, and landscapes are characterized by various mixed soil types. Brown forest soils predominate on hilltops of Mecsek, while alluvial soils on floodplains [1]. According to the underlying soil types, the landscapes are characterized by mixed vegetation types. The most typical is Pannonian mixed forests of temperate broadleaf and mixed forests, common in Euro-Siberian region. There are also forests of Turkey and hornbeam oak in the catchment area of Mecsek region. The dominating vegetation coverage types on the slopes of Mecsek Hills include beech forests, ravine forests and oaks. Some regions of the Mecsek Hills include unique biogeographic areas with endemic species, not founded elsewhere in Carpathian Basin. The overall climate change, especially the global temperature increase, controls balance of heat and water budget on the Hungarian landscapes, and has considerable impact on the agricultural landscapes. In the past decades there were changes in climate, detected in the Carpathian Basin region, which illustrate general fluctuations in the climatic settings in Hungary and change of overall average air temperatures [2]. Recently, considerable increase in the occurrence of hazards is detected in Carpathian Basin: rainfalls, drought and heat periods in summer. Climate change makes impact on local soil properties, which affects ecosystem structure. Various ecological factors have impact on ecosystems with different impact factor, according to vulnerability and sensitivity: the main impact have temperatures and precipitation, affecting soil water regime, evaporation and water runoff. The overall impact of various factors make a joint effect on ecosystems structure. Recent climate changes mostly influence regional hydrological regime, e.g. increased temperature warming, regime and intensity of precipitation [3, 4]. Hydrology strongly affect soil properties (texture, moisture), nutrient regime (organic matter content) and fertility. The main environmental problems nowadays in Hungary are aridification and desertification. It is reflected in increased annual temperatures and decreased precipitation [5]. A new hydrological and meteorological balance triggers evolution of landscapes and cause landscape dynamics [6]. Reduced availability of water affects ecosystems. Vegetation coverage is the most vulnerable and least resisting elements of landscapes, with the most rapid response to external changes, like water shortage. Hence, since 1961, the net primary production dropped from 67% to 49% [7]. Recently in the Carpathian Basin there is considerable increase in extreme hazardous events: droughts, water shortage and floods. Driving factor is changes in precipitation distribution in the past decades. The local flood hazard risk can be assessed as moderate to high [8]. Thus, lowlands are potentially exposed to floods, since the majority of river discharge is collected by the runoff from the hills [9], which is intensified by the hazards, and lead to floods. Cumulative effects of environmental, climate and anthropogenic factors (intensive agricultural activities) affect Hungarian landscapes. Combination of the satellite images with GIS techniques is a key method for land patterns identification and classification of ecosystems. Research methodology is based on the GIS spatial analysis tools and classification of Landsat TM image, which was used for visualizing landscapes. An ILWIS GIS was applied to perform spatial analysis and mapping. The research algorithm is clustering, which classifies pixels with similar value of Digital Numbers (DNs) to thematic classes. As a result, spatial analysis on distribution of land cover patterns was performed. Data processing include image pre-processing, enhancement, classification, spatial analysis and interpretation. A land cover map was created by classifying study area into land categories. The core method used in the current work for the interpretation of imagery is clustering algorithm. This method is based on the remote sensing general principle that each unique pixel on a multichannel image has spectral signature defined by the reflectance of its DN in each spectral band. The DNs of pixels create unique signatures for various objects, distinguishable from other objects. Multispectral cluster classification was applied for the Landsat TM image, by extracting information about values of the pixels DNs, analyzing their spectral signatures. During classification, digital cells are measured according to the similarity of their * Издается в авторской редакции.