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Modelling the effects of long-term urban land use change on the water balance
143-159Views:62The level of land consumption for housing and transport contrasts sharply with both the necessity and the legal obligation to maintain the ecological potential afforded by open spaces to meet the needs of current and future generations in terms of resource protection and climate change. Owing to the increasing intensity of soil usage, in many urban landscapes the soil conditions has deteriorated. The natural filter and run-off regulating functions of soils are impaired or even disappeared altogether by land surfacing. Since such soil functions closely depend on the soil’s biophysical properties, the decline of water balance functionality caused by urbanisation and increasing imperviousness varies. In response to the demand to sustainably secure urban water resources, it needs to be assessed exactly how land surfacing affects the functions concerned. Analysing and evaluating the urban land use change and the respective imperviousness on the long-term water balance ought to improve our general understanding of the water household related impact of urbanisation. Therefore, the aim of this paper is to assess the impact of urban land use change and land surfacing on the long-term water balance over a 130-year trajectory using the example of Leipzig. In particular, attention is to be paid to evapotranspiration, direct runoff and groundwater recharge.
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Agricultural sector, rural environment and biodiversity in the Central and Eastern European EU member states
46-64Views:50During the second half of the 20th century, agriculture and the rural environment diverged in Western and Central and Eastern European countries (CEEC). CEE countries itself are heterogeneous in the respect of land use intensity and history. In the current review we focus on the comparison of the agricultural sector and threats on biodiversities of EU new-member countries from Central and Eastern Europe and the old EU(15) member states. The clustering of countries revealed groups distinguished according to the level of their economic productivity, discriminating mostly among eastern and western European countries. CEE countries sub-divided according to geographic region, including also some old members of the EU. Within the western cluster, two large sub-clusters became evident according to economy affected by altitudinal and climatic differences. Partly because there are still areas where the intensity of land use remained low, the biological diversity in many regions of Central and Eastern Europe has remained high. However, loss of extensively used habitats, the restoration on intensive agriculture, reforestation with exotic species and urbanization are major threats to nature in CEE countries. The estimated variability among CEE countries is caused by different historical and cultural backgrounds of those countries. Due to the complexity and geographical diversity of driving forces, there remains much uncertainty in the possible impacts of particular factors on land use. This complexity and diversity have to be considered when planning economic as well as ecological means for developing the agricultural sector and conserving biodiversity in the future of CEE countries.
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Evaluation of the possibilities for stream restoration: preassessment of the Váli-stream (Hungary)
26-44Views:240The purpose of this study is to evaluate the potential of restoration of a stream section. The starting point of the multiple-step assessment process was a historical analysis, which resulted in the definition of different sections within the study area, providing a base for the further restoration goals. The assessment of the current conditions was elaborated particularly to determine those factors, which could limit restoration. These assessments cover the land use pattern, furthermore the analysis of vegetation and habitat patches. As a result of the historical analysis, it has been found that the stream side habitat patches have decreased significantly despite the constant space available. This change was not caused by the increased area of the settlement, but rather by the higher dominancy of arable forms of land use. The greatest share of wet and mesic meadows and agricultural habitats in the study areas, covering 57.5% of the total area, indicates significant anthropogenic effects. Consequently it can be stated that the reference conditions are not the only determining factors of the restoration possibilities. Restoration style and intensity have been defined on basis of all assessed factors.
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Vegetation changes of Sundarbans based on Landsat imagery analysis between 1975 and 2006
1-9Views:365The Sundarbans in Bangladesh and India is the largest single block of tidal halophytic mangrove forest in the world. This forest is threatened by effect of climate change and manmade activities. The aim of this paper is to show changes in vegetation cover of Sundarbans since 1975 using Landsat imagery. Normalized Difference Vegetation Index is applied to quantify and qualify density of vegetation on a patch of land. Estimated land area (excluded water body) of this forest is 66% in Bangladesh, and 34% in India, respectively. Net erosion since 1975 to 2006 is ~5.9%. In vicinity of human settlement, areal changes are not observed since 1975. The mangrove forest is decreased by 19.3% due severe tropical cyclone in 1977 and 1988. Moreover, the dense forest is damaged by about 50%. However, more than 25 years is taken by Sundarbans to recover from damage by a severe tropical cyclone. The biodiversity of Sundarbans depends to fresh water flow through it. Therefore, the future of Sundarbans depends to the impact of climate change which has further effect to increasing intensity and frequency of severe tropical cyclone and salinity in water channels in Sundarbans.