URBAN SMS Soil Management Strategy

Transcription

1 URBAN SMS Soil Management Strategy Assessment of Soil Protection Efficiency And Land Use Change G. Siebielec, A. Lopatka, T. Stuczynski, M.Kozak, M. Gluszynska, J. Koza, A. Zurek & R. Korzeniowska-Puculek September, 2010 updated: December 2010

2 Deliverable report ASSESSMENT OF SOIL PROTECTION EFFICIENCY AND LAND USE CHANGE Deliverable number: Partner responsible for this deliverable: PP8 Institute of Soil Science and Plant Cultivation State Research Institute Partners Involved: LP: City of Stuttgart PP2: City of Vienna, PP3: Umweltbundesamt, Environment Agency Austria, Vienna/ Austria PP4: City of Milan, Executive Plans and Programs for Buildings Department- Office for Reclamation Plans, Italy PP9: Czech University of Life Sciences, Prague PP10: Soil Science and Conservation Research Institute, Bratislava, Slovakia PP11: District Authority Stuttgart, Germany

3 Authors: Grzegorz Siebielec Artur Lopatka Tomasz Stuczynski Malgorzata Kozak Magdalena Gluszynska Joanna Koza Anna Zurek Renata Korzeniowska-Puculek 2

4 CONTENT: 1. INTRODUCTION MATERIALS AND METHODS Data sources Satellite images Soil maps Land use change analysis Approach for analysis of soil protection efficiency LAND USE CHANGES AND SOIL CONSUMPTION IN TEST AREAS Milan Bratislava Wroclaw Prague Stuttgart Salzburg Vienna SUMMARY OF LAND USE CHANGE AND SOIL PROTECTION EFFICIENCY IN TEST AREAS KEY MESSAGES REFERENCES ANNEXES Land use maps Land use change maps

5 1. INTRODUCTION Urbanization can be considered as a pressure on landscape reducing its buffering capacity and resistance to degradation (Antrop, 2004). Evaluation of these pressures is fundamental for development of strategies for protection of soils and soil functions. Sealing is one of threats identified in the framework of Strategy for Soil Protection (COM231, 2006). The sealing process may limit performance of soil functions (retention, production, filtering, biodiversity, etc.) and accelerate other soil threats such as decline in organic matter, contamination, floods, compaction. Land use changes are closely related to competition between different sectors, creating a specific demand for land controlled by macroeconomic situation, socio-economic variables, spatial planning, European and national policies and regulations concerning land or soil management. A policy (e.g. soil protection strategies) impact on land use change is difficult to assess as land transformation into different functions is, to some extent, an autonomous process and not always clearly responding to policy variables. The objective of the presented task was to conduct an ex-post analysis of land use change, responding to different soil protection regulations in several Central Europe cities. It is essential to understand what is the rate and pattern of changes in land use and how these changes, especially soil sealing, affect the overall performance of the soil function within the city area. Such an analysis is thought to raise awareness on trends of soil consumption within urban development process and provide information on effectiveness of the current soil protection measures. Soils differ in properties and, thus, ability to fulfill such functions as retention, biodiversity, filtering, crop productivity. Correlation between soil protection measures and loss of valuable soil resources was analyzed, identifying city-specific patterns of land use change and preservation of soils under urbanization pressure. Seven cities served as test areas for the analysis: Milan, Bratislava, Prague, Wroclaw, Stuttgart, Vienna, Salzburg. 4

6 2. MATERIALS AND METHODS The conceptual framework of the analysis of loss of high quality soils in test areas is presented in Figure 1. It involved development of land use change maps based on consistent satellite image data, analysis of land use change trends within 15 years period and subsequent assessment of valuable soils consumption for urban expansion as an indicator of soil protection efficiency. Milan Bratislava Test areas Prague Wroclaw Stuttgart Vienna Salzburg Soil maps Satellite images 10m resolution for 1990/1992 and 2006/2007 Classification of image objects Soil quality maps Land use maps (1990/1992 and 2006/2007) Land use change maps Spatial analysis of soil consumption for urbanization Transition indexes for soils of different quality Analysis of efficiency of current soil protection regulations Figure 1. Concept of soil protection efficiency analysis in test areas 2.1. Data sources Satellite images One of major constraints in spatial analysis of land use change is the quality of mapping and uncertainties of cartographic information related to different sources, scales and methodologies of land use map preparation. Resolution of official European land use database Corine Land Cover (CLC) is inadequate for detailed analysis of transition occurring in urban and suburban zones (EAA, 2005). 5

7 Thus, satellite images gathered from one source were employed for analysis of land use conversion trends in order to ensure consistency of land cover data and allow comparability of results between cities. These were 10-meter resolution SPOT satellite images. The B&W SPOT image is monospectral, color photo is a combination of 4 bands of different wavelengths. The images used represented two periods in order to study land use changes within approximately 15 year timeframe black and white photos captured in and color photos taken in period. One or two year difference between cities was justified by the necessity to avoid low quality images, e.g. due to excessive cloudiness Soil maps Soil maps were provided by the project partners responsible for the respective test cities. Due to diverse soil quality assessment systems, present in different Central European countries, and content of the soil maps the polygons on each map were grouped into 3 classes. They represented high, medium and low quality soils (either from perspective of production function, ecosystem function, buffering, retention etc.). Milan Discrimination of soil quality classes was generally based on the soil texture information. Coarse soils were classified as the least valuable while fine-texture soils as high quality soils due to their high retention and buffering-filtering capacity and, generally, greater crop productivity. Additional land use information provided by Milan partner was used to verify the soil value. The land use class vegetation of humid areas and peat bogs was classified as high quality regardless soil texture due to their role as water reservoir and ecological value. The land use type dismissed areas not used and not grown with flora was classified as low quality soil regardless the soil texture. Bratislava The soil map of Bratislava contains soil quality classes according to Slovakian valorization system in the 1 to 9 scale. Classes 1-4 were taken to the high quality soils group, 5-6 to medium quality while classes 7-9 were considered as low quality soils. Wroclaw Soil agricultural map of Wroclaw region in scale 1:25000 was used for Wroclaw case study. Soil valorization system in Poland involves soil suitability units at the range 1-14 for arable lands and 1z-3z for grasslands. This classification basically reflects productivity potential of the soil (suitability to produce certain crops) and the units were delineated based 6

8 on various soil properties as well as climatic conditions, water conditions and slope. Units 1, 2, 4, 1z were classified as high quality soils, units 3, 5, 8, 2z as medium, while units 6, 7, 9, 14, 3z and barren lands as low quality soils. The soil suitability units generally well describe other soil functions such as water retention, buffering capacity or biodiversity. Prague For purpose of the analysis we used the pedological map of Prague by Tomasek, Discrimination of quality classes was primarily based on soil typology. After consultations with the PP9 (Czech University of Life Sciences) the chernozems were classified as high quality while brown soils as medium quality soil cover. The group of soil with the lowest quality included rankers, rendzinas and brown soil with upper elevation. Stuttgart Soil quality map of Stuttgart contains an overall assessment of the natural soil functions with classes 1-5. The functions are derived of the natural soil functions in the Soil Protection Act of the Federal Republic of Germany. The indicators for the natural soil quality in Stuttgart are: - habitat function for natural and cultural vegetation which is characterised by soil depth, available water capacity, air capacity and nutrient supply, - water balance which is characterised by the available water capacity, - filter and buffer which is characterised by humus content, clay content, ph-value and microbiological decomposition. Classes 1 and 2 were categorized as low quality soil, class 3 as medium and classes 4 and 5 as the highest quality cover. Salzburg and Vienna Soil maps contained 3-class system of soil quality assessment (NSQ value) so no reclassification was needed. If two descriptions appeared as attributes (e.g. low value cropland, medium value grassland) the first one was taken as dominating land use. Currently available digital soil map of Vienna area does not cover whole city administration area. However, most of recorded land use changes in the studied period appeared within the area with available soil quality information this means that the fragmentation of soil map did not substantially affect the analysis Land use change analysis Land use maps of 10-meter resolution were produced for two periods representing years and through classification of the satellite images (Fig.2) 7

9 in Definiens Professional software. Process of land use map development in this software basically consists with two major steps: segmentation and classification. The satellite image is represented by 10mx10m pixels described by spectral information (reflectance data at various wavelengths). Segmentation phase is a process based the fact that land use types (e.g. built up area, forest, water) posses different spectral information. Segmentation delineates spectrally homogenous areas the segmentation algorithms are used to subdivide the entire image represented by the pixel level domain or specific image objects from other domains into smaller image objects (groups of pixels) (Fig. 3). Figure 2. BW and color SPOT satellite images used for development of land use maps. Figure 3. Segmentation (left) and classification phase (right) of land use map development. The segmented objects can be characterized by number of different features for measuring color, shape, texture, size, neighborhood. This information contained in image objects is used as a filter for classification (Fig. 3). Based on this, image objects can be analyzed according defined criteria and assigned to classes that best meet these criteria. Classification is a procedure that associates image objects with an appropriate land use class labeled by a name and a color. 8

10 After careful manual revision of the classification using all available spatial information the obtained final layers were used as land use maps of the pilot areas (Fig. 4). Figure 4. Example of the produced land use map with 13 land use classes The land use maps contained 13 different land use types: 1. continuous residential areas 2. commercial and industrial areas 3. green recreation areas (parks) 4. airports 5. sport and leisure facilities (with generally impermeable or reconstructed surfaces with limited performance of soil functions e.g. stadiums, tennis courts) 6. dump and mineral extraction sites 7. arable lands 8. grasslands (pastures and meadows) 9. forests 10. semi-natural areas (covered by shrubs, trees, not used by agriculture) 11. discontinuous residential areas (residential area with dispersed buildings, still can fulfill some soil functions since most of surface is unsealed) 12. water bodies 9

11 13. transport facilities. For some cities the classes forests and semi-natural areas were combined into one class for soil consumption analysis in order to avoid misleading observations related to the fact that these two land uses may look similarly on satellite images, especially when semi-natural areas are of long-term character and are covered by trees. It must be noted that the our data regarding different types of green areas (forest, semi-natural, green park) may differ from the official statistics due to the mentioned uncertainties in distinguishing these classes. The land use change information (Fig. 5) for each pilot area was produced through comparison of land use layers derived for different periods. Figure 5. Urban fabrics sprawl on the new satellite image as background 2.3. Approach for analysis of soil protection efficiency The information on land use change was superimposed on maps characterizing soil quality in order to detect to what extend the urbanization took place on valuable soils. The new sealed area, reflecting the built up sprawl of last 15 years, consisted with expansion of the following land use classes: continuous residential area, commercial/industrial area and transport facilities. The soils under these new land use types fully lost their environmental functions. 10

12 In order to assess what is the scale of consuming valuable soils by urban sprawl, a transition index was used. It reflects the intensity of land use flows in the context of soil quality [Stuczynski, 2007]. Looking at land use stocks and flows occurring on soils belonging to different quality classes, it is difficult to make a straightforward assessment whether the observed land use change is equally distributed among classes distinguished, or is it nonproportional and consumes areas of certain characteristics, less or more intensely, as compared to a general pattern of a given soil quality or parameter. Difficulties arise from the fact that the contribution of e.g. soils of high productivity or high water retention potential to the total soil cover may vary greatly between regions therefore the size (measured in hectares) of change on soils of certain characteristics is not a good indicator if these soils are preferentially taken by urbanization. Preferential flows occur when a certain soil type (characteristics) represents a larger share in the changed land as compared to the share of this type in the general soil cover. Thus, a simple transition index (TI) is proposed to characterize the intensity of conversion of agricultural land observed on different soils, classified according to the ranges of land suitability or quality. The ratio between the share of a given soil type (class) within the changed area and the share of this class in the total soil cover is calculated. percent of soil class" n" in newbuilt area transition index( TI ) = percent ofsoil class" n" in whole urban area It must be noted that for calculation of share of different soil quality classes in whole area only soils that were not sealed in were taken into account. In most cities soil maps did not cover forest areas, except Stuttgart and Prague, for these two cities forest areas were excluded from the calculation since they are protected against urbanization. Interpreting the transition index is straightforward for example, index value of 2 for a flow on a given soil class (e.g. high quality soils) means that within changed land the share of this class is twice as high as in the entire soil cover, therefore the intensity of high quality soils consumption is much larger than can be expected from a structural pattern of soil quality. In contrast, if, for instance, the percentage share of high quality soils within area changed into built-up areas is considerably smaller than 1 (e.g 0.5) it means that these soils are protected from expansion of artificial surfaces. Interpretation of the transition index values is somewhat arbitrary - values in a range of 0.8 to 1.2 are interpreted as indicative of nonpreferential flows consuming soils representing a given range of parameters. Such a range of 11

13 flows considered as non-preferential is necessary to account for the uncertainty of change analysis, resulting from generalization and automatization of the analytical procedure. 3. LAND USE CHANGES AND SOIL CONSUMPTION IN TEST AREAS 3.1. Milan High density of continuous urban fabrics is characteristic for Milan. This land use type covers up to 60 percent of total city area within administrative borders. The increase of urban fabrics in Milan within 15 y period did not exceed 400 ha (Table 1). The increase refers to continuous residential areas. Over 470 ha of arable lands were taken into other land use types. Some urban sprawl appeared on wooded areas mostly on semi-natural areas covered by trees and shrubs. It is worth to note that the green urban areas increased by approx. 230 ha which in combination with the observed decrease in dump and mineral extraction and industrial sites area may indicate substantial city effort into revitalization of brownfield sites. Most of new sealing in Milan were observed in northern and southern-east part of the city (Fig. 6). Forty percent of available soil pool in early nineties was of high quality. The transition index for conversion of these soils into urban area was only slightly over 1. It indicates that high quality soils were not protected in Milan, however they were not preferentially urbanized. Low quality soils that in this case mean coarse soils were preferentially taken for construction purposes (TI>7). It must be noted, however, the pool of these soils is nearly depleted. Table 1. Summary of land use changes in Milan Land use class area in 2006 area in 1991 difference [ha] % of total area [ha] % of total area [ha] % continuous residential areas commercial and industrial areas green urban areas airports sports and leisure facilities dump and mineral extraction sites arable land grasslands wooded areas (forest or seminatural) discontinuos residential areas water bodies transport facilities total area x x x 12

14 Figure 6. Urban sprawl in Milan between 1991 and 2006 on soil quality map Table 2. Statistics for transition of soils of different quality into sealed area for Milan* soil quality class Area of soil class Share of soil class in total area Area converted Percent converted Transition index (TI) (ha) [%] (ha) [% of soil class area] high quality medium quality low quality * The newly sealed area may differ from the provided in Table 1 since Table 2 refers to the area covered by the soil map while Table 1 to the total area presented on Fig. 6. Similar note refers to the other cities 3.2. Bratislava The share of sealed surfaces does not exceed 27% in Bratislava area. It increased by approximately 370 hectares since early nineties (Table 3). Greater increase concerns areas of commercial or industrial facilities. Sealing process was purely at the expense of arable lands 13

15 almost 440 hectares were lost within urban development process. There was a slight increment of green recreational area which was equal to semi-natural area loss. Surfaces used as dump and mineral extraction sites noticeably increased within last 15 years which likely was a cost of development of waste management systems. As indicated by the applied assessment methods the area of dispersed residential area increased by near 20 hectares but still covers not more than 1.2 % of total city area. Arable lands currently cover approximately 35% of total area that in combination with forest and semi-natural areas become a substantial soil reservoir performing a number of functions. Despite that the high quality soils covered as much as 47 % of available soil resources they were effectively protected within last 15 years. The share of high quality soils in new sealed area was 5 times smaller than their contribution to whole available soil pool (TI =0.2). Only 0.5% of high quality soils were transformed into construction within 15 y period. Low quality soils were much more intensively taken for urbanization purposes (Table 4). Table 3. Summary of land use changes in Bratislava Land use class area in 2007 area in 1992 difference % of % of [ha] total area [ha] total area [ha] % continuous residential areas commercial and industrial areas green urban areas airports sports and leisure facilities dump and mineral extraction sites arable land grasslands wooded areas (forest or seminatural) discontinuos residential areas water bodies transport facilities total area x x x 14

16 Figure 7. Urban sprawl in Bratislava between 1992 and 2007 on soil quality map Table 4. Indexes for transition of soils of different quality into sealed area for Bratislava soil quality class Area of soil class Share of soil class Area converted Percent converted Transition index (TI) (ha) in total area [%] (ha) [% of soil class area] high quality medium quality low quality Wroclaw Continuous urban fabrics cover 35 % of total area of the city and surroundings enclosed in Wroclaw LAU-2 region. Areas able to fulfill soil functions other than surface for construction consist with arable lands, semi-naturally covered lands, grasslands and forests their share in total area is 22, 14.5, 11 and 7.7 %, respectively, which together exceeds 55% of 15

17 total area (Table 5). The area of continuous sealed area increased by over 500 hectares within the period of interest. Most of this change can be referred to residential areas. Discontinuous residential zones did not expand recently - they cover approximately 6 % of total area. Such areas with dispersed pattern of buildings may perform soil functions in certain extend due to substantial share of uncovered surfaces and undisturbed soil profiles. The statistics of soil consumption for urbanization indicate preferential use of high quality soils in Wroclaw (TI>1.3, 3.6% of high quality soils consumed). Share of the weakest soils in newly sealed area was much smaller than their share in total resources despite that their supply is substantial (Table 6). Table 5. Summary of land use changes in Wroclaw Land use class area in 2006 area in 1991 difference % of % of [ha] total area [ha] total area [ha] % continuous residential areas commercial and industrial areas green urban areas airports sports and leisure facilities dump and mineral extraction sites arable land grasslands forest seminatural discontinuos residential areas water bodies transport facilities total area x x x 16

18 Figure 8. Urban sprawl in Wroclaw between 1991 and 2006 on soil quality map Table 6. Indexes for transition of soils of different quality into sealed area for Wroclaw soil quality class Area of soil class Share of soil class Area converted Percent converted transition index (TI) (ha) in total area [%] (ha) [% of soil class area] high quality medium quality low quality

19 3.4. Prague Continuous urban fabrics increased by 780 hectares in Prague between 1990 and Most of the increase refers to residential areas that currently cover approximately 37% of total area (Table 7). The urban built up sprawl was entirely at the expense of arable lands. Arable lands, however, still constitute substantial part of land resources (30% of total area). No significant increases were detected for such land use types as parks, sport facilities, transport infrastructure or dispersed residential zones. The soils classified as the most valuable (chernozems) were preferentially taken for urbanization within period (TI>1.8) (Table 8). This process can be partly explained by the fact that chernozems are homogenously and exclusively located in northern part of the city. Thus any urban development in this zone would cost loss of these soils. Most of urbanization as measured by absolute values took place on medium quality soils which represent 66% of area taken for calculation (with soil information and not covered by forest or construction). Low quality soils were relatively omitted in the urbanization process their share in newly urbanized area was twice smaller than the share in total area of soil resources (Table 8). Table 7. Summary of land use changes in Prague Land use class area in 2006 area in 1990 difference % of % of [ha] total area [ha] total area [ha] % continuous residential areas commercial and industrial areas green urban areas airports sports and leisure facilities dump and mineral extraction sites arable land grasslands forest seminatural discontinuos residential areas water bodies transport facilities total area x x x 18

20 Figure 9. Urban sprawl in Prague between 1990 and 2006 on soil quality map Table 8. Indexes for transition of soils of different quality into sealed area for Prague soil quality class Area of soil class Share of soil class Area converted Percent converted transition index (TI) (ha) in total area [%] (ha) [% of soil class area] high quality medium quality low quality Stuttgart The applied assessment method revealed that the urbanization process between 1992 and 2006 captured over 215 hectares of land approximately 190 hectares were converted into continuous sealed area (Table 9). These absolute numbers may differ somewhat from the official statistics data our assessment was aimed at recognition of spatial trends. Residential 19

21 area increase was considerably responsible for the urban sprawl it included both continuous zones and areas of dispersed separate buildings. Discontinuous residential zones cover over 7% of total area these lands still perform some environmental functions including retention, filtering or temperature increase mitigation. The increment was observed in such land use types as airports, transport facilities, sport infrastructure but also green parks. The urbanization took partly place on arable lands but mainly on semi-natural areas such as, for example, abandoned former fruit tree orchards. No clear preferential trends in consumption of particular soil quality classes were observed. They were rather taken for urbanization proportionally to their contribution to the total area covered by the soil map (TI ) (Table 10). Low quality soils were less consumed which might be explained by the fact that they cover only 6% of total soil resources and are not evenly distributed over the city area (Figure 10). The recorded urbanization data leads to the conclusion that the most valuable soils have not been efficiently protected in Stuttgart. Table 9. Summary of land use changes in Stuttgart Land use class area in 2006 area in 1992 difference % of % of [ha] total area [ha] total area [ha] % continuous residential areas commercial and industrial areas green urban areas airports sports and leisure facilities dump and mineral extraction sites arable land grasslands wooded areas (forest or seminatural) discontinuos residential areas water bodies transport facilities total area x x x 20

22 Figure 10. Urban sprawl in Stuttgart between 1992 and 2006 on soil quality map Table 10. Indexes for transition of soils of different quality into sealed area for Stuttgart soil quality class Area of soil class (ha) transition index (TI) Share of soil class in total area [%] Area converted (ha) Percent converted [% of soil class area] high quality medium quality low quality Salzburg Equal increase of continuous residential and commercial/industrial area was observed in Salzburg area between 1991 and The total sealing area exceeded 160 hectares 21

23 (Table 11). The new urban fabrics were located on arable lands (3/4 of changes) and likely semi-natural wooded areas (1/4 of changes). The available satellite images for Salzburg and, subsequently, land use maps did not fully cover the Salzburg region. However it did not substantially affect the assessment. Areas behind the land use maps are mostly covered by forests and no substantial land use changes would be expected there. High quality soils occupy only 1/10 part of the area covered by the analysis. However, 35% of new urban fabrics appeared on these most valuable soils (TI=3) (Table 12). Low quality soils were also taken for urbanization preferentially. It must be noted that medium quality soils constitute above ¾ of the analyzed area. Most of land use changes took place on soils of medium quality when expressed in absolute values. Nevertheless, the most valuable soils were not protected and their pool was drained more intensively than their share in total area. Table 11. Summary of land use changes in Salzburg Land use class area in 2007 area in 1991 difference % of % of [ha] total area [ha] total area [ha] % continuous residential areas commercial and industrial areas green urban areas airports sports and leisure facilities dump and mineral extraction sites arable land grasslands wooded areas (forest or seminatural) discontinuos residential areas water bodies transport facilities total area x x x 22

24 Figure 11. Urban sprawl in Salzburg between 1991 and 2007 on soil quality map Table 12. Indexes for transition of soils of different quality into sealed area for Salzburg soil quality class Area of soil class (ha) Share of soil class in total area [%] Area converted (ha) Percent converted [% of soil class area] transition index (TI) high quality medium quality low quality Vienna Most land use changes in Vienna took place in northern-east part of the city (Fig. 12). The substantial increase in commercial/industrial area was observed since 1991 which was greater than sprawl of residential urban fabrics. However residential zones cover up to 40% of total area. Total increase in sealed area exceeded 300 hectares. Most of this enlargement was 23

25 located on arable lands their share lowered from 13.8 to 13.2% of total area within 16 years (Table 13). Soils of high quality are most significant part of the soil resources and constitute 67% of total area for which the soil map is available. Most of new sealing took place on these soils and they were even taken slightly preferentially (TI=1.3). Low quality soils cover less than 1/10 of all soils and they were hardly used for urbanization (Table 14). It must be noted, however, that zone of the recent city expansion is located in northern-east direction where the valuable soils are predominant. Table 13. Summary of land use changes in Vienna Land use class area in 2007 area in 1991 difference % of % of [ha] total area [ha] total area [ha] % continuous residential areas commercial and industrial areas green urban areas airports sports and leisure facilities dump and mineral extraction sites arable land grasslands wooded areas (forest or seminatural) discontinuos residential areas water bodies transport facilities total area x x x 24

26 Figure 12. Urban sprawl in Vienna between 1991 and 2007 on soil quality map Table 14. Indexes for transition of soils of different quality into sealed area for Vienna pilot area soil quality class Area of soil class (ha) Share of soil class in total area [%] Area converted (ha) Percent converted [% of soil class area] transition index (TI) high quality medium quality low quality SUMMARY OF LAND USE CHANGE AND SOIL PROTECTION EFFICIENCY IN TEST AREAS This report summarizes outputs of our analysis of relationships between current soil protection policies and the land use change in selected test regions of Central Europe between 25

27 1990/92 and 2006/2007. Land use change size and pattern usually reflects a combination of the geographic location, a specific setting of socioeconomic, historical and environmental conditions and national or regional land/soil protection policies. Therefore it is not practical to analyze these changes for the group of cities as a whole, but instead analyzing them separately since the test areas represent different mechanisms driving land conversion processes. In our analysis we performed analysis for 7 cities representing Germany, Czech Republic, Poland, Slovakia, Austria and Italy. It is well known that the size of conversion of agricultural land into artificial surfaces such as into urban and industrial/commercial units is mainly driven by population growth (both through natural growth and migrations) as well as GDP whereas the spatial sprawl of urban fabrics is partly an independent process and partly is steered by spatial planning. Summarizing our analysis, the area sealed within 15 y period in the test areas ranged from 160 to 780 ha. The data provided here may be somewhat different from the official statistics that use different methodologies. Our study utilized satellite images for detection of land use changes such a method is burdened with a dose of uncertainty. However the advantage of the applied approach is that it enables analysis of spatial trends of land use change and their linkage to soil quality information. The expansion of artificial surfaces took place mostly on arable lands, except Wroclaw and Stuttgart where semi-natural areas were also sealed substantially. New artificial surfaces mostly comprised with residential fabrics, however in some cities (Bratislava and Vienna) development of industrial and commercial constructions was predominant. Bearing in mind some uncertainty of land use change data and that soil data do not cover whole city area the analysis fills the information gap on the quality of soils lost in urbanization process and, thus, efficiency of soil protection approaches. It is evident in the light of this study that the best soils are efficiently protected in Bratislava (Fig. 13). The share of best soils in newly urbanized areas is in Bratislava 5 times smaller than their share in total area. It is assumed that the regulations present in Slovakia help to protect the most valuable soils. The soils classified as high quality in our assessment are covered by a fee payment system (1-4 classes from total 9). Transformation of these agricultural lands into other purposes is loaded with obligatory payment with a range of payment from 6 to 15 EUR per square meter. The similar system had existed in Poland until However this practice did not ensure the efficient protection of most valuable soils in Wroclaw (Table 6, Fig. 13). In Stuttgart and Milan the consumption of high quality soils was rather proportional to their share in the total soil pool. The assessments performed for Wroclaw, Prague, Vienna and 26

28 Salzburg revealed negative trends of preferential use of the most valuable soils. It must be noted that the analysis of soil protection efficiency refers to the period between early nineties to 2006/2007, thus it assesses the regulations existing within this period. It should not be referred to the soil management systems introduced recently. 3,5 TI for high quality soils 3 2,5 2 1,5 1 0, Prague Wroclaw Vienna + Salzburg Stuttgart Bratislava TI for low quality soils Milan Figure 13. Indexes of transition of high and low quality soils into sealed area in the test areas. ( + means presence of positive trend, - presence of negative trend. Positive trend is understood as TI <0.8 for high quality soils and/or TI>1.2 for low quality soils. The negative trend is characterized by the opposite observations) The similar analytical approach as presented in this report can be used for testing how urban growth alters degradation processes (e.g. erosion, contamination) and affects soil function performance (organic matter accumulation, retention potential, buffering capacity) if such spatial information layers are employed in the assessment. 27

29 A comparison of a sealing rate within last 15 years and availability of low and medium quality soils indicates that there is no strong conflict between soil protection goals and a city development needs (Table 15). Such competition may exist locally but, considering this in context of overall city area, the pool of available low and medium quality soils is, for most cities, much greater than land demand for the city development (industry, commerce, transport infrastructure, sport facilities, etc.). This demand is measured by the rate of land transformation into artificial surfaces within last 15 years. Land demand 3 Table 15. Comparison of soil availability and land demand in the test areas. Test area Low quality Low and medium soils 1 quality soils 2 Milan Bratislava Wroclaw Stuttgart Prague Salzburg Vienna soils belonging to low quality agricultural lands (arable and grasslands) within areas covered by the soil maps 2 soils belonging to low and medium quality agricultural lands (arable and grasslands) within area covered by the soil maps 3 rate of artificial surface increase within 15 years in the area covered by the soil maps 5. KEY MESSAGES Expansion of artificial surfaces takes place mostly on arable lands High quality soils were efficiently protected in Bratislava which, at least partly, might be the effect of the fee payment system The most valuable soils were preferentially taken for urbanization in Vienna, Wroclaw, Prague and Salzburg while in Stuttgart and Milan their consumption was proportional to their share in total area. Soil management systems in these cities did not efficiently protect the best soils until 2006 There is no strong conflict between soil protection goals and demand for land related to economic development of cities 6. REFERENCES Antrop M Landscape change and the urbanization process in Europe. Landscape and Urban Planning, 67:

30 COM Communication from the Commission to The Council and European Parliament, The European Economic and Social Committee of The Regions. Thematic Strategy for Soil Protection EAA Image 2000 and CLC Products and methods. European Commission 7. ANNEXES 7.1. Land use maps 29

31 30

32 31

33 32

34 33

35 34

36 35

37 7.2. Land use change maps 36

38 37

39 38

40 39

41 40

42 41

43 42

44 URBAN SMS Soil Management Strategy This paper belongs to the following section of URBAN SMS work plan: WP6 Acceptance and awareness / 6.1 Soil protection measures / Assessment of soil protection efficiency and land use change Contact details of project partner commissioning / responsible for this paper: Mr Grzegorz Siebielec, Institute of Soil Science and Plant Cultivation, ul. Czartoryskich 8, Pulawy, PL, gs@iung.pulawy.pl Other URBAN SMS Partners contributing to this paper: Petra Blümlein & Michael Schweiker, City of Stuttgart, Department for Environmental Protection, DE Isabel Wieshofer, City of Vienna, Environmental Protection, AT Monika Tulipan & Sigbert Huber, Umweltbundesamt, Federal Environment Agency, Vienna, AT Marco Parolin, City of Milan, Executive Plans and Programs for Buildings Department- Office for Reclamation Plans, I Petra Vokurková, Czech University of Life Sciences Prague, CZ Jaroslava Sobocká, Soil Science and Conservation Research Institute, Bratislava, SK Siegmar Jaensch, District Authority Stuttgart, DE This project is implemented through the CENTRAL EUROPE Programme co-financed by the ERDF. The paper in hand reflects the author s views and the Managing Authority of the INTERREG IV B CENTRAL Programme is not liable for any use that may be made of the information contained therein.