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Table 2 shows that Belgium has by far the lowest values for effective share of open space
(indicator 5): that is, the urbanisation patterns found here fragment open space excessively
(see also gure 1, Brussels). Other countries that rank highly in the fragmentation of open
space are the Netherlands, Denmark, Luxemburg, and Croatia. Although there is certainly
some correlation between these indicator results and the amount of urban area that is present
in a country ( gure 2), the values do deviate where signi cant differences in settlement
patterns are present. An example is Greece, which has a similar proportion of total land area
to, for example, Estonia—but it is obviously much more fragmented because effective open
space is 0.1 points less than in Estonia. The map also shows that fragmentation is not simply a
function of population density and urbanisation: the spatial con guration and shape of urban
areas has a signi cant impact on the amount of effective open space, measured especially
when irregular shapes of urban patches dominate settlement patterns. Examples can be
found in Saxony in eastern Germany or the eastern foothills of the Carpathian mountains in
Romania.
Most countries in our sample show that ongoing urbanisation leads to further fragmentation
(indicator 6, decline in effective open space). Figure 4(b) identi es areas with the largest
decrease in effective open space in the Netherlands, Portugal, and Spain, in parts of Germany,
Italy, and Ireland. Sprawl-typical strip or ribbon development along interregional highways
become visible, especially in corridors between Warsaw and Berlin, Dresden and Kassel
(Germany), from Nantes (northeast France), and in the Po river region in Northern Italy.
We assume that mostly commercial and industrial land uses alongside main transportation
corridors can be held responsible for the emergence of these ‘strip developments’. Amongst
the highest ranking countries are certainly the ones that have experienced the highest growth
in urban area (Portugal, Spain, Ireland). However, as the examples of the Netherlands and
Belgium show, effective open space is more affected by additional growth where the country
is already highly fragmented. Although the growth rate of urban areas in the Netherlands is
below that in Ireland, Portugal, or Spain, the additional fragmentation is much higher. The
same is true for Belgium where the growth of urban land was average compared with all
other countries—the decline of effective open space, however, is amongst the highest. This
highlights the value of larger patches of open space from an ecological point of view: although
substantial in size, the urban expansions in Spain, Portugal, or Ireland are concentrated along
the coast and around the main centres, while the remote areas remain largely undisturbed. In
contrast, the widespread additions of urban areas across the countryside in the Netherlands
and Belgium have an impact on a higher number of undisturbed habitats, thus adding up to a
higher decline in effective open space.
This interpretation is further substantiated by the values of the Gini index (indicator 7) that
measures the spatial concentration of new urban areas across a country. The lowest values—
indicating an even distribution of urban growth throughout the country—can be found in the
Netherlands, Belgium, Germany, Denmark, and Italy. From an urban sprawl perspective,
the conclusion is that the concentration of new urban area does not impact on open space
as much as an even distribution of urban growth. In other words, a highly unbalanced urban
system with a large concentration of economic functions and population may not be desirable
from an economic or social point of view, but does not exercise as much pressure on natural
resources as a spatially balanced growth pattern.
3.3 Urban density
The last indicator (indicator 8 in table 2 and gure 5) in this overview shows how average
national urban densities vary across the countries. It is important to note the difference in
population density which measures the number of people per unit area of total land. The
urban density indicator that was used here, in contrast, looks at the number of people per unit