with the Common Database on Designated Areas 
(CDDA) of the European Environment Agency 
(http://www.eea.europa.eu/data-and-
maps/data/natura-6#tab-european-data, last accessed 
February 1, 2017).  
Regarding to the information needed to develop 
the LULC scenarios, maps from CLC project for the 
years 1990, 2000 and 2006 were downloaded 
(http://centrodedescargas.cnig.es/CentroDescargas/b
uscadorCatalogo.do?codFamilia=02113, last 
accessed February 1, 2017). We did not consider the 
most recent map (CLC 2012) because it is still under 
review. 
A collection of auxiliary geographic data was 
taken into account in order to map the driving 
factors and the restrictive and incentive factors 
during design of future LULC scenarios. A Digital 
Elevation Model (raster 30 m GMES RDA, EU-
DEM) was used to generate altitude and slope maps. 
Roads, rivers and railway stations (Numerical 
Cartographic Base 1:100,000, obtained from the 
Spanish National Geographical Institute) were 
considered to calculate cost of transport and 
distances to the city of Madrid, to other cities, to the 
airport and to the roads themselves. Other 
information used was the lithological map of 
Madrid, the map of public-utility forest areas 
(Regional Government of Madrid), PA zoning in the 
region (Autonomous Body for National Parks) and 
specific legislation on land and territorial planning 
(General Urban Land Plan for Madrid for 1997, Law 
9/2001 of 17 July on land in the Region of Madrid, 
Law 9/1995 of 28 March on measures for territorial 
policy, land and planning, and Law 3/1991 of 7 
March on roads in the Region of Madrid).   
CLC vector maps were converted to 50*50m 
pixel size raster format. To simulate future LULC in 
2025, a simplification of CLC legend was made, 
from CLC level 3 to seven categories was made: (1) 
urban fabric, (2) industrial and commercial, (3) 
arable land and permanent crops, (4) heterogeneous 
agricultural areas, (5) forests, (6) shrubs and 
herbaceous vegetation, and (7) others (open spaces 
with little vegetation, wetlands and water bodies). 
Using CLUE three different scenarios were 
developed: (a) “business as usual” scenario, (b) 
economic crisis scenario and (c) green scenario. The 
first one, shows what would happen if the past trend 
observed during 1990-2000-2006 was to continue 
until 2025. The crisis scenario shows what would 
happen if the economic crisis in Spain and the region 
of Madrid was to continue until 2025. The green 
scenario shows what would happen if there were 
more active reforestation policies and if greater 
importance was placed on the natural environment. 
It does, however, take into account that Madrid is an 
urban region and that built-up areas will continue to 
grow. This means on the one hand, that greater 
protection is offered to natural uses than in the past 
and, on the other, that greater growth is assigned to 
built-up land (for more information see Gallardo 
2014; Gallardo et al. 2016).  
LULC and driving factors were related by means 
of logistic regressions (LR). Previously, correlations 
between the selected variables were observed by a 
Pearson’s correlation analysis. The future demand 
for each land use was assigned specifying the 
number of hectares for each land use in 2025, based 
on what had happened in previous years. For the 
trend scenario, each LULC type evolves according 
to the observed past trend. For the economic crisis 
scenario, experts’ opinion was included as input 
data. A questionnaire was distributed among 117 
experts that were asked about how much the 
different LULC types could grow or decrease under 
an economic crisis scenario and where these LULC 
changes could preferentially be located. Finally, the 
green scenario was calculated as a halfway scenario 
between the trend and the economic crisis scenarios 
for agricultural and artificial LULC types while for 
forest and shrub and pastures, an increase of about 
13 and 0.2 %, respectively, comparing to 2006 is 
defined. 
Calibration processes were taken into account in 
order to improve the scenario results. This was done 
in different ways: changing the future 
demand/extension of each LULC, changing the 
conversion matrix, selecting the driving factors, etc. 
Taking the sequence of maps 1990-2000 as a base, a 
simulation of a land-use model in 2006 was carried 
out and compared it with the real map for 2006. The 
amount of land-use change, the driving factors used 
and/or the size or weight of the neighbourhood were 
changed in order to obtain a better result. For 
validation, comparisons in terms of quantity and 
location were analysed.  Kappa statistics, K Location 
(location) and K Histogram (quantity) (Pontius 
2000; Van Vliet 2009) was used. Results were 
compared with a null model and a random model. 
Values and maps of hits, misses and false alarms 
were obtained (Eastman 2012; Sangermano et al. 
2012).  (See Gallardo, 2014) 
PAs were analysed regarding to their level of 
priority. Areas that overlapped are classified as areas 
of greatest protection. In descending order, the level 
of priority is as follows: (1) Nature Reserve, (2) 
National Park, (3) Regional Park, (4) SAC, (5) SPA,