Riconquistiamo il paesaggio - ACCA software SpA

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CAPITOLO III - Paesaggi d’Italia
for the high environmental diversity that characterizes the region (Balletto & Casale 1991; Cowling
et al. 1996; Preiss et al. 1997; Blondel & Aronson 1999; Heywood 1999; Lobo et al. 2001).
In the last 40 years, a particular pattern of land-use/land-cover change has taken place in the
Mediterranean basin, especially in Mediterranean Europe: plains are being increasingly utilized,
hilly and mountain areas are being abandoned by humans and naturally reforested, human settlements
are quickly increasing along the coastline, with resident population doubling every 30
years and tourist presence doubling every 15 years (UNEP 1989; Ales et al. 1992; Garcia-Ruiz
et al. 1996; Debussche et al. 1999; MacDonald et al. 2000; Santos 2000; Lambin et al. 2003).
These new patterns are largely independent from planned conservation strategies and appear
to have a substantial impact on landscape and biodiversity (Ales et al. 1992; Covas & Blondel
1998; Tellini-Florenzano 2004), especially because they affect large areas. However, most of the
studies on land-use/land-cover change in the Mediterranean have concerned limited areas (Garcia-Ruiz
et al. 1996; Preiss et al. 1997; Debussche et al. 1999), and have not analyzed the large
scale effects of these patterns. Moreover, no spatially explicit analyses have considered the entire
Italian peninsula, one of the most important areas for biodiversity conservation in Europe.
1. Measuring land-use/land-cover change in Italy
We used three land-use/land-cover maps (the Map of Land Cover produced from 1956 to 1968
by the National Research Council – MLC1960 – and two Corine Land Cover maps – CLC –
for 1990 and 2000) to measure landscape change in Italy over the last 40 years.
We reclassified each map in order to obtain 8 land-use/land-cover categories (thematic generalization
sensu Petit & Lambin 2002): “agricultural areas” (AGRICULTURE), “heterogeneous agricultural
areas” (HETEROGENEOUS), “wooded cultivations” (WOODED), “forests” (FOREST),
“pastures and grasslands” (PASTURE), “barren areas” (BARREN), “artificial areas” (ARTIFICIAL),
and “water” (WATER). Different classification options were available on the basis of the definitions
of the land-use/land-cover classes in the original legends (e.g. the class “Chestnut woods”
in the MLC1960 could be reclassified in the final legend as FOREST or as WOODED; on the
contrary, the class “Artificial areas” in the MLC1960 can only be reclassified as ARTIFICIAL; Fig.
1). We performed 6 alternative thematic aggregations for the CLC legend and 4 for the MLC1960,
giving a total of 24 combinations for the time frame 1960-1990 (4 trials in 1960 by 6 trials in
1990), and a total of 6 combinations for the time frame 1990-2000 (each trial in 1990 compared
with the corresponding trial from 2000).
To account for the inherently scale dependency of landscape patterns (Turner et al. 1989; Wu
2004) we performed the analyses using 5 different cell sizes: 100 m, 200 m, 300 m, 400 m, and
500 m. Thus, we obtained 120 possible combinations for 1960 versus 1990 (24 thematic combinations
times 5 pixel sizes) and 30 possible combinations for 1990 versus 2000 (6 thematic
combinations times 5 pixel sizes).
We then performed a land-use/land-cover change detection for pairs of successive maps, using
post-classification comparisons (Petit & Lambin 2002), and we obtained the mean change and
the standard deviation for 1960 versus 1990 and for 1990 versus 2000. This method, despite its
limitations (Coppin & Bauer 1996), was the only available option, primarily because no collateral
spectral information was available for 1960.
From 1960 to 1990, 51.63% (± 2.31%) of the Italian peninsula changed from one land-use/landcover
class to another. From 1990 to 2000, changes in land-use/land-cover occurred for 23.34%
(± 1.51%) of the Italian peninsula (Fig. 2).
In the 1960s, the agricultural land-use classes dominated the Italian landscape (58.12%), in par-