International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B7. Istanbul 2004 
  
mainly around the coastal rim and, abandonment of agricultural 
terraces inland. 
The other area of study is the northern Aegean island of Lesbos, 
Greece, which covers an area of approximately 163000ha and 
has a maximum altitude of 947m. The climate is characterised 
by strong seasonal and spatial variations of rainfall and high 
oscillations between minimum and maximum daily 
temperatures, typical of the Mediterranean region (Kosmas et 
al., 2000b). Kosmas et al. (2000a) divided the island in three 
climatic zones: the semi-arid in the West with an average 
annual rainfall of 415mm, the largest dry sub-humid zone in the 
East with 677mm and a transitional zone between the two. The 
soils are developed on various lithological formations such as 
shale, schist-marble, volcanic lava, pyroclastics, and ignimbrite 
and are classified as Typic Xerochrept, Lithic Xerochrept, or 
Lithic Xerorthent (Kosmas et al., 2000a; Kosmas et al., 2000b; 
Loumou et al., 2000). 
3. METHODS AND RESULTS 
3.1 Data 
The datasets available for the Xalé area were: (a) a Landsat 
ETM+ image taken in August 2000, (b) a Landsat MSS image 
taken in July 1978, (d) a Digital Elevation Model (DEM) with a 
25x25m resolution, (e) 1:50000 aerial photographs taken in 
1977, (f) 1:30000 aerial photographs taken in 1997, (g) soil 
samples at 16 point locations in the wider catchment area and 
(h) digital 1:50000 soil erodibility and lithological data. For the 
island of Lesbos the respective data were: (a) a Landsat TM 
image taken in August 1999, (b) a Landsat MSS of May 1975, 
(c) a DEM with a 30x30m resolution, and (d) 1:200000 soil 
map. 
3:2 Landuse changes 
3.2.1 LULC changes in Xaló 
The mapping of the various types of LULC for the area of Xaló 
was achieved using the Landsat data and the fuzzy 
classification and fuzzy convolution modules of Erdas Imagine 
8.5. The data were first rectified for the effect of relief using the 
25x25m DEM and projected to the right geographical 
projection using 54 ground control points with a total RMSE of 
2524m. In order to further assist the fuzzy classifier in 
distinguishing between the different classes, one additional 
layer of information was stacked to the four MSS bands of the 
1978 image and the six ETM- bands of the 2000 image, namely 
the Normalised Difference Vegetation Index (NDVI, Justice et 
al. 1985), thus forming a 5-layered and a 7-layered image, 
respectively. The four principal components of these multi- 
layered images were then extracted, the last three of which were 
then used for the delineation of the sampling areas that would 
serve as ‘training? for the classifier. Five fuzzy layers per pixel 
were used and the resulting classified images were assessed 
using 100 random points and the aerial photographs as ground 
truth. The accuracy of the classification methodology was 
tested only for the 2000 data and produced an overall accuracy 
of 86% and an overall kappa statistic of 0.82. These figures 
compare favourably with the results of a hard maximum- 
likelihood (ML) classification of the same area (Symeonakis et 
al., 2003; Symeonakis et al, in press). 
The result of the fuzzy classification for 1978 (Figure la), 
shows that the vast majority of the catchment area was covered 
by the various types of orchards, with an area of approximately 
12392ha or 41% of the entire catchment. The second LULC 
type, in terms of area covered, was matorral (7541ha), 
554 
followed closely by ‘bare’ (7363ha), the two of which together 
cover almost half of the entire catchment area (49%). Finally, 
forests, urban areas and the various horticultural types all 
shared approximately a 3% of the entire catchment area, with 
1039ha, 889ha and 879ha, respectively. For the year 2000 
(Figure 1b) the fuzzy classification gives the following figures: 
matorral 9480ha (31%), orchards 8955ha (30%), bare 6508 
(22%), horticulture 2527ha (8%), urban areas 1937ha (6%), and 
forests |. 817ha (39^). 
  
a. LULC classes, 1978 
Sl urban lhorbculture CO matormral 
CTotchards Wi forests. C3bare 
  
: b. LULC classes, 2000 
) 25 10 Kimeta urban horticulture Cimatorral 
l1 LL ELE U3orchard Eliforest bare 
Figure 1: Landuse/landcover (LULC) maps of the Xaló 
catchment with predominant LULC types produced 
from fuzzy classification of, (a) Landsat MSS data 
of 1978, and (b) Landsat ETM- data of 2000 
A comparison of the landuse/landcover maps for 1978 and 2000 
in figures 1a and 1b respectively, produced the graph in Figure 
2 below: 
  
  
  
  
  
  
  
  
  
100 4 14000 
12000 
80 
| 10000 Dag 
@ urban 
60 > 
$ 8000 5 mforest 
m 
5 = t | 
T Omatorra 
3 20 6000 5 7 
2 DO bare | 
4000 @area 2000 
20 marea 1978 
2000 
0 Li +0 
  
  
  
  
  
bare matorral forest agri urban 
landuse in 1978 
Figure 2: Percentage of change observed between 1978 and 
2000 for five distinct types: bare, matorral, forest, 
agricultural (orchards and horticultural together) and 
urban, along with the area (ha) occupied by each of 
the types in both years 
Some of the changes that appear to have taken place between 
1978 and 2000 have a direct relationship with the land 
degradation process, namely: 
eo A 21% decrease in forested areas (223ha), most likely 
due to the large number of fires that have occurred in 
the area (Belda 1997). 
e A 13% loss of agricultural land to matorral (1890ha) 
and urban areas (1038ha), due to the abandonment of 
agricultural terraces. 
In 
[9] 
ha 
Fi