I.e. storms) frequently result in local disasters in Sicily. Common
ofthat territory, but this is not the ultimate cause ot‘instabllEd TVbuild rescn:oirs. due to the long summer aridity (from May to
arnfy done with concrete works. On the contrary. it is imponant to
5~s of Phrs sieuatron resuEEfrom the ecological degradation of the landscape, and to try to
occurring. The importance of this analysis concerns the necessity to create and follow a
in m-kr k, zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
I -CS~CK C zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
rhs mast
preca-ious basin areas, Consequently. also preventing the
e case study of the hilly basin of Xagazzofo River. in the municipalities of Bivona and Santa
ity of proposing an unusual approach to the Province Author
it and clay. The control of the river must be done pr;ncipaH)
e ecology of the landscape
rtant alteratio
of the local land
e necessity to exten
storation of the suitable structure of the
~ar&q:C, based on new vegetate
interacting with the most altered f
The objective of this study, t
comes crucial for the future of warm
ranean iandscapes in Italy, as we can see by
e continental part (North ) wit
nean (Center, South) (Table 1
ve interventions zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
Note that 99. i 96 of water resources of the So
are dependent on reservoirs: their jmteractions
with the landscape is very importa
The present study, based on landscape ecolPresent address: Department of Biology, Section of Ecology,
University of Milan, Milan, Italy.
@ I993 Elsevizr Science Publishers
landscape ecologica
It is important to underline t e existence of
an ~3ogical
\rW
and ethological meaning of terri-
B.V. All rights resewed 0 169-2046/9;/$06.00
Thermodynamic constraints may determine
an attractor (minimurn external energy dissi-
degrees
Naveh, 1984;
ifferent types o
volution ) can
of metastability
The history of the interactions between
landscape elements in a iven area shows a
articular domain, charac
recess allows a so
1
a radical
It, zyxwvutsrqponmlkji
belt
Fig. 2. Principal geomorphological
characters of the landscape. The geological structure of local soils indicates the differences in
hydrology. The vegetational belt which includes Bivona and Santo Stefano is the submedkcrrawan
one. ?!ote the ‘rscation of the
clay zones.
sity
itte
sea.
ificial lake has be
un~cipality of ivona, a town 5 k
Santo Stefano, where t
basin (270 m above se
d buffering corridors
natural and anthropic disturbances, linked
to the into
pacities of a system
of ecosyste
aintenance of maximum biological diver-
ogical structure of
summarized
as follows: the su
ountains of limestone
luvial detritus below t
between Santo Stefano and Bivona there are
layers of clay and scaly clay (Fig. 2 ).
Annual temperature: Bivona (600 m ), 1618°C (min. 8-lo), Santo Stefano (740 m),
14-16°C (min. 6-8).
Annual rainfall: lower part (reservoir/Bi-
r
(0.5
HA zyxwvutsrqponmlkjihgfe
0.5-l HA
0
500
woo m.
a
a>2
Fig. 3. Grain size oftbe landscape. The river acts as an attractor
resent. along the river, it ma) indicate a structural gap.
for the fme-grained
l-2
HA
WA
etements zyxwvutsrqponmlkjihgfedcbaZYXWVUT
of the ecotissue. Where a coarse
Fig. 5. Porosity pattern: wood and forest patches and corridors. Even if not complete at the borders, two areas ofaltered
are visible in the central part, southeast and southwest of Bivona.
structure
Fig 6. Lmtat sample for measuring landscape hctcrogcr,cit>. Transect .-I -.A. on the northern side of the ri~,er i I.C. tight hank ).
Obscn~ the quite well-defined structure of the landscape and the \vcll-distributed tou Btc (SW tclt ) clemcnts.
__....__“_ _
-_---_
---.-+
--_ _
-_
-I-F-
--
.-
-
-
--
_.--
-
-_*
-____
.
_-
_
_--
__
_
_-.._
c__
-.
_-_._
/
500
zyxwvutsrqponmlk
400
300
---.-_______
--__
-__-
___
-_ - - _ _-_ zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
--------.___
_ _
_
Fig.
7.
%wr~t:
200
5 MCAL
MQYear
Linear sample for measuring landscape heterogeneity. Transect B-B, on the sotithcrn side of the river (i.e. left bank).
khe more confused structure of the landscape and tb4e \vorse distriblrtion of Ycu Btc ccotope elements.
s
“z
3
,-
Table 5
Comparison
with the regional scale, 1968
Landscape elements
onal scale 1987
@%I
area
Btc
%Iarea
Btc
Il.2
43.6
17.6
6.1
9.9
1I.,c
11
4.8
2.6
I.5
0.7
0.9
0.2
8.3
22.5
41.5
Il.7
6.2
3.5
6.2
2.4
1.4
0.8
I.0
3.3
100.0
2.09
100.0
Case study
Sicily region
% area
Btc
oioarea
Btc
10.2
35.7
37.4
3.6
6.7
6.0
4.9
2.6
1.5
0.7
0.9
0.2
6.6
2 !.5
52.4
10.3
1.7
6.1
6.2
2.4
!.4
0.8
1.o
0.3
Wood and forest
Orchard
Arable land
Meadow and pasture
Uncultivated and bush
Unproductive and urban
Total. 1968
100.0
2.08
iP?.C
-_
1.80
1.82
Table 5
Stability type of ecotope subsystems
Table 4
State of the ccotissue.
Landscape elements
Urbanized. dense
River. lake
Bare soil
Arable field
Orchard
Olive orchard
Meadow, pasture
Bush
Pine wood
Wood, forest
Total, 1968
I968
ha
86.25
18.37
45.00
942.50
600.00
290.93
90.25
166.50
17.50
235.98
2493.28
'HH.human habitat (Oh).
Ciass
Btc range
Ordination’
K-O.5
A
RC/D > 1. RS/D < I. or totally
%HH’
O!oarea zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
E&C
subsidized, or xtural very high
0.2
100
resilience
3.46
0.5-1.5
0.1
10
0.74
B
Techno-agricultural
fields. or natural
5
degraded ecotopvs. or natural resilience
0.2
1.80
1.5-2.5
lc)O
RC/D= RS/D=- 1. or semi-natural
1.5
C
37.80
100
2.4
agricultural fielc s, or semi-degraded zyxwvutsrqponmlkjihgfedcba
24.06
3.0
100
CCU iQJ Cb
11.67
2.5-3.5
0.7
90
3.62
D
i& diit ~~~~nt -~n
‘,gardens’, or semi0.9
20
natural olive wol)ds. or natural low Btc
6.68
3.5
25
ecotopes
0.70
3.5-B
5.0
30
E
RC/D < 1, RS/D > 1, or non9.46
subsidized ecotopes, or natural
85
100.00
2.08
resistance ecotnpes
‘RC. recover)?; RS, resistance;
D, disturbanre.
Seasonai distribution:
-winter
f
max
).
spring
Zoological pecuiiarity of t e river corridor:
the upstream migration of eels (,~n~l4~~~a
anand trout (Sairno trutia) has
about 10 years ago. with the bui
ax
ilicrS: submediterranean,
ciiof the dam. Some carp ( Qprinus carpio) seem
ax of Qtrerciolr ilkis, mixed with Qliercl4.spzrto remain in the reservoir. No peculiartty in
ks~ens, in this case dominant; submontane
amphibians and insects.
climax of Quercion zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
prrhescenti- pelreae. River
The urbanization of the two sma’ll towns has
corridors: Poprt~etlJllz- Salicetzrin
associations
remained compacted around their old centers,
(Tommaselli. i 973: ignatti, 1988 ).
which show the same orientation. These towns
Synthetic description of the vegetation along
have a population of about 5 100 each.
207
c: ecotopes, 1987. Note the quite different distribution from Fig. 1C. The two hip&er classes of ecotope
t-er less area today. aboue - 6%. zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
Table 7
Variation ofecotope
and 1987
Class
subsystems
per class of stability in I968
i 968
ha
1987
%
ha
%
3
C
B
K
*A
98.7
I 144.8
444.0
497.0
308.7
4.0
45.9
17.8
20.0
12.3
146.2
855.2
726.3
288.7
476.9
6.0
34.5
29.0
1 I.5
19.0
Total
2493.3
100.0
2493.3
100.0
805.7
32.3
765.6
30.5
.A
n plus
E
river system becomes visible and measurable
in this area.
The case study area (25 km2) covers the
principal part of the Magazzolo River Basin
north to the reservoir (40 km’) (Fig. 2). The
This ;t l
Jys;z could be summarized in three
principal steps: (a) grain an
landscape; i b) differences i
ogeneity; (c ) cornposit: .n
mosaic, today and ir. the recent past. zyxwvutsrqponmlkjih
(a) Grain and porosity
All the elements of the landscape
patches) had been surveyed by orderi
in four classes: less than 0.5 ha, 0.5- 1.O
2.0 ha, greater than 2.0 ha. The distri
(i.e.
Fig. 12. Network connectivity, today. On over 2 _y theoretically
At least 30 to 36 new links need to hi restored.
possible links. 5 1 ri~w corridors plus rcn v.xmdcd patches exist.
ind
0
,
0
0PrIMuM
zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
ENVELOPE
_-
___
_
I
0
-.
---+-+--$~~
It
L-l
zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
0’
0
+
1++_..+ “____
b
d,
Ind.
these spatial patterns
itional human utilizations.
of wooded and forested
err (i.e. porosity), reprem a clear linkage with the
inance (D): zyxwvutsrqponmlkjihgfedcbaZYXWVUTS
, 0.183.
Regions of low Btc: AA, 0.133; BB, 0.303.
(c)Lartdscapr mosaic
The analysis of an ecotissue needs also to investigate the map of the distribution of the
fkient convergence betwee: strustural
tdee to understand this environmental
and functional
design.
character of the landscape. Compare this figure with
pose three indexes have
(Turner,
1989), and biolog
tc) defined on the basis of. ( I ) the
f resistance stability, (2 ) the princiof ecosystems of the biosphere, and
( 3 ) their metaboiic data (biomass, gross prirespiration ) (Ingegnoli,
mary production,
19912):
Btc,=1/2
The ecological evaluation of the transformation pattern of the case study ecotissue
needs some ecological indexes, to be applied
on the landscape mosaic maps. To this pur-
(a,+b,)=R,
(Mcalm-‘year-‘)
where. zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONML
al= (R/GP)J(R/GP),,,
and b,= (dS/
S),i,/ (dS/S), (R is respiration, GP is gross
production, dS/S= R jB denote maintenance
to structure ratio, i denotes principal ecosystems of the biosphere, S is entropy, B is
biomass ) .
Four tables were elaborated with the aim of
studying the recent changes of the ecotissue,
referring to the 1968 and 1987 local landscapes (Tables 2 and 4) and their comparison
zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
loo0
900
@OS
700
602
SC3
40:
?OJ
q-.
."I
:
100
’
0
of a right landscape conxu-gcnw beturen str~~cture an
Fig. 15. Change of the fractal dimension rcrerrcli w Ar: ;c;:wstion
function. The \.ari;ltion of zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
fractal
dimtznsion ( D) must hc mlnilnum. in order to maintain the ecological character of tf-le lands~apc.
I
:s
I
f
I
I
I
I
i I
I 1
1I
I
:
2ai
I
1
’
_I
/
BTC
I, zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
--
_
BTC
:
1 .I
1.2
Fig. 16. Gen eraI control gf the lscal landscape evolution.
: see test ).
1.4
3
1
LOCAL
‘REGIONAL
1.6
1.5
FOREST
r
1.:
AREA
in order to check the state transition
( i.e. its movement
) of the ecotiswe
se reasons, it is intere~tin
rincipal geomorpholog-
ering methods, is capa-
continuous
distribution does not remain good enough, because no high stability ecotopes are present
where the landscape structure is vanishing, especially in the central part af the ecotissue. In
the absence of higher stability ecotopes, it is
obvious that even normal disturbances (e.g.
buffer zones between the river, its
At this point vve met a new problem:
urn requirements for co
restoration, not only for economic reasons, but
in order to avoid too great a change in the type
of local landscape. It is thus necessary to conpropriate connections of t
easure of the network co
ity allows us to resolve the above-mentioned
problem.
Existing river corridors and wooded patches
must be (Fig. 12) connected by suitable new
links mainly in the clay areas. In over 265 theoretically possible links, there are 5 1 river corridors plus te wooded patches. The experience suggests
at at least 30 to 36 new links
have to be restored. For this purpose, in order
to control the connectivity of the landscape, the
construction of an optimum envelope
plotted with the help of two indexes: index zyxwvutsrqpo
1 is
a measure of linkages, and index 2 is a measure
of circuitry of the graph (Fig. 13 ). The higher
thresholds limit the change of the type of landscape, the lower ones avoid a negative circuitry. Today the connectivity value is completely
outside the envelope; the minimum interven-
C+onscqucnccs for I%otic Divcrslty and Ecologrcal Ffou s
Spnngcr-Vcrlag
Nch ‘I’ork.
lngv~n~ll. t’., 1980, Ecologra c ProgettaJlonc. C‘I JSL. hl~lano.
Ingcgnoll. c’., 199 la, Human zyxwvutsrqponmlkjihgfedcbaZYXW
Inc lwwx
ITI landscape change.
thresholds of mctastanlllt>. fn, 0 Rakcra f f-:ditor 1. ~-CTrcgtr1al and Aquatic Ecosystems, Ikrtllrbatron and
orwood. NCM I’i)rE\ pp X13-3.19
99 1b. Ecologicsll PIannmg on Ab
Lombard!: a Case Stud! from the East
Magglorc, In: Procccdlngs of the European
on Practical Landscape Ecolog>. Vol. 1:
IAI zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
restore the clay zones (
Ingcpnoli, V., 1992, asi s,.wntifichc dell’cc
g io c ’ ~113 im po rta wn
tc o ruza c applicat
55(A): z?c>-4.3.
efe
ces
., 19S4. Ecologic dc la \‘t@tation Tcrrcstrc. Masson. Paris.
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Odum. E.P.. 1989. Ecology and our Endangered Life-Suppcrt
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