Environmental Engineering Reference
In-Depth Information
Rising to heights of 2100 m, Mount Lebanon is a critical habitat for the Lebanese
cedar in Lebanon. The species is not threatened at a global level, but only small
patches remain in Lebanon. Outside Lebanon there are two major groups of
Cedrus
atlantica
populations, one distributed through the Rif and Middle Atlas mountains
in Morocco and the other through the Algerian Tell Atlas and Aures mountains as
well as the Middle Atlas (Terrab
et al.,
2008).
In the Madonie mountains of Sicily there are relict forests of
Ilex aquifolium
and
a high number of endemics and narrow endemics. The active volcano of Moun-
tain Etna in the east of Sicily is also rich in endemics such as
Astragalus siculus
,
Genista aetnensis
and
Betula aetnensis
. The significant difference in the vegetation
between the Madonie mountains and Etna reflect their vegetation history. Madonie
has a well-developed Tertiary vegetation while Etna shows a post-glacial vegeta-
tion (Pignatti, 1978). The mountains of Sicily are the southern distribution limit for
a number of northern and central European species such as beech (
Fagus sylvat-
ica
), which is widely present in the Nebrodi mountains, and yew (
Taxus baccata
)
(Benedetto and Giordano, 2008).
6.3.1 Endemism
Both insularity and mountain terrain are considered to be significant causes of high
endemism. The analysis of data by Medail and Verlaque (1997) for comparable
territories in the Mediterranean and throughout southern Europe showed that:
mountain isolation has generally been more favourable to endemism than in-
sularity;
often the degree of endemism decreases as floristic richness increases;
rates of endemism range from 10% to 42%.
Rates of endemism of over 20% occur in the Baetic-Rifan complex on either side
of the Strait of Gibraltar, in the Middle Atlas and High Atlas in Morocco, in the
Iberian Sistema Central, in the Pindos Mountains of Greece, in the southern moun-
tains of Turkey (Taurus and Amanus) and the Lebanon mountain range (Medail and
Quezel, 1997). According to Dominguez
et al.
(1996), 60% of the Iberian endemic
flora occurs in high mountain habitats. For example, in the Pyrenees chain there are
180 endemics confined to the alpine zone (Gomez
et al.,
2003), while the alpine
communities of the Apennines contain more endemic and rare species than their
eco-functional counterparts in the Alps (Pedrotti and Gafta, 2003)
Mountain endemism may be the result of specific and localized factors such as
discrete orogenies and rare substrates (Kruckenberg and Rabinowitz, 1985; Major,
1988). Limestone, serpentine and gypsum are well known to botanists for being
associated with this phenomenon. For example, in Greek mountains limestone
and serpentine in particular host the largest concentration of endemics (Strid and
