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Figure 4. Influence of climate change on all the sequential transitions of a successful invasion process.
(Walther et al., 2009).

Effects of climate
The Mediterranean Sea is land-locked and its dynamics are mainly linked to climate.
Its geochemistry depends on marine dynamics, on Atlantic input and on atmospheric
and terrestrial sources of matter of natural or anthropogenic origin. From a
geographic point of view, with a mean depth of about 1500 m and a coastal zone (O-
200 m depth) covering about 20% of the area, it cannot be considered as a coastal
sea (Bethoux and Gentili, 1996). The evolutions in physical and chemical
characteristics occurring in offshore waters as well as in coastal biological species
showed that the Mediterranean Sea reacts rapidly to environmental changes. These
evolutions may be used as signatures and modelling constraints of changes that
occurred in the coastal area. Examples of ecosystem evolutions may be found in the
Eastern Basin where more than 350 species have immigrated (Por, 1990; Galil, 1993).
This event was coupled with the increase of Red Sea inflow (after the deepening and
widening of the Suez Canal and the vanishing of salinity effect along the Bitter Lakes)
and the disappearance of Nile low salinity water along the Egyptian coast
consecutive to the High Dam closing in 1964.
From 1985 to 2006 the temperature in the upper layer of the Mediterranean
-1
Sea has been increasing at an average rate of 0.03°C year for the Western
-1
Mediterranean Sea and 0.05°C year for the Eastern Mediterranean Sea (Nykjaer,
2009). Abrupt rising temperature since the end of the 1990s has modified the
potential thermal habitat available for warm-water species, facilitating their
settlement at an unexpectedly rapid rate, and it has been shown that the
introduction of tropical alien species has been exacerbated by the warming of the
Eastern Mediterranean Sea (Raitsos et al., 2010).
The rate of Lessepsian non indigenous species extending their distribution in
the Adriatic Sea has doubled the last two decades. It seems that the changes in the
patterns of water exchange between the Adriatic Sea and the Mediterranean as well
as a rise in the eastern Adriatic Sea surface temperatures in 1985-1987 and 1990-
1995 are correlated with the occurrence of Indo-Pacific species, some of them for