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174 M. Masseti: Homogenisation and the loss of biodiversity of mammals of the Mediterranean islands
Figure 6 Third inferior molar of straight-tusked elephant, Ele- focused their speculation on the former existence in Mid-
phas (Palaeoloxodon) antiquus Falconer and Cautley 1847, dle-Pleistocene Sicily of a pygmy proboscidean, the ele-
reported from the island of Kalymnos, Dodecanese (Greece) phant of Falconer, Elephas falconeri Busk 1867, which
(courtesy of the 22nd Ephorate of Prehistoric and Classical was only 0.90 m tall at the withers, with this being,
Antiquities, Rhodes). according to Roth (1992) and Lister (1993), the smallest
elephant that ever lived (Figure 8). A very abundant fossil
and phylogenetic affinities (cf. Raia and Meiri 2006). population (at least 104 specimens) of this species was
Dwarfism seems to be the only alternative large-sized recovered at the cave of Spinagallo, in eastern Sicily
animals have to lower selective pressure when they move (Ambrosetti 1968). Raia et al. (2003) computed the sur-
into insular settings (Mazza 2007). Most of all, the low vivorship curve for this fossil population in order to inves-
availability of resources sets insular populations under tigate both the great juvenile abundance and the high calf
the strict control of both genetic and ecological con- mortality revealed. Through the analysis of the survivor-
strains. Population densities are therefore confined ship of the elephant of Falconer, certain reconstructed
between a critical minimum number of individuals need- life-history traits, and its supposed ecology – and taking
ed to avoid extinction and a maximum number deter- into account the theory of ‘‘island rule’’ – they concluded
mined by the carrying capacity of the environment that E. falconeri veered somewhat towards the ‘fast’
(Mazza 2007). Recently, Raia et al. (2003) and Raia and extreme of the slow-fast continuum in life-history traits in
Meiri (2006) proposed a new explanation for the evolution comparison to its mainland ancestor, the straight-tusked
of body size in large insular mammals – and of elephants elephant, i.e., it was somehow r-selected. Thus, Raia et
in particular – using evidence from both living and fossil al. (2003) proposed a new explanation for the common
island faunal assemblages. They observed that the occurrence of dwarfism in large mammals living on
dimensional evolution of large mammals in different tro- islands: the interplay of competition, resource allocation
phic levels has different underlying mechanisms, result- shift and feeding niche width could successfully explain
ing in different patterns. Absolute body size may be only this pattern. Furthermore, Raia and Meiri (2006) sug-
an indirect predictor of size evolution, with ecological gested that the extent of dwarfism in ungulates depends
interactions playing a major role. Raia et al. (2003) on the existence of competitors and, only to a lesser
extent, on the presence of predators. According to Raia
and Meiri (2006), dwarfism in large herbivores is an out-
come of the increase in fitness resulting from the accel-
eration of reproduction in low-mortality environments.
In any case, I personally am of the opinion that we
should not undervalue the importance of the selection
exerted in relation to such specialisations by the principal
characteristics of the physical environment. If we pause
to reflect on the general appearance of the Mediterra-
nean islands in the Upper Pleistocene, or even only in
the Early Holocene, we realise how incommensurably dif-
ferent it was from that of today. In fact, there is possibly
no other place in the world which has been so intensively
influenced by human activity over a prolonged period as
the Mediterranean. Civilisations have been continuously
present for over 10,000–12,000 years, modifying entire
landscapes, disrupting or destroying the majority of
Figure 7 Map of the Mediterranean basin showing the islands where Middle and Upper Pleistocene remains of elephants have been
discovered.
