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M. Masseti: Homogenisation and the loss of biodiversity of mammals of the Mediterranean islands 185
Characters of the extant insular mammals:
generalist colonisers of pre-deserts
As already observed, the majority of the non-volant
mammals which occur today on the Mediterranean
islands can be considered as having been imported by
man, except in the cases of the islands that were joined
to the nearest land masses during the Late Pleistocene
(Masseti 1998). With a few exceptions, the extant fauna
reveals a distinctly homogeneous composition of ele-
ments, being no longer characterised by any of the
endemic taxa previously reported (Masseti 2002b). Its
structure is balanced by the presence of carnivores,
essentially made up of continental species. In any case,
the extant mammalian composition of the Mediterranean
islands consists almost essentially of species that are
more or less common to the present fauna of the rest of
the Mediterranean region, and shows a generic conti-
nental origin influenced by the faunal composition of the
nearest mainland (Alcover 1980, Sanders and Reumer
1984, Blondel and Vigne 1993, Masseti and Mazza 1996,
Masseti 1993b, 1998, 2002b, 2006). Today, the most
common insular carnivore is, for example, the aforemen-
tioned stone marten (Masseti 1995a), a species regarded
as a follower of human cultures, which probably entered
Europe from the continental Near East only at the end of
the Pleistocene or in the early Holocene (Kurte´ n 1968,
Anderson 1970, Sala 1992, Masseti 1995a, Yalden 1999).
The non-flying terrestrial mammals which today inhabit
the Mediterranean islands are mainly represented by
generalist species, animals which are able to thrive in a
wide variety of environmental conditions and can exploit
a range of different resources. When environmental con-
ditions change, generalists are better able to adapt, while Dragonada (Dhionysiades archipelago), and Gavdos,
specialists tend to fall victim to local extinction much
more easily (Townsend et al. 2003). Since these are
almost exclusively species of continental origin, they are
also those that manage to react better to the conditioning
imposed by human cultural control and even to the
effects of domestication. It is scarcely surprising that
ungulates, such as the wild boar, the Asiatic mouflon,
and the red deer, which were imported as tamed and/or
semi-domestic livestock onto the islands since Neolithic
times, occasionally escaped from their guardians’ con-
trol, giving origin to the free-ranging population, the
descendants of which persist up to the present time.
Back in the wild, they maintained the morphological
patterns of their Near-Eastern ancestors. In fact, as
observed by Ryder (1983), the recognition of the origin
of domestication is complicated by the fact that the first
domestic animals did not differ greatly from their wild
counterparts.
There are even phytophages of small and medium size
that can survive in the most hostile of insular habitats,
comparable in terms of both environmental and trophic
characteristics to veritable pre-deserts. These are wild
goats, hares and rabbits (Masseti 2003a, Masseti and De
Marinis 2008). The islands of Youra, Antimilos, Crete and
Montecristo are still inhabited today by populations of
wild goats that feature the morphological patterns of
Capra aegagrus (Erhard 1858, Reichenow 1888, von
Lorenz-Liburnau 1899, Toschi 1953, Zimmermann 1953,
De Beaux 1955, von Wettstein 1955, Couturier 1959,
Schultze-Westrum 1963, Kahmann 1959, Masseti 1981,
Groves 1989, Ciani and Masseti 1991, Masseti 1997,
Ciani et al. 1999) (Figure 20). Other historical populations
of wild goats of the Mediterranean islands, such as Sam-
othrace (Greece), Tavolara (Italy) and La Galite (Tunisia),
became extinct in the course of this century (Ciani et al.
1999, Masseti 2009b). Apart from Crete, all these popu-
lations survive in territories characterised by very low tro-
phic conditions, and without any artificial food supply.
And yet, if we consider some of the biogeographical
parameters of the islands, such as area and altitude, as
indirect indices of habitat heterogeneity (iihh) (Table 3),
we note that wild goat populations can still prosper in
small rocky islands with a mean altitude of less than 600
(571) m above sea level, and a mean surface area of less
than 10 km2 (9 km2) (Masseti 2003a) (Figure 21). Survival
in such peculiar insular environments may also be ren-
dered possible by the integration into the diet of mineral
salts, which are assumed both by licking the deposits
that form on the foreshore and by consuming the excreta
of birds. For example, we can cite the case of the wild
goats of Montecristo which occasionally feed on the
excreta of yellow-legged gulls, Larus michahellis micha-
hellis Naumann 1840. Several years ago, it was possible
to document this feeding behaviour directly on the small
island of the northern Tyrrhenian Sea, where the wild
goats are in the habit of licking the excreta deposited by
the gulls on the rocks that they use as roosts (Masseti
2009b).
Hares can survive on even smaller islands than wild
goats, with an area of 3–3.5 km2, as shown by the pop-
ulations that still inhabit the islets of Ghiannissada and
Chrissi and Koufonissi, respectively, off the north-eastern
and the southern coasts of Crete (Masseti 2003a, cf.
Masseti and De Marinis 2008). Rabbits too can now be
found on many Mediterranean islands of even much
smaller dimensions (Masseti and De Marinis 2008). They
can, however, damage vegetation, accelerate soil denu-
dation and erosion, and may ultimately be responsible for
the decline or extinction of various species of reptiles and
birds (e.g., Martin 2002, Courchamp et al. 2003, Chapuis
et al. 2004, Genovesi 2005). Consequently, in view of the
Figure 20 Pictorial representation of the Cretan wild goat or
agrimi, Capra aegagrus cretica Schinz 1838, from the 16th
century Ulisse Aldrovandi Fond of the University of Bologna.