(993l. of BiogeographY 20'39H12 lourrtal 2 Gd" ilty {iammals, vegetation and the initial human setflement of palaeoecological tne Mediterranean islands: a approach 'rofion: l Afric¿, S c s Ü I a Institut Ur- und F rühgeschich¡e, Albert-Ludn'igs- Universit¿it, D7800 F re i. llins. \\ rl r, r. M für iburg Br., Gennant' ' ¡on. II1. J, shop qt .ur A, ¿l carbon of the lack of carnivores. the genetically fixed behaviour bon patterns for flight and attack are lost in island endemics. +7. u.s. During the Middle (Corso-Sardinia) and Upper Pleistocene, suspected or established (Sardinia, Cyprus, A Sicily) invasions of Homo sp. led to the near-complete ry extinction of the unwary endemic fauna. Some islands \rc$. as are the reasons for the extinction of the (Sicily, Corso-Sardinia) were repopulated by swimming t)uatcrìaü fauna. Small arboricole mammals may have ungulates which were exterminated by later human inva- n,,checi the islands on vegetation-rafts. Some larger mam- sions. For lack of game, a permanent human settlement mirls, like Myotragus on the Balearic Islands, Prolagus on was nearly impossible before the Neolithic. All extant wild Srrdinia, and possibly endemic deer on the Aegean islands, ungulates on the Mediterranean islands are feral domestic irruld be relics of the desiccation of the Mediterranean on animals, or continental game with intact behavioural pat- rhc Mio/Pliocene border. Hippos, elephants and giant deer terns introduced for religious or hunting purposes during alched the islands by swimming. At the a¡rival of new the Neolithic or later. None of them has Pleistocene ances- rpcies, older endemic species became extinct by ecologi- tors on the islands. rirl competition. Overpopulation consisting of a single or rcw species with corresponding damages to the vegetation KeY words. Mediterranean geology, island colonization, lctl to dwarfìng and an adaptation to hard foods. Because mammals, extinctions, human settlement, palaeoecology. THE PROBTEM Palaeontologically. there are no reliable traces of hominids on the Mediterranean islands prior to Upper Pleistocene (Juaternary mammalian faunas of the Mediterranean islands Honto s. sapiens. Archaeologically, there is evidence for the I Jrc poor in species, as all insular faunas are. Pleistocene presence f of Homo on Sicily and Sardinia in the Middle I \nliìll-animal faunas on the islands were similar or identical I 'pical Pleistocene. B.H. ro those of the Holocene. By way of contrast, the larger ter- I shall try to explain the striking differences in the rcstrial vertebrates not only were ol different species than launal evolution -'.;:i Quaternary of the Meditenanean islands. ,rocedu¡c¡.;fl r\tant ones, but the Pleistocene ungulates, carnivores, giant and any human involvement in them. I shall point out the rodents, torloises and flightless swans lrom the islands also ecological disturbances (Crosby. 1986) caused by the ,iil'ttred from their conrinental relations (Kahlke, 198 l; islands' successive colonization by different mammals. in- Kowalski, 197 1, 1986; Kurtén, 1968). Not one species of , cluding man. For this we must consider the general geology hrge Pleistocene mammals, flightless birds or giant tortois- (Seibold & Berger, 1982), the platetecronics (Briggs, 1987; ¡ cs survived on the Meditenanean islands. Extant ungulates, Closs, Giese & Jacobshagen, 1986; Le Pichon et al.,1982) rrdents and carnivores are of the same species as continental and the morphology of the bottom of the Meditenanean (Le ()nes. or may at least be classified as subspecies. None of the Pichon & Biju-Duval Sihe ahho), the genetic background of c\tant island ungulates are present in the islands' animal behaviour (lmmelmann, 1983; Lorenz, l969a,b), l)lcistocene record, whereas on the continents they are well and many other problems ftrr which the fossil record by I'nown tiom Upper Pleistocene contexts. itsellcannot provide the answers. It can only be achieved by On some Mediterranean islands, e.g. Sardinia, a com- a rather general approach, and many problems still remain to erns plete of change in larger vertebrate faunas occured at some be solved. Ve ttme during the Pleistocene. On oihers, like the Balearic Palaeontology is by no means an adequate instrument to lslands, such changes have been observed. questions not resolve of causality; archaeology even less so. r^ \J 399 -( -ii.\t'. ,'"1 400 wilhetm schüte Fossil records, be they archaeological or palaeontological, Eurasia. About 2-5 million years ago the Alrican and Asian are by nature incomplete and lull of gaps. In interpreting continental blocks collided where Mesopotamia is today. their flnds, palaeontologists and archaeologists tend to That er ent denotes the birth of the Meditenanean as a more ignore the fact that most potential fossils or artefacts do not or less isolated Sea. which has been growing smaller ever even survive to be studied. Biological invasions (Crosby, since. The biotic interchange of the Eurasian and African 198ó: Groves & Burdon, 1986: Higgs, l98l) may leave so flora and fauna via the Arabian land-bridge which followed few direct traces that these are readily overlooketl, regard- the collision, antl the beginning uf separution uf the Indo- less of how grave the ecological consequences were. This is Pacific and Meditenanean-Atlantic regions mark the especially true if only a small area of land such as an island Oli goce ne/-lvf iocene border. is concerned. Accretionary wedges form in compression-zones of Most palaeontological sites on the Mediterranean islands oceanic plates. These wedges may become attached to, be are not reliably dated, and the same applies to palaeolithic pushed on top of. or be subducted under neighbouring archaeological sites. One should not forget that the state- plates. South of Crete a system of such accretionary wedges ment 'of lower Middle Pleistocene age' covers several runs from the southern tip of Italy to the Gulf of lskenderun. hundred thousand years. Less reliable still are dates for Cyprus. which marks the highest peak of this system, was extinctions. This of course does not only pertain to the created from the old Tethys sea floor and marine sediments. Mediterranean islands, but is a worldwide problem. The dis- Monte Gargano and Toscana-Elba have a history similar appearance of a certain species from the fossil record does to that of Cyprus but merged with the forming Appennine not necessarily mean that the species became extinct, it only Peninsula in the Middle or Upper Tertiary. The shelf proves that it was no longer recorded. The fossil records of between Elba-Capraia and the Toscanan coast was exposed numerous extant species have either million-year gaps or are during times of low sea levels in the Pleistocene. Southern I altogether non-existent. In recent years, the search for the Calabria was an island until the Middle(?) Pleistocene. point research the Eolian and Liparian Islands, Ustica, I causes of extinctions has been a focal of Stromboli, '(Alvarez et al., 1980: Donovan, 1989: Nitecki, 1984; Pantelleria, and some islands in the southern Aegean were Wolbach, Lewin & Anders, 1985), especially for the formed by volcanic activity. Thera-Santorini is the most Quaternary (Martin, 1984; Martin & Klein, 1984; Martin & famous of the islands of a purely volcanic origin. Wright, l9ó7, Olson & James, 1982; Remmert, 1989; A. With the exception of Elba, these islands of marine origin Schüle, 1989; W. Schüle, 1990a,b, 1992; Vigné, 1987; were never connected to any continent. only for the (geo- Ziswiler, l9ó5). logically) short time-span of the Upper Miocene In searching for the causes of faunal changes and extinc- (Messinian) Salinity Event, 5 or 6 million years ago, could tions, we shall take an hypothetical and actualistic approach, there have been land-connections between the islands and consider the possible biotic and abiotic consequences of continents, but most islands of r¡olcanic origin had most island colonizations, and check the results of thes€ consider- likely not yet existed at that time. ations against the fossil and archaeological record. Comparisons with islands outside the Mediterranean will be prob- drawn when they aid the understanding of particular lslands of uncertaln land-connect¡ons lems. Insight into such small-scale processes as the colo- nization of islands by different species may, in the end, help Crete is part of an island-arc of non-volcanic origin which us to understand the effects of the human colonization of probably owes its formation to the subduction of Mesozoic Earth. ocean-bottom under the Aegean part of the European megaplate (Jacobshagen, l9S6J. tt is unlikely that Crete was { I ever connected to the mainland in the last 5 million years. It THE MEDITERRANEAN ISTANDS was isolated by deep canyons during the Messinian Salinity Obviously, islands are not all alike. Some islands arose from Crisis, and the sea between Crete and the Cycladic Islands is coral-reefs, submarine volcanoes. transoceanic ridges or far too deep to har e been drained during Pleistocene low sea forming accretionary wedges; others were once parts of con- levels. tinents. Which life-forms a particular island is able to sus- The situation on Kásos and Kárpathos is more or less the tain depends in no small measure on the geology of that same. Only the islands at the extremities of the arc, Kithira island. So in order to understand the biological processes on in the west and Rhodos in the east, were connected with the the Mediterranean islands, we must first look at their geo- mainland during periods of low eustatic sea levels. logical history. Malta-Gozo and Lampedusa emerged by tectonic uplift of old Tethys sea-bottom overlain by marine sediments of lslands of ocean¡c or¡g¡n Mesozoic and Lower Tertiary age. Their unfolded Transoceanic ridges are typical of spreading ocean basins Oligocene globigerine limestone was deposited about 2000 and of forming or growing oceans.