Holocene are extinct, and a further nine reptile
species are today found only on the off-lying
islands, among them the ‘living fossil’ tuatara
(Sphenodon punctatusandS. guntheri), the single rep-
resentatives of the order Sphenodontia (the rest of
the lineage died out by 60 Ma). These offshore
island populations are relictual distributions follow-
ing extinctions from the mainland consequent upon
Polynesian settlement. A similar pattern is found in
the Caribbean, where several species became extinct
during aboriginal occupation on islands such as
Hispaniola and Puerto Rico; others have become
extinct within the past century. The large herbivo-
rous iguanine Cyclurahas become extinct on a num-
ber of islands in the recent past, and the giant
Cyclura pinguis, lost from Puerto Rico during the
Holocene, survives on the small offshore island of
Anegada. Among the lost reptiles of the Caribbean
were giant tortoises (Geochelonespp.) from the
Bahamas, Mona island, and Curaçao. Giant tor-
toises also once occurred on Sicily, Malta, and the
Balearic islands in the Mediterranean, as well as in
the Canaries, and on the Mascarene islands. Their
disappearance from the latter followed shortly after
human contact, but in the Mediterranean the role of
humans in the losses is not yet so clearly established
(Schüle 1993). The Canaries, in the eastern Atlantic,
lost a number of lizard species following their colo-
nization by the aboriginal Guanches between 2500
and 2000BP. In the Canaries, fossil lizards are found
in association with human artefacts, but lizards
were probably not a major item of the diet, and the
introduction of commensals, such as rats, dogs,
goats, and pigs, was probably of greater significance
in the demise of the largest species. Interestingly,
populations of two Canarian giant lizards (Gallotia
simonyiandG. gomerana) thought to have been
extinct, have been rediscovered on El Hierro and
La Gomera respectively in recent years: examples
of so-called Lazarus species.
●The second category identified by Case et al.
(1992) was of islands with a colonial period but no
aboriginal history, on which island endemics sur-
vived to be described as living species, very often to
meet their demise shortly after. Two spectacular
large geckos, Phelsumaspp., co-occurred briefly
with Europeans on Rodrigues island in the Indian
Ocean in the late seventeenth century, until hunted
to extinction by rats and cats. A similar fate befell
many endemic reptiles on Mauritius. None of the
endemic reptile species of the Galápagos has
become extinct yet, but population densities have
declined and local extirpations, for instance, of
giant tortoises, have occurred. Land iguanas have
also been lost from Baltra and James islands, prob-
ably as a result of predation by feral dogs.
●Caseet al.’s (1992) third category was of islands
with no permanent human settlement to date. Such
islands are generally too bleak or small to support
human settlement. For this reason they also tend to
support few endemic species. Losses from this cat-
egory of islands have thus mostly been local rather
than global extinctions, and of interest principally
for the insights they offer into natural turnover.Caribbean land mammals
Extinctions have dramatically altered the biogeog-
raphy of West Indian land mammals over the past
20 000 years (Morgan and Woods 1986). Of 76 non-
volant mammals, as many as 67 species (88%) have
become extinct since the late Pleistocene, including
all known primates and Edentata (Table 11.7). Late
Pleistocene extinctions are attributable to climatic
change and the postglacial rise in sea level, but most
late Holocene losses are due to humans. Thirty-
seven of the losses post-date the arrival of people in
the West Indies, which Morgan and Woods assumed
occurred some 4500 years ago (although it may
have been rather earlier than this: Table 11.5). Based
on the 4500 years time line, species have been lost at
the average rate of 1 per 122 years since human col-
onization, the figure for the preceding 15 500 years
being about 1 per 517 years. In contrast to the data
for non-volant mammals, bats appear to have fared
relatively well, only 8 of the 59 species having dis-
appeared over the past 20 000 years.
Many species of extinct West Indian mammals,
especially rodents, are common in archaeological
sites, indicating them to have been an important
part of the Amerindian diet. In common with other
studies cited here, humans brought about extinc-
tions in the West Indies through predation, habitat
destruction, and (especially in post-Columbian314 ANTHROPOGENIC LOSSES AND THREATS TO ISLAND ECOSYSTEMS