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camelids, and American cheetah (Donlan 2005, Donlan et al. 2006). Donlan et al. suggest
that introducing large African and Asian vertebrates to North American landscapes will not
only help to ensure their long-term survival, but will also restore evolutionary potential by
increasing the number of individuals worldwide, thereby increasing the chances of generat-
ing new phenotypic and genotypic variants. As many of these species are already present in
zoos in the USA and attract large numbers of visitors, Donlan et al. anticipate popular sup-
port for such reintroductions. Modelling experiments suggest that based on climate factors
alone, some regions of the American southwest and southern Great Plains might be suitable
for cheetah and lion, but that suitable climate space for Asian elephants is much more limited
(Richmond et al. 2010). Furthermore, it can be argued that the present-day rural landscape of
cattle ranches, cereal monocultures, and plantations is less natural than one populated by
species that, though exotic, restore some of the ecological processes and possibly vegetation
structures that were lost during the Pleistocene extinctions.
These bold plans have also met with scepticism and various scientific, practical and soci-
etal objections have been raised, including the difficulty, expense, and welfare concerns over
introductions (Rubenstein et al. 2006, Caro 2007). In a review of Donlan's arguments, Ruben-
stein et al. (2006) concluded that Pleistocene re-wilding with exotic species will not restore
the evolutionary or ecological potential of native North American species nor extinct Pleisto-
cene megafauna and their ancient ecosystems, but may instead jeopardize indigenous spe-
cies and North American ecosystems. They argue that biogeographic assemblages and
evolutionary lineages would be co-mingled in novel ways; new parasites and diseases could
be introduced; and food chains would be disrupted. Rather than a recreated, Pleistocene
landscape, the result might be a novel ecosystem with unique species compositions and
unpredictable ecosystem functioning (Figure 3.4) (Rubenstein et al. 2006). Many introduced
species have unexpected effects and concern has been raised over 'Frankenstein ecosystems'
(Oliveira‐Santos and Fernandez 2010).
An expensive Pleistocene park could also divert funds away from in situ conservation of
African and American fauna (Dinerstein and Irvin 2005, Rubenstein et al. 2006). Reversing
local extinctions is less risky and ecologically more beneficial and there is therefore no
Pleistocene
re-wilding
?
?
Pleistocene
Extinctions
“Historic”
wild ecosystem
“Contemporary”
wild ecosystem
“Re-wilded”
novel ecosystem
Figure 3.4
Re-wilding might create novel ecosystems, because the Holocene climate is warmer than
the Pleistocene and different and anthropogenic factors like land use and exotic species affect contem-
porary ecosystem processes (Rubenstein et al. 2006). Reproduced with permission from Elsevier.
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