caballus) in Mongolia (Ryder 1993), and the addax (Addax nasomaculatus) in Niger
(Dixon et al. 1991). In any event the liberated nucleus should be large enough to
avoid demographic malfunction. Twelve individuals are an absolute minimum for an
introduction. Twenty are relatively safe. Cade and Jones (1993) detail the successful
captive breeding and reintroduction of the Mauritius kestrel (Falco punctatus). In the
1970s it was down to two breeding pairs, but by the 1990s some 235 birds had been
reintroduced and established in new habitats.
When the cause of a local extinction is unknown, and when we therefore do not
know whether the factor causing the extinction is still operating, a trial liberation
should precede any serious attempt to repopulate the area. The 20 or more indi-
viduals forming the probe are instrumented where possible (e.g. with radiocollars)
and monitored carefully to determine whether they survive and multiply or, if not,
the cause of their decline. If the latter, the factor operating against the species can
be identified and countermeasures can then be formulated. It is worth noting that a
closely related species may be used as a probe when it is too risky to use individuals
of the endangered species. For example, a successful probe release of Andean condors
(Vultur gryphus) cleared the way for the release of two California condors from a
captive breeding population in 1992 (Collar et al. 1992).
Short et al. (1992) showed the importance of probing for reintroductions of sev-
eral wallaby species. Of 10 liberations into areas where the species had once been
present but had died out, all failed. Of 16 liberations into areas where the species
had not previously occurred, about half were successful. Apparently the factors that
had caused the original extinctions of the first category were still operating. The authors
suggested that exotic predators were probably the dominant factor causing the ori-
ginal extinctions and militating against successful reintroduction.National parks and reserves are pre-eminently important as instruments of conserva-
tion. In these areas alone the conservation of species supposedly takes precedence
over all other uses of the land. Debate over whether protected areas, such as national
parks, or community conservation areas are best for conservation is probably unnec-
essary because both have their advantages and disadvantages, as outlined in Box 18.2.On one level that question is trite and it leads to the equally trite answer that parks
and reserves are to conserve nature. When the question is refined to “what are the
precise objectives of thispark,” the answer must be more concrete. However, even
the general question is not as trite as it might seem. It is instructive to follow the
history of ideas about the function of reserves, of which national parks can serve as
the type example. Here we summarize those changing perceptions as outlined by
Shepherd and Caughley (1987).
The national park idea has two quite separate philosophical springs whose streams
did not converge until about 1950. The first is American, exemplified by the US Act
of 1872 proclaiming Yellowstone as the world’s first national park. The intent was
to preserve scenery rather than animals or plants. Public hunting and fishing were
at first entirely acceptable.
The second spring is “British colonial,” with the Crown asserting ownership over
game animals and setting aside large tracts of land for their preservation. The great
national parks of Africa grew out of these game reserves, some physically and the
others philosophically. Wildlife was the primary concern and scenery came second324 Chapter 18
18.5 Conservation in national parks and reserves
18.5.1What are
national parks and
reserves for?