Populations: re-introductions - Restoration Ecology - page 82

7

Populations: re-introductions

Sipke E. van Wieren

7.1 Re-introduction of species and
restoration ecology

the International Union for the Conservation of
Nature's (IUCN's) Species Survival Commission has
developed guidelines (IUCN 1995), which are imple-
mented in the context of the IUCN's broader policies
pertaining to biodiversity conservation and sustain-
able management of natural resources. According to
the IUCN, the principal aim of any re-introduction
should be to establish a viable, free-ranging popula-
tion in the wild, of a species, subspecies or race, which
has become globally or locally extinct, or extirpated,
in the wild. The population should be re-introduced
within the species' former natural habitat and range
and should require minimal long-term management.
The objectives of a re-introduction may include the
enhancement of the long-term survival of a species,
the re-establishment of a keystone species in an eco-
system (or an emblematic species from a cultural
point of view), or the maintenance and/or restoration
of biodiversity in (semi-)natural landscapes. In the
literature, both the terms re-introduction and trans-
location are being used. Strictly speaking these terms
do not mean exactly the same thing. A re-introduction
is an attempt to establish a species in an area that
was once part of its historical range, but from
which it has been extirpated or become extinct. Re-
establishment is often used as a synonym, but implies
that the re-introduction has been successful. A
translocation is a deliberate and mediated movement
of wild individuals or populations from one part of
their range to another.
Community, ecosystem and landscape changes and
transformations carried out in the past may have
great consequences for the success of re-introduction
attempts because the ecosystem or habitat at issue may
have become permanently unsuitable for the species

According to the Society for Ecological Restoration (SER
International; SER 2002), ecological restoration is the
process of assisting the recovery of an ecosystem that
has been degraded, damaged or destroyed. The very
first 'attribute of restored ecosystems' mentioned in the
SER Primer on Ecological Restoration (SER 2002;
www.ser.org) is that 'The restored ecosystem con-
tains a characteristic assemblage of the species that
occur in the reference ecosystem and that provide
appropriate community structure.' In this context,
intended introductions of species are an important tool,
because dispersal is very often a major constraint, esp-
ecially in highly fragmented habitats and landscapes.
Thus, restoring diversity is a crucial part of eco-
logical restoration, but while the SER (2002) considered
it primarily in an ecosystem context, the issue of the
re-introduction of species has also frequently been
considered at the species, or subspecies, level. For
example, Falk et al. (1996), in their volume on strat-
egies for the re-introduction of endangered plant
species, considered re-introductions also as a conser-
vation tool. In this chapter I will examine experiences
with re-introductions, independent of whether they
have been performed in a strict restoration context
or rather as a species-conservation tool. Indeed, re-
introductions are nearly always experiments and the
science of re-introduction is in its infancy, which urges
us to learn from earlier experiences (Falk et al. 1996).
In response to the increasing occurrence of re-
introduction projects worldwide and to help ensure that
the re-introductions achieve their intended conserva-
tion benefit, the Re-introduction Specialist Group of

82