1992 for Saddlebacks on several islands; Williams .... genetic considerations (Williams 1986; Crouchley ..... Melody Serena, Clare Veltman and Euan Young.
New Zealand translocations: theory and practice DOUG P. ARMSTONG' and IAN G. McLEAN2
One of the most common tools in New Zealand conservation is to trans!ocate species to new locations. There have now been over 400 translocations done for conservation reasons, mainly involving terrestrial birds. Most translocations have been done strictly as management exercises, with little or no reference to theory. Nevertheless, translocations always involve some underlying theory, given that people must inevitably choose among a range of potential translocation strategies. We review theory relevant to translocations in the following areas: habitat requirements, susceptibility to predation, behavioural adaptation, population dynamics, genetics, metapopulation dynamics, and community ecology. For each area we review and evaluate the models that seem to underpin trans!ocation strategies used in New Zealand. We report experiments testing some of these models, but note that theory underlying translocation strategies is largely untested despite a long history of translocations. We conclude by suggesting key areas for research, both theoretical and empirical. We particularly recommend that translocations be designed as experimental tests of hypotheses whenever possible. Key words: Reintroduction, Translocations, New Zealand, Species Recovery.
INTRODUCTION "'T'
.iRANSLOCATION" is the inientional movement of living organisms from one area with free release to another (IUCN 1987; DOC 1990). New Zealand has a long history of translocations, conducted for many reasons. Maori colonists brought Ki ore (Pacific Rat Rattus exulans) and many plants to New Zealand as food sources. Europeans subsequently brought a huge range of organisms to New Zealand, for agriculture, horticulture, forestry, hunting, fishing, fur, biological control, and "enhancement" of the biota. Over the last 100 years, translocations have been used frequently for conservation. Translocations can have at least four conservation objectives (Towns et al. 1990b): (1) restoring species to their former ranges, (2) restoring whole communities, (3) saving species threatened by extinction, and ( 4) salvaging populations threatened by operations such as logging. The first known "conservation translocations" in New Zealand were Richard Henry's attempts in the 1890s to establish Kakapo Strigops habroptilus and Kiwi Apte1yx spp. on islands in Dusky Sound (Atkinson 1990). There have subsequently been over 400 translocations involving 40 different taxa (mostly birds), with a rapid acceleration in the number of translocations over the last 30 years (Saunders 1995). Translocations are particularly important to New Zealand conservation, given that many native plants and animals are still declining and that n1any offshore islands are available that can be used as natural sanctuaries. Island translocations have already saved son1e birds from extinction (Little Spotted Kiwi A. oweni, South Island Saddleback Philesturnus c. carunculatus, Black Robin Perroica traversi), en1phasizing the value of 1ranslocations as a conservation tool.
The recent acceleration in the number of translocations is partially due to an increasing number of islands becoming available, due primarily to eradication of introduced mammals. Improved techniques are resulting in mammals being eradicated from progressively larger islands (e.g., cats Felis catus from Little Barrier and Brush-tailed Possums Trichosurus vulpecula from Kapiti, Veitch and Bell 1990; Veitch 1995), with the experience to date suggesting that resources and cultural issues rather than technology will be the primary constraint on removals from large islands. Mammals are also being eradicated from fenced "islands" on the mainland (such islands are in place or in development at Te Anau) Twizel, Wellington, Banks Peninsula, North Cape and Te Kuiti). Translocations have a broadening taxonomic base, involving plants, herptiles and invertebrates in addition to birds. There will also be more translocations of captivereared animals, something that has happened little in New Zealand to date (Saunders 1995). Despite a long history of translocations in New Zealand there is little understanding of consequences; i.e., the causes of success or failure. This is not a criticism of the people involved, whose dedication has been nothing short of extraordinary. However, most translocations (in New Zealand and world-wide) have been conceived as one-off management exercises, and have not been designed to address research objectives. Consequently, there have been few publications, little post-release monitoring, and few detailed records of procedures followed (IUCN 1987; Griffith el al. 1989; Towns et al. 1990b; Maunder 1992). An improved knowledge base for translocation biology requires greater en1phasis on infonnation exchange and research. Benefits are 1naximization of the success of each
'Depanment of Ecolog), Mas;ey University. Private Bag l l'.!22. P~lmcr~aoo North. New Zc.iland 'Department of Zoology. Umversny ui Camcrbmy. P.CJ. f:l
