Wildlife translocation: Hoisting the heffalump (source: www.sanparks.org)
In the last few weeks, the word ‘translocation’ has been flying across the press, into the realm of public debate and landing in the homes of many people. But why is this? Well, it probably has a lot to do with the recently revised management protocol concerning dispersing Chacma baboon males in the Cape Peninsula (see ‘Getting Smart on Bart’). According to this protocol, the endpoint of three failed dispersals for a male is euthanasia. Translocation is being championed as the humane alternative to this endpoint.
Take Bart for instance. Bart is a dispersing male (variously regarded as villain and hero) who has repeatedly failed to integrate with a troop, choosing to spend his time alone in places like UCT upper campus and Newlands, among others. Bart is the first male selected for euthanasia under the new protocol. In response to this, many people are asking ‘Why can’t we move Bart off the Peninsula, where he can be free to live out his life naturally?’ Or, in other words, ‘Why can’t we translocate him?’ There are even farmers (see Carte Blanche) who are willing to supply their land as a release site. In response to these questions and to inform public debate, BRU decided to post some information regarding translocation.
The big picture of translocation
What is translocation?
Also sometimes referred to as relocation or transplantation, translocation is the management practice of capturing a live wild animal, transporting it from the geographic area where it currently resides to another area, and releasing it.
When is translocation used as a management tool?
Managers might opt for translocation in the hopes of saving rare or endangered species from extinction, to provide hunting and/or wildlife viewing opportunities, or to reduce human-wildlife conflict. Animals may be translocated in order to augment existing populations, to re-establish populations in areas where local extinctions have occurred or to establish new populations in areas which are suitable but have not been previously occupied by the animal in question. Where human-wildlife conflict is the reason for translocation (so-called ‘problem animals’), managers might transport the individuals involved to areas where the potential for future conflict is reduced. In this way, the managers might end the conflict without having to euthanize the animals in question.
Defining success
- Was the animal captured, transported and released without harm?
- Did the animal remain at or near the chosen site of release?
- Did the animal integrate into a social group/establish its own territory (whichever is appropriate for the species)?
- In the case of an endangered species, did the translocated animal mate and reproduce?
- In the case of human-wildlife conflict, was the conflict reduced at the site of capture?
- In the case of human-wildlife conflict, did the translocated animal stop showing problematic behaviour (that resulted in conflict at its capture site)?
Raccoon (source: www.dnr.sc.gov)
For a successful translocation, each question must be answered affirmatively. Based on these criteria it is not surprising that translocation is a difficult and stressful endeavour. While the selection of a release site, the transfer and the actual release of an animal is, to some extent, in the control of wildlife managers, what follows this can be unpredictable. For example, translocation in raccoons (a ‘problem animal’ in United States) sees a 50% mortality rate within three months and 75% within a year. Caribou (Northern Hemisphere ungulates) that were translocated into a mountain ecotype (which differed from their home range ecotype) struggled to feed in their new habitat and experienced higher mortality than local herds.
While there are unpredictable outcomes of translocation, there are certain consequences that have been documented time and again. These consequences can be both positive and negative and both sides must be considered before approving or dismissing it as a management option.
Pros of translocation
Management of Threatened/Endangered Species
Species that occur in geographically-isolated populations (e.g. where a large population has been divided by human development) can benefit from translocation as it mimics the natural movement of animals in a large, continuous population. This can be particularly important where inbreeding depression occurs. Inbreeding depression is the process whereby the fitness (or survival and reproductive ability) of animals in a population drops due to a loss of genetic diversity which occurs as a result of inbreeding. While isolated populations of common species can be managed in this way, it may be ethically unsound to use funding for common species when it could be going towards the management of species at risk of extinction. In the case of these threatened species, translocation can prove to be an invaluable management tool.
Solution to a local problem
Where translocation is not being used for endangered species, it is invariably being used to resolve human-wildlife conflict. Where an animal population is under pressure, living close to humans and having frequent negative encounters with those humans, translocation can be a solution. For example, a black-backed jackal may have a territory bordering a sheep farm. This jackal may prey on sheep. This is costly to the farmer, and results in conflict. The sheep-hunting jackal can be caught and translocated away from the area (and into a nature reserve where there are no sheep). In this way, the animal is removed from the area, and consequently, the problems that are associated with it are also removed: the sheep farmer is pleased to be rid of the jackal, the jackal is not under threat from the farmer and the conflict is resolved. It is important to note that the removal of the problem animal is not necessarily addressing the root of the problem (see below).
Assuagement of public conscience
Translocation has been described as a ‘feel-good solution.’ It is the intuitive panacea to human-wildlife conflict. It is also an ‘animal-friendly’ answer to the guilt associated with human-wildlife conflict. Perhaps it is more comfortable to see the result of this conflict to be the transfer of problem animals away from areas of concern rather than euthanasia or culling. For these reasons, the general public may be in favour of translocation. Management needs always to take into account public opinion (although it is only one of many factors to consider). In short, translocation can be a quick way to gain public approval.
Cons of translocation
Spread of disease
One of the chief concerns of translocating animals from one population to another is the unintended spread of disease. This disease transfer can occur between animals of the same species, between animals of a different species, and between people and animals. Both rabies and bovine tuberculosis have been documented to spread through translocation. This disease transfer occurred largely because wildlife managers lacked information regarding the consequences of these translocations. This type of uninformed translocation can have serious financial and ethical implications.
Is it better for the animal?
Moving a problem animal to a ‘safer’ area can be perceived to be in that animal’s best interests. However, the risks entailed in translocating animals question the validity of this perception. Firstly, injury (or even death) can occur through the capture/transport of an animal. Moving large numbers of animals simultaneously increases this risk. Following successful translocations, an animal may come into conflict with resident animals. Further, animals capable of moving large distances may leave their release site, sometimes travelling hundreds of kilometres (as is the case in the North American black bear). These movements can negate any benefits of a carefully-selected release site. They can also put the animal at risk from traffic collisions and conflicts with local residents (where animals may be shot or poisoned).
Caribou (source: www.fseee.org)
Passing the buck?
The impact of translocation must also be considered for the human population at or near the release site. This is particularly relevant for the translocation of problem animals. Animals displaying problematic behaviour (e.g. raiding), will often resume that behaviour at their release site. Translocated animals may actively seek out a familiar food source or situation (e.g. a human settlement) where they exhibit that problematic behaviour. This downside to translocation is often why it is viewed not as a solution to a problem, but rather a way of transferring the problem to some other place.
The Danger in DNA
Translocating animals between two populations that do not mix (geographically isolated from one another) has genetic implications for the target population (the population into which the translocated animals are being moved). The field of genetics is complex, and this paragraph will not suffice to cover a fraction of its complexity. Two primary concerns are outbreeding depression, and hybridisation. Outbreeding depression occurs when the adaptive phenotypic traits of an animal (e.g. fur colour, body size, territorial behaviour etc.) are not suited to its new habitat. As translocated animals mate with local animals, so the unfavourable phenotypic trait may spread through the population, putting the local population at risk.
Hybridisation occurs when two closely-related species mate to produce offspring that cannot be classified as either one of the parent species. This results in the emergence of a new species. Although this is by no means a new phenomenon, it can be problematic where endangered species are concerned. If an endangered animal pairs and mates with an animal of a closely-related species to produce hybrid offspring, it means that the endangered species has effectively ‘lost’ a reproductive individual. For this reason, hybridisation can be viewed as highly undesirable by those responsible for endangered species.
Photo: John Burnside
Bringing things home: what does this mean for baboons on the Peninsula?
Translocation is a high-risk management strategy. There are many points throughout the process where things may, and do, go wrong.
A poignant reminder of this is David’s story. In 2007, a dispersing male baboon, David was seen in Tokai and Claremont, presumably having come from Tokai forest. The SPCA took him into their care three times before transferring him to the Cape CROW (Centre for the Rehabilitation of Wildlife) in Barrydale. David was re-released in the Cape Peninsula after which he moved into the Southern suburbs. After this, he was translocated to Limietberg Nature Reserve in the Dutiotskloof mountains. He moved 18km from his release site, allegedly raiding a couple of farmhouses. In what must have been a highly traumatic situation, David died in a fight with four dogs as he was being chased off a farm by a local foreman. It is difficult to see any silver lining in David’s story.
Although David’s story is a worrying one, in the history of translocation, it is by no means unique. Before translocation can be used, the question of whether it is actually in the best interests of the animal must be asked. The downsides of translocation must be weighed against its benefits, and a rational, balanced decision needs to be made. Is translocation a long-term solution? Are we simply passing the problem to somebody else? Are we trying to assuage our consciences? These are difficult questions, but they must all be addressed.
Furthermore, investigations into the genetic implications of translocation, risk of disease transfer and appropriate site investigation needs to be carried out. These investigations must be rigorous and thorough. Lastly, a comprehensive monitoring system needs to be devised to quantify the results of any translocations (e.g. the animal’s condition, behaviour, movements etc.) and to understand the factors that cause the success or failure of translocations.
The final word
Thus, translocation is by no means a simple solution. Its use is being advised against by a growing number of biologists and managers. This is largely to do with its low success rate across a range of species. It is a low-odds management option, and perhaps is better suited where success is measured by whether or not a species succumbs to extinction rather than whether human-wildlife conflict was temporarily mollified.
Further reading
Mills, L.S. 2007. Conservation of wildlife populations: demography, genetics and management. Blackwell Publishers, Malden, MA.
Linnell, J.D.C., Aanes, R., Swenson, J.E., Odden, J. and Smit, M.E. 1997. Translocating of carnivores as a method for managing problem animals: a review. Biodiversity and Conservation 6: 1245–1257.
Chipman, R., Slate, D., Rupprecht, C. and Mendoza, M. 2008. Downside risk of wildlife translocation. Developments in Biologicals 131: 223–232.
Craven, S., Barnes, T. and Kania, G. 1998. Toward a professional position on the translocation of problem wildlife. Wildlife Society Bulletin 26: 171–177.
