Elephant Management: To Cull or not to Cull?
During the 20th Century the number of elephants declined dramatically, due to threats such as poaching for ivory and loss of habitat due to human encroachment. In some areas however the trend to declining was reversed after elephants were placed on Appendix I of CITES and a world wide ban imposed on ivory sales. Unfortunately the resulting recovery of elephant numbers within both national and privately owned game parks potentially poses a threat to the survival of many other species.
Almost 70% of Africa’s elephants occur in Southern Africa and most large populations occur within protected areas – the issue with this is that when a species is confined, dispersal is inhibited so you end up with a large numbers of elephants in a relatively small space. Also by protecting elephants it generally means that their resources are not so limited which allows their numbers to get much higher than they would in a natural system.
In a natural system elephants have to travel long distances to find the resources that they need and not all of them survive these harsh conditions - this is what controls their numbers. In a reserve, fencing means that this migration can’t happen and resources must be provided for the elephants therefore allowing numbers to reach levels that have the potential to negatively affect the rest of the ecosystem.
When elephant numbers exceed the carrying capacity of a park or reserve, destruction of vegetation and habitat can be catastrophic. Obviously an elephant is a big animal which requires a lot of food – the average elephant requires around 660 pounds (300kg) of food per day. Observation has shown that large populations of elephants are capable of turning woodland into grassland – clearly this is going to have a devastating effect on any woodland species.
So, as stated above most large populations of elephants in southern Africa occur within protected areas; and the bottom line is once we start putting fences around animals it becomes our responsibility to manage those animals. One strategy for managing elephant populations – and probably the most debated strategy – is culling.
The practice of culling was first adopted in the 1960s but was later banned in Zimbabwe in 1988 and in South Africa in 1995 mostly due to public outcry. However it was reinstated in South Africa in 2009 under strict regulations.
Many people consider the practice of culling to be a morally grey area. Elephants are a charismatic, beautiful animal and people generally feel uncomfortable with the idea of killing them. However, any conservationist will argue that decisions about managing animal populations must be based on science, not human emotion; having said that, there are also many conservationists who oppose culling on a scientific basis.
One argument against culling is that elephants have a highly complex social structure and are considered to be very intelligent animals. Culling in the past is thought to have led to abnormal behaviours such as depression, unpredictable asocial behaviour and higher aggression. There are now strict regulations on the way in which culls are carried out – whole families are culled in order to avoid selective culling of animals in certain age classes which could disrupt population structure and enhance rather than suppress growth, as well as having a negative effect on the emotional well being and behaviour of the remaining family members. However some argue that our understanding of elephant social structure is still too limited and we know little about the relationships between neighbouring elephant families, therefore even if whole families are culled this could still have a detrimental effect on social structure.
Another argument against culling is that culling may give rise to immigration, which is what has been found in Kruger NP in the past, where movement into culled areas increased the number of elephants in that area which was thought to have intensified the local impact of elephants.
Many who oppose culling argue that there are other options for managing elephant populations and therefore we need not resort to culling. However this is not to say that culling should definitely not be considered a viable option as other management strategies also come with problems, as I will discuss below.
A method that has traditionally been used is translocation – the movement of animals from one area to another. There are benefits to this method, for example movement of elephants to a new Reserve increases the genetic diversity at that reserve. However, there are also drawbacks to this method. One of the problems with translocation is that many Reserves and National Parks are in the same boat – they all have too many elephants. Also there have been some behavioural problems with translocated elephants in the past – on several reserves introduced elephants have exhibited behavioural abnormalities mainly due to disrupted social structure.
Translocation is very time consuming and can be highly expensive depending on the equipment needed and the number of elephants to be translocated. As there are several factors affecting the cost of translocation it is difficult to put an exact figure on it, but it can cost anywhere from R6000 to R60, 000 per elephant.
One recent development in the management of elephant populations is the use of immunocontraception. In case you are wondering what on earth immunocontraception is – it is a non-hormonal, non-steroid method of a contraception based on the use of porcine zona pellucida (pZP) proteins. There is a membrane known as Zona Pellucida which surrounds all mammalian eggs. This membrane contains several glycoproteins, one of which is thought to be the sperm receptor. The pZP vaccine is derived from pig eggs and once injected the vaccine stimulates an immunological response to produce antibodies that attach to the ZP of the target animal, thereby preventing fertilisation as the sperm cannot attach to and penetrate the egg.
Immunocontraception has proven to be effective and has been successfully implemented at some Game Reserves as a management strategy for elephant populations. One of the major benefits of this method is that the vaccine is reversible which allows for adaptive management – you have control over how many and which elephants are treated. It is also a fairly cost effective method; it costs around R1000 per elephant.
However the down side is that you have to be able to identify individual elephants in order to administer initial vaccinations and booster vaccinations. At Kruger NP (an area where culling is currently being seriously considered as an option) there are around 12,500 elephants and some argue that with such a large population it would be impractical to have to identify individual females on a regular basis (with the current vaccine the elephant must receive in initial vaccine, 2 boosters 2-3 weeks apart and then 2 annual boosters).
Another issue is that this vaccine serves to stabilise populations and to limit population growth, it cannot however decrease the number of elephants that are currently in the population. So in areas such as Kruger where elephants are already seriously exceeding the carrying capacity of the park (the carrying capacity of Kruger is thought to be 7,500 and the population currently stands at around 12,500) many people feel that action needs to be taken now to prevent the elephants from having a detrimental effect on the rest of the ecosystem.
In conclusion, there will be no conclusion to this article as my intention was merely to give a (fairly) brief account of some of the issues and opinions surrounding culling and elephant management in general. I will it leave open to you as readers to form your own opinions on the topic. However I ask that you bare in mind that I have only touched on the subject and there are many many factors that need to be considered when making decisions on managing elephant populations.
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