The Impact of Elephants on the Environment
Figure 1: Two bulls sizing each other up.
The African Elephant is a magnificent animal, their sheer size and magnitude makes one feel very small when in close proximity to these enormous animals. They are highly intelligent and have complex social structures as well as interesting ways of communicating. Elephants’ brains are in many ways similar to ours, as it enables them to empathize, recognize and memorize. Through extensive research it has been proven that elephants communicate through means of infra sound at low frequencies that humans are unable to hear, this enables elephants to communicate with others over several kilometers. Elephants can differentiate between 200 elephants and mourn their dead, this can lead to one feeling that we share more and more characteristics with these giants.
The African Elephant is the largest land mammal on earth and an adult bull can weight in at six tons and have a shoulder height of three to four meters. To keep such a big body going an elephant has to eat a large amount of food, an adult bull eats around 170kg of food a day, this includes a mixture of grasses, shrubs, bark, twigs, fruits, flowers and leaves. Elephants are key species within n ecosystem as they assist in transforming their environment. Elephants change their eating habits during different seasons and in drier times will more often push over large trees to reach the nutrient leaves and will consume the roots as well. The fallen trees provide food for smaller mammals such as impala, kudu and bushbuck which are normally too small to reach the upper branches of these tall trees.
Not only do the fallen trees provide food for others, it also creates seed beds for grasses. The branches cover the grasses and prevents other herbivores from reaching and consuming it. In time these seed beds allow grass seeds to disperse and this enables grasses to spread to different areas after the winter. What goes in must come out, dung beetles lay their eggs in elephant dung, after the larvae hatch they consume the dung. Elephant dung plays a vital role in seed dispersal of various trees such as acacia’s or marula trees. Most of the food consumed by an elephant passes through the digestive tract without being fully digested, stomach fluids break down the hard-outer shell of some seed pods and this enables the seeds to germinate quicker than normal come the rainy season. Although both elephant and tree benefit from this, parent trees are on occasions not so lucky when visited by an elephant. Elephants de-bark and ring-bark trees, tree bark is highly nutritious and is a key element of an elephant’s diet, however by removing the bark
damages or kills the tree. The bark protects the tree from disease and insects, once removed the tree becomes vulnerable and weak. Elephants are key species within the savanna biome as they help to shape the environment by opening up thickets and keeping the balance between grass and woody foliage. Elephants are called facilitators within an ecosystem as they create certain niches for other species, such as shortening tall underutilized grass into new grass shoots more regularly utilized by other herbivores.
Figure 2: Indicates mixed feeding by elephants. Notice the grass and leaves in her mouth.
There is no doubt that elephants are important, but when they exceed the carrying capacity for a certain area it becomes a critical issue. High densities of elephants can have dire effects on the environment and other creatures living within it, as too many elephants force savanna habitat to become a grassland dominated area. During 1965 a decision was made to start culling elephants, culling continued until 1994, at the time 16 027 elephants were removed. Animal welfare groups got involved with the way elephant management was handled, this led to SANParks reviewing their entire elephant policy. The Kruger has a carrying capacity of 7000 elephants, four elephants per 10 square kilometres, at this stage there are nearly 20 000 elephants. Their impact is evident, everywhere you drive you will notice large trees that have been pushed over or de-barked. Most of the time trees will be toppled over and up rooted by bulls and not so much by breeding herds, this was one of the reasons that culling was questioned, as the culling process removed whole herds of elephants and trees were still damaged even when elephant numbers were low.
Figure 3: Dead trees are a common sight on Mjejane Game Reserve and Kruger.
The impact of elephants and other elements have resulted in the loss in large trees all over the park and created areas with dense shrub cover, this can have some serious effects on the bird species within the park. Raptors and storks use tall trees for nesting, in Kruger there are only around 10 vulture nests per 100 square kilometres, where as in other areas such as Kimberley there were 100 nests per 100 square kilometres. This has dire effects on vulture populations, seeing as how these raptors are already on the endangered list. Mjejane Game Reserve was once used for agricultural reasons, after land claims were settled and it was established as a conservation zone, the Kruger agreed to drop the fences. This allowed for animals to move freely between the Park and Mjejane, resulting in large numbers of elephants streaming into Mjejane to utilize the untouched resources. Over the last few years elephant destruction within Mjejane has become obvious, tall de-barked and up rooted trees are a common sight as you drive around.
The solution is complex, contraceptives interfere with herd dynamics and cause other problems, it is very costly and only work in smaller reserves, translocation worked until all other reserves reached their carrying capacity and culling is still a battle zone between conservationists and animal welfare groups. However, extensive research was done on how to manage elephants and some strategies seems to be well worth the effort. The Kruger is attempting to expand its boundaries, creating larger areas for elephants to move in and out of, they have also closed down artificial water holes to control elephant movement. Elephants are dependant on water and migrate between water resources during dry and wet seasons, by manipulating the water points the Kruger can control elephant movement, this reduces the impact of elephants on specific areas.
Figure 4: Elephants quenching their thirst at Mjejane Dam
Elephants are complex, intelligent and magnificent creatures that play important roles within ecosystems as they transform one habitat into another. As conservationists, bush enthusiasts or just a by-stander it is important to try and understand what will be best for the environment, whether it is to reduce elephant numbers or to manage their impact through other methods. We are responsible for the wellbeing of biodiversity as a whole, not one entity at a time.
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