August 24, 2016 Biodiversity No Comments
The role of elephants in maintaining a healthy ecosystem

Elephants are one of Africa’s most iconic species.

Their sheer size, intelligence and prehistoric origins – elephants are the descendants of mammoths-  has captured human imagination for many years while their precious tusks have put them at the centre of an ever-increasing network of illegal wildlife trade. All this has perhaps superseded the significant role that elephants play in maintaining the ecosystems in which they live. Simply put, Africa’s savannah landscapes and biodiversity would be very different without elephants. The same is true for Asian elephants.

Due to their unique role in shaping their ecosystem, elephants are often called “keystone species”, a term attributed to species that provide vital services to an ecosystem in relation to their abundance. To appreciate how the majestic elephants of Africa and Asia fulfil this crucial role it is worth exploring in some detail the various services they provide to their natural habitat.
 

Digging for water

Elephants can dig for water using their tusks. In this way, they can survive in relatively dry environments which suffer frequently from droughts. By digging for water, elephants also make this precious resource available to other animals helping local biodiversity flourish¹. They create waterholes large enough for them to bathe and can smell water from five kilometres away².
 

Clearing out the vegetation

The savannah landscape would look very different without elephants. This is because African elephants feed on tree sprouts and shrubs that help keep African plains open and create grazing habitats for dozens of grassland species. When elephants move on, the savannah grows into scrubs and then once more it becomes woodland³. More generally, the eating habits of elephants create gaps in the vegetation of otherwise dense woodlands. These gaps facilitate the growth of other plants which provide food for different species and create pathways for a range of other animals to use, such as gorillas, forest hog, bush pig, bongo, buffalo and duiker³.

By reaching and tearing high branches of trees such as acacia trees, elephants also create food sources for other animals. When elephants almost stand on their tip toes to get to the high branches of acacia trees, the movement makes beanlike pods fall from the tree which then become food sources for warthogs, kudu and baboons³.
 

Dispersing seeds

Perhaps most surprisingly, elephants greatly contribute to dispersing seeds. African forest elephants are considered the most effective seed dispersers compared to any other African forest animal³,. This is both because of the amount of intact seeds they can disperse but also because of the great distances they can disperse those seeds. More precisely, elephants can disperse seeds at distances over 57 kilometers, whereas most animals can only do so for a few hundred meters away from the source. What is more, some plant species depend entirely on elephants for their dispersal. One such example is the seeds of a plant called ‘Balanites Wilson’ found in Uganda, which only savannah elephants can consume and subsequently disperse³.
 

Providing nutrients and habitat

While elephant dung is another way in which elephants can help disperse seeds, their dung is important in many other ways for the habitat. Elephant dung is very rich in minerals and fiber as only about 50% of what elephants eat is actually digested. Elephant dung is therefore a great fertilizer and extremely important for maintaining nutrient-rich soils³,,.

Given how rich elephant dung is, it also constitutes a source of food for other species. Species include ground hornbills, banded mongooses, vervet monkeys, baboons and many insect species. Unsurprisingly, elephant dung is of particular importance to dung beetles, which use it as a food supply for their larvae. In turn, this becomes a food source for honey badgers which dig up the dung and feed off the grubs.

It has also been suggested that the dung itself provides a habitat for several species, such as beetles, ants, centipedes, millipedes, scorpions, crickets, spiders and termites, but it was recently discovered that in Sri Lanka three species of frog also reside in dung. The exact reason why frogs live in the dung is unclear but experts believe it is linked to the fact that the dung provides good shelter and a good source of food given the abundances of invertebrates living there³.

 


References

¹ http://savetheelephants.org/about-elephants/importance-of-elephants/
² http://africageographic.com/blog/elephants-dig-water/
³ http://thinkelephants.blogspot.gr/2012/10/elephants-ecosystems-engineers.html
http://www.wwf.org.uk/wildlife/african_elephant/
http://www.soselephants.org/about_elephants.html

Written by Greentumble Editorial Team