Thursday, October 4, 2012

Elephants, the ecosystem’s engineers, gardeners and architects


Elephants are keystone species and are like the gardeners, engineers and architects of many ecosystems. Without elephants many other species would suffer as they are a vital link in the ecosystem and play a profound role.

A keystone species is a species that has a large affect on its environment relative to its abundance. It is a species which plays an important role in maintaining and balancing the structure of an ecological community and affecting many other organisms within this community. The loss of elephants from one particular site would mean that all the biological interactions and ecosystem processes in which they are involved, would also be lost.

Elephants as seed dispersers

Elephants disperse seeds by eating them, transporting them, and then spreading them through their dung. The overall body size of an elephant and their highly frugivorous diet make them particularly impressive seed dispersers. Out of the three species of elephants, African forest elephants (Loxodonta cyclotis) are the most effective dispersers of seeds and they disperse more intact seeds than any other African forest animal. They are also responsible for spreading seeds the longest distances. In one study, it was found that elephants dispersed seeds over 57km, whereas most animals will just spread seeds a few hundred meters away from the source. There are some plant species which depend entirely on elephants for their dispersal. For example, in Uganda, the seeds of a plant called ‘Balanites Wilson’ are completely dependent on savannah elephants (Loxodonta africana) to consume and disperse their seeds, as no other animals perform this function. Elephants are able to rejuvenate some habitats due to them constantly transporting many different species of seeds and their ability to disperse seeds long distances.

The importance of elephant dung

After seeds are dispersed by elephants, their dung provides a suitable germination environment in which seeds can grow. It is very common to find fungi growing in elephant dung as it provides the ideal environment.

Elephant dung is extremely rich in minerals and is very fibrous. This is because only about 50% of what elephants eat is actually digested. Thus, elephant dung is extremely important in nutrient cycling, as dung provides rich nutrients to soils, acting as a great fertilizer.
Elephant dung also provides an important food source for other species. Many species will feed on elephant dung as it is a treasure cove of nutrients. These species include ground hornbills, banded mongooses, velvet monkeys, baboons and many insect species. For dung beetles, elephant dung is extremely important. The beetles roll balls of dung and bury them to store as a food supply for their larvae. This then provides the honey badgers with a rich food source as they will then dig up the dung beetle balls and feed off the plump grubs inside.

Elephants also provide an opportunity for other animals to feed on rich fruits. For example, in Africa, elephants can almost stand on tip toes to reach and tear the very high branches of protein rich acacia trees. This means that all the beanlike pods which rain down from these movements provide a feast for nearby wildlife, including warthogs, kudu and baboons.

Not only does dung provide food for other species, it also provides a suitable habitat for them, suggesting that a dung pile could be a small ecosystem in itself! For example, many invertebrates including beetles, ants, centipedes, millipedes, scorpions, crickets, spiders and termites are found living in dung. Not only are invertebrates found living in elephant dung but, recently in Sri Lanka, it was discovered that there were 3 species of frogs that also reside in dung. The exact reason why frogs live in dung is unknown, but it is thought that dung provides a good shelter and provides the frogs with amble opportunity to feed on its invertebrate neighbors.

Elephants as water providers

Elephants also provide water for other species. The desert elephants in Africa will travel miles in search of water and they will remember underground spots for water in which they will dig wells. This water is then opened up for other animals, enabling them to drink. In Kenya, people will actually follow elephants for many miles, as the elephants will lead them to water sources.

Elephants as habitat modifiers

Elephants are like engineers, as they alter and modify habitats by pushing over trees, stripping bark from trees and generally stomping around being elephants. For example, in Africa they transform woodlands into open savanna, creating grazing habitat for dozens of grassland species. When they move on, the savanna grows into scrubs for a host of browsing animals and then once more becomes woodland.

Elephants also open up dense woodlands by creating forest gaps. They open up dense woodland canopies, allowing a proliferation of species into the light gaps which are created. These light gaps help to diversify tropical forests. The upper canopy layers intercept so much light that little reaches the forest floor. Under-storey vegetation is therefore very sparse, reflected by low numbers of vertebrates found on the forest floor. Elephants create and expand these gaps and, in the process, open up a more productive and varied ground layer to a range of other vertebrates, including gorillas, forest hog, bush pig, bongo, buffalo and duiker.

Asian and African elephants are facing dramatic population declines because of habitat loss and fragmentation, human-elephant conflict and poaching, all human induced activities. Numbers of elephants worldwide have plummeted in the last century. If we do not do anything to help these beautiful creatures then in our lifetimes they will become extinct. Not only would this be a tragedy that humans allowed to occur, but the loss of elephants would have detrimental effects on the ecosystem.

7 comments:

  1. This was a very informative, and educational article. It was simplistically perfect for my 9 yr. old daughter to read and comprehend for her science project on the savanna ecosystem!
    Thank you!

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  2. Very interesting point about elephants dispersing seeds in their dung. If you think about what do elephants eat, they spread all types of seeds from various vegetables, fruits, and even grasses. They travel for miles to find food sources and eat hundreds of pounds of food a day - that's a lot of dispersing.

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  3. This is retarded

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  4. i didnt even read it
    lol
    sucks ass

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  5. Hello, i just started a blog where i would like to talk more about problems, innovations and tell stories about nature itself. here: https://tiazim.com/what-are-keystone-species/i also talked about elephants as ecosystem engineers.

    These creatures are really amazing, whenever i read about them i found them even more fascinating.

    ReplyDelete