The fundamental chords that hold a symphony together aren’t always apparent to the untrained ear. The symphony of an ecosystem is often more complex than we comprehend.
A recent study draws a vital connection between elephant poaching, tree reproduction and forest ecosystems. Certain trees – in this case, large bush mango trees – have evolved alongside large animals, in this case, forest elephants (Loxodonta cyclotis). The trees have developed seeds which are best dispersed via elephants eating the seeds, walking long distances, and then depositing digested seeds far from the parent tree. The seeds of these trees are too large to be properly digested and dispersed by smaller mammals.
Unfortunately for both the wild trees and the elephants, up to 75% of the elephant population has been killed in the Democratic Republic of Congo (DRC), where this study was carried out, and an estimated 60% of all forest elephants in the world have been killed in the service of the illegal ivory trade – all in the last ten years.
Sunset over the Congo rainforest
Photo: David Beaune via Mongabay.com
From an interview in an article on Mongabay.com:
“[The] Congo forest without elephants would certainly lose part of its soul, but elephant extinction with their seed dispersal services would also affect the entire plant community,” lead author David Beaune with the Max Planck Institute for Evolutionary Anthropology told mongabay.com. Forest elephants are “important gardeners of the forest,” says Beaune, so important in fact that when elephants go extinct in a part of the forest, important trees are unable to reproduce. “If we can’t replace elephants, then the reproduction of these plant species is hugely compromised.”
The bush mango tree used in the study, Irvingia gabonensis, happens to be one that is also important to the economy of many African regions, and has been successfully cultivated. Its reproductive patterns are well-known. It plays a key role in preventing soil erosion as well as being useful as a cash crop.
What of the many other fruits and seeds eaten by forest elephants which are less-studied, with lesser known roles in the ecosystem? Without the massive ‘gardeners of the forest’, what aspects of the ecosystem will crumble?
It puts me in mind of the final movement of Haydn’s Symphony No. 45, in which all the instruments disappear. There is a final song of the remaining violins, but it is thin and lonely without the other melodies.
Original study in Forest Ecology and Management: Density-dependent effect affecting elephant seed-dispersed tree recruitment (Irvingia gabonensis) in Congo Forest by D., L. Bollache, B. Fruth, G. Hohmann1 and F. Bretagnolle
Scientific American blog post
VOA news article – Ivory Poaching Decimates Forest Elephant Population