Grazing in the forest
Recent research published by the National Academy of Sciences (PNAS) has highlighted the vital role that elephants play in the growth, diversity and maintenance of forests. It’s often thought that elephants cause nothing but damage to the trees where they eat – stripping off leaves, ripping off branches or even uprooting saplings as they munch their way through the forest. But Stephen Blake, assistant professor of biology at Saint Louis University and a senior author of this recent research, explains that in a forest with plenty of large, high carbon density trees, the elephants are helping these trees to grow and thrive by stripping out the smaller, lower carbon density trees which grow quickly and steal much of the sunlight.
This “thinning” of the fast growing, but very palatable and nutritious trees, reduces competition among the trees and provides more light, space and soil nutrients to help the high carbon density trees flourish. And if that wasn’t enough help for the forests, elephants also disperse the seeds of the high carbon density trees by eating their fruits and passing the seeds out onto the forest floor in the their dung – the perfect place for the seeds to germinate and grow into some of the largest trees in the forest.
“Elephants are the gardeners of the forest” says Blake. “They plant the forest with high carbon density trees and they get rid of the “weeds” which are low carbon density trees. They do a tremendous amount of work maintaining the diversity of the forest”.
Although the study was carried out on African forest elephants, it is highly likely that Asian elephants, whose natural habitat is forestry, are also contributing significantly to the growth of the high carbon density trees that are so important to the planet. Fabio Berzaghi from the Laboratory of Climate and Environmental Sciences in France, and lead author of this research paper, aims to extend his study to other regions of the world. His findings make the need to conserve elephants all the more important. Their demise could already be having a significant impact on the world’s atmospheric carbon levels.
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