Apr 24, 2017
The Long Term Effects of Poaching on Forest Elephants
In recent years, African forest elephants have come under increasing threat of extinction from poaching for ivory. A recent study found that Minkébé National Park in Gabon, one of the most important sanctuaries for the species in Central Africa, has been emptied of 80% of its elephants by poachers². This increase in poaching is largely due to roads being built in the equatorial forest home of the elephants for the extraction of natural resources such as minerals and lumber. The elephants are also targeted at the forest clearings or “Bais” where they congregate². In addition to the obvious effects of poaching, the deaths of individual animals, there are also many other long and short-term effects. Much research has been done on the ways poaching affects savannah elephants and the results could potentially apply to forest elephants.
Fifteen years after the 1989 CITES ban on the international trade in ivory was passed, multiple studies were conducted in Mikumi National Park, Tanzania, where most of the savannah elephant population was wiped out by poachers. One study involved 218 female elephants from 109 different groups. It found that heavy poaching was correlated with the members of social groups being less related to each other and having a lower reproductive output³. The researchers also determined that elephants from disrupted groups had higher levels of a stress hormone associated with muscle weakness and a malfunctioning immune system³. A different study found that less related groups had less cooperative members and less beneficial interactions with other groups⁴.
While elephant family groups typically consist of an older matriarch and her adult female relatives⁴, the structure of disrupted groups oftentimes lacks these characteristics. 40% of the elephant groups in the first study did not have a matriarch and 30% had only one adult female³. Since matriarchs act as repositories of knowledge, such as the location of resources, not having one can be detrimental to the health of a group⁵.
The effects of poaching on elephants go far beyond individual deaths and can span decades after the actual killings occur. They include disruption of social organization, reduction of reproductive output, and increases in stress hormone levels. Expanding this research to focus on forest elephants as well as savannah elephants increases our understanding of the effects of poaching on their populations and hopefully will lead to policies that protect and preserve them all.
References:
¹Poulsen, John R., Sally E. Koerner, Sarah Moore, Vincent P. Medjibe, Stephen Blake, Connie J. Clark, Mark Ella Akou et al. “Poaching empties critical Central African wilderness of forest elephants.” Current Biology 27, no. 4 (2017): R134-R135. http://www.sciencedirect.com/science/article/pii/S0960982217300246
²Fishlock, Vicki, and Thomas Breuer. Studying Forest Elephants. Stuttgart: Neuer Sportverlag, 2015. Print.
³Gobush, Kathleen S., Benezeth M. Mutayoba, and Samuel K. Wasser. “Long‐Term Impacts of Poaching on Relatedness, Stress Physiology, and Reproductive Output of Adult Female African Elephants.” Conservation Biology 22, no. 6 (2008): 1590–1599. http://onlinelibrary.wiley.com/doi/10.1111/j.1523-1739.2008.01035.x/full
⁴Gobush, Kathleen S., and Samuel K. Wasser. “Behavioural correlates of low relatedness in African elephant core groups of a poached population.” Animal Behaviour 78.5 (2009): 1079–1086. http://www.sciencedirect.com/science/article/pii/S0003347209003558
⁵"Elephants Are Socially Complex.” Www.elephantvoices.org.
Find out more about the Elephant Listening Project
To conserve the tropical forests of Africa through acoustic monitoring, sound science, and education, focusing on forest elephants
