DNA assessment confirms Gabon as last stronghold of forest elephants

  • A new survey has found that there are more than 95,000 critically endangered forest elephants in Gabon, which is considered to be the last remaining stronghold for the species.
  • The researchers came to this estimate after collecting elephant dung samples across Gabon and analyzing each sample’s genetic material.
  • The survey found that forest elephants were present in about 90% of the country, in both protected and nonprotected areas.
  • Forest elephants have been heavily poached in Gabon in the last couple of decades, with 25,000 killed in Gabon’s Minkébé National Park alone between 2004 and 2014.

A new study has found that the small nation of Gabon is the “last stronghold” for the critically endangered African forest elephant.

Researchers reached this conclusion after conducting a DNA-based population assessment of forest elephants (Loxodonta cyclotis) across Gabon, which involved extracting genetic material from fresh elephant dung. The results, published Nov. 18 in Global Ecology and Conservation, suggest there are more than 95,000 forest elephants present throughout the country, which represents about 60-70% of the species’ global population.

“Gabon has definitely experienced some poaching … particularly in the border area with Cameroon in the northeast of the country,” study co-author Emma Stokes, regional director for Central Africa at the Wildlife Conservation Society (WCS), told Mongabay in a phone interview. “I guess we were quietly confident that the population status of elephants in the rest of the country was reasonably good. But I would say this [survey result] was definitely as good as we could have hoped for.”

Researchers from WCS and Gabon’s National Park Agency (ANPN) conducted this survey over a period of three years, collecting dung samples and then analyzing each sample’s DNA.

“You get kind of a unique genetic print from that — like a unique fingerprint — from that dung pile,” Stokes said. “And then if you sample lots of dung piles, you start to be able to see differences between those genetic fingerprints and you can identify which are the same individuals and which are different individuals.”

In March 2021, the IUCN declared that African forest elephants (Loxodonta cyclotis) were a separate species from African savanna elephants (Loxodonta africana), and also listed African forest elephants as critically endangered. Image courtesy of WCS.

She added that forest elephants are difficult to detect in their habitat, which is why the researchers did not conduct aerial surveys, a chosen method in other parts of Africa where open savanna makes it easier to spot elephants.

Prior to this study, the last nationwide elephant population estimate in Gabon took place in the 1980s, with the results published in 1995. That study relied on dung pile counts across line transects, and concluded that there were 62,000 forest elephants in Gabon. However, many experts say this old method was flawed and did not yield accurate results.

The new study, using the newer spatial capture-recapture model to measure how often and where an individual animal is counted, found that elephants were present across more than 90% of Gabon, both in protected areas like national parks and nonprotected areas like timber concessions.

Forest elephants in Gabon have previously experienced substantial population declines due to poaching. A 2017 study found that more than 25,000 forest elephants were killed for their ivory in Gabon’s Minkébé National Park — a decline of between 78 and 81% of the park’s forest elephant population — between 2004 and 2014.

After Gabon, the second-largest forest elephant population is found in the northern part of the Republic of Congo.

John Poulsen, an ecologist at Duke University’s Nicholas School of the Environment, who was not involved in the new research, called the study “remarkable” since it raises considerably the population estimate for forest elephants in Gabon, and also because it is a “proof of concept of a new country-level monitoring methodology.”

“Scientists have long known that previous dung-based transect methods were flawed because they relied on highly variable multipliers — dung production and especially dung decay rates,” Poulsen told Mongabay in an email. “The genetic spatial capture-recapture approach is much more accurate and provides additional information such as sex ratios. The challenge will be to make these methods accessible, both financially and scientifically, to research teams across the forest elephant range.”

Forest elephants can be hard to detect in their habitat, which is why the researchers used DNA sampling to do a population count. Image courtesy of WCS.

He added that while the study “gives hope for the species,” it also heightens our shared responsibility to protect the forest elephant population from poaching and human-elephant conflicts, such as those that occur when elephants feed on crops.

“Protecting the species comes at a cost to the people of Gabon,” Poulsen said, “thus this burden needs to be shared by the international community to perpetuate the survival of one of the last remaining megafauna.”

Stokes said that while the survey results are a piece of “good news for Gabon,” it’s important to understand that elephant populations in the Congo Basin Region are far below what they used to be.

“What we’re seeing now is a shadow of the former forest elephant range and population, but Gabon is still an important stronghold,” Stokes said. “So I think being able to secure forest elephants in those strongholds is critical. Once elephants have gone it’s much harder to bring them back.”

Citations:

Laguardia, A., Bourgeois, S., Strindberg, S., Gobush, K. S., Abitsi, G., Bikang Bi Ateme, H. G., … Stokes, E. J. (2021). Nationwide abundance and distribution of African forest elephants across Gabon using non-invasive SNP genotyping. Global Ecology and Conservation, e01894. doi:10.1016/j.gecco.2021.e01894

Poulsen, J. R., Koerner, S. E., Moore, S., Medjibe, V. P., Blake, S., Clark, C. J., … White, L. J. (2017). Poaching empties critical Central African wilderness of forest elephants. Current Biology, 27(4), R134-R135. doi:10.1016/j.cub.2017.01.023

Banner image caption: A forest elephant (Loxodonta cyclotis) lifting its trunk.

Elizabeth Claire Alberts is a staff writer for Mongabay. Follow her on Twitter @ECAlberts.

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