A pioneering study over five decades and 475 survey sites reveals dramatic declines in Africa’s elephant population densities – 90% for forest elephants and 70% for savannah elephants. Despite widespread losses, localised gains offer hope for their conservation future.
A ground-breaking study has used over half a century of data to track changes in the population density of forest and savannah elephants at more than 400 survey sites across Africa. The study found that the average decline across the sites was 90% for forest elephants and 70% for savannah elephants.
The study’s authors evaluated 53 years’ worth of data gathered during more than 1,300 surveys of both critically endangered forest elephants (Loxodonta cyclotis) and endangered savannah elephants (Loxodonta africana) at hundreds of sites in 37 countries, from Benin to Zimbabwe.
“We’re pretty confident that the decline we’ve measured with the data that we have is pretty representative of what’s going on [across the continent],” says Charles Edwards, an independent statistical consultant and coauthor of the study, which was published in Proceedings of the National Academy of Sciences (PNAS).
Edwards says that poaching and the expansion of farming and other human activities into former elephant habitats have driven the decline. “It’s the usual mix of poaching and habitat loss.”
Because of the different methods used by different teams of people in various countries over more than five decades, be it aerial surveys to count savannah elephants or ground surveys and transect counts for forest elephants, Edwards and his colleagues used a statistical model to sift through all this variable data and work out changes in population density at each of the 475 different survey sites in Southern, Central, West and East Africa.
According to Edwards, this helped to create “a more complete picture” of what has been happening to elephants across the continent beyond simply counting them to work out their abundance.
“Everyone wants to know how many elephants there are now and how that is different from how many there were 100 years ago,” he says. But calculating elephant abundance alone provides insight into the trends of the largest populations while leaving gaps in our knowledge about areas where there are smaller ones.
Abundance estimates are also subject to bias. For instance, if survey area sizes change from one year to the next, the number of elephants counted can be altered, even if their abundance hasn’t actually changed. This can give a false impression of either growth or decline in populations.
“You get these artefacts [artificial signals] in the data that make it look like a population change in abundance, even when there might not be, but if you look instead at the density of elephants, then you’re more likely to get an understanding of the trend in elephants that is independent of the survey area size.”
The data for forest elephants was gleaned from 150 sites surveyed between 1974–2015; the data for savannah elephants came from 375 sites surveyed from 1964–2016. Despite the grim overall picture of widespread declines these presented, there were some positive findings.
In Southern Africa, for example, 42% of the sites surveyed registered increases in population density (of just under 1% per site per year on average) over the period of the study. Southern Africa hosts the Kavango-Zambezi Transfrontier Conservation Area (TFCA), which covers nearly 520,000 square kilometres and incorporates dozens of parks and game reserves across Angola, Botswana, Namibia, Zambia and Zimbabwe. The last census in 2022 estimates the number of savannah elephants in this area at nearly 228,000.
Ten percent of sites in East Africa registered increases, including the Serengeti and the Moyowosi-Kigosi Game Reserve in Tanzania, the Amboseli National Park and the Maasai Mara National Reserve in Kenya, and the Jonglei ecosystem in South Sudan.
In West Africa, the study registered increases at 3% of sites where forest elephants live: the Pendjari National Park in Benin and three sites in Burkina Faso that included Arly National Park.
“Our results tell us that if well protected and managed, elephant populations can still increase despite increasing pressures surrounding them and their habitats,” Fiona Maisels, a study coauthor, said in a press statement.
Elephant researcher Timothy O’Connor, from the University of Witwatersrand, who was not involved in the study, praised its “rigorous statistical analysis” and “clear-cut conclusions”.
“The paper is another timely reminder that elephants are not doing well, but the nuance is that their dramatic decline is not universal across Africa,” he says.
“Most Southern African populations are stable or increasing slightly, whereas East African or West African populations, and forest elephants, have declined ultra-alarmingly.”
O’Connor, who recently published research on the impact an 11,000-strong elephant population is having on native forests and woodlands in Zimbabwe’s Gonarezhou National Park, says that while the PNAS study’s continent-wide picture offers clarity on elephant declines, it should not be seen as a management aid.
“The fact that savannah elephants are – or have been – declining dramatically in West Africa does not influence what is done in Zimbabwe where elephant populations are, overall, thriving,” he says.
“A country is expected to approach the management of elephants in terms of its specific challenges and needs.”
The PNAS study’s authors acknowledge that most of the data they relied on were obtained through surveys conducted in protected areas. This means declines in some regions may have been underestimated by not capturing the loss of unprotected populations.
And although the survey data spans over half a century, that is only equivalent to the single life of a long-lived elephant. This means that no insight into longer-term trends is offered.
“We don’t know what happened [to elephant density] prior to 1960,” says Edwards. “We have a lot of anecdotal information, but it’s different from everywhere – some places it might be going up, prior to 1960, some places it was getting hammered.”
The data analyst says he hopes his team’s methodology can be used to examine other species across vast areas in similarly variable numbers.
“Elephants have been in trouble for a long time,” says Edwards. “I wasn’t necessarily surprised by the result [that shows this], but it was interesting to me to establish a way of looking at it across the continent.”
Further reading
- There is some good news: there are more forest elephants in Gabon than previously believed. Read more about Gabon’s first countrywide elephant population estimate in 30 years here.
- A new study from Kibale has laid the groundwork for distinguishing between forest/savannah elephant hybrids and different elephant species. Read more about Kibale’s hybrid elephants here.
- KAZA has released the 2022 KAZA Elephant Survey results, revealing that elephant populations within the region are stable. Check out KAZA’s elephant survey results here.
- How do elephants move across southern Africa through protected areas and beyond? New research explores the value of habitat connectivity. Check it out here.
- Does the hunting of elephant bulls with large tusks lead to the decline of Africa’s tuskers? We examine the science here.
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