A mother elephant leads her calf away from danger in northern Kenya. Credit: George Wittemyer/ Colorado State University. 

A new study has analysed 53 years of population survey data and found large-scale declines in most populations of both species of African elephants.

Habitat loss and poaching have driven dramatic declines in African elephants, but it is challenging to measure their numbers and monitor changes across the entire continent.

From 1964-2016, forest elephant populations decreased on average by 90%, and savanna elephant populations fell on average by 70%. In combination, populations declined by 77% on average.

The study compiled survey data from 475 sites in 37 countries, making it the most comprehensive assessment of African elephants to date. 

Declines were not uniform across the continent, with some populations disappearing completely and others showing rapid growth.

Colorado State University’s Professor George Wittemyer, one of the architects of the study and chair of the scientific board of Save the Elephants, said that identifying success stories where elephant populations are stable or increasing could help with their conservation.  

He advised: “The context and the solutions at different sites can be quite different, but there are examples where people are effectively managing and protecting these populations.

“It helps to have a contextually relevant model for elephant conservation, and we’ve got that in a lot of different places.” 

The study modelled site-level elephant density rather than numbers because the survey area was not constant over time for most survey sites. A clear trend toward smaller populations emerged. 

Wittemyer said: “This paper shows the scale of the declines and how widespread they are across the continent. It shines a light on how quickly even something as big and noticeable as elephants can just disappear.” 

As several families cross the Ewaso Ngiro River, a female elephant responds to her calf’s distress call. Credit: George Wittemyer/ Colorado State University.

Not simple arithmetic 

Elephants may be big and noticeable, but counting them is complicated and resource intensive.

Surveys of savanna elephants are done by spotters in planes, and forest elephants must be counted on foot.

Drones aren’t yet capable of the long flights over remote areas necessary to survey elephants, and processing drone imagery also is resource intensive. 

Africa is more than three times the size of the United States, and each African country has its own wildlife management policies and political system. Some places survey regularly, and others not at all.

Existing surveys were conducted through careful logistical planning and resource investment. 

Wittemyer said: “We were really happy to bring all of that data together and leverage it, given the effort and care taken to collect it.” 

As elephant populations declined, some protected spaces were condensed and survey borders changed.

To compensate for shrinking survey areas and gaps in data, the study authors had to use places with good information to estimate population change for nearby places with less information.

They looked at site-based trends to get a picture of the overall distribution of trends.  

Co-author Charles Edwards, a research scientist with CEscape consultancy services, said: “The strength of our approach is that we were able to infer these trends, even in places where the data were extremely poor, in a way that allowed the results from each survey site to be compared.

“Understanding how and where trends are different across the range of a species is arguably more important for their conservation than an overall change in abundance, which may only reflect change in the largest populations.” 

Wittemyer added: “It’s not a metric of the number of elephants left on the continent – it’s an assessment of how each population is doing, and they’re generally not doing great.”

An elephant family forages together during the rainy season. Credit: George Wittemyer/ Colorado State University. 

Shifting distribution 

The study examined how African elephants fared by species and region.

In the war-torn Sahel region of northern Africa, elephant populations have been decimated.

Eastern and central Africa generally saw declines from ivory poaching as well as from human population growth and wilderness conversion crowding out elephants.  

However, elephants are thriving in parts of southern Africa, particularly in Botswana, where populations have been protected and sustainably managed.  

The authors said that the study’s comprehensive assessment of the status of African elephants is fundamental to management decisions like knowing where to invest limited funding and capabilities to best protect elephants. 

Wittemyer said: “The overall story is one of decline, but we’re focusing on long-term stability of the species. I think we can do that in a bunch of places, but not all places.”

The study is published in Proceedings of the National Academy of Sciences.